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Availability and Structure of Coarse Woody Debris in Hemiboreal Availability and Structure of Coarse Woody Debris in Hemiboreal

Mature to Old-Growth Aspen Stands and Its Implications for Mature to Old-Growth Aspen Stands and Its Implications for

Forest Carbon Pool Forest Carbon Pool

Silva Šēnhofa Latvian State Forest Research Institute Silava

Guntars Šnepsts Latvian State Forest Research Institute Silava

Kārlis Bičkovskis Latvian State Forest Research Institute Silava

Ieva Jaunslaviete Latvian State Forest Research Institute Silava

Līga Liepa Latvia University of Life Sciences and Technologies

Inga Straupe Latvia University of Life Sciences and Technologies

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Recommended Citation Recommended Citation Šēnhofa S Šnepsts G Bičkovskis K Jaunslaviete I Liepa L Straupe I Jansons Ā Availability and Structure of Coarse Woody Debris in Hemiboreal Mature to Old-Growth Aspen Stands and Its Implications for Forest Carbon Pool Forests 2021 12 901 httpsdoiorg103390f12070901

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Authors Authors Silva Šēnhofa Guntars Šnepsts Kārlis Bičkovskis Ieva Jaunslaviete Līga Liepa Inga Straupe and Āris Jansons

This article is available at DigitalCommonsUSU httpsdigitalcommonsusueduaspen_bib7943

Article

Availability and Structure of Coarse Woody Debris inHemiboreal Mature to Old-Growth Aspen Stands and ItsImplications for Forest Carbon Pool

Silva Šenhofa 1 Guntars Šn epsts 1 Karlis Bickovskis 1 Ieva Jaunslaviete 1 Lıga Liepa 2 Inga Straupe 2

and Aris Jansons 1

Citation Šenhofa S Šn epsts G

Bickovskis K Jaunslaviete I Liepa

L Straupe I Jansons A Availability

and Structure of Coarse Woody

Debris in Hemiboreal Mature to

Old-Growth Aspen Stands and Its

Implications for Forest Carbon Pool

Forests 2021 12 901 httpsdoiorg

103390f12070901

Received 8 June 2021

Accepted 9 July 2021

Published 11 July 2021

Publisherrsquos Note MDPI stays neutral

with regard to jurisdictional claims in

published maps and institutional affil-

iations

Copyright copy 2021 by the authors

Licensee MDPI Basel Switzerland

This article is an open access article

distributed under the terms and

conditions of the Creative Commons

Attribution (CC BY) license (https

creativecommonsorglicensesby

40)

1 Latvian State Forest Research Institute Silava Rigas Street 111 LVndash2169 Salaspils Latviasilvasenhofasilavalv (SŠ) guntarssnepstssilavalv (GŠ) karlisbickovskissilavalv (KB)ievajaunslavietesilavalv (IJ)

2 Forest Faculty Latvia University of Life Sciences and Technologies Liela Street 2 LVndash3001 Jelgava Latvialigaliepallulv (LL) ingastraupellulv (IS)

Correspondence arisjansonssilavalv Tel +371-291-095-29

Abstract European aspen deadwood is extensively studied as a habitat for saproxylic specieswhile less is known of its dynamics and role in carbon sequestration We studied unmanagedmature (41ndash60 years) moderately overmature (61ndash80 years) overmature (81ndash100 years) and old-growth (101ndash140 years) and managed mature and moderately overmature aspen stands on fertilemineral soils In unmanaged stands marginal mean CWD volume was from 673 plusmn 121 m3 haminus1 inmoderately overmature to 924 plusmn 51 m3 haminus1 in old-growth stands with corresponding marginalmean CWD carbon pool 82 plusmn 16 t haminus1 and 125 plusmn 07 t haminus1 (all p gt 005) respectively High CWDvolume was present in most stands by at least two-thirds of plots comprising more than 20 m3 haminus1and about half of CWD was larger than 30 cm in diameter Changes in CWD species compositiontoward a higher proportion of deciduous deadwood in old-growth stands together with a highvolume of recently dead trees suggest early senescence of the dominant aspen cohort

Keywords aspen senescence carbon pool deadwood decline overmature Populus tremula

1 Introduction

European aspen (Populus tremula L) is an early-succession species in boreal andhemiboreal forests [1] with scattered occurrence [2ndash4] but high ecological importanceAspen is commonly regarded as lsquokeystone speciesrsquo in the boreal and hemiboreal forestsbecause both living and dead aspen trees host more specialist and endangered speciesthan other tree species in the region [4ndash7] Information of aspen deadwood volume andcharacteristics however is limited with only some insights from studies in boreal [68ndash11]and hemiboreal [12] forests

Besides the maintenance of biodiversity [1314] deadwood has an important rolein carbon dynamics [15] estimated to comprise 8 of the total carbon pool in forestsglobally [16] The deadwood persistence and turnover are affected by a number of factorsincluding disturbance dynamics forest zone site type and soil moisture regime dominantspecies stand age and productivity [17ndash19] Large knowledge gaps on the effect of theabovementioned factors on carbon pools remain and are substituted by internationallyaccepted standards Latest studies show that even seemingly small improvement byempirical-based variables has a substantial effect on estimated global carbon stock [20]Currently the majority of knowledge on forest carbon pools is derived from studiesperformed in managed forests The vast deadwood diversity in unmanaged old-growthforests however hampers accurate estimations of carbon storage within it and has derivedcontrasting results on whether old-growth forests are a carbon sink or source [21ndash28] Whilefew studies have addressed the carbon budget in hemiboreal deciduous forests [29ndash32]

Forests 2021 12 901 httpsdoiorg103390f12070901 httpswwwmdpicomjournalforests

Forests 2021 12 901 2 of 16

including one in the old-growth forests [33] none have been performed in aspen-dominatedstands However studies of stands older than the longevity of the pioneer cohort areemphasized as critical to improve the understanding of old forests in the global carboncycle [34] Knowledge of carbon balance in stands dominated by relatively short-livedspecies and how this balance changes with stand age is necessary in order to improve theaccuracy of greenhouse gas emission and carbon sequestration models

We aimed to quantify the availability of coarse woody debris (CWD) and its carbonpool and to characterize CWD structure in hemiboreal aspen stands We intended torepresent CWD and its carbon pool regarding species composition pose diameter anddecay classes with regard to its variation along with stand age from maturity to old-growthstate

2 Materials and Methods

This study was conducted in European aspen (Populus tremula L) stands in hemiborealforests (based on European Forest Types [35]) in Latvia According to Latvian NationalForest Inventory (NFI 2014ndash2018) forests cover 52 of the land Aspen is the fourth mostcommon tree species following Scots pine (Pinus sylvestris L) silver and downy birch(pooled Betula pendula Roth and Betula pubescens Ehrh) and Norway spruce (Picea abies (L)Karst) and constitutes 8 and 9 of the total forest land and volume respectively Dataconsist of two sets our measured stands at the age of 101 to 140 years and NFI (2014ndash2018)measured stands at the age of 41 to 100 years (Figure 1)

Forests 2021 12 x FOR PEER REVIEW 2 of 16

managed forests The vast deadwood diversity in unmanaged old-growth forests how-

ever hampers accurate estimations of carbon storage within it and has derived con-

trasting results on whether old-growth forests are a carbon sink or source [21ndash28] While

few studies have addressed the carbon budget in hemiboreal deciduous forests [29ndash32]

including one in the old-growth forests [33] none have been performed in aspen-domi-

nated stands However studies of stands older than the longevity of the pioneer cohort

are emphasized as critical to improve the understanding of old forests in the global carbon

cycle [34] Knowledge of carbon balance in stands dominated by relatively short-lived

species and how this balance changes with stand age is necessary in order to improve the

accuracy of greenhouse gas emission and carbon sequestration models

We aimed to quantify the availability of coarse woody debris (CWD) and its carbon

pool and to characterize CWD structure in hemiboreal aspen stands We intended to rep-

resent CWD and its carbon pool regarding species composition pose diameter and decay

classes with regard to its variation along with stand age from maturity to old-growth state


This study was conducted in European aspen (Populus tremula L) stands in hemi-

boreal forests (based on European Forest Types [35]) in Latvia According to Latvian Na-

tional Forest Inventory (NFI 2014ndash2018) forests cover 52 of the land Aspen is the fourth

most common tree species following Scots pine (Pinus sylvestris L) silver and downy

birch (pooled Betula pendula Roth and Betula pubescens Ehrh) and Norway spruce (Picea

abies (L) Karst) and constitutes 8 and 9 of the total forest land and volume respec-

tively Data consist of two sets our measured stands at the age of 101 to 140 years and

NFI (2014ndash2018) measured stands at the age of 41 to 100 years (Figure 1)

Figure 1 Distribution of sample plots in mature ( 41ndash60 years) moderately overmature ( 61ndash80

years) overmature ( 81ndash100 years) and old-growth ( 101ndash140 years) European aspen (Populus

tremula L) stands with dark symbols indicating unmanaged stands in all age groups and clear

circles () and pentagons ( ) indicating managed mature and moderately overmature stands

Our measured stands were randomly pre-selected from protected forests across Lat-

via based on species composition (at least 50 of the overstory growing stock comprised

by aspen) age limit (ge101 years) and site type We included stands located on Hylo-

comiosa and Oxalidosa (local classification by Bušs [36] site types on fertile mesic mineral

soils as these are two the most common site types (17 and 44 of the area respectively)

Figure 1 Distribution of sample plots in mature (bull 41ndash60 years) moderately overmature (


































61ndash80 years) overmature ( 81ndash100 years) and old-growth (N 101ndash140 years) European aspen(Populus tremula L) stands with dark symbols indicating unmanaged stands in all age groups andclear circles () and pentagons (D) indicating managed mature and moderately overmature stands

Our measured stands were randomly pre-selected from protected forests across Latviabased on species composition (at least 50 of the overstory growing stock comprised byaspen) age limit (ge101 years) and site type We included stands located on Hylocomiosaand Oxalidosa (local classification by Bušs [36] site types on fertile mesic mineral soils asthese are two the most common site types (17 and 44 of the area respectively) for theaspen-dominated stands in Latvia The selected forests have various types of protectiondetermined by legislation and voluntary by state forests mostly microreserves for protectedspecies and habitats These forests have received no silvicultural measures for at leastfour decades although no documentation of prior management was available Sites thatshowed signs of former logging were excluded Only sites that met all aforementioned

Forests 2021 12 901 3 of 16

criteria were measured Overall our study included 150 sample plots (mean 58 plots perstand) from 26 aspen-dominated stands at the age of 104 to 134 years (Table 1) Throughoutthis paper this group is referred to as lsquoold-growth standsrsquo (101ndash140 years) with the degreeof naturalness based on the Buchwald [37] classification lsquon6mdashOld-growth forestrsquo

Table 1 Characteristics (marginal mean plusmn standard error) of old-growth European aspen (Populus tremula L) stands

No N

Overstory Understory CWDVolumem3 haminus1

SpeciesA DBH cm Height m Growing Stock

m3 haminus1Species Growing Stock

m3 haminus1Aspen Other

1 6 10 ndash 109 490 plusmn 16 394 plusmn 01 687 plusmn 99 5S5L 1183 plusmn 286 1235 plusmn 972 6 9 1S 114 571 plusmn 32 382 plusmn 03 555 plusmn 40 5S5L 1163 plusmn 207 1422 plusmn 2053 6 9 1S 118 480 plusmn 17 381 plusmn 02 602 plusmn 42 10S 1688 plusmn 149 281 plusmn 1014 6 9 1B 118 440 plusmn 22 389 plusmn 05 620 plusmn 83 10S 780 plusmn 144 1112 plusmn 1055 6 10 ndash 108 460 plusmn 19 395 plusmn 02 812 plusmn 55 10S 1118 plusmn 166 796 plusmn 1546 8 7 1B1P1S 109 410 plusmn 27 321 plusmn 06 623 plusmn 73 9S1Ba 1268 plusmn 128 752 plusmn 1527 8 8 2B 106 470 plusmn 27 323 plusmn 05 471 plusmn 31 8S1O1B 813 plusmn 132 503 plusmn 1308 3 9 1B 134 535 plusmn 08 352 plusmn 01 579 plusmn 90 9S1A 2244 plusmn 210 610 plusmn 2789 6 8 1S1B 114 449 plusmn 20 367 plusmn 02 628 plusmn 50 10S 1094 plusmn 114 1134 plusmn 104

10 6 9 1S 104 556 plusmn 28 392 plusmn 07 783 plusmn 66 10S 1937 plusmn 178 1378 plusmn 29011 6 8 1B1S 113 561 plusmn 29 387 plusmn 02 753 plusmn 35 10S 1389 plusmn 139 749 plusmn 13712 6 9 1S 109 473 plusmn 17 384 plusmn 01 770 plusmn 51 6S3L1A 678 plusmn 115 597 plusmn 11013 6 8 2S 104 463 plusmn 22 372 plusmn 07 601 plusmn 52 7S3L 1058 plusmn 190 602 plusmn 9114 6 9 1S 104 493 plusmn 20 393 plusmn 02 712 plusmn 71 9S1L 954 plusmn 121 1741 plusmn 22915 6 8 2S 117 477 plusmn 21 330 plusmn 05 598 plusmn 52 10S 1225 plusmn 203 1045 plusmn 21816 6 8 1S 117 542 plusmn 12 362 plusmn 01 761 plusmn 69 5S4L1B 462 plusmn 31 700 plusmn 15417 6 9 1B 116 520 plusmn 24 391 plusmn 02 721 plusmn 64 7S2L1M 854 plusmn 95 266 plusmn 10718 6 9 1S 111 501 plusmn 36 399 plusmn 03 950 plusmn 77 10S 903 plusmn 86 946 plusmn 14919 6 10 ndash 118 452 plusmn 11 371 plusmn 02 764 plusmn 48 9S1L 1853 plusmn 275 1474 plusmn 27620 6 7 2S1B 107 520 plusmn 29 374 plusmn 04 622 plusmn 60 10S 999 plusmn 96 1325 plusmn 35421 6 7 2S1B 113 516 plusmn 22 364 plusmn 03 709 plusmn 71 10S 1066 plusmn 149 1123 plusmn 18722 4 9 1S 107 504 plusmn 29 338 plusmn 02 381 plusmn 37 5Ga3As1Bc1S 141 plusmn 33 710 plusmn 34923 2 5 4P1O 117 378 plusmn 101 276 plusmn 32 446 plusmn 31 9L1S 53 plusmn 00 107 plusmn 3824 3 9 1B 104 414 plusmn 15 294 plusmn 03 617 plusmn 61 9S1B 770 plusmn 140 568 plusmn 42225 8 8 1S1B 118 467 plusmn 20 377 plusmn 02 599 plusmn 47 9S1M 1319 plusmn 145 1065 plusmn 24626 6 9 1S 108 556 plusmn 21 381 plusmn 01 689 plusmn 50 8S2M 1025 plusmn 72 993 plusmn 206

Nmdashnumber of sample plots species composition is based on the proportion of the species growing stock in the respective stand layer10 = 90 100 9 = 8089 8 = 7079 etc Amdashaspen Smdashspruce (Picea abies (L) Karst) Bmdashbirch (pooled Betula pendula Rothand Betula pubescens Ehrh) Pmdashpine (Pinus sylvestris L) Lmdashlime (Tilia cordata Mill) Bamdashblack alder (Alnus glutinosa (L) Gaertn) Omdashoak(Quercus robur L) Asmdashash (Fraxinus excelsior L) Mmdashmaple (Acer platanoides L) Gamdashgray alder (Alnus incana (L) Moench) Bcmdashbirdcherry (Padus avium Mill)

All measurements were performed in 2019 In each sample plot for living treesa diameter at breast height (DBH) of ge61 cm was measured using a caliper (accuracyplusmn01 cm) and data on species and stand layer were noted Height was measured usingVertex clinometer (accuracy 01 m) for five overstory and three understory trees of thedominant species stand height was estimated by corresponding height to the quadraticmean diameter of overstory aspen The same overstory trees were sampled by incrementcores to measure age For each standing dead tree (stems and snags) we measured DBHge61 cm and height and noted species (aspen other deciduous or coniferous) and decayclass For lying CWD we measured length (ge10 m) using a ruler (accuracy 01 m) andthe diameter at both ends (diameter at thicker end ge61 cm) and noted species (aspenother deciduous or coniferous) and decay class at the thickest end The decay class wasobserved visually and using the lsquoknife methodrsquo All CWD was divided into five decayclasses (applied from Maumlkinen et al [38] Table 2)

Forests 2021 12 901 4 of 16

Table 2 Description of decay classes density (dry weight per raw volume) and carbon concentration [38] Basic densityand carbon concentration are applied from Koumlster et al [39]

Decay Class Description Basic Densitykg m3

CarbonConcentration

1 Recently dead Wood hard knife blade penetrates a few millimetersBark attached to the stem 3913 472

2 Weakly decayed The outer layer of wood starts to soften knife bladepenetrates 1ndash2 cm Loose bark branches present 3306 474

3 Moderately decayed The wood of outer layers of stem soft the core still hardknife blade penetrates lt5 cm Loose fragmented bark 2306 474

4 Very decayedWood soft through the log knife blade penetrates thewood in its entirety No branches most of the surface

covered with mosses1611 466

5 Almost completelydecomposed

Lost consistency of wood breaks up easily Surfacecovered with lichens mosses and dwarf shrubs 607 463

National Forest Inventory (NFI 2014ndash2018) data with the corresponding parameterswere used (Table 3) We selected 111 sample plots with an overstory dominated by aspen(at least 40 of the growing stock) at the age of 41 to 100 years growing on Hylocomiosaand Oxalidosa site types The selected plots were divided into lsquomanagedrsquo and lsquounmanagedrsquobased on the presence of fresh stumps found during the previous 15 years (since the firstNFI measurement) while no information on tree removal before that time was availableThe NFI data were first used to characterize the mean quantity of CWD and CWD carbonpool in managed and unmanaged stands followed by further assessment of unmanagedstands only The selected NFI plots were divided into age groups of lsquomature standsrsquo at theage of 41 to 60 years lsquomoderately overmaturersquo at the age of 61 to 80 years and lsquoovermaturersquoat the age of 81 to 100 years and are referred respectively throughout this paper

Table 3 Characteristics (marginal mean plusmn standard error) of mature (41ndash60 years) moderately overmature (61ndash80 years)overmature (81ndash100 years) and old-growth (101ndash140 years) European aspen (Populus tremula L) stands according tomanagement type

CharacteristicsStand Type and Age

Managed Unmanaged

41ndash60 61ndash80 41ndash60 61ndash80 81ndash100 101ndash140

Stand age years 501 plusmn 13 679 plusmn 11 531 plusmn 10 701 plusmn 12 869 plusmn 11 1118 plusmn 05Site index m 280 plusmn 10 272 plusmn 10 288 plusmn 04 273 plusmn 07 257 plusmn 08 254 plusmn 02

DBH cm 362 plusmn 22 428 plusmn 27 371 plusmn 15 395 plusmn 13 504 plusmn 22 490 plusmn 06Height m 280 plusmn 11 319 plusmn 11 297 plusmn 04 324 plusmn 07 338 plusmn 09 368 plusmn 02

Total basal area m2 haminus1 292 plusmn 25 342 plusmn 30 322 plusmn 14 395 plusmn 23 418 plusmn 19 503 plusmn 09Total growing stock m3 haminus1 330 plusmn 30 447 plusmn 48 377 plusmn 21 526 plusmn 36 577 plusmn 37 774 plusmn 16Total number of trees haminus1 1388 plusmn 245 1049 plusmn 241 1421 plusmn 173 1087 plusmn 143 942 plusmn 108 1134 plusmn 67

Overstory basal area m2 haminus1 218 plusmn 17 261 plusmn 26 243 plusmn 15 299 plusmn 23 304 plusmn 17 389 plusmn 08Overstory growing stock m3 haminus1 278 plusmn 26 383 plusmn 45 320 plusmn 21 443 plusmn 36 470 plusmn 34 664 plusmn 14Overstory number of trees haminus1 308 plusmn 34 262 plusmn 29 366 plusmn 34 345 plusmn 33 229 plusmn 25 246 plusmn 7

Aspen basal area m2 haminus1 140 plusmn 20 176 plusmn 24 146 plusmn 12 203 plusmn 23 219 plusmn 21 321 plusmn 08Aspen growing stock m3 haminus1 187 plusmn 25 276 plusmn 42 205 plusmn 18 316 plusmn 38 355 plusmn 39 566 plusmn 15Aspen number of trees haminus1 363 plusmn 139 162 plusmn 35 296 plusmn 71 273 plusmn 68 126 plusmn 18 202 plusmn 18

Objects 19 19 30 26 17 26Sample plots 19 19 30 26 17 150

Latvian National Forest Inventory data are used for mature moderately overmature and overmature stands and our measured data areused for old-growth stands

Forests 2021 12 901 5 of 16

Jansons and Lıcıte [40] describe inventory plot sampling design in detail All mea-surements were performed in circular sample plots (500 m2) If the sample plot crossedtwo distinctly different stands it was divided into sectors Only plots with a sector area ofge400 m2 were used in this study For all overstory trees DBH was measured and the standbasal area was calculated Tree height was measured for 8 to 19 trees of each overstoryspecies depending on the number of species in the plot and stand height was calculatedIncrement cores of three overstory trees were used to determine stand age Measurementsof CWD were conducted using a concentric design within a 1262 m radius standingCWD with a diameter at breast height and lying CWD with a diameter of the thicker endge141 cm was measured and within a 564 m radius CWD with a respective diameterge61 cm was measured Height of all standing trees and length (ge10 m) of lying treeswas measured and decay class and species (aspen other deciduous or coniferous) werenoted CWD was divided into three groups according to decay class lsquorecently deadrsquo withwood hard bark intact lsquomoderately decayedrsquo with all succeeding phases of decompositionstarting from loose bark to the cover of epiphytic mosses on lt10 of the visible stemsurface and lsquovery decayedrsquo with a cover of epiphytic mosses on ge10 of the visible stemsurface Our measured decay classes were integrated according to NFI descriptions tocompare the volume of CWD among decay classes at different stand ages The adjusteddecay classes were (1) lsquorecently deadrsquo (2) lsquoweakly decayedrsquo and (3 + 4 + 5) lsquomoderately toalmost completely decomposedrsquo (Table 2)

For both data sets the volume of whole trees was calculated using equations devel-oped by Liepa [41] and the volume of stumps and snags was calculated using Huberrsquosformula (Equation (1)) For CWD carbon pool calculation volume was converted to massusing decay class-specific density and carbon content for aspen (Table 2) both appliedfrom a study by Koumlster et al [39]

Huberrsquos formula

V =L π dm

2

4(1)

V = Stumpsnag volumeL = Length of the log or height of the stump anddm = Mid-diameter of the log or the stumpWe used linear mixed models incorporating lsquostandrsquo as a random effect (several plots

were measured in the same stand) to assess how quantities of CWD and CWD carbonpool differed among groups based on stand parameters (age site index basal area) standmanagement CWD pose species composition and decay class The same models wereused to calculate marginal mean values of stand and CWD parameters and their standarderrors Data were analyzed using SPSS 140 for Windows all tests were performed atα = 005

3 Results

We did not find a significant (both p gt 005) difference between managed and unman-aged stands within both mature and moderately overmature stands (Table 4) as well as nosignificant difference (all p gt 005) appeared among the age groups

Lying CWD was 62 to 85 of the total volume among the age groups and manage-ment types however we did not find significant differences (p gt 005) for quantities ofstanding and lying CWD among the stand age groups of each management type withthe exception of significantly lower standing CWD volume in unmanaged mature standscompared to that in old-growth stands (p lt 005) The CWD carbon pool size also had nosignificant differences (p gt 005) among stand age groups for each CWD type and in totalwith the exception of significantly higher standing CWD carbon pool in old-growth standscompared to that in unmanaged mature and moderately overmature stands (both p lt 005)

Forests 2021 12 901 6 of 16

Table 4 Coarse woody debris (CWD) volume and CWD carbon pool size in mature (41ndash60 years) moderately overmature(61ndash80 years) overmature (81ndash100 years) and old-growth (101ndash140 years) European aspen (Populus tremula L) stands byCWD pose and stand type

CWD Pose Stand Type Stand AgeYears

Number ofSample Plots

CWD Volume m3middothaminus1 CWD Carbon Pool tmiddothaminus1

Marginal Mean SE Marginal Mean SE

Standing

Managed 41ndash60 19 76 60 10 0961ndash80 19 53 60 07 09

Unmanaged

41ndash60 30 166 48 22 0761ndash80 26 138 52 19 07

81ndash100 17 261 64 35 09101ndash140 150 319 22 46 03

Lying


Unmanaged

41ndash60 30 533 96 66 1261ndash80 26 535 103 64 13

81ndash100 17 475 129 53 16101ndash140 150 605 43 80 05

Total


Unmanaged

41ndash60 30 699 113 87 1561ndash80 26 673 121 82 16

81ndash100 17 735 153 88 20101ndash140 150 924 51 125 07

Latvian National Forest Inventory data are used for mature moderately overmature and overmature stands and our measured data areused for old-growth stands SEmdashstandard error

We further analyzed deadwood characteristics within unmanaged stands Standage and site index were significant factors for CWD volume and CWD carbon pool (allp lt 0001) contrary to stand basal area (both p gt 005) However this was described by onlyweak positive correlations between both stand age and site index and CWD volume (forboth p lt 005 r = 015) and CWD carbon pool size (p lt 001 r = 019 and p lt 005 r = 014respectively)

A large CWD volume was frequently present in assessed stands (Figure 2) Thevolume of at least 20 m3 haminus1 was found in 77 to 89 of sample plots depending onstand age This proportion gradually decreased for larger CWD quantities yet at least50 m3 haminus1 was present in 43 to 75 of sample plots


Table 4 Coarse woody debris (CWD) volume and CWD carbon pool size in mature (41ndash60 years) moderately overmature

(61ndash80 years) overmature (81ndash100 years) and old-growth (101ndash140 years) European aspen (Populus tremula L) stands by

CWD pose and stand type

CWD Pose Stand Type Stand Age Years Number of

Sample Plots



Standing

Managed 41ndash60 19 76 60 10 09

61ndash80 19 53 60 07 09

Unmanaged

41ndash60 30 166 48 22 07

61ndash80 26 138 52 19 07

81ndash100 17 261 64 35 09

101ndash140 150 319 22 46 03

Lying

Managed 41ndash60 19 125 120 14 15

61ndash80 19 310 120 41 15

Unmanaged

41ndash60 30 533 96 66 12

61ndash80 26 535 103 64 13

81ndash100 17 475 129 53 16

101ndash140 150 605 43 80 05

Total

Managed 41ndash60 19 201 142 24 18

61ndash80 19 363 142 48 18

Unmanaged

41ndash60 30 699 113 87 15

61ndash80 26 673 121 82 16

81ndash100 17 735 153 88 20

101ndash140 150 924 51 125 07

Latvian National Forest Inventory data are used for mature moderately overmature and overmature stands and our

measured data are used for old-growth stands SEmdashstandard error

We further analyzed deadwood characteristics within unmanaged stands Stand age

and site index were significant factors for CWD volume and CWD carbon pool (all p lt

0001) contrary to stand basal area (both p gt 005) However this was described by only

weak positive correlations between both stand age and site index and CWD volume (for

both p lt 005 r = 015) and CWD carbon pool size (p lt 001 r = 019 and p lt 005 r = 014

respectively)

A large CWD volume was frequently present in assessed stands (Figure 2) The vol-

ume of at least 20 m3 haminus1 was found in 77 to 89 of sample plots depending on stand

age This proportion gradually decreased for larger CWD quantities yet at least 50 m3

haminus1 was present in 43 to 75 of sample plots

Figure 2 Occurrence of a particular coarse woody debris (CWD) volume according to stand age in

unmanaged European aspen (Populus tremula L) stands

Most of the CWD consisted of deciduous deadwood (Figure 3) Aspen and other de-

ciduous species (mostly Betula pendula Roth B pubescens Ehrh Alnus incana (L) Moench

Corylus avellana L and Salix caprea L) together accounted for 55 to 85 of CWD among

0

20

40

60

80

100

ge20 ge30 ge40 ge50

Pro

po

rtio

n o

f

sam

ple

plo

ts

CWD volume msup3haminus1

41ndash60

61ndash80

81ndash100

101ndash140

Figure 2 Occurrence of a particular coarse woody debris (CWD) volume according to stand age inunmanaged European aspen (Populus tremula L) stands

Forests 2021 12 901 7 of 16

Most of the CWD consisted of deciduous deadwood (Figure 3) Aspen and otherdeciduous species (mostly Betula pendula Roth B pubescens Ehrh Alnus incana (L) MoenchCorylus avellana L and Salix caprea L) together accounted for 55 to 85 of CWD among thestand age groups The proportion of aspen CWD was similar (all p gt 005) in all age groupsThe proportion of coniferous CWD was similar among mature moderately overmatureand overmature stands (all p gt 005) and in all these age groups coniferous deadwoodconstituted a significantly higher (p lt 005) portion of CWD than that in old-growth standsFor deciduous deadwood significant (p lt 005) differences were only found betweenmature and old-growth stands


the stand age groups The proportion of aspen CWD was similar (all p gt 005) in all age

groups The proportion of coniferous CWD was similar among mature moderately over-

mature and overmature stands (all p gt 005) and in all these age groups coniferous dead-

wood constituted a significantly higher (p lt 005) portion of CWD than that in old-growth

stands For deciduous deadwood significant (p lt 005) differences were only found be-

tween mature and old-growth stands

Figure 3 The proportion of coarse woody debris (CWD) by groups of species (aspen other decidu-

ous and coniferous) in mature (41ndash60 years) moderately overmature (61ndash80 years) overmature (81ndash

100 years) and old-growth (101ndash140 years) unmanaged European aspen (Populus tremula L) stands

Mean CWD diameter was 156 plusmn 14 cm (plusmn standard error) in mature stands 209 plusmn 14

cm in moderately overmature 204 plusmn 18 cm in overmature and 206 plusmn 06 cm in old-growth

stands Mature stands had a significantly thinner mean diameter of debris than old-

growth stands (p lt 005) but similar to that in both groups of overmature stands (both p gt

005)

The volume of large CWD tended to increase with stand age yet no significant dif-

ferences (all p gt 005) were found within each diameter group (Figure 4) About half of the

CWD volume consisted of debris larger than 30 cm in diameter from 48 (335 plusmn 93 m3

haminus1) in mature stands to 64 (473 plusmn 123 m3 haminus1) in overmature stands Moreover debris

with a diameter greater than 40 cm formed from 19 (132 plusmn 70 m3 haminus1) in mature stands

to 44 (323 plusmn 92 m3 haminus1) in overmature stands

0

20

40

60

80

100

41ndash60 61ndash80 81ndash100 101ndash140

Pro

po

rtio

n o

f C

WD

Stand age years

Aspen Other deciduous Coniferous

Figure 3 The proportion of coarse woody debris (CWD) by groups of species (aspen other decid-uous and coniferous) in mature (41ndash60 years) moderately overmature (61ndash80 years) overmature(81ndash100 years) and old-growth (101ndash140 years) unmanaged European aspen (Populus tremula L)stands

Mean CWD diameter was 156plusmn 14 cm (plusmnstandard error) in mature stands 209 plusmn 14 cmin moderately overmature 204 plusmn 18 cm in overmature and 206 plusmn 06 cm in old-growthstands Mature stands had a significantly thinner mean diameter of debris than old-growthstands (p lt 005) but similar to that in both groups of overmature stands (both p gt 005)

The volume of large CWD tended to increase with stand age yet no significantdifferences (all p gt 005) were found within each diameter group (Figure 4) Abouthalf of the CWD volume consisted of debris larger than 30 cm in diameter from 48(335 plusmn 93 m3 haminus1) in mature stands to 64 (473 plusmn 123 m3 haminus1) in overmature standsMoreover debris with a diameter greater than 40 cm formed from 19 (132 plusmn 70 m3 haminus1)in mature stands to 44 (323 plusmn 92 m3 haminus1) in overmature stands

We used adjusted decay classes to assess differences in CWD volume among standage groups (Figure 5) The most distinct differences were found for recently dead woodwith the highest volume of such CWD in old-growth and mature stands 12 and 17respectively However old-growth stands had significantly higher recently dead CWDvolume than both overmature stand groups (both p lt 005) while mature stands had nosignificant differences from others (all p gt 005) The proportion of weakly decayed debriswas similar in all age groups ranging from 31 of total CWD in moderately overmature to40 in mature stands

Forests 2021 12 901 8 of 16Forests 2021 12 x FOR PEER REVIEW 8 of 16

Figure 4 The marginal mean volume (plusmn standard error of total volume) of aspen (black stacked bars) other deciduous

(gray stacked bars) and coniferous (clear stacked bars) coarse woody debris (CWD) in mature (41ndash60 years n = 30) mod-

erately overmature (61ndash80 years n= 26) overmature (81ndash100 years n = 17) and old-growth (101ndash140 years n = 150) un-

managed European aspen (Populus tremula L) stands by groups of CWD diameter (a) gt10 cm (b) gt20 cm (c) gt30 cm and

(d) gt40 cm

We used adjusted decay classes to assess differences in CWD volume among stand

age groups (Figure 5) The most distinct differences were found for recently dead wood

with the highest volume of such CWD in old-growth and mature stands 12 and 17

respectively However old-growth stands had significantly higher recently dead CWD

volume than both overmature stand groups (both p lt 005) while mature stands had no

significant differences from others (all p gt 005) The proportion of weakly decayed debris

was similar in all age groups ranging from 31 of total CWD in moderately overmature

to 40 in mature stands

In all stand age groups moderately to almost completely decomposed wood formed

from 44 (404 plusmn 35 m3 haminus1) in old-growth stands to 68 (456 plusmn 89 m3 haminus1) in moderately

overmature stands In old-growth stands CWD distribution was categorized into five de-

cay classes The first two were the same as for adjusted decay classes (Figure 5) moder-

ately decayed CWD accounted for 21 (198 plusmn 18 m3 haminus1) and very decayed and almost

completely decomposed CWD accounted for 14 (126 plusmn 15 m3 haminus1) and 9 (79 plusmn 11 m3

haminus1) of total CWD in old-growth stands respectively

Figure 4 The marginal mean volume (plusmn standard error of total volume) of aspen (black stacked bars) other deciduous (graystacked bars) and coniferous (clear stacked bars) coarse woody debris (CWD) in mature (41ndash60 years n = 30) moderatelyovermature (61ndash80 years n= 26) overmature (81ndash100 years n = 17) and old-growth (101ndash140 years n = 150) unmanagedEuropean aspen (Populus tremula L) stands by groups of CWD diameter (a) gt10 cm (b) gt20 cm (c) gt30 cm and (d) gt40 cm

In all stand age groups moderately to almost completely decomposed wood formedfrom 44 (404 plusmn 35 m3 haminus1) in old-growth stands to 68 (456 plusmn 89 m3 haminus1) inmoderately overmature stands In old-growth stands CWD distribution was categorizedinto five decay classes The first two were the same as for adjusted decay classes (Figure 5)moderately decayed CWD accounted for 21 (198 plusmn 18 m3 haminus1) and very decayed andalmost completely decomposed CWD accounted for 14 (126 plusmn 15 m3 haminus1) and 9(79 plusmn 11 m3 haminus1) of total CWD in old-growth stands respectively


Figure 5 The marginal mean volume (plusmn standard error) of coarse woody debris (CWD) in mature

(41ndash60 years n = 30) moderately overmature (61ndash80 years n = 26) overmature (81ndash100 years n =

17) and old-growth (101ndash140 years n = 150) unmanaged European aspen (Populus tremula L) stands

by adjusted decay classes (1) recently dead (2) weakly decayed and (3 + 4 + 5) moderately to almost

completely decomposed

4 Discussion

This study characterizes CWD volume composition and structure in aspen stands

from mature to old-growth age The information on the histories of the studied old-

growth stands is not available however we assume that the age of the overstory corre-

sponds well with time since stand origin after disturbance The present stand composition

0

10

20


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(a) 1

0

10

20

30

40


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(b) 2

0

20

40

60


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(c) 3 + 4 + 5

Figure 5 The marginal mean volume (plusmn standard error) of coarse woody debris (CWD) in mature(41ndash60 years n = 30) moderately overmature (61ndash80 years n = 26) overmature (81ndash100 years n = 17)and old-growth (101ndash140 years n = 150) unmanaged European aspen (Populus tremula L) stands byadjusted decay classes (1) recently dead (2) weakly decayed and (3 + 4 + 5) moderately to almostcompletely decomposed

4 Discussion

This study characterizes CWD volume composition and structure in aspen standsfrom mature to old-growth age The information on the histories of the studied old-growthstands is not available however we assume that the age of the overstory corresponds wellwith time since stand origin after disturbance The present stand composition with aspen

Forests 2021 12 901 10 of 16

as the dominant species in the overstory could almost exclusively form only if regenerationof the species is abundant enough ie after a large-scale disturbance such as forest fireor clear-cutting This is supported by the species-specific regeneration requirements asaspen is essentially a pioneer species [9] with limited regeneration capacity under lackof sufficiently large canopy gaps [42ndash44] and as a shade-intolerant species [45] it hasdifficulties to reach canopy-layer if regenerated in gaps

We did not find a significant differences between managed and unmanaged standsthat could indicate an effect of the continuous removal of lower-dimension and vitalitytrees (ie potential deadwood) from the conventionally managed stands [4647] The CWDvolume in the studied managed stands however considerably exceeded deadwood volumethat is reported in other countries in Northern Europe 59 m3 haminus1 for managed standsin Finland [48] 76 m3 haminus1 for managed stands in Sweden [47] and 137 m3 haminus1 acrossforests in Estonia [49] Our results are also somewhat higher than the mean CWD volumeacross forests in Latvia for managed and unmanaged stands together according to NFI198 m3 haminus1 The studied unmanaged stands comprised about 70 to 90 m3 haminus1 whichis in between average deadwood volume of 40 to 170 m3 haminus1 in boreal unmanagedforests [1150ndash52]

As expected age was a significant factor affecting CWD volume in the unmanagedstands since deadwood tends to accumulate under the absence of tree removal [53ndash55]Such tendency has been often reported in coniferous-dominated forests [817475456]whereas for birch stand age was not a significant factor affecting CWD volume at therange of 71 to 150 years [33] For trembling aspen (Populus tremuloides Michx) the volumeof CWD significantly increased for older stands and was comparable with our estimates631 m3 haminus1 in young stands 768 m3 haminus1 in mature and 1014 m3 haminus1 in old stands [57]

Site index showed a significant but very weak positive effect on CWD volume and wasin accordance with results of other studies in younger stands [58ndash60] However anotherindicator of stand productivity stand basal area had a non-significant effect on CWDvolume presumably due to a wide range of the studied stand age

In stands undergoing increased tree death from senescence and natural disturbancea negative relationship between deadwood volume and stand basal area occur ie dis-turbance decreases the basal area of living trees and simultaneously increases deadwoodvolume [8] Our study only included stands where old aspen still formed the dominantcohort The old aspen trees with large diameters were still alive and did not contributedto CWD thus lacking a relation between CWD volume and basal area Likewise therelation between basal area and CWD volume was absent in old-growth hemiboreal birchstands [33] Both aspen and birch are pioneer species typically undergoing canopy transi-tion from early- to late-successional species after reaching their life span [61] For aspenlifespan commonly reaches 90 years [62] although species longevity might reach up to200 years [963] The studied old-growth stands were somewhere in between these agesthus might represent stands in early senescence (see below) although aspen might persistin old-growth conditions for a prolonged time [44]

In European boreal forests the majority of deadwood-dependent species need from20 to 30 m3 haminus1 deadwood for their presence [64] Yet deadwood volume per se is aninsufficient measure [65ndash67] and additional characteristics are important for saproxylicspecies diversity This includes deadwood species diversity especially the abundance oftemperate deciduous deadwood [47] and deadwood spatial and temporal continuity [68]Our studied aspen stands had a high proportion of deciduous debris (pooled aspen andother deciduous species) accounting for 55 of total CWD in mature stands to 85 inold-growth stands (Figure 3) The higher portion of coniferous deadwood in mature standslikely originated from understory spruce which typically forms small fractions of debrisdue to self-thinning [11] As stand ages death from the senescence of aspen and otherpioneer species (B pendula B pubescens and A incana were most common) increasesforming canopy gaps These might provide access to more resources for understory trees

Forests 2021 12 901 11 of 16

decreasing their mortality hence probably explaining the thrice lower volume of coniferousCWD in old-growth stands than that in mature stands

Various deadwood species supply substrates of different chemical compositionsas well as provide a more diverse layout of debris poses as a share of standing treesand snags and lying deadwood is species-specific [54] We found about 60 to 85 ofCWD lying similarly to findings of aspen deadwood in old-growth coniferous-dominatedforests 60 to 75 [89] Aspen typically tends to snap forming both broken snags andlying deadwood [5469] Stems of low density are more fragile to breakage [7071] andaspen stems are characteristic of crumbling into pieces when a tree falls possibly leadingto underestimation of aspen CWD if the broken pieces are shorter than the minimummeasured length of a particular study Additionally smaller (shorter) debris has a largerproportion of surface area exposed to decomposer colonization and a higher degree of soilcontact that increases moisture of the deadwood [70] Both of these factors contribute to anincreased deadwood turnover rate for smaller debris Besides the size deadwood poselargely affects substrate conditions with dry snags and leaning logs being a less suitablesubstrate for wood-decaying fungi compared to moist deadwood [1872] thus prolongingdeadwoodrsquos life span [1073]

Our estimated CWD volume in the old-growth stands was affected by gradual decayThis should most certainly apply to aspen as it is among the species with a relatively fastturnover rate with 85 of the initial mass lost in 27 years for logs 5ndash25 cm 43 years for logs25ndash60 cm and 106 years for bark [74] Another study has suggested a much longer aspendecomposition time 110 to 120 years [10] Still aspen has the strongest loss of wood densityduring decomposition also if compared with other short-lived species ie birch [1039]and black alder [39]

Softwood CWD has a longer turnover time than hardwoods [10] Although no distinc-tion between the softwood species was made it should predominantly consist of spruceas pine rarely occurred in the studied stands For spruce in unmanaged boreal forestsdeadwood half-lives varied from 12 to 27 years for standing snags and from 20 to 40 yearsfor lying debris [52] Relatively rapid decomposition for spruce was also reported in theboreal old-growth forest where spruce at the last decay stage was estimated to be dead for34 years [75] A longer half-life duration was found for softwood snags in forests acrossSwitzerland about 45 to 48 years [76]

Considering the decomposition times the old-growth stands could comprise somelegacy deadwood in the last decay classes that have originated from the previous (pre-disturbance) generation Alternatively deadwood from the previous generation could beomitted in our measurements That could be if the legacy deadwood appears in the formof buried CWD [77] as only visible debris was measured including that overgrown bymosses but still forming distinctive appearance from the ground layer This might leadto underestimation of total deadwood stocks as well as total carbon stocks if the buriedCWD is not accounted into forest floor carbon estimates

The overmature stands had low or absent recently dead and weakly decomposedCWD A similar pattern of CWD availability regarding stand age has been described for Ptremuloides [19] The wood of more decomposed classes was similar for all stand age groupsindicating that overmature stands are at a state of stand development when mortality dueto self-thinning has diminished while mortality due to senescence has not become apparentyet This might be a concern for saproxylic species as they show a preference for deadwoodof a particular decomposition level [78ndash80]

The spatial availability showed rather regular CWD distribution for all stand agegroups with at least two-thirds of the plots comprising at least 20 m3 haminus1 at all age groupsOur results coincide with an extensive study across Europe by Puletti et al [81] that showedthat 72 of sample plots comprise deadwood amount up to 25 m3 haminus1 Observations ofmuch higher deadwood volume are often related to damage to living trees [5582] howeverstands with signs of notable damage to living trees were omitted in the selection of ourstudy areas

Forests 2021 12 901 12 of 16

Deadwood is also an important carbon pool that partly acts as a carbon source tothe atmosphere and partly redistributes carbon to soil [8384] The vast heterogeneity ofdeadwood (eg tree species type size pose level of decay) that determine the richnessof saproxylic organisms [6785] makes it complicated to assess carbon storage withinit For aspen controversial findings of its carbon concentration throughout proceedingdecomposition have been reported claiming no effect [20] reduced [3986] or increased [87]carbon concentration along the decay stages Precise calculations are also hampered byspecies-specific features related to characteristic decay from inside of living trees thatcomplicate both live and dead aspen wood estimations

Aspen is susceptible to heart rot infection caused by Phellinus tremulae (Bond) Bondand Borisov [8889] Infected aspen trees are found through all stand development stagesincluding these younger than 40 years Trees severely infected while alive have a fastertransition through decay classes after death [90] This on the one hand hinders theassessment of total deadwood volume due to part of already-dead wood still enclosed orattached to living trees On the other hand mature aspen stems are commonly hollowedby heart rot [950] leading to overestimated deadwood volume if the hollow of the deadstem is not excluded from deadwood estimates

Forest restructuration by senescence among dominant trees or disturbances altersstand carbon balance with reduced photosynthesis and increased heterotrophic respirationThere are various mutually non-exclusive hypotheses for stand biomass dynamics withrespect to carbon pathways along stand succession [91] Whether old-growth forestscontinue to accumulate decline or stabilize carbon balance largely depends on standdevelopment after early succession [34] Small-scale disturbances could have a minoreffect on ecosystem production as forests shifting from early- to late-successional speciesremained stable ecosystem production regardless of increased heterotrophic respirationfrom enlarged deadwood volume [92] However debris as discussed above persists asa CO2 source over several decades af-fecting the net carbon balance of the stand [26]especially for aspen with a relatively fast decomposition rate [1074] Thus alternativelyeven with relatively small patches of increased deadwood volume (increased net emissions)gradual changes in species composition could switch forests from a carbon sink to a sourceof CO2 to the at-mosphere [26] A study that focused on multiple succession pathwaysin old boreal forests found a decline in total ecosystem carbon pool from transition tolate-succession stages irrespective of tree species combinations [34] All these relationshowever might be inter-rupted by unpreventable stand-replacing disturbances that causeold carbon-saturated forests to release large amounts of carbon into the atmosphere [9394]This might also af-fect forest landscapes as the disturbance regimes are changing withclimate change [95]

5 Conclusions

There was a large CWD volume in both managed and unmanaged stands The CWDprofile was diverse in species composition and layout of debris poses Substantial CWDvolume was comprised of large diameter units and was frequently found in the studiedstands Our estimated CWD volume and CWD carbon pool represent rather maximummean quantities regarding the high probability of decayed heartwood or hollowed trees(assessment not included in this paper) in aspen stands that have reached maturity Con-sidering stand age changes in CWD species composition together with the high volume ofrecently dead debris suggests early senescence of dominant aspen cohort in old-growthstands Further monitoring studies would render the understanding of stand developmentpathway through dominant pioneer species substitution regarding CWD carbon pool andCWD dynamics for a relatively short-lived tree species

Forests 2021 12 901 13 of 16

Author Contributions Conceptualization AJ IJ and GŠ methodology GŠ and SŠ formalanalysis GŠ KB and IJ data curation IS and IJ writingmdashoriginal draft preparation SŠ andIJ writingmdashreview and editing GŠ AJ and LL project administration AJ All authors haveread and agreed to the published version of the manuscript

Funding This research was funded by the LVM project ldquoCarbon cycle in forest ecosystemrdquo

Data Availability Statement Not applicable

Conflicts of Interest The authors declare no conflict of interest

References1 Caudullo G de Rigo D Populus tremula in Europe Distribution habitat usage and threats In European Atlas of Forest Tree

Species San-Miguel-Ayanz J de Rigo D Caudullo G Houston Durrant T Mauri A Eds Publication Office of the EuropeanUnion Luxembourg 2016 pp 138ndash139

2 Heraumljaumlrvi H Junkkonen R Wood density and growth rate of European and hybrid aspen in Southern Finland Balt For 200612 2ndash8

3 Global Forest Resources Assessment Country Report Sweden Global Forest Resources Assessment Rome Italy 20154 Rogers PC Pinno BD Šebesta J Albrectsen BR Li G Ivanova N Kusbach A Kuuluvainen T Landhaumlusser SM Liu

H et al A global view of aspen Conservation science for widespread keystone systems Glob Ecol Conserv 2020 21 e00828[CrossRef]

5 Sverdrup-Thygeson A Ims RA The effect of forest clearcutting in Norway on the community of saproxylic beetles on aspenBiol Conserv 2002 106 347ndash357 [CrossRef]

6 Kouki J Arnold K Martikainen P Long-term persistence of aspenmdashA key host for many threatened speciesmdashIs endangered inold-growth conservation areas in Finland J Nat Conserv 2004 12 41ndash52 [CrossRef]

7 Kivinen S Koivisto E Keski-Saari S Poikolainen L Tanhuanpaumlauml T Kuzmin A Viinikka A Heikkinen RK Pykaumllauml JVirkkala R et al A keystone species European aspen (Populus tremula L) in boreal forests Ecological role knowledge needsand mapping using remote sensing For Ecol Manag 2020 462 118008 [CrossRef]

8 Siitonen J Martikainen P Punttila P Rauh J Coarse woody debris and stand characteristics in mature managed andold-growth boreal mesic forests in southern Finland For Ecol Manag 2000 128 211ndash225 [CrossRef]

9 Latva-Karjanmaa T Penttilauml R Siitonen J The demographic structure of European aspen (Populus tremula) populations inmanaged and old-growth boreal forests in eastern Finland Can J For Res 2007 37 1070ndash1081 [CrossRef]

10 Shorohova E Kapitsa E Influence of the substrate and ecosystem attributes on the decomposition rates of coarse woody debrisin European boreal forests For Ecol Manag 2014 315 173ndash184 [CrossRef]

11 Halme P Purhonen J Marjakangas EL Komonen A Juutilainen K Abrego N Dead wood profile of a semi-natural borealforest-implications for sampling Silva Fenn 2019 53 10010 [CrossRef]

12 Laarmann D Korjus H Sims A Stanturf JA Kiviste A Koumlster K Analysis of forest naturalness and tree mortality patternsin Estonia For Ecol Manag 2009 258 S187ndashS195 [CrossRef]

13 Doerfler I Gossner MM Muumlller J Seibold S Weisser WW Deadwood enrichment combining integrative and segregativeconservation elements enhances biodiversity of multiple taxa in managed forests Biol Conserv 2018 228 70ndash78 [CrossRef]

14 Koivula M Vanha-Majamaa I Experimental evidence on biodiversity impacts of variable retention forestry prescribed burningand deadwood manipulation in Fennoscandia Ecol Process 2020 9 1ndash22 [CrossRef]

15 Covey KR Bueno de Mesquita C Oberle B Maynard DS Bettigole C Crowther TW Duguid MC Steven B ZanneAE Lapin M et al Greenhouse trace gases in deadwood Biogeochemistry 2016 130 215ndash226 [CrossRef]

16 Pan Y Birdsey RA Fang J Houghton R Kauppi PE Kurz WA Phillips OL Shvidenko A Lewis SL Canadell JGet al A large and persistent carbon sink in the worldrsquos forests Science 2011 333 988ndash993 [CrossRef]

17 Ranius T Kindvall O Kruys N Jonsson BG Modelling dead wood in Norway spruce stands subject to different managementregimes For Ecol Manag 2003 182 13ndash29 [CrossRef]

18 Cornelissen JHC Sass-Klaassen U Poorter L Van Geffen K Van Logtestijn RSP Van Hal J Goudzwaard L SterckFJ Klaassen RKWM Freschet GT et al Controls on coarse wood decay in temperate tree species Birth of the LOGLIFEexperiment Ambio 2012 41 231ndash245 [CrossRef]

19 Garbarino M Marzano R Shaw JD Long JN Environmental drivers of deadwood dynamics in woodlands and forestsEcosphere 2015 6 30 [CrossRef]

20 Martin A Dimke G Doraisami M Thomas S Carbon fractions in the worldrsquos dead wood Nat Commun 2021 12 889[CrossRef]

21 Carey EV Sala A Keane R Callaway RM Are old forests underestimated as global carbon sinks Glob Chang Biol 2001 7339ndash344 [CrossRef]

22 Roumlser C Montagnani L Schulze E-D Mollicone D Kolle O Meroni M Papale D Marchesini LB Federici S ValentiniR Net CO2 exchange rates in three different successional stages of the ldquoDark Taigardquo of central Siberia Tellus B Chem PhysMeteorol 2002 54 642ndash654 [CrossRef]

Forests 2021 12 901 14 of 16

23 Wardle DA Houmlrnberg G Zackrisson O Kalela-Brundin M Coomes DA Long-term effects of wildfire on ecosystemproperties across an island area gradient Science 2003 300 972ndash975 [CrossRef] [PubMed]

24 Luyssaert S Schulze ED Boumlrner A Knohl A Hessenmoumlller D Law BE Ciais P Grace J Old-growth forests as globalcarbon sinks Nature 2008 455 213ndash215 [CrossRef]

25 Seedre M Kopaacutecek J Janda P Bace R Svoboda M Carbon pools in a montane old-growth Norway spruce ecosystem inBohemian Forest Effects of stand age and elevation For Ecol Manag 2015 346 106ndash113 [CrossRef]

26 Hadden D Grelle A Net CO2 emissions from a primary boreo-nemoral forest over a 10 year period For Ecol Manag 2017 398164ndash173 [CrossRef]

27 Pukkala T Does management improve the carbon balance of forestry For Int J For Res 2017 90 125ndash135 [CrossRef]28 Nord-Larsen T Vesterdal L Bentsen NS Larsen JB Ecosystem carbon stocks and their temporal resilience in a semi-natural

beech-dominated forest For Ecol Manag 2019 447 67ndash76 [CrossRef]29 Uri V Varik M Aosaar J Kanal A Kukumaumlgi M Lotildehmus K Biomass production and carbon sequestration in a fertile silver

birch (Betula pendula Roth) forest chronosequence For Ecol Manag 2012 267 117ndash126 [CrossRef]30 Uri V Kukumaumlgi M Aosaar J Varik M Becker H Morozov G Karoles K Ecosystems carbon budgets of differently aged

downy birch stands growing on well-drained peatlands For Ecol Manag 2017 399 82ndash93 [CrossRef]31 Varik M Aosaar J Ostonen I Lotildehmus K Uri V Carbon and nitrogen accumulation in belowground tree biomass in a

chronosequence of silver birch stands For Ecol Manag 2013 302 62ndash70 [CrossRef]32 Varik M Kukumaumlgi M Aosaar J Becker H Ostonen I Lotildehmus K Uri V Carbon budgets in fertile silver birch (Betula

pendula Roth) chronosequence stands Ecol Eng 2015 77 284ndash296 [CrossRef]33 Šenhofa S Jaunslaviete I Šn epsts G Jansons J Liepa L Jansons A Deadwood characteristics in mature and old-growth

birch stands and their implications for carbon storage Forests 2020 11 536 [CrossRef]34 Gao B Taylor AR Searle EB Kumar P Ma Z Hume AM Chen HYH Carbon Storage Declines in Old Boreal Forests

Irrespective of Succession Pathway Ecosystems 2017 21 1168ndash1182 [CrossRef]35 European Environment Agency European Forest Types Categories and Types for Sustainable Forest Management Reporting and Policy

Technical Report European Environment Agency Copenhagen Denmark 200736 Bušs K Forest ecosystem classification in Latvia Proc Latv Acad Sci Sect B Nat Exact Appl Sci 1997 51 204ndash21837 Buchwald E A hierarchical terminology for more or less natural forests in relation to sustainable management and biodiversity

conservation In Proceedings of the Proceedings of the Third Expert Meeting on Harmonizing Forest-related Definitions RomeItaly 11ndash19 January 2005

38 Maumlkinen H Hynynen J Siitonen J Sievaumlnen R Predicting the decomposition of scots pine norway spruce and birch stems inFinland Ecol Appl 2006 16 1865ndash1879 [CrossRef]

39 Koumlster K Metslaid M Engelhart J Koumlster E Dead wood basic density and the concentration of carbon and nitrogen for maintree species in managed hemiboreal forests For Ecol Manag 2015 354 35ndash42 [CrossRef]

40 Jansons J Lıcıte I Latvia In National Forest Inventories Pathways for Common Reporting Tomppo E Gschwantner T LawrenceM McRoberts RE Eds Springer Dordrecht The Netherlands 2010 pp 341ndash350

41 Liepa I Pieauguma macıba LLU Jelgava Latvia 199642 Bobiec A The influence of gaps on tree regeneration A case study of the mixed lime-hornbeam (Tilio-Carpinetum Tracz 1962)

communities in the Białowieza Primeval Forest Polish J Ecol 2007 55 441ndash45543 Jonaacutešovaacute M Matejkovaacute I Natural regeneration and vegetation changes in wet spruce forests after natural and artificial

disturbances Can J For Res 2007 37 1907ndash1914 [CrossRef]44 Vehmas M Kouki J Eerikainen K Long-term spatio-temporal dynamics and historical continuity of European aspen (Populus

tremula L) stands in the Koli National Park eastern Finland Forestry 2009 82 135ndash148 [CrossRef]45 Kull O Niinemets Uuml Distribution of leaf photosynthetic properties in tree canopies Comparison of species with different shade

tolerance Funct Ecol 1998 12 472ndash479 [CrossRef]46 Yatskov M Harmon ME Krankina ON A chronosequence of wood decomposition in the boreal forests of Russia Can J For

Res 2003 33 1211ndash1226 [CrossRef]47 Jonsson BG Ekstroumlm M Esseen PA Grafstroumlm A Staringhl G Westerlund B Dead wood availability in managed Swedish

forestsmdashPolicy outcomes and implications for biodiversity For Ecol Manag 2016 376 174ndash182 [CrossRef]48 Similauml M Kouki J Martikainen P Saproxylic beetles in managed and seminatural Scots pine forests Quality of dead wood

matters For Ecol Manag 2003 174 365ndash381 [CrossRef]49 Adermann V Estonia In National Forest Inventories Pathways for Common Reporting Tomppo E Gschwantner T Lawrence M

McRoberts RE Eds Springer Dordrecht The Netherlands 2010 pp 171ndash18450 Siitonen J Forest management coarse woody debris and saproxylic organisms Fennoscandian boreal forests as an example

Ecol Bull 2001 49 11ndash41 [CrossRef]51 Rouvinen S Kuuluvainen T Karjalainen L Coarse woody debris in old Pinus sylvestris dominated forests along a geographic

and human impact gradient in boreal Fennoscandia Can J For Res 2002 32 2184ndash2200 [CrossRef]52 Aakala T Coarse woody debris in late-successional Picea abies forests in northern Europe Variability in quantities and models

of decay class dynamics For Ecol Manag 2010 260 770ndash779 [CrossRef]53 Lee P Dynamics of snags in aspen-dominated midboreal forests For Ecol Manag 1998 105 263ndash272 [CrossRef]

Forests 2021 12 901 15 of 16

54 Vasiliauskas R Vasiliauskas A Stenlid J Matelis A Dead trees and protected polypores in unmanaged north-temperate foreststands of Lithuania For Ecol Manag 2004 193 355ndash370 [CrossRef]

55 Bujoczek L Bujoczek M Zieba S How much why and where Deadwood in forest ecosystems The case of Poland Ecol Indic2021 121 107027 [CrossRef]

56 Krankina ON Treyfeld RF Harmon ME Spycher G Povarov ED Coarse Woody Debris in the Forests of the St PetersburgRegion Russia Ecol Bull 2001 93ndash107 [CrossRef]

57 Lee PC Crites S Nietfeld M Nguyen HV Stelfox JB Characteristics and origins of deadwood material in aspen-dominatedboreal forests Ecol Appl 1997 7 691ndash701 [CrossRef]

58 Koumlster K Jotildegiste K Tukia H Niklasson M Moumlls T Variation and ecological characteristics of coarse woody debris inLahemaa and Karula National Parks Estonia Scand J For Res 2005 20 102ndash111 [CrossRef]

59 Nilsson SG Niklasson M Hedin J Aronsson G Gutowski JM Linder P Ljungberg H Mikusinski G Ranius T Densitiesof large living and dead trees in old-growth temperate and boreal forests For Ecol Manag 2002 161 198ndash204 [CrossRef]

60 Framstad E de Wit H Maumlkipaumlauml R Larjavaar M Vesterdal L Karltun E Biodiversity Carbon Storage and Dynamics of OldNorthern Forests Nordic Council of Ministers Copenhagen Denmark 2013

61 Chen HYH Popadiouk RV Dynamics of North American boreal mixedwoods Environ Rev 2002 10 137ndash166 [CrossRef]62 Liepin a L Apses In Meža Enciklopedija Broks J Ed Zelta Grauds Rıga Latvia 200563 Lankia H Wallenius T Vaacuterkonyi G Kouki J Snaumlll T Forest fire history aspen and goat willow in a Fennoscandian old-growth

landscape Are current population structures a legacy of historical fires J Veg Sci 2012 23 1159ndash1169 [CrossRef]64 Muumlller J Buumltler R A review of habitat thresholds for dead wood A baseline for management recommendations in European

forests Eur J For Res 2010 129 981ndash992 [CrossRef]65 Brin A Brustel H Jactel H Species variables or environmental variables as indicators of forest biodiversity A case study using

saproxylic beetles in Maritime pine plantations Ann For Sci 2009 66 306 [CrossRef]66 Hottola J Ovaskainen O Hanski I A unified measure of the number volume and diversity of dead trees and the response of

fungal communities J Ecol 2009 97 1320ndash1328 [CrossRef]67 Lassauce A Paillet Y Jactel H Bouget C Deadwood as a surrogate for forest biodiversity Meta-analysis of correlations

between deadwood volume and species richness of saproxylic organisms Ecol Indic 2011 11 1027ndash1039 [CrossRef]68 Hekkala AM Ahtikoski A Paumlaumltalo ML Tarvainen O Siipilehto J Tolvanen A Restoring volume diversity and continuity

of deadwood in boreal forests Biodivers Conserv 2016 25 1107ndash1132 [CrossRef]69 Liu Q Hytteborn H Gap structure disturbance and regeneration in a primeval Picea abies forest J Veg Sci 1991 2 391ndash402

[CrossRef]70 Cornwell WK Cornelissen JHC Allison SD Bauhus J Eggleton P Preston CM Scarff F Weedon JT Wirth C Zanne

AE Plant traits and wood fates across the globe Rotted burned or consumed Glob Chang Biol 2009 15 2431ndash2449 [CrossRef]71 Niklas KJ Spatz H-C Worldwide correlations of mechanical properties and green wood density Am J Bot 2010 97 1587ndash1594

[CrossRef]72 Jacobsen RM Sverdrup-Thygeson A Kauserud H Mundra S Birkemoe T Exclusion of invertebrates influences saprotrophic

fungal community and wood decay rate in an experimental field study Funct Ecol 2018 32 2571ndash2582 [CrossRef]73 DeLong SC Daniels LD Heemskerk B Storaunet KO Temporal development of decaying log habitats in wet spruce-fir

stands in east-central British Columbia Can J For Res 2005 35 2841ndash2850 [CrossRef]74 Tarasov ME Birdsey RA Decay rate and potential storage of coarse woody debris in the Leningrad region Ecol Bull 2001

137ndash147 [CrossRef]75 Jonsson BG Availability of coarse woody debris in a boreal old-growth Picea abies forest J Veg Sci 2000 11 51ndash56 [CrossRef]76 Hararuk O Kurz WA Didion M Dynamics of dead wood decay in Swiss forests For Ecosyst 2020 7 36 [CrossRef]77 Moroni MT Morris DM Shaw C Stokland JN Harmon ME Fenton NJ Merganicovaacute K Merganic J Okabe K

Hagemann U Buried Wood A Common Yet Poorly Documented Form of Deadwood Ecosystems 2015 18 605ndash628 [CrossRef]78 Tikkanen O-P Martikainen P Hyvaumlrinen E Junninen K Kouki J Red-listed boreal forest species of Finland Associations

with forest structure tree species and decaying wood Ann Zool Fennici 2006 43 373ndash383 [CrossRef]79 Ranius T Martikainen P Kouki J Colonisation of ephemeral forest habitats by specialised species Beetles and bugs associated

with recently dead aspen wood Biodivers Conserv 2011 20 2903ndash2915 [CrossRef]80 Shorohova E Kushnevskaya H Ruokolainen A Polevoi A Borovichev E Behavior in a wide range of choices Substrate

preferences of threatened wood-inhabiting species in a mixed old-growth boreal forest In Proceedings of the ECCB2018 5thEuropean Congress of Conservation Biology Jyvaumlskylauml Finland 12ndash15 June 2018 Open Science Centre University of JyvaumlskylaumlJyvaumlskylauml Finland 2018

81 Puletti N Canullo R Mattioli W Gawrys R Corona P Czerepko J A dataset of forest volume deadwood estimates forEurope Ann For Sci 2019 76 1ndash8 [CrossRef]

82 Priewasser K Brang P Bachofen H Bugmann H Wohlgemuth T Impacts of salvage-logging on the status of deadwood afterwindthrow in Swiss forests Eur J For Res 2013 132 231ndash240 [CrossRef]

83 Kahl T Baber K Otto P Wirth C Bauhus J Drivers of CO2 Emission Rates from Dead Wood Logs of 13 Tree Species in theInitial Decomposition Phase Forests 2015 6 2484ndash2504 [CrossRef]

Forests 2021 12 901 16 of 16

84 Błonska E Lasota J Tullus A Lutter R Ostonen I Impact of deadwood decomposition on soil organic carbon sequestrationin Estonian and Polish forests Ann For Sci 2019 76 1ndash14 [CrossRef]

85 Seibold S Baumlssler C Brandl R Buumlche B Szallies A Thorn S Ulyshen MD Muumlller J Microclimate and habitatheterogeneity as the major drivers of beetle diversity in dead wood J Appl Ecol 2016 53 934ndash943 [CrossRef]

86 K enin a L Maca S Jaunslaviete I Jansons A Carbon pools in old-growth Scots pine stands on organic soils and itsconcentration in deadwood Cases study in Latvia In Proceedings of the 9th International Scientific Conference ldquoRuralDevelopment 2019rdquo Kaunas Lithuania 26ndash28 September VDU Kaunas Lithuania 2019 pp 284ndash288

87 Stakenas V Varnagiryte-Kabašinskiene I Sirgedaite-Šežiene V Armolaitis K Araminiene V Muraškiene M Žemaitis PDead wood carbon density for the main tree species in the Lithuanian hemiboreal forest Eur J For Res 2020 139 1045ndash1055[CrossRef]

88 Witt C Characteristics of aspen infected with heartrot Implications for cavity-nesting birds For Ecol Manag 2010 2601010ndash1016 [CrossRef]

89 Lotildehmus A Aspen-inhabiting aphyllophoroid fungi in a managed forest landscape in Estonia Scand J For Res 2011 26 212ndash220[CrossRef]

90 Andelic M Tangnaes M-J The Effect of Secondary Metabolites Nutrients and Invertebrates on Fungal Establishment andDecomposition Rates in European Aspen (Populus tremula) Masterrsquos Thesis Norwegian University of Life Sciences Arings Norway2019

91 Wirth C Lichstein JW The Imprint of Species Turnover on Old-Growth Forest Carbon BalancesmdashInsights From a Trait-Based Model ofForest Dynamics Springer BerlinHeidelberg Germany 2009 pp 81ndash113

92 Schmid AV Vogel CS Liebman E Curtis PS Gough CM Coarse woody debris and the carbon balance of a moderatelydisturbed forest For Ecol Manag 2016 361 38ndash45 [CrossRef]

93 Harmon ME Bond-Lamberty B Tang J Vargas R Heterotrophic respiration in disturbed forests A review with examplesfrom North America J Geophys Res Biogeosci 2011 116 G00K04 [CrossRef]

94 Nabuurs GJ Lindner M Verkerk PJ Gunia K Deda P Michalak R Grassi G First signs of carbon sink saturation inEuropean forest biomass Nat Clim Chang 2013 3 792ndash796 [CrossRef]

95 Senf C Seidl R Mapping the forest disturbance regimes of Europe Nat Sustain 2021 4 63ndash70 [CrossRef]

Availability and Structure of Coarse Woody Debris in Hemiboreal Mature to Old-Growth Aspen Stands and Its Implications for Forest Carbon Pool

Recommended Citation

Authors

Introduction

Materials and Methods

Results

Discussion

Conclusions

References

Authors Authors Silva Šēnhofa Guntars Šnepsts Kārlis Bičkovskis Ieva Jaunslaviete Līga Liepa Inga Straupe and Āris Jansons

This article is available at DigitalCommonsUSU httpsdigitalcommonsusueduaspen_bib7943

Article



and Aris Jansons 1









103390f12070901







iations








40)






1 Introduction




Forests 2021 12 901 2 of 16










































































Forests 2021 12 901 3 of 16



No N









Forests 2021 12 901 4 of 16



CarbonConcentration











Managed Unmanaged









Forests 2021 12 901 5 of 16



Huberrsquos formula

V =L π dm

2

4(1)



3 Results



Forests 2021 12 901 6 of 16






Standing


Unmanaged

41ndash60 30 166 48 22 0761ndash80 26 138 52 19 07

81ndash100 17 261 64 35 09101ndash140 150 319 22 46 03

Lying


Unmanaged

41ndash60 30 533 96 66 1261ndash80 26 535 103 64 13

81ndash100 17 475 129 53 16101ndash140 150 605 43 80 05

Total


Unmanaged

41ndash60 30 699 113 87 1561ndash80 26 673 121 82 16

81ndash100 17 735 153 88 20101ndash140 150 924 51 125 07









Sample Plots



Standing

Managed 41ndash60 19 76 60 10 09

61ndash80 19 53 60 07 09

Unmanaged

41ndash60 30 166 48 22 07

61ndash80 26 138 52 19 07

81ndash100 17 261 64 35 09

101ndash140 150 319 22 46 03

Lying

Managed 41ndash60 19 125 120 14 15

61ndash80 19 310 120 41 15

Unmanaged

41ndash60 30 533 96 66 12

61ndash80 26 535 103 64 13

81ndash100 17 475 129 53 16

101ndash140 150 605 43 80 05

Total

Managed 41ndash60 19 201 142 24 18

61ndash80 19 363 142 48 18

Unmanaged

41ndash60 30 699 113 87 15

61ndash80 26 673 121 82 16

81ndash100 17 735 153 88 20

101ndash140 150 924 51 125 07








respectively)










0

20

40

60

80

100

ge20 ge30 ge40 ge50

Pro

po

rtio

n o

f

sam

ple

plo

ts


41ndash60

61ndash80

81ndash100

101ndash140


Forests 2021 12 901 7 of 16
















005)







0

20

40

60

80

100


Pro

po

rtio

n o

f C

WD

Stand age years











(d) gt40 cm
























4 Discussion





0

10

20


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(a) 1

0

10

20

30

40


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(b) 2

0

20

40

60


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(c) 3 + 4 + 5


4 Discussion


Forests 2021 12 901 10 of 16







Forests 2021 12 901 11 of 16








Forests 2021 12 901 12 of 16




5 Conclusions


Forests 2021 12 901 13 of 16




























Forests 2021 12 901 14 of 16






























Forests 2021 12 901 15 of 16




























Forests 2021 12 901 16 of 16















Authors

Introduction


Results

Discussion

Conclusions

References

Article



and Aris Jansons 1









103390f12070901







iations








40)






1 Introduction




Forests 2021 12 901 2 of 16










































































Forests 2021 12 901 3 of 16



No N









Forests 2021 12 901 4 of 16



CarbonConcentration











Managed Unmanaged









Forests 2021 12 901 5 of 16



Huberrsquos formula

V =L π dm

2

4(1)



3 Results



Forests 2021 12 901 6 of 16






Standing


Unmanaged

41ndash60 30 166 48 22 0761ndash80 26 138 52 19 07

81ndash100 17 261 64 35 09101ndash140 150 319 22 46 03

Lying


Unmanaged

41ndash60 30 533 96 66 1261ndash80 26 535 103 64 13

81ndash100 17 475 129 53 16101ndash140 150 605 43 80 05

Total


Unmanaged

41ndash60 30 699 113 87 1561ndash80 26 673 121 82 16

81ndash100 17 735 153 88 20101ndash140 150 924 51 125 07









Sample Plots



Standing

Managed 41ndash60 19 76 60 10 09

61ndash80 19 53 60 07 09

Unmanaged

41ndash60 30 166 48 22 07

61ndash80 26 138 52 19 07

81ndash100 17 261 64 35 09

101ndash140 150 319 22 46 03

Lying

Managed 41ndash60 19 125 120 14 15

61ndash80 19 310 120 41 15

Unmanaged

41ndash60 30 533 96 66 12

61ndash80 26 535 103 64 13

81ndash100 17 475 129 53 16

101ndash140 150 605 43 80 05

Total

Managed 41ndash60 19 201 142 24 18

61ndash80 19 363 142 48 18

Unmanaged

41ndash60 30 699 113 87 15

61ndash80 26 673 121 82 16

81ndash100 17 735 153 88 20

101ndash140 150 924 51 125 07








respectively)










0

20

40

60

80

100

ge20 ge30 ge40 ge50

Pro

po

rtio

n o

f

sam

ple

plo

ts


41ndash60

61ndash80

81ndash100

101ndash140


Forests 2021 12 901 7 of 16
















005)







0

20

40

60

80

100


Pro

po

rtio

n o

f C

WD

Stand age years











(d) gt40 cm
























4 Discussion





0

10

20


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(a) 1

0

10

20

30

40


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(b) 2

0

20

40

60


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(c) 3 + 4 + 5


4 Discussion


Forests 2021 12 901 10 of 16







Forests 2021 12 901 11 of 16








Forests 2021 12 901 12 of 16




5 Conclusions


Forests 2021 12 901 13 of 16




























Forests 2021 12 901 14 of 16






























Forests 2021 12 901 15 of 16




























Forests 2021 12 901 16 of 16















Authors

Introduction


Results

Discussion

Conclusions

References

Forests 2021 12 901 2 of 16










































































Forests 2021 12 901 3 of 16



No N









Forests 2021 12 901 4 of 16



CarbonConcentration











Managed Unmanaged









Forests 2021 12 901 5 of 16



Huberrsquos formula

V =L π dm

2

4(1)



3 Results



Forests 2021 12 901 6 of 16






Standing


Unmanaged

41ndash60 30 166 48 22 0761ndash80 26 138 52 19 07

81ndash100 17 261 64 35 09101ndash140 150 319 22 46 03

Lying


Unmanaged

41ndash60 30 533 96 66 1261ndash80 26 535 103 64 13

81ndash100 17 475 129 53 16101ndash140 150 605 43 80 05

Total


Unmanaged

41ndash60 30 699 113 87 1561ndash80 26 673 121 82 16

81ndash100 17 735 153 88 20101ndash140 150 924 51 125 07









Sample Plots



Standing

Managed 41ndash60 19 76 60 10 09

61ndash80 19 53 60 07 09

Unmanaged

41ndash60 30 166 48 22 07

61ndash80 26 138 52 19 07

81ndash100 17 261 64 35 09

101ndash140 150 319 22 46 03

Lying

Managed 41ndash60 19 125 120 14 15

61ndash80 19 310 120 41 15

Unmanaged

41ndash60 30 533 96 66 12

61ndash80 26 535 103 64 13

81ndash100 17 475 129 53 16

101ndash140 150 605 43 80 05

Total

Managed 41ndash60 19 201 142 24 18

61ndash80 19 363 142 48 18

Unmanaged

41ndash60 30 699 113 87 15

61ndash80 26 673 121 82 16

81ndash100 17 735 153 88 20

101ndash140 150 924 51 125 07








respectively)










0

20

40

60

80

100

ge20 ge30 ge40 ge50

Pro

po

rtio

n o

f

sam

ple

plo

ts


41ndash60

61ndash80

81ndash100

101ndash140


Forests 2021 12 901 7 of 16
















005)







0

20

40

60

80

100


Pro

po

rtio

n o

f C

WD

Stand age years











(d) gt40 cm
























4 Discussion





0

10

20


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(a) 1

0

10

20

30

40


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(b) 2

0

20

40

60


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(c) 3 + 4 + 5


4 Discussion


Forests 2021 12 901 10 of 16







Forests 2021 12 901 11 of 16








Forests 2021 12 901 12 of 16




5 Conclusions


Forests 2021 12 901 13 of 16




























Forests 2021 12 901 14 of 16






























Forests 2021 12 901 15 of 16




























Forests 2021 12 901 16 of 16















Authors

Introduction


Results

Discussion

Conclusions

References

Forests 2021 12 901 3 of 16



No N









Forests 2021 12 901 4 of 16



CarbonConcentration











Managed Unmanaged









Forests 2021 12 901 5 of 16



Huberrsquos formula

V =L π dm

2

4(1)



3 Results



Forests 2021 12 901 6 of 16






Standing


Unmanaged

41ndash60 30 166 48 22 0761ndash80 26 138 52 19 07

81ndash100 17 261 64 35 09101ndash140 150 319 22 46 03

Lying


Unmanaged

41ndash60 30 533 96 66 1261ndash80 26 535 103 64 13

81ndash100 17 475 129 53 16101ndash140 150 605 43 80 05

Total


Unmanaged

41ndash60 30 699 113 87 1561ndash80 26 673 121 82 16

81ndash100 17 735 153 88 20101ndash140 150 924 51 125 07









Sample Plots



Standing

Managed 41ndash60 19 76 60 10 09

61ndash80 19 53 60 07 09

Unmanaged

41ndash60 30 166 48 22 07

61ndash80 26 138 52 19 07

81ndash100 17 261 64 35 09

101ndash140 150 319 22 46 03

Lying

Managed 41ndash60 19 125 120 14 15

61ndash80 19 310 120 41 15

Unmanaged

41ndash60 30 533 96 66 12

61ndash80 26 535 103 64 13

81ndash100 17 475 129 53 16

101ndash140 150 605 43 80 05

Total

Managed 41ndash60 19 201 142 24 18

61ndash80 19 363 142 48 18

Unmanaged

41ndash60 30 699 113 87 15

61ndash80 26 673 121 82 16

81ndash100 17 735 153 88 20

101ndash140 150 924 51 125 07








respectively)










0

20

40

60

80

100

ge20 ge30 ge40 ge50

Pro

po

rtio

n o

f

sam

ple

plo

ts


41ndash60

61ndash80

81ndash100

101ndash140


Forests 2021 12 901 7 of 16
















005)







0

20

40

60

80

100


Pro

po

rtio

n o

f C

WD

Stand age years











(d) gt40 cm
























4 Discussion





0

10

20


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(a) 1

0

10

20

30

40


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(b) 2

0

20

40

60


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(c) 3 + 4 + 5


4 Discussion


Forests 2021 12 901 10 of 16







Forests 2021 12 901 11 of 16








Forests 2021 12 901 12 of 16




5 Conclusions


Forests 2021 12 901 13 of 16




























Forests 2021 12 901 14 of 16






























Forests 2021 12 901 15 of 16




























Forests 2021 12 901 16 of 16















Authors

Introduction


Results

Discussion

Conclusions

References

Forests 2021 12 901 4 of 16



CarbonConcentration











Managed Unmanaged









Forests 2021 12 901 5 of 16



Huberrsquos formula

V =L π dm

2

4(1)



3 Results



Forests 2021 12 901 6 of 16






Standing


Unmanaged

41ndash60 30 166 48 22 0761ndash80 26 138 52 19 07

81ndash100 17 261 64 35 09101ndash140 150 319 22 46 03

Lying


Unmanaged

41ndash60 30 533 96 66 1261ndash80 26 535 103 64 13

81ndash100 17 475 129 53 16101ndash140 150 605 43 80 05

Total


Unmanaged

41ndash60 30 699 113 87 1561ndash80 26 673 121 82 16

81ndash100 17 735 153 88 20101ndash140 150 924 51 125 07









Sample Plots



Standing

Managed 41ndash60 19 76 60 10 09

61ndash80 19 53 60 07 09

Unmanaged

41ndash60 30 166 48 22 07

61ndash80 26 138 52 19 07

81ndash100 17 261 64 35 09

101ndash140 150 319 22 46 03

Lying

Managed 41ndash60 19 125 120 14 15

61ndash80 19 310 120 41 15

Unmanaged

41ndash60 30 533 96 66 12

61ndash80 26 535 103 64 13

81ndash100 17 475 129 53 16

101ndash140 150 605 43 80 05

Total

Managed 41ndash60 19 201 142 24 18

61ndash80 19 363 142 48 18

Unmanaged

41ndash60 30 699 113 87 15

61ndash80 26 673 121 82 16

81ndash100 17 735 153 88 20

101ndash140 150 924 51 125 07








respectively)










0

20

40

60

80

100

ge20 ge30 ge40 ge50

Pro

po

rtio

n o

f

sam

ple

plo

ts


41ndash60

61ndash80

81ndash100

101ndash140


Forests 2021 12 901 7 of 16
















005)







0

20

40

60

80

100


Pro

po

rtio

n o

f C

WD

Stand age years











(d) gt40 cm
























4 Discussion





0

10

20


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(a) 1

0

10

20

30

40


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(b) 2

0

20

40

60


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(c) 3 + 4 + 5


4 Discussion


Forests 2021 12 901 10 of 16







Forests 2021 12 901 11 of 16








Forests 2021 12 901 12 of 16




5 Conclusions


Forests 2021 12 901 13 of 16




























Forests 2021 12 901 14 of 16






























Forests 2021 12 901 15 of 16




























Forests 2021 12 901 16 of 16















Authors

Introduction


Results

Discussion

Conclusions

References

Forests 2021 12 901 5 of 16



Huberrsquos formula

V =L π dm

2

4(1)



3 Results



Forests 2021 12 901 6 of 16






Standing


Unmanaged

41ndash60 30 166 48 22 0761ndash80 26 138 52 19 07

81ndash100 17 261 64 35 09101ndash140 150 319 22 46 03

Lying


Unmanaged

41ndash60 30 533 96 66 1261ndash80 26 535 103 64 13

81ndash100 17 475 129 53 16101ndash140 150 605 43 80 05

Total


Unmanaged

41ndash60 30 699 113 87 1561ndash80 26 673 121 82 16

81ndash100 17 735 153 88 20101ndash140 150 924 51 125 07









Sample Plots



Standing

Managed 41ndash60 19 76 60 10 09

61ndash80 19 53 60 07 09

Unmanaged

41ndash60 30 166 48 22 07

61ndash80 26 138 52 19 07

81ndash100 17 261 64 35 09

101ndash140 150 319 22 46 03

Lying

Managed 41ndash60 19 125 120 14 15

61ndash80 19 310 120 41 15

Unmanaged

41ndash60 30 533 96 66 12

61ndash80 26 535 103 64 13

81ndash100 17 475 129 53 16

101ndash140 150 605 43 80 05

Total

Managed 41ndash60 19 201 142 24 18

61ndash80 19 363 142 48 18

Unmanaged

41ndash60 30 699 113 87 15

61ndash80 26 673 121 82 16

81ndash100 17 735 153 88 20

101ndash140 150 924 51 125 07








respectively)










0

20

40

60

80

100

ge20 ge30 ge40 ge50

Pro

po

rtio

n o

f

sam

ple

plo

ts


41ndash60

61ndash80

81ndash100

101ndash140


Forests 2021 12 901 7 of 16
















005)







0

20

40

60

80

100


Pro

po

rtio

n o

f C

WD

Stand age years











(d) gt40 cm
























4 Discussion





0

10

20


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(a) 1

0

10

20

30

40


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(b) 2

0

20

40

60


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(c) 3 + 4 + 5


4 Discussion


Forests 2021 12 901 10 of 16







Forests 2021 12 901 11 of 16








Forests 2021 12 901 12 of 16




5 Conclusions


Forests 2021 12 901 13 of 16




























Forests 2021 12 901 14 of 16






























Forests 2021 12 901 15 of 16




























Forests 2021 12 901 16 of 16















Authors

Introduction


Results

Discussion

Conclusions

References

Forests 2021 12 901 6 of 16






Standing


Unmanaged

41ndash60 30 166 48 22 0761ndash80 26 138 52 19 07

81ndash100 17 261 64 35 09101ndash140 150 319 22 46 03

Lying


Unmanaged

41ndash60 30 533 96 66 1261ndash80 26 535 103 64 13

81ndash100 17 475 129 53 16101ndash140 150 605 43 80 05

Total


Unmanaged

41ndash60 30 699 113 87 1561ndash80 26 673 121 82 16

81ndash100 17 735 153 88 20101ndash140 150 924 51 125 07









Sample Plots



Standing

Managed 41ndash60 19 76 60 10 09

61ndash80 19 53 60 07 09

Unmanaged

41ndash60 30 166 48 22 07

61ndash80 26 138 52 19 07

81ndash100 17 261 64 35 09

101ndash140 150 319 22 46 03

Lying

Managed 41ndash60 19 125 120 14 15

61ndash80 19 310 120 41 15

Unmanaged

41ndash60 30 533 96 66 12

61ndash80 26 535 103 64 13

81ndash100 17 475 129 53 16

101ndash140 150 605 43 80 05

Total

Managed 41ndash60 19 201 142 24 18

61ndash80 19 363 142 48 18

Unmanaged

41ndash60 30 699 113 87 15

61ndash80 26 673 121 82 16

81ndash100 17 735 153 88 20

101ndash140 150 924 51 125 07








respectively)










0

20

40

60

80

100

ge20 ge30 ge40 ge50

Pro

po

rtio

n o

f

sam

ple

plo

ts


41ndash60

61ndash80

81ndash100

101ndash140


Forests 2021 12 901 7 of 16
















005)







0

20

40

60

80

100


Pro

po

rtio

n o

f C

WD

Stand age years











(d) gt40 cm
























4 Discussion





0

10

20


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(a) 1

0

10

20

30

40


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(b) 2

0

20

40

60


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(c) 3 + 4 + 5


4 Discussion


Forests 2021 12 901 10 of 16







Forests 2021 12 901 11 of 16








Forests 2021 12 901 12 of 16




5 Conclusions


Forests 2021 12 901 13 of 16




























Forests 2021 12 901 14 of 16






























Forests 2021 12 901 15 of 16




























Forests 2021 12 901 16 of 16















Authors

Introduction


Results

Discussion

Conclusions

References

Forests 2021 12 901 7 of 16
















005)







0

20

40

60

80

100


Pro

po

rtio

n o

f C

WD

Stand age years











(d) gt40 cm
























4 Discussion





0

10

20


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(a) 1

0

10

20

30

40


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(b) 2

0

20

40

60


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(c) 3 + 4 + 5


4 Discussion


Forests 2021 12 901 10 of 16







Forests 2021 12 901 11 of 16








Forests 2021 12 901 12 of 16




5 Conclusions


Forests 2021 12 901 13 of 16




























Forests 2021 12 901 14 of 16






























Forests 2021 12 901 15 of 16




























Forests 2021 12 901 16 of 16















Authors

Introduction


Results

Discussion

Conclusions

References






(d) gt40 cm
























4 Discussion





0

10

20


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(a) 1

0

10

20

30

40


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(b) 2

0

20

40

60


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(c) 3 + 4 + 5


4 Discussion


Forests 2021 12 901 10 of 16







Forests 2021 12 901 11 of 16








Forests 2021 12 901 12 of 16




5 Conclusions


Forests 2021 12 901 13 of 16




























Forests 2021 12 901 14 of 16






























Forests 2021 12 901 15 of 16




























Forests 2021 12 901 16 of 16















Authors

Introduction


Results

Discussion

Conclusions

References







4 Discussion





0

10

20


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(a) 1

0

10

20

30

40


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(b) 2

0

20

40

60


CW

D v

olu

me

msup3

ha⁻

sup1

Stand age years

(c) 3 + 4 + 5


4 Discussion


Forests 2021 12 901 10 of 16







Forests 2021 12 901 11 of 16








Forests 2021 12 901 12 of 16




5 Conclusions


Forests 2021 12 901 13 of 16




























Forests 2021 12 901 14 of 16






























Forests 2021 12 901 15 of 16




























Forests 2021 12 901 16 of 16















Authors

Introduction


Results

Discussion

Conclusions

References

Forests 2021 12 901 10 of 16







Forests 2021 12 901 11 of 16








Forests 2021 12 901 12 of 16




5 Conclusions


Forests 2021 12 901 13 of 16




























Forests 2021 12 901 14 of 16






























Forests 2021 12 901 15 of 16




























Forests 2021 12 901 16 of 16















Authors

Introduction


Results

Discussion

Conclusions

References

Forests 2021 12 901 11 of 16








Forests 2021 12 901 12 of 16




5 Conclusions


Forests 2021 12 901 13 of 16




























Forests 2021 12 901 14 of 16






























Forests 2021 12 901 15 of 16




























Forests 2021 12 901 16 of 16















Authors

Introduction


Results

Discussion

Conclusions

References

Forests 2021 12 901 12 of 16




5 Conclusions


Forests 2021 12 901 13 of 16




























Forests 2021 12 901 14 of 16






























Forests 2021 12 901 15 of 16




























Forests 2021 12 901 16 of 16















Authors

Introduction


Results

Discussion

Conclusions

References

Forests 2021 12 901 13 of 16




























Forests 2021 12 901 14 of 16






























Forests 2021 12 901 15 of 16




























Forests 2021 12 901 16 of 16















Authors

Introduction


Results

Discussion

Conclusions

References

Forests 2021 12 901 14 of 16






























Forests 2021 12 901 15 of 16




























Forests 2021 12 901 16 of 16















Authors

Introduction


Results

Discussion

Conclusions

References

Forests 2021 12 901 15 of 16




























Forests 2021 12 901 16 of 16















Authors

Introduction


Results

Discussion

Conclusions

References

Forests 2021 12 901 16 of 16















Authors

Introduction


Results

Discussion

Conclusions

References

Availability and Structure of Coarse Woody Debris in ...

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