ICFR KZN MIDLANDS INTEREST GROUP FIELD DAY · The presence of competing vegetation during...

© ICFR 2011 ICFR KZN Midlands Regional Field Day

ICFR KZN MIDLANDS INTEREST GROUP FIELD DAY

Date: Thursday 8th September 2011 Venue: Hebron Haven Hotel, Dargle & Shaw Research Centre, Tweedie Time: 08h30 for 09h00

PROGRAMME

08h30 Meet for tea and coffee

Indoor Presentations

09h00 Welcome and objectives for the field day Paul Viero Mondi

09h10

The interaction between three pine species and

weed competition on two contrasting sites in

Mpumalanga, South Africa

Keith Little ICFR

09h40 Preliminary results of mid-rotation fertilisation in

pulpwood eucalypt stands Louis Titshall ICFR

10h10 Is mechanised wattle debarking the way forward? John Eggers Sappi

10h40 TEA

11h10 Update on research from the South African Pitch

Canker Control Programme Andrew Morris Sappi

11h40 Management of the eucalyptus gall wasp,

Leptocybe invasa Brett Hurley FABI

12h10 Improvement and genetic gain in 2nd generation

Eucalyptus dunnii Tammy Swain ICFR

12h40 LUNCH

Field Visits

13h30 Travel to Sappi Shaw Research Station

14h00 Vegetative propagation of pine hybrids

(Sappi Shaw Research Centre) Craig Ford Sappi

14h30 Sustaining fertility of productive plantations:

The role of atmospheric deposition. Steven Dovey ICFR

15h00 End of Field Day

Directions to the Hebron Haven:

• From Pietermaritzburg/Johannesburg: Take the Howick North/Tweedie off ramp

off the N3.

• Follow signs towards Tweedie and at the T-junction turn right onto the R103.

• Turn left onto the Dargle/Impendle Road, and after about 1.5 km turn left again

onto the D128 (both turns have sign posts for Hebron Haven).

• Follow the road, over the railway line to the hotel.


The interaction between three pine species and weed competition

on two contrasting sites in Mpumalanga, South Africa

Keith Little [email protected]

Institute for Commercial Forestry Research, PO Box 100281, Scottsville 3209 Introduction

Mpumalanga province has long been a key region for the growth of pines and currently it accounts for 48.1% of South Africa’s softwood production. The diversity in terms of physiography, climate and underlying geology mean that different pine species are matched to appropriate sites, of which Pinus patula is by far the most widely planted (61% of the area planted to pines), with P. elliottii and P. taeda contributing 29.5% and 4.4% respectively (94.9% in total). In general, the most appropriate pine species for a site is determined primarily by temperature regime when a minimum level of water is supplied, with P. patula growing best at higher altitudes and P. elliottii at lower altitudes.

The presence of competing vegetation during re-establishment can have a major impact on tree performance in terms of growth, survival and variability, particularly for eucalypts grown on a short, pulp-wood rotation where any negative effects from early competition are likely to result in a significant reduction in yield at harvest. Research conducted in the early 1990’s also indicated similar, early negative impacts on pine performance. However, due to the longer rotation length of pines, questions were raised as to whether any negative impacts from competition would be carried through to felling. In addition, there was a general lack of information related to the susceptibility/sensitivity, if any, of the pine species specifically grown in Mpumalanga to weed competition. Research also conducted at this time at Usutu, Swaziland, indicated that the most vigorous vegetation growth occurred on lower elevation sites. To improve our understanding on these aspects, three trials incorporating three pines species (P. patula, P. elliottii and P. taeda) were initiated in 1995 on contrasting sites in Mpumalanga (based on an altitudinal gradient: low, mid and high) in combination with two weeding scenarios (weedy and weedfree). Unfortunately, no long-term data could be obtained from these trials as the low-altitude trial was abandoned due to an early, unscheduled weeding, with the remaining two lost through wild-fire in 2007. This report however highlights weed and tree growth interactions for the mid- and high-altitude trials up until 11.5 years of age. Trial Design and Treatments

Table 1. Site characteristics for two Species and Weeding interaction trials in eastern Mpumalanga, South Africa.

Site characteristic Ceylon plantation Spitzkop plantation

Latitude; Longitude 25o 06.008’ S; 30o 39.378 E 25o 09.344’ S; 30o 48.301’ E Altitude (m a.s.l.) 1 939 1 412

MAP (mm) 1 211 1 155

MAT (oC) 13.8 16.6

Soil type Mispah Inanda

Previous crop P. patula on a saw-log rotation

Site preparation Harvest residues burned. Site ripped to 30 cm

Date planted 07th November 1995 02th November 1995

Spacing (stems per hectare - sph) 3.5 x 3.5 m (1633 sph)

Species planted P. patula; P. elliottii; P. taeda

Climate zone CT3 (cool temperate) WT3 (warm temperate)

Growing conditions Risk of snow damage Optimum for all species Date trial terminated (fire) 16th May 2007; 11 yrs, 6 mths 23rd April 2007; 11 yrs, 6 mths


• 3 x 2 factorial arrangement of six treatments replicated four times • Each treatment plot will consisted of 5 x 9 trees with inner 3 x 7 = measured plot • Pre-plant spray; no fertiliser applied; planted with 2 L water

Results

Figure 1. Mean percentage vegetation cover at 2 years 2 months after planting in two pine species x

weeding interaction trials in Mpumalanga, South Africa. Bars indicate standard deviation.

Figure 2. Estimated volume (m3 ha-1) at 11.5 years for the main factors of pine species and weeding

in two trials in Mpumalanga, South Africa.

P. patula

P. elliottii

P. taeda

Weedfree

Weedy

0 40 80 120 160

Volume (m3 ha-1)

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P. elliottii

P. taeda

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Take Home Points

� Pine x site interaction o Overall growth of pines was better at the mid- than the higher-altitude site. o There was a significant difference between pines with P. patula > P. elliottii > P. taeda

at both sites. o The importance of this site x species interaction is increasing with time.

� Weed growth o As expected, weed growth and species diversity was greater at mid-altitude site, with

woody vegetation predominating. o Natural pine regeneration was more abundant at the higher altitude site and persisted

throughout the duration of the study. � Weed x pine growth

o The negative influence of weed competition on tree performance was greater at the mid-altitude site than the higher altitude site

o The significance of weed competition becoming less with time at mid-altitude site. o At the higher-altitude site all three pines seem equally impacted by weed competition,

whereas at the mid-altitude site P. patula and P. elliottii seem more susceptible than P. taeda.


Early growth responses of mid-rotation fertilisation of

Eucalypt pulpwood plantations

Louis Titshall [email protected]

Institute for Commercial Forestry Research, PO Box 100281, Scottsville, 3209

Introduction

While the effects of fertiliser application at planting are well documented (Germishuizen and Smith, 2007), the effects of fertiliser application after planting on the productivity of Eucalyptus is not well known (Germishuizen, 2007). Benefits of post-planting fertilisation of plantations may include an increase in final tree volume and a reduction in rotation length (reduced risk). This effect may well be considerable on South African forestry soils as these are reported to be relatively infertile. This series of trials investigates the potential for productivity responses to nutritional inputs applied at two to three years prior to clear-felling of pulpwood eucalypt stands, across a wide range of sites. This presentation reports on the basal area growth responses at about 15 months after fertilisation at these sites. Trial design and treatments

Table 1. A summary of trial details for all ICFR Hardwood Nutrition mid-rotation fertilisation trials implemented since 2007.

Trial No Location Comp. Species Fertilisatio

n age Stems per

hectare Altitude

(m) Climate Zone Lithology

MRF 1 Canewoods A 055 E. grandis x E. urophylla

4 yrs 6 mnths 1333 66 Sub-tropical Sand

MRF 2 Ixopo, Sutton

S 10 E. dunnii 8 yrs 3 mnths

1667 1055 Warm temperate Dolerite

MRF 3 Ixopo, Sutton E 14 E. dunnii 7 yrs 1667 1060 Warm temperate Shale

MRF 4 Dukuduku C 23 E. grandis x E. camaldulensis

8 yrs 8 mnths

1111 60 Sub-tropical Sand

MRF 5 Dukuduku D 12 E. grandis x E camaldulensis

3 yrs 7 mnths 1667 60 Sub-tropical Sand

MRF 6a Bloemhoff, Dumbe B 013 E. dunnii 7 yrs 1667 1050 Warm temperate Granite

MRF 7b Bloemhoff, Dumbe B 018 E. dunnii 7 yrs 1667 1050 Warm temperate Granite

MRF 8 Watersmeet, Iswepe

C 137 E. grandis x E. nitens

6 yrs 1667 1426 Cool temperate Granite

MRF 9 Babanango K 002 E. grandis/ E. nitens 6 yrs 1667 1319 Warm temperate

Shale/ sandstone

MRF 10 Melmoth F 079 E. grandis 6 yrs 8 mnths

1667 1070 Warm temperate Sandstone

MRF 11 Clan, Howick T 68 A E. grandis 6 yrs

6 mnths 1667 1000 Warm

temperate Shale

MRF 12 Makatweskop, Paulpietersburg M 02 E. grandis x

E. nitens 6 yrs

2 mnths 1351 1326 Warm temperate Shale

MRF 13 Riverbend, Ermelo H 04 E. nitens 6 yrs

10 mnths 1667 1493 Cool temperate Gabbro

MRF 14 Woodstock, Ermelo W 20 A E. nitens 7 yrs 1667 1600 Cool temperate Granite

MRF 15 Windy Hill, Howick A 49 E. grandis 5 yrs 9 mnths

1667 850 Warm temperate

Sandstone

MRF 16 Highflats, Ixopo H 21 E. dunnii

7 yrs 11 mnths 1667 882

Warm temperate Tillite

a Lost to fire in November 2010 (15 month results reported). b Lost to premature felling shortly after fertilisation.


• Each site has three treatments (Table 2) with a single replicate (n = 2) • Each site consists of 16 x 16 outer trees and 6 x 6 inner measured trees. • Trees selectively removed from each plot to reduce plot variance across a site. • Soil samples collected prior to fertiliser application. • Granular fertiliser applied in rainy season (summer). • DBH measured at prior to fertiliser application and then six monthly thereafter.

Table 2. Fertiliser type and rates applied to the Control, NPK and NPK+ treatments.

Nutrient Nutrient Source Application rate (kg ha-1) Control NPK NPK+

Nitrogen (N) LAN (28%) 300 no yes yes

Phosphorous (P) Single phosphate (10.5%) 200 no yes yes

Potassium (K) Potassium Chloride (50%) 100 no yes yes

Calcium (Ca) Calcium Nitrate (19%) 140 no no yes

Magnesium (Mg) Magnesium Sulphate (10%) 50 no no yes

Boron (B) Solubor (17%) 5 no no yes

Copper (Cu) Copper sulphate (25.6%) 5 no no yes

Zinc (Zn) Zinc Sulphate (35%) 2 no no yes

• Similarities between sites based on soil properties compared using multivariate ordination analysis.

• The increases in basal area (basal area increment; BAI) at 15 months from time of fertilisation are reported for all sites.

• Data were analysed using ANOVA (site x fertiliser structure).

Results

Soils • The primary differentiation between sites was largely due to differences in soil texture, N, P

and organic carbon (OC) content. • Typically, sites with sandy soils (e.g. MRF 1, 2, 3, 4 and 5) had lower amounts of N, P and

OC and as clay content increased, so did amounts of N, P and OC, (e.g. MRF 8, 10, 13 and 14).

Growth data • Overall (F-statistic) no significant (p > 0.1) interaction effect of site x fertiliser for BAI at 15

months after fertilisation. • No significant (p > 0.1) effect of fertilisation alone across sites. • Site (location) has highly significant (p < 0.001) effect on BAI at 15 months after fertilisation. • Some sites do show positive response (10 of 15) to fertiliser when expressed relative to

control treatment (Figure 1). • The response to NPK and NPK+ is variable between sites (Figure 1).


-80

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Figure 1. The difference in BAI of the NPK and NPK+ treatments from the control treatment,

expressed relative to the control treatment (as a percentage) at about 15 months after mid-rotation fertilisation of eucalypt pulpwood stands. Positive and negative values indicate that a treatment had a higher or lower BAI relative to the control treatment, respectively. MRF 7 not shown as it was prematurely felled.

Take Home Points

� 15 month growth responses inconclusive. � Response to NPK and NPK+ is variable across sites. � Additional factors not considered here, may be influencing response to fertiliser. � However, though not significant, some sites may benefit from mid-rotation fertilisation. � Require final felling tree growth data and volumes to determine true benefit of mid-rotation

fertilisation. References

Campion J. 2006. The effects of mid- and late-rotation fertiliser application on tree growth and wood quality in sawtimber stands: A critical review of the literature. ICFR Bulletin Series 16/2006. Institute for Commercial Forestry Research, Pietermaritzburg, South Africa.

Germishuizen I. 2007. A review of the current knowledge of the effects of re-fertilisation on the growth of eucalypts. ICFR Bulletin Series 09/2007. Institute for Commercial Forestry Research, Pietermaritzburg, South Africa.


Acacia mearnsii debarking: Comparing different debarking

technologies in the KwaZulu-Natal and Mpumalanga forestry regions of

South Africa

John R Eggers*, Andrew McEwan and Jaap C Steenkamp *[email protected]

Sappi Forests

Introduction

In South Africa, most debarking of Acacia mearnsii is carried out manually. Finding labour to carry out cost effective debarking is becoming increasingly difficult. Further to this, Acacia mearnsii trees are usually small with bark that is difficult to remove. Often no debarking takes place during the drier winter months, due to the wood-bark bond being too strong. If the bark is to be used by a processing facility, then bark quality in terms of dimensions, amount of damage to the bark and time after debarking also becomes important. One of the most limiting factors to mechanised Acacia mearnsii debarking, is the quality of the bark that is produced. The mechanical debarkers also produce bark of varying length and size. Consistency of bark size once chipped, is of vital importance for the processing plants. It determines the quality of the end product, due to it affecting the defusing process, by influencing the amount of possible extractives to leach out. The processing plants are able to overcome incorrect chip sizes by using drum chippers to create acceptable sizes from larger chips of bark.

Machines researched

This research project covered the effect of these bark dimensions/shapes on the extraction efficiency as well as the effect on the quality of the end product. The project investigated the debarking of Acacia mearnsii using:

1. The Demuth mobile debarker (DDM 420), which is a ring debarker that loosens the bark from de-branched logs with rollers, cuts it to size with knives and removes it with scrapers. The bark is removed in chip form (Demuth machines, 2008).

2. The Hypro debarker, which is a tractor mounted processor that removes the bark from tree lengths by applying pressure with the feed rollers. The bark is removed in strips of varying length depending on the wood-bark bond strength (Hypro, 2008).

3. The Hyena MK 3 debarking head, which removes the bark from tree lengths by applying pressure with the feed rollers. The bark is removed in strips of varying length depending on the wood-bark bond strength. The Hyena was used only to debark the tree lengths, no processing took place.

Research data

The research sites for the Demuth and the Hypro debarkers were conducted in the KwaZulu-Natal midlands, and in Mpumalanga, for the Hyena debarker. The research trials for each of the debarking technologies were conducted during summer as well during winter, when traditionally, no debarking of Acacia mearnsii takes place. This was done to determine the effect of a stronger wood-bark bond strength on the productivity of each of the technologies. The effect that tree volume, strippability and tree form had on the effectiveness of the three debarking machines was determined. The machines were analysed in terms productivity (m³ per productive machine hour), cost per m³, quality of debarking and the quality of the bark produced for the processing facilities. Bark samples were collected on a daily basis from each of the three debarking technologies. Samples were taken under different tree volume, tree form and strippability classes. Manually debarked samples were also taken under the same conditions as each of the technologies, and from the same compartments. The samples were then analysed at the laboratory of one of the processing facilities. The samples taken from each of the three debarking technologies showed that the quality was acceptable when compared to the manually debarked samples.


Update on research from the

South African Pitch Canker Control Programme

Andrew Morris [email protected]

Sappi Shaw Research Centre, Sappi Forests

Summary

Fusarium circinatum, the pitch canker fungus (PCF), is associated with severe post-planting mortality of Pinus patula. The situation is so serious that many growers will now select an alternative species to plant where ever possible. In order to boost applied research into effective control Forestry South Africa in 2010 began funding the South African Pitch Canker Control Programme in a range of projects. This talk presents an update on this programme of work. Post-planting survival is linked to asymptomatic seedlings that are infected with PCF in the nursery. Infection can be detrimental to post-planting survival even when not evident in the nursery. Various additional nursery control options are being evaluated. Development of PCF tolerant P. patula hybrids are an important component of future control of this disease.


Management of the Eucalyptus gall wasp, Leptocybe invasa

Brett Hurley

[email protected] Department of Zoology and Entomology, Tree Protection Cooperative Programme (TPCP)

Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002 www.fabinet.up.ac.za

Summary

The Eucalyptus gall wasp, Leptocybe invasa has rapidly become a serious forest pest in South Africa. Leptocybe invasa attacks new growth (leaves, petioles and stems) of all ages of Eucalyptus, including nursery stock. Heavy galling causes the leaves to warp, malformation and stunted growth of the tree, and in extreme cases tree death (Photoplate 1). For this reason, various TPCP studies have been initiated to deal with the pest. In the short to medium term, these are focused in two main domains, namely resistance screening and biological control. Screening procedures have been developed to enable forestry companies to identify patterns of susceptibility between Eucalyptus genotypes. Following a pilot trial in 2009, a larger screening trial with 50 genotypes was completed in 2010. Results from this trial show distinct differences between Eucalyptus genotypes, but also great variation within species and clones, noticeably GC and GU clones (see Graph). These results clearly demonstrate that planting resistant material can assist in the management of this insect. From these trials, the techniques have now been established and refined to a point where they can be routinely implemented. Apart from technical information, the TPCP members are already using data from this trial to make decisions regarding planting stock. A much more extensive screening trial is currently being run which will provide further information on the most suitable genotypes to plant. Possibly the best available option to deal with the growing L. invasa invasion is via biological control. Considerable effort is being made to identify effective parasitoid wasps that can be used for this purpose. Collections have thus been made by the TPCP team in Australia and concurrently, imported via collaboration with Dr. Zvi Mendel in Israel. There are consequently various agents that have been studied under quarantine conditions in the facilities at the UP Experimental Farm with the aim of supplying the necessary data to enable us to apply for release permits in South Africa. Of the four agents studied thus far, a newly discovered species of Selitrichodes appears to hold particular promise (Photoplate 2). Research at the FABI quarantine facility at the UP Experimental Farm to investigate the biology, specificity and effectiveness of this parasitoid has been completed. Results have been very positive, showing the Selitrichodes sp. to be specific to L. invasa and obtain high parasitism levels. The process to apply for permission to release this parasitoid as a biological control agent has started. Further studies on the biology of L. invasa and the Selitrichodes sp. are underway, which will provide information needed for the successful establishment of Selitrichodes sp. in South Africa. Investigation as to the use of other biological control agents will also continue.


Photoplate 1. Symptoms and damage of L. invasa. a. Galls on midrib of leaves; b. galls on leaf

petioles; c,d. extensive galling causing shoot die-back; e,f. young tree killed by heavy L. invasa infestation (trees in background are uninfested trees of the same age).

a

c

b

d

f e


Photoplate 2. Selitrichodes sp. parasitising L. invasa. a. Adult female Selitrichodes ovipositing in L.

invasa induced gall on Eucalyptus; b. egg of Selitrichodes sp. (see arrow) on pupa of L. invasa; c,d. Selitrichodes larva (see arrow) in L. invasa induced gall with remains of parasitized L. invasa.

a b

c d


Improvement and genetic gain in 2nd generation Eucalyptus dunnii

Tammy Swain [email protected]

Institute for Commercial Forestry Research, PO Box 100281, Scottsville, 3209

Introduction

Eucalyptus dunnii remains an important temperate and mid-altitude species, which is robust enough to withstand challenges due to possible climate change, and therefore tree improvement in this species is ongoing at the ICFR. A series of 2nd generation E. dunnii progeny trials was established by the ICFR to assess the performance of individuals that offer the greatest potential for genetic improvement. At the same time, a series of genetic gain trials was established to quantify the gain that has been made in the breeding programme in the 1st generation. Second generation progeny trials

Seed was collected from 1st generation Breeding Seed Orchards (BSOs) at Kia Ora (E90/01) and Vlakkloof (E90/02), as well as from grafted selections included in the ICFR Clonal Seed Orchards (CSOs) at Tweedie (Howick, KwaZulu-Natal) and Piet Retief (Mpumalanga). A series of 2nd generation progeny trials and BSOs was then established at three different sites in KwaZulu-Natal (i.e. Enon (Richmond), Salpine (Paulpietersburg), and Commondale (Paulpietersburg)) at the end of 2004 and early in 2005. Table 1 presents details of the sites and trial designs. Due to the large numbers of seedlots to be included in the progeny trials and the resultant large trial size, the 2nd generation material was divided into two trial series, based on seed orchard origin (i.e., ex-Kia Ora (K series) and ex-Vlakkloof (V series)), with eight common families and seven common bulk treatments. Material from a cold tolerant trial series in Brazil was also included with the ex-Vlakkloof BSO material in the progeny trials. Comprehensive details of the material included in these trials can be found in Swain and Komakech (2008).

Diameter at breast height (DBH) was measured in all trials at 65 months during 2010, and family means calculated. Heritabilities and genotype by environment interactions (GEI) were also estimated. Table 2 presents a summary of the trial means and heritabilities.

• With respect to survival, Enon performed significantly better for both the K and V series. For growth, Commondale performed best in both series with moderately high heritabilities. The heritability at Salpine for the K series was also moderately high.

• There were significant (p < 0.05) differences for growth between families for all trials and sites.

Table 1. Site and trial details of 2nd generation Eucalyptus dunnii progeny trials, genetic gain trials and Breeding Seed Orchards (BSOs). All trials fall within KwaZulu-Natal province.

Locality Trial type1 Date planted Company Latitude

(S) Longitude

(E) Altitude

(m) MAP (mm)

MAT (oC)

Soil depth (mm)

Material origin

No. of families Design Trees/

plot Replica-

tions

Survival prior to

blanking Enon B17, Richmond

K 2nd gen progeny trial

24/01/05 NCT 29o49' 30o13' 1080 980 16.5 >1000 Kia Ora BSO 99 9x11 lattice 6 4 99.4%

Enon B17, Richmond

V 2nd gen progeny trial 24/01/05 NCT 29o48' 30o43' 1080 980 16.5 >1000

Vlakkloof BSO, Brazil & CSOs 110 10x11 lattice 6 4 99.2%

Enon B17, Richmond

B 2nd gen BSO 14/12/04 NCT 29o49' 30o13' 1110 980 16.5 >1000 Brazil 23 Unbal latt 2 6 6 90.5%

Ingwe A047, Balgowan

Genetic gain 27/01/05 NCT 29o23' 30o08' 1200 1008 16.3 >1000 - 16 4x4 lattice 25

(measure inner 9)

4 99.4%

Ingwe A047, Balgowan K 2nd gen BSO 27/01/05 NCT 29o23' 30o08' 1200 1008 16.3 >1000 Kia Ora BSO 82 Unbal latt 6 6 97.0%

Ingwe A047, Balgowan V 2nd gen BSO 28/01/05 NCT 29o23' 30o07' 1230 1027 16.3 >1000 Vlakkloof BSO 62 Unbal latt 6 6 97.8%

Salpine 30, Paulpietersburg

K 2nd gen progeny trial 09/02/05 Mondi 27o19' 30o45' 1121 930 17.9 >1000 Kia Ora BSO 99 9x11 lattice 6 4 99%, then

76.4% Salpine 30, Paulpietersburg

V 2nd gen progeny trial 10/02/05 Mondi 27o19' 30o45' 1121 930 17.9 >1000 Vlakkloof BSO,

Brazil & CSOs 3 110 10x11 lattice 6 4 98.2% then 71.6%

Salpine 30, Paulpietersburg Genetic gain 14/12/04 Mondi 27o19' 30o45' 1121 930 17.9 >1000 - 16 4x4 lattice

25 (measure inner 9)

4 82.7% then

87.4%


K 2nd gen BSO 08/02/05 Mondi 27o19' 30o45' 1121 930 17.9 >1000 Kia Ora BSO 82 Unbal latt 6 6

98.5% then 76.6%


V 2nd gen BSO 10/02/05 Mondi 27o19' 30o45' 1121 930 17.9 >1000 Vlakkloof BSO 62 Unbal latt 6 6 98.3% then 76.1%

Commondale 568, Paulpietersburg

K 2nd gen progeny trial 17/12/04 CTC 27o17' 30o45' 1140 920 17.8 >1200

Kia Ora BSO & Brazil 99 9x11 lattice 6 4 75.6%


V 2nd progeny trial

28/01/04 CTC 27o17' 30o45' 1140 920 17.8 >1200 Vlakkloof BSO, Brazil & CSOs

110 10x11 lattice 6 4 74.5%


Genetic gain 09/12/04 CTC 27o17' 30o45' 1140 920 17.8 >1200 - 16 4x4 lattice 25

(measure inner 9)

4 94.7%

Commondale 568, Paulpietersburg B 2nd gen BSO 07/12/04 CTC 27o17' 30o45' 1140 920 17.8 >1200 Brazil 23 Unbal latt 6 6 80.8%

1 in this column, “K” denotes material ex-Kia Ora BSO, “V” denotes material ex-Vlakkloof BSO and “B” denotes material ex-Brazil 2 Unbalanced lattice design 3 Clonal Seed Orchard


Table 2. Trial means and heritabilities (h2) for DBH, with associated standard errors (SE), in trials of the K and V progeny series at approximately 65 months of age.

Site N (Survival %) Mean SE h2 SE(h2)

K progeny series: Commondale 1988 (83.7) 15.278 0.060 0.124 0.045 Enon 2287 (96.2) 13.639 0.051 0.063 0.035 Salpine 1895 (77.4) 12.727 0.067 0.145 0.048 V progeny series: Commondale 2135 (80.8) 15.419 0.076 0.161 0.049 Enon 2448 (92.7) 14.361 0.062 0.077 0.034 Salpine 2179 (85.4) 12.518 0.070 0.082 0.038

• The moderately high heritabilities at Commondale and Salpine, and significant family differences, indicate that selection for improved growth at these sites would be effective.

• Genotype by environment interaction exists between Salpine and the other two sites for the K series, and although a similar trend is evident in the V series, there is a much lower magnitude of GEI in the latter series. This indicates that selections or families that perform well at Salpine may not perform in a similar manner at Commondale and Enon.

Genetic gain trials

Three genetic gain trials were established to determine whether significant gain has been made in the 1st generation of breeding, and to quantify these gains if present. Information on the sites and trial designs of the genetic gain trials are also included in Table 1 and Table 3 provides details of the material included in the trials.

Table 3. Treatments included in three Eucalyptus dunnii genetic gain trials.

ICFR 2nd generation treatment number Seedlot origin

GG1 GG2 GG3 GG4 GG5 GG6 GG7 148 (GG8) 334 (GG9) 332 (GG10) GG11 GG12 GG13 GG14 GG15 GG16

Improved ICFR commercial Kia Ora bulk (2003) Improved ICFR commercial Vlakkloof bulk (2001) Elite bulk of top 15 families ex ICFR Kia Ora BSO1 Elite bulk of top 15 families ex ICFR Vlakkloof BSO ICFR Piet Retief PSO2 bulk (2000) Improved ICFR commercial Kia Ora bulk (2004) Elite ICFR Tweedie CSO bulk (2004) Family 25, Top performing 1st generation family ex Kia Ora BSO Selection 5 ex Piet Retief CSO Selection 20 ex Tweedie CSO Improved commercial bulk ex Sappi (S/N 60456) Unimproved commercial bulk ex Sappi (SN 12639) (Queensland)4 Top performing 1st gen/Aus family at Kia Ora [7 – or Dead Horse Track 10] Top performing 1st gen/Aus family at Vlakkloof [52 – or Moleton 92/5-90] Bulk 1st gen (Australia) families ex Kia Ora Bulk 1st gen (Australia) families ex Vlakkloof

1 Breeding Seed Orchard 2 Production Seed Orchard 3 Clonal Seed Orchard 4 same commercial control as in E90/02 trial series

• There were no significant differences between any treatments in the genetic gain trials (Table 4). • Despite this, there were notable volume differences between treatments, e.g. Treatments GG3

(Elite bulk of top 15 families ex ICFR Kia Ora BSO) and GG7 (Elite ICFR Tweedie CSO bulk) performed generally well across all three sites, and differed from the unimproved commercial bulk (Treatment GG12) in that GG7 produced 7.6%, 38.8% and 6.9% more volume than GG12 at Commondale, Salpine and Ingwe, respectively, and GG3 produced 7.4%, 12.9% and 14.9% more volume than GG12 at the same sites.

• A comparison of the best treatment at each site with the trial mean showed a 12.9% increase in total volume at Commondale, and 27.3% and 14.9% at Salpine and Ingwe, respectively.

• In addition, although not significant (p > 0.05), Treatment GG2 (Improved ICFR commercial Vlakkloof bulk) performed better than comparative bulk treatment GG1 (Improved ICFR commercial Kia Ora bulk) at all sites, but GG3 (Elite bulk of top 15 families ex ICFR Kia Ora BSO)


performed better than comparative bulk treatment GG4 (Elite bulk of top 15 families ex ICFR Vlakkloof BSO) at two of the sites.

• The non-significance between improved treatments is similar to that found in genetic gain trials of E. nitens (Jones, pers comm1) and E. macarthurii (Swain et al., 1999) in South Africa.

Table 4. Total volumes per hectare of treatments in three Eucalyptus dunnii genetic gain trials.

Commondale Salpine Ingwe

Treatment Total vol

(m3ha-1) Treatment

Total vol

(m3ha-1) Treatment

Total vol

(m3ha-1)

GG13 205.39 GG7 137.8 GG11 100.38

GG5 202.42 GG5 125.34 GG4 99.94

GG9 202.21 GG11 120.35 GG10 93.73

GG7 196.21 GG3 119.07 GG3 92.63

GG3 195.78 GG2 117.23 GG9 90.90

GG10 194.97 GG6 111.26 GG7 90.78

GG2 186.25 GG1 109.95 GG14 89.61

GG12 182.27 GG16 106.93 GG2 88.91

GG6 180.10 GG14 106.3 GG15 88.76

GG14 173.44 GG13 105.98 GG5 86.94

GG16 172.45 GG15 104.70 GG12 84.89

GG11 171.72 GG12 99.24 GG1 81.72

GG4 162.73 GG4 97.06 GG13 80.97

GG15 161.69 GG10 96.17 GG16 76.51

GG8 161.65 GG9 91.02 GG8 75.45

GG1 160.14 GG8 83.03 GG6 75.09

Mean 181.84 108.21 87.33

Take Home Points:

� There are significant differences between 2nd generation families, which can be used to selectively improve the E. dunnii population. � Due to the presence of genotype by environment interaction in the K series, material that

performed well at both Commondale and Enon may have a broader application than those seedlots that only performed well at Salpine. � There were no significant differences between seed orchard bulks of improved and unimproved

E. dunnii, although volume differences between treatments were notable. � Past studies have indicated that there are significant differences between families for wood

properties, and that these traits are highly heritable. These results thus suggest that improvement in this species should focus on wood properties in addition to growth characteristics.

References

Swain T and Komakech C. 2008. Establishment of 2nd generation Eucalyptus dunnii progeny trials. ICFR Technical Note 03/2008. Pietermaritzburg, Institute for Commercial Forestry Research. South Africa.

Swain T, Gardner R and Chiappero C. 1999. 1984-1998: Fifteen years of South African E. macarthurii tree improvement trials at the ICFR. ICFR Bulletin Series 03/1999. Pietermaritzburg, Institute for Commercial Forestry Research, South Africa. 29 pp.

1 Jones, W. 2010. Sappi Shaw Research Centre, Tweedie, PO Box 473, Howick, 3290.


Vegetative propagation of pine hybrids

Craig Ford [email protected]

Sappi Shaw Research Centre, Sappi Forests

Summary

Selectively breeding within and between species for high yield and disease tolerance is possible using the controlled pollination (CP) technique. Selections for high fibre gain (FG) and Pitch Canker Fungus (PCF) tolerance have been undertaken for P. patula and P. patula hybrids. Controlled pollination is, however, an expensive and labour intensive exercise, which yields low numbers of viable seed. To overcome the problem of limited CP seed for commercial deployment, research into vegetative propagation has been undertaken at Sappi. By establishing cutting production hedges, we are able to supply many more plants of known genetic quality, from each seed, than through direct deployment of seedlings. Current trials involving the PCF-tolerant P. patula hybrids have shown that production and rooting in the hybrid cuttings is as good as the pure species. The PCF tolerances of the various hybrid species, predicted by the Tree Breeding Programme, translated strongly into survival differences in the production hedges in the nursery. Hedge deaths which were positively linked to PCF through screening work at the University of Pretoria (FABI) were highest in open pollinated P. patula and lowest the hybrid species selected for tolerance. High FG or PCF-tolerant plant material can thus be effectively produced and deployed into the field using cuttings.


Monitoring nutrient cycling processes in forest plantations:

The role of atmospheric deposition

Steven Dovey [email protected]

Institute for Commercial Forestry Research, PO Box 100281, Scottsville 3209

Summary

One of the aspects to consider in achieving a sustainable timber supply in the southern African forestry industry is the need to meet tree growth nutrient demands now and into the future. Sustainable forest management implies that site quality is not degraded and future land use options are not compromised. To understand nutrient supply and demand, the numerous processes affecting changes in nutrients during each plantation growth phase need to be monitored and understood. This must include the effect of management on these nutrient fluxes during each phase. Having this knowledge will allow calculation of the impact of management practices on site nutrient reserves, nutrient supply and long-term sustainability. Nutrient cycling is important in plantation forestry where addition of nutrients through processes such as mineral weathering, nitrogen (N) fixation and atmospheric deposition offset losses incurred through harvesting and indirectly through other management practices (Figure 1). The role nutrient cycling processes plays in site fertility has been described in natural forests and a few plantation forests in international literature (Smethurst, 2010; Attiwill and Adams, 1993; Binkley, 1986; Blanco et al., 2005; du Toit and Scholes, 2002; Jorgenson et al., 1975; Laclau et al., 2005; Ranger and Turpault, 1999; Wells, 1976). Here, the balance of additions, losses and fluxes within the ecosystems has been used to develop nutrient budgets that scrutinise present and future sustainable nutrient supply (Laclau et al., 2003). Natural nutrient addition may become more important in offsetting nutrient losses where high costs and environmental concerns have reduced the use of fertiliser. That is, provided that management practices do not promote or accelerate other loss mechanisms, such as soil erosion and nutrient leaching. Frequent removal of large quantities of timber on low fertility sites may lead to nutrient depletion under conditions where nutrients are not replaced by natural processes or fertilisation. In addition, further biomass removal has the potential to exacerbate nutrient loss. Little work has been done in South Africa to directly quantify nutrient cycling processes for commercial plantation forestry. This is alarming since many highly productive site are located on soils that are both highly weathered and limited in nutrient storage capacity (du Toit and Scholes, 2002). Although the contributions made by most natural processes are often too small to make any significant contribution (Jorgenson et al., 1975; Binkley, 1986; du Toit and Scholes, 2002) some research data indicates the potential of atmospheric deposition to significantly contribute certain elements in South Africa (Lowman, 2004; Olbrich, 1993; van Wyk, 1990; Zunckel et al., 2000). Atmospheric deposition is the addition of nutrients as wet deposition (precipitation, including mist interception), dry deposition (dry particulate fallout) and as foliar gaseous uptake (EPA, 2001). Compounds found in atmospheric deposition are derived primarily from industrial pollution (mainly fossil fuel burning), biomass burning, lightning and coastal windblown sea-spray or mist (Hill et al., 2005). Wet and dry atmospheric deposition can add N as organic-N compounds and mineral forms (ammonium (NH4+), nitrate (NO3-) and nitrite (NO2

-) to the ecosystem (Hill et al., 2005; Zimmermann et al., 2003). In addition, calcium (Ca), magnesium (Mg) and potassium (K) are typically added in large amounts, while only small amounts of phosphorus (P) may be added through atmospheric deposition (de Vries et al., 2003; Binkley, 1986; Ranger and Turpault, 1999). As rainfall penetrates the tree canopy, ions are exchanged between the canopy and the rainfall, resulting in either uptake of ions or leaching of ions from the tree canopy (Draaijers and Erisman, 1995). Interception and interaction of rainfall with tree canopies, which South African research has neglected in the past, may produce significantly different dry deposition fluxes (Lindberg et al., 1986) to those derived though past methods. Atmospheric deposition was assessed at three sites in post canopy closed (mature) Eucalyptus stands in the northern Dukuduku (3.5 years of data), southern KwaMbonambi (4.1 years of data) and Tweedie in the KwaZulu-Natal Midlands (1.2 years of data) commercial plantation forestry areas of South Africa. The aim of this study was to determine the magnitude and relevance of macro-nutrient addition with rainfall, throughfall and stemflow to commercial forestry in this region. Atmospheric deposition was shown to be responsible for large quantities of nutrients added to the eucalypt stands at each site. Total deposition averaged across all years at each site are given in Table 1. Although K deposition values were very high,


additions of all other nutrients, although also high, were within the ranges reported in local and international literature. The relevance and verity of the large proportion of organic-N deposited at each site may need further investigation and validation.

Table 1: Total annualised addition of macro-nutrients at each site kg ha-1 yr-1

DukuDuku Kwambonambi Tweedie*

NH4 - nitrogen 7.2 3.7 3.0

NO3 - nitrogen 3.2 0.4 7.5

Ca 7.2 14.7 9.4 Mg 3.8 12.1 6.3

K 17.3 32.8 11.4 O - nitrogen 26.6 21.2 43.1

*Tweedie only includes one year of data

Over the course of a full rotation, the atmospheric deposition levels recorded at these sites may have potential to replenish a large proportion of the nutrients that are lost during stem-wood harvesting. An example of this is shown in (Figure 2) where data collected at Dukuduku is projected to a full seven year rotation. Removal of additional biomass may reduce the role or significance that atmospheric deposition had on nutrient replacement. This study adds value to understanding of nutritional sustainability of fast growing plantation forests, demonstrating the importance of atmospheric deposition as a nutrient input source to plantation grown eucalypts along the Zululand coastal plain. This study needs to be expanded and replicated across the commercial forestry areas of South Africa, so that atmospheric deposition may be included in completing nutrient budget assessments that determine the consequences of plantation management practices to nutritional sustainability.


Atmospheric inputs

Canopy leaching

Soil leaching

Forest nutrient cycles

Storagein trees

Storagein litter layer

Storagein soil

Litterfall

DecompositionMineralisationlockup Uptake

Internal cycling

Figure 1: Simplified view of nutrient cycling in plantation forests.

Nutr

ients

(kg

ha

-1)

0

100

200

300

400

500

600

700

N K Ca Mg

BurnWhole tree harvestStem + BarkStemdeposition

Figure 2: Atmospheric Deposition and macro-nutrients in stemwood, residue and forest floor at

Dukuduku over a seven year rotation (kg ha-1)


References

Attiwill PM and Adams MA. 1993. Nutrient cycling in forests : Tansley review no. 50. New Phytol Vol. 124: 561-582

Binkley D. 1986. Forest Nutrition Management. Wiley, New York Blanco J, Zavala M, Imbert J and Castillo F. 2005. Sustainability of forest management practices:

Evaluation through a simulation model of nutrient cycling. Forest Ecology and Management 213 (1-3): 209-228. doi:10.1016/j.foreco.2005.03.042

de Vries W, Reinds GJ and Vel E. 2003. Intensive monitoring of forest ecosystems in Europe: 2: Atmospheric deposition and its impacts on soil solution chemistry. Forest Ecology and Management 174 (1-3): 97-115. doi: 10.1016/s0378-1127(02)00030-0

Draaijers GPJ and Erisman JW. 1995. A canopy budget model to assess atmospheric deposition from throughfall measurements. Water, Air and Soil Pollution 85 (4):2253-2258. doi:10.1007/bf01186169

du Toit B and Scholes MC. 2002. Nutritional sustainability of Eucalyptus plantations : A case study at Karkloof, South Africa. Southern African Forestry Journal 195: 63-72

EPA. 2001. Frequently Asked Questions About Atmospheric Deposition. A Handbook for Watershed Managers. United States Environmental Protection Agency. Office of Air Quality Planning and Standards Research, Washington, DC, Washington, DC

Hill KA, Shepson PB, Galbavy ES and Anastasio C. 2005. Measurement of wet deposition of inorganic and organic nitrogen in a forest environment. Journal of Geophysical Research 110 (G02010, doi:10.1029/2005JG000030):14. doi:10.1029/2005jg000030

Jorgenson JR, Wells CG and Metz LJ. 1975. The nutrient cycle : Key to continuous forest production. Journal Forestry 73: 400-403

Laclau J-P, Ranger J, Bouillet J-P, Nzila JdD and Deleporte P. 2003. Nutrient cycling in a clonal stand of Eucalyptus and an adjacent savanna ecosystem in Congo 1. Chemical composition of rainfall, throughfall and stemflow solutions. Forest Ecology and Management 176: 105-119

Laclau J, Ranger J, Deleporte P, Nouvellon Y, Saintandre L, Marlet S and Bouillet J. 2005. Nutrient cycling in a clonal stand of Eucalyptus and an adjacent savanna ecosystem in Congo3. Input–output budgets and consequences for the sustainability of the plantations. Forest Ecology and Management 210 (1-3): 375-391. doi:10.1016/j.foreco.2005.02.028

Lindberg SE, Lovett GM, Richter DD and Johnson DW. 1986. Atmospheric Deposition and Canopy Interactions of Major Ions in a Forest. Science 231 (4734): 141-145. doi:10.1126/science.231.4734.141

Lowman GRP. 2004. Deposition of nitrogen to grassland versus forested areas in the vicinity of Sabie, Mpumalanga. Unpublished MSc thesis. MSc Thesis, University of the Witwatersrand, Johannesburg, South Africa

Olbrich K. 1993. Final Report: The chemistry and frequency of mist events on the Eastern Transvaal escarpment. DWAF report FOR-DEA 658.

Ranger J and Turpault MP. 1999. Input-output nutrient budgets as a diagnostic tool for sustainable forest management. Forest Ecology and Management 122: 139-154

Smethurst P. 2010. Forest fertilization: Trends in knowledge and practice compared to agriculture. Plant and Soil 335: 83-100. doi:10.1007/s11104-010-0316-3

van Wyk DB. 1990. Atmospheric deposition at selected sites in the mountain catchments of South Africa. In: Proceedings of the 1st IUAPPA regional Conference on Air Pollution: Towards the 21st Century. National Association for clean air, 24-26 October 1990, Pretoria, South Africa, 1990.

Wells CG. 1976. Nutrient cycling and it's relationship to fertilization. Proc 6th South For Soils Workshop, pp 78-87

Zimmermann F, Lux H, Maenhaut W, Matschullat J, Plessow K, Reuter F and Wienhaus O. 2003. A review of air pollution and atmospheric deposition dynamics in southern Saxony, Germany, Central Europe. Atmospheric Environment 37: 671-691

Zunckel M, Robertson L, Tyson PD and Rodhe H. 2000. Modelled transport and deposition of sulphur over southern Africa. Atmos Environ 34: 2797-2808

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