Pest pressure, site conditions, hurricanes, and genetics ...
1
Pest pressure, site conditions, hurricanes, and genetics affect stem morphology in young lob- lolly pine (Pinus taeda L.) plantations in the upper and lower coastal plains of North Carolina Alexia M. Kelley and John S. King Department of Forestry and Environmental Resources, North Carolina State University Loblolly pine ( • Pinus taeda L.) is one of the most important crops in the southeastern US, comprising 45% of the area’s commercial forestry land. Improving the productivity and quality of loblolly pines through genetics and site management practices will ensure the success of this region’s economy. Stem defects, such as stem forking, can reduce the quality of the timber product. In this study we examined the • role of genetics and site management practices (such as Nantucket Pine Tip Moth (Rhyacionia frustrana (Com- stock) control and herbicide/fertilizer use) on stem defects at two sites in the upper and lower coastal plains of North Carolina. Additionally, we were interested in how the experimental treatments affected • stem response to Hurricane Irene at our site in the lower coastal plain. Introduction Experimental Design In late 2008, we established a stand-level study examining the impacts of the following treatments on loblolly • pine trees at two sites in the upper and lower costal plains of North Carolina (UCP and LCP, respectively): – Improved pine genetics: 2 full-sib genotypes (C1 and C2) and two clones (V1 and V2) – Tip moth control with SilvaShield, an insecticide containing imidacloprid (control and treated) – Resource availability (low and high phosphorus fertilization treatments at LCP and low and high herbicide treatments at UCP). Acknowledgements Funding for this project was been provided by Bayer Environmental Sciences. The following NCSU undergraduates helped collect date for this project: Jordan Siminitz, Matt Ziglar, Garrett Lewis, Sam Griffith, and Brian Johnson. Results and Discussion Tree Stem Response to Hurricane Irene’s Influence V1 was most strongly affected by Hur- • ricane Irene, with a greater percentage of trees leaning more than >30°. Pri- or to the hurricane, this genotype had the tallest trees, possibly making them more susceptible to hurricane winds. There was a reduction in the hurricane • effects on C1 with tip moth protection, indicating that tip moth pressure may make this genotype more susceptible to hurricane damage. Conclusions Our study shows that site-specific genotype selection has the ability to reduce the occurrences of stem defects. • This management strategy will add in the success of both planation resilience to biotic (e.g. tip moth pest pressure) and abiotic (e.g. hurricane winds) environmental variables on timber quality, and thereby increasing the chances of plantation success. Stem Defects in Response to Plantation Management Strategies Trees at the LCP site permanently bent due to the high winds of Hurricane Irene (2011). Loblolly tree with a major stem fork at the UCP field site. Loblolly tree with multiple stem forks and a severe fusiform rust in- fection. On August 27, 2011, Hurricane Irene made landfall on the coastal North Carolina, resulting in high winds at • the LCP site near Jacksonville, NC, that caused the stems of many of the experimental trees to be permanent- ly bent. In December 2011, we categorized the degree of “leaning” of each tree as follows: no leaning, >0°- 15°, >15°-30°, >30°-45°, >45°. To determine the effects of our treatments of stem morphology, we surveyed 9 trees in each of our experi- • mental plots for stem defects, which were defined as the presence of one or more stem forks or ramicorn branches in March 2013. Left: Adult Nantucket pine tip moth (Rhyacionia frus- trana). Right: Example of dam- aged pine bud caused by Nantucket pine tip moth. C1 C2 V1 V2 600 400 200 100 300 500 0 Height (cm) C1 C2 V1 V2 LCP UCP Low Herbicide, No Insecticide Low Herbicide, Insecticide High Herbicide, No Insecticide High Herbicide, Insecticide No Insecticide (Control) Insecticide 60 40 20 50 0 % of Trees with Stem Forks 30 10 C1 V2 V1 C2 LCP C1 V2 V1 C2 UCP 80 40 20 60 0 Low Herbicide High Herbicide C1 V2 V1 C2 UCP % of Trees with Stem Forks C1 V2 V1 C2 UCP Control Insecticide Tree Growth in response to Plantation Management Strategies Tip moth control resulted in taller trees • at both LCP (p=0.0569) and UCP (p=0.0278), indicating that tip moth pressure significantly reduces plantation productivity at both sites. Genetic differences also resulted in variation in tree height • . However the patterns differed at the two field sites with V1 being the tallest at UCP, while C1 was significantly taller than C1 at LCP. Additionally, the low herbicide treatment resulted in taller trees at UCP. • Genetic differences are a key determinant in the occurrence of • stem defects. However, the susceptibility of genotype to stem defects may vary by geographic location. At the LCP, we found that C2 experienced nearly twice as many stem defects as the other genotypes. At UCP, C1 had the greatest number of trees with defects and C2 the fewest. At UCP, an interaction between genetics and insecticide use re- • sulted in V1 and V2 having fewer trees with stem defects with tip moth control use. This indicates tip moth pressure may be partially responsible for increased stem defects. Additionally, an interaction between genetics and herbicide use • resulted in C1 and V2 having more stem defects with high her- bicide. Some studies have found that increased herbicide use can result in great tip moth pressure, which could have resulted in more stem defects. 0° >0°- 15° >45° >15°- 30° >30° -45° 0° >0°- 15° >45° >15°- 30° >30° -45° 0° >0°- 15° >45° >15°- 30° >30° -45° 0° >0°- 15° >45° >15°- 30° >30° -45° C1 V2 V1 C2 60 0 40 20 % Trees in each leaning category Control Insecticide Genetic Differences between Sites Site Management Practices at UCP
Transcript of Pest pressure, site conditions, hurricanes, and genetics ...
Pest pressure, site conditions, hurricanes, and genetics affect stem morphology in young lob-lolly pine (Pinus taeda L.) plantations in the upper and lower coastal plains of North Carolina
Alexia M. Kelley and John S. KingDepartment of Forestry and Environmental Resources, North Carolina State University
Loblolly pine (• Pinus taeda L.) is one of the most important crops in the southeastern US, comprising 45% of the area’s commercial forestry land. Improving the productivity and quality of loblolly pines through genetics and site management practices will ensure the success of this region’s economy.
Stem defects, such as stem forking, can reduce the quality of the timber product. In this study we examined the •role of genetics and site management practices (such as Nantucket Pine Tip Moth (Rhyacionia frustrana (Com-stock) control and herbicide/fertilizer use) on stem defects at two sites in the upper and lower coastal plains of North Carolina.
Additionally, we were interested in how the experimental treatments affected • stem response to Hurricane Irene at our site in the lower coastal plain.
Introduction
Experimental DesignIn late 2008, we established a stand-level study examining the impacts of the following treatments on loblolly •pine trees at two sites in the upper and lower costal plains of North Carolina (UCP and LCP, respectively):
– Improved pine genetics: 2 full-sib genotypes (C1 and C2) and two clones (V1 and V2)– Tip moth control with SilvaShield, an insecticide containing imidacloprid (control and treated) – Resource availability (low and high phosphorus fertilization treatments at LCP and low and high herbicide treatments at UCP).
AcknowledgementsFunding for this project was been provided by Bayer Environmental Sciences. The following NCSU undergraduates helped collect date forthisproject:JordanSiminitz,MattZiglar,GarrettLewis,SamGriffith,andBrianJohnson.
Results and Discussion
Tree Stem Response to Hurricane Irene’s InfluenceV1 was most strongly affected by Hur-•ricane Irene, with a greater percentage of trees leaning more than >30°. Pri-or to the hurricane, this genotype had the tallest trees, possibly making them more susceptible to hurricane winds.
There was a reduction in the hurricane •effects on C1 with tip moth protection, indicating that tip moth pressure may make this genotype more susceptible to hurricane damage.
ConclusionsOurstudyshowsthatsite-specificgenotypeselectionhastheabilitytoreducetheoccurrencesofstemdefects.•This management strategy will add in the success of both planation resilience to biotic (e.g. tip moth pest pressure) and abiotic (e.g. hurricane winds) environmental variables on timber quality, and thereby increasing the chances of plantation success.
Stem Defects in Response to Plantation Management Strategies
Trees at the LCP site permanently bent due to the high winds of Hurricane Irene (2011).
Loblolly tree with a major stem fork attheUCPfieldsite.
Loblolly tree with multiple stem forks and a severe fusiform rust in-fection.
On August 27, 2011, Hurricane Irene made landfall on the coastal North Carolina, resulting in high winds at •the LCP site near Jacksonville, NC, that caused the stems of many of the experimental trees to be permanent-ly bent. In December 2011, we categorized the degree of “leaning” of each tree as follows: no leaning, >0°-15°, >15°-30°, >30°-45°, >45°.
To determine the effects of our treatments of stem morphology, we surveyed 9 trees in each of our experi-•mentalplotsforstemdefects,whichweredefinedasthepresenceofoneormorestemforksorramicornbranches in March 2013.
Left: Adult Nantucket pine tip moth (Rhyacionia frus-trana).
Right: Example of dam-aged pine bud caused by Nantucket pine tip moth.
C1 C2 V1 V2
600
400
200
100
300
500
0
Hei
ght (
cm)
C1 C2 V1 V2
LCP UCP Low Herbicide, No Insecticide
Low Herbicide, Insecticide
High Herbicide, No Insecticide
High Herbicide, Insecticide
No Insecticide (Control)
Insecticide
60
40
20
50
0%
of T
rees
with
Ste
m F
orks
30
10
C1 V2V1C2
LCP
C1 V2V1C2
UCP80
40
20
60
0
Low Herbicide
High Herbicide
C1 V2V1C2
UCP
% o
f Tre
es w
ith S
tem
For
ks
C1 V2V1C2
UCP Control
Insecticide
Tree Growth in response to Plantation Management Strategies
Tip moth control resulted in taller trees• at both LCP (p=0.0569) and UCP(p=0.0278),indicatingthattipmothpressuresignificantlyreducesplantation productivity at both sites.
Genetic differences also resulted in variation in tree height• . However thepatternsdifferedatthetwofieldsiteswithV1beingthetallestatUCP,whileC1wassignificantlytallerthanC1atLCP.
Additionally, the low herbicide treatment resulted in taller trees at UCP. •
Genetic differences are a key determinant in the occurrence of •stem defects. However, the susceptibility of genotype to stem defects may vary by geographic location. At the LCP, we found that C2 experienced nearly twice as many stem defects as the other genotypes. At UCP, C1 had the greatest number of trees with defects and C2 the fewest.
At UCP, an interaction between genetics and insecticide use re-•sulted in V1 and V2 having fewer trees with stem defects with tip moth control use. This indicates tip moth pressure may be partially responsible for increased stem defects.
Additionally, an interaction between genetics and herbicide use •resulted in C1 and V2 having more stem defects with high her-bicide. Some studies have found that increased herbicide use can result in great tip moth pressure, which could have resulted in more stem defects.
0° >0°-15°
>45°>15°-30°
>30°-45°
0° >0°-15°
>45°>15°-30°
>30°-45°
0° >0°-15°
>45°>15°-30°
>30°-45°
0° >0°-15°
>45°>15°-30°
>30°-45°
C1 V2V1C260
0
40
20
% T
rees
in e
ach
lean
ing
cate
gory
ControlInsecticide
Genetic Differences between Sites Site Management Practices at UCP
