Influence of Herbaceous Interference on Growth and Biomass Partitioning in Planted Loblolly Pine (Pinus taeda)

Weed Science ◽  
1990 ◽  
Vol 38 (6) ◽  
pp. 497-503 ◽  
Author(s):  
John R. Britt ◽  
Bruce R. Zutter ◽  
Robert J. Mitchell ◽  
Dean H. Gjerstad ◽  
John F. Dickson
Keyword(s):  
Leaf Area ◽  
Pinus Taeda ◽  
Loblolly Pine ◽  
Growth Efficiency ◽  
Biomass Partitioning ◽  
Lower Percentage ◽  
Total Biomass ◽  
Growth Responses ◽  
Area Index ◽  
Weed Interference

Three herbaceous regimes were established, using herbicides, to examine the effects of interference on growth and biomass partitioning in loblolly pine (Pinus taedaL.). Trees were sampled near Auburn and Tallassee, AL. Trees at the Auburn site grown with low weed interference (LWI) had 4, 10, 10, 8, and 4 times greater total aboveground biomass than did trees with high weed interference (HWI) for ages one through five, respectively. Medium weed interference (MWI, Auburn site only) resulted in three times greater biomass the first 4 yr and two times greater total biomass by the fifth year compared to trees grown with HWI. Trees growing with LWI were 5, 8, 10, and 6 times larger than those with HWI for ages one through four, respectively, at the Tallassee site. At all levels of interference, the percentage of total biomass in foliage decreased, and stem and branch components increased, with increasing tree size at both sites. Trees growing with HWI had a lower percentage of total biomass in foliage and a greater percentage of total biomass in stem than those growing with LWI when compared over a common size. Growth efficiency per tree, expressed as annual increase in stem biomass per unit leaf area (g m−2), was slightly greater for trees growing with LWI compared to HWI when leaf area index (LAI3, total surface) was less than 0.2. For LAI values greater than 0.2 the relationship was reversed. The latter contradicts the idea that growth efficiency can be used as a measure of vigor for young loblolly pine. Changes in carbon partitioning to the development of leaf area are suggested to be driving the accelerated growth responses associated with a reduction of weed interference.

Effects of ontogeny and soil nutrient supply on production, allocation, and leaf area efficiency in loblolly and slash pine stands

2000 ◽  
Vol 30 (10) ◽  
pp. 1511-1524 ◽  
Author(s):  
Eric J Jokela ◽  
Timothy A Martin
Keyword(s):  
Leaf Area ◽  
Weed Control ◽  
Loblolly Pine ◽  
Aboveground Biomass ◽  
Soil Nutrient ◽  
Growth Efficiency ◽  
Pinus Elliottii ◽  
Nutrient Supply ◽  
Slash Pine ◽  
Growth Responses

The effects of ontogeny and soil nutrient supply on aboveground biomass accumulation, allocation, and stemwood growth efficiency of loblolly (Pinus taeda L.) and slash pine (Pinus elliottii Engelm. var. elliottii) were investigated in north-central Florida over 16 years using a 2 × 2 × 2 factorial experiment (species, fertilization, weed control). Aboveground biomass growth responses to the combined fertilizer and weed control treatments (FW) averaged ~2- and 2.8-fold for slash and loblolly pine, respectively. In the same treatment, annual needlefall (NF) production for slash pine approached a "steady state" of 6 Mg·ha-1 at ages 8-14 years, while loblolly pine NF production peaked at 7 Mg·ha-1 at age 10 years, and then declined 17% following curtailment of the fertilizer treatment. Periodic stemwood biomass increment (PAI) for the FW treatment for both species culminated at about 15 Mg·ha-1·year-1 at age 8 years and then declined rapidly (~275%) to <4 Mg·ha-1·year-1 at 15 years; reductions for the untreated control were considerably slower. The progressive decline in PAI following peak leaf area development was closely associated with a decrease in stemwood production per unit leaf area (growth efficiency). A unit increase in leaf area index in the 7- to 9-year-old stands produced about 3.0 and 3.1 times more stemwood biomass per year than in the 14- to 16-year-old stands for loblolly and slash pine, respectively.

scholarly journals Validation of an Integrated Estimation of Loblolly Pine (Pinus taeda L.) Leaf Area Index (LAI) Using Two Indirect Optical Methods in the Southeastern United States

2008 ◽  
Vol 32 (3) ◽  
pp. 101-110 ◽  
Author(s):  
John S. Iiames ◽  
Russell Congalton ◽  
Andrew Pilant ◽  
Timothy Lewis
Keyword(s):  
United States ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Pinus Taeda ◽  
Loblolly Pine ◽  
Southeastern United States ◽  
Area Ratio ◽  
Allometric Equations ◽  
Area Index ◽  
Whole Tree

Abstract Quality assessment of satellite-derived leaf area index (LAI) products requires appropriate ground measurements for validation. Since the National Aeronautics and Space Administration launch of Terra (1999) and Aqua (2001), 1-km, 8-day composited retrievals of LAI have been produced for six biome classes worldwide. The evergreen needle leaf biome has been examined at numerous validation sites, but the dominant commercial species in the southeastern United States, loblolly pine (Pinus taeda), has not been investigated. The objective of this research was to evaluate an in situ optical LAI estimation technique combining measurements from the Tracing Radiation and Architecture of Canopies (TRAC) optical sensor and digital hemispherical photography (DHP) in the southeastern US P.taeda forests. Stand-level LAI estimated from allometric regression equations developed from whole-tree harvest data were compared to TRAC–DHP optical LAI estimates at a study site located in the North Carolina Sandhills Region. Within-shoot clumping, (i.e., the needle-to-shoot area ratio [γE]) was estimated at 1.21 and fell within the range of previously reported values for coniferous species (1.2–2.1). The woody-to-total area ratio (α = 0.31) was within the range of other published results (0.11–0.34). Overall, the indirect optical TRAC–DHP method of determining LAI was similar to LAI estimates that had been derived from allometric equations from whole-tree harvests. The TRAC–DHP yielded a value 0.14 LAI units below that retrieved from stand-level whole-tree harvest allometric equations. DHP alone yielded the best LAI estimate, a 0.04 LAI unit differential compared with the same allometrically derived LAI.

Monthly leaf area index estimates from point-in-time measurements and needle phenology for Pinus taeda

2003 ◽  
Vol 33 (12) ◽  
pp. 2477-2490 ◽  
Author(s):  
D A Sampson ◽  
T J Albaugh ◽  
K H Johnsen ◽  
H L Allen ◽  
S J Zarnoch
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Pinus Taeda ◽  
Loblolly Pine ◽  
Significant Treatment ◽  
Area Index ◽  
Annual Cohort ◽  
Harvest Data ◽  
Pinus Taeda L ◽  
Bud Initiation

Leaf area index (LAI) of loblolly pine (Pinus taeda L.) trees of the southern United States varies almost twofold interannually; loblolly pine, essentially, carries two foliage cohorts at peak LAI (September) and one at minimum (March–April). Herein, we present an approach that may be site invariant to estimate monthly LAI for loblolly pine using point-in-time measurements from a LI-COR LAI-2000 plant canopy analyzer (PCA). Our analyses used needle accretion and abscission data from monthly needle counts and destructive harvest data from a replicated 2 × 2 factorial experiment of water and nutrition amendments. No significant treatment effects on relative needle accretion or abscission were observed. Cohort (interannual) differences in needle accretion were found but appeared trivial. Cohort year had variable effects on needle abscission. Abscission of current-year foliage began in July and continued through November of the third year; however, only 7%–9% remained 23 months following bud initiation. A treatment-invariable regression of PCA measurements on cohort foliage biomass (r2 [Formula: see text] 0.98) was used to estimate annual cohort LAI. We derived monthly estimates of LAI from cohort accretion and abscission and cohort LAI. Monthly estimates of LAI for loblolly pine, using point-in-time measurements from the PCA, appear possible, although further testing is required.

scholarly journals Genotypic Stability Effects on Predicted Family Responses to Silvicultural Treatments in Loblolly Pine

1997 ◽  
Vol 21 (2) ◽  
pp. 84-89 ◽  
Author(s):  
Steven E. McKeand ◽  
Robert P. Crook ◽  
H. Lee Allen
Keyword(s):  
Pinus Taeda ◽  
Loblolly Pine ◽  
Growth Responses ◽  
Intensive Culture ◽  
Genotype By Environment ◽  
Silvicultural Treatments ◽  
Genotypic Stability ◽  
Superior Genotypes ◽  
Using Data ◽  
Pinus Taeda L

Abstract The lack of rank change in growth characteristics when open-pollinated families of loblolly pine (Pinus taeda L.) are planted on different sites in the Southeast has greatly simplified breeding for superior genotypes. Although family rank does not usually change, genotype by environment interactions (GxE) may be very important in operational deployment of families in regeneration programs. Using data from GxE trials and two site preparation-fertilization-herbicide trials, we estimated the growth that different families should achieve following application of these silvicultural practices. Better performing families tend to be most responsive to site changes (i.e. genetically unstable). Growth responses to silvicultural treatment will be overestimated if only the most responsive families are used in silvicultural research trials. Similarly, genetic gains will be overestimated if gain trials are planted on only the best sites or receive intensive culture. South. J. Appl. For. 21(2):84-89.

Leaf Area Index (LAI) of Loblolly Pine and Emergent Vegetation Following a Harvest

2011 ◽  
Vol 54 (6) ◽  
pp. 2057-2066 ◽  
Author(s):  
D. A. Sampson ◽  
D. M. Amatya ◽  
C. D. Blanton Lawson ◽  
R. W. Skaggs
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Loblolly Pine ◽  
Emergent Vegetation ◽  
Area Index

Response of aboveground biomass increment, growth efficiency, and foliar nutrients to thinning, fertilization, and pruning in young Douglas-fir plantations in the central Oregon Cascades

1992 ◽  
Vol 22 (9) ◽  
pp. 1278-1289 ◽  
Author(s):  
Alejandro Velazquez-Martinez ◽  
David A. Perry ◽  
Tom E. Bell
Keyword(s):  
Leaf Area ◽  
Aboveground Biomass ◽  
Cultural Practices ◽  
Growth Efficiency ◽  
Douglas Fir ◽  
Nitrogen And Phosphorus ◽  
Area Index ◽  
Biomass Increment ◽  
Oregon Cascades

The effect of thinning and cultural practices (multinutrient fertilization, pruning) on total aboveground biomass increment and growth efficiency was studied over three consecutive 2-year periods (1981–1987) in young Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) plantations. Net aboveground biomass increment over the 6-year period averaged 14.5, 7.8, and 5.5 Mg•ha−1•year−1 for the high-, medium-, and low-density plots, respectively. Growth efficiency, after dropping sharply between leaf area indexes of 1 and 6 m2/m2, remained relatively constant up to a leaf area index of 17, the highest measured. Consequently, aboveground biomass increment continued to increase at leaf area indexes well above that at which the Beer–Lambert law predicts maximum light should be absorbed. Foliage analyses indicate that thinning improved nitrogen, potassium, and magnesium nutrition and increased the translocation of potassium from 1-year-old foliage to support new growth. However, fertilization increased foliar nitrogen and phosphorus contents only when coupled with pruning, suggesting that trees favor total leaf area over individual needle nutrition. Indications of potassium and magnesium limitations in this study are supported by other recent studies in Douglas-fir. Further work on the role of multinutrient deficiencies in this species is warranted.

scholarly journals Simulated insect defoliation and duration of weed interference affected soybean growth

Weed Science ◽  
2006 ◽  
Vol 54 (4) ◽  
pp. 735-742 ◽  
Author(s):  
Travis C. Gustafson ◽  
Stevan Z. Knezevic ◽  
Thomas E. Hunt ◽  
John L. Lindquist
Keyword(s):  
Leaf Area ◽  
Defense Mechanism ◽  
Field Studies ◽  
Area Index ◽  
Early Season ◽  
Weed Interference ◽  
Insect Defoliation ◽  
Weed Growth ◽  
Simultaneous Control ◽  
Vegetative And Reproductive Growth

An improved understanding of crop stress from multiple pests is needed for better implementation of integrated pest management (IPM) strategies. Field studies were conducted in 2003 and 2004 at two locations in eastern Nebraska to describe the effects of simulated early-season insect defoliation of soybean and duration of weed interference on soybean growth. Three levels of simulated defoliation (undefoliated, 30, and 60%) and seven durations of weed interference (weedy and weed free; weed removal at V2, V4, V6, R3, and R5) were evaluated in a split-plot design. Defoliation significantly reduced soybean leaf-area index (LAI), total dry matter (TDM), and crop height in season-long weedy treatments only. Biomass partitioning during vegetative and reproductive growth was affected by both defoliation and weed interference. Increase in soybean relative growth rate (RGR) and biomass production soon after defoliation occurred (e.g., V5 stage) indicated potential defense mechanism by which soybean is able to adjust its physiology in response to the loss of leaf area. Weed interference combined with defoliation caused the greatest yield losses up to 97%. Results from this study indicate the need for monitoring early-season insect density and weed growth to determine if simultaneous control of both pests may be needed.

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