A framework for modeling the dynamics of first-order branches and spatial distribution of knots in loblolly pine trees

2009 ◽  
Vol 39 (3) ◽  
pp. 566-579 ◽  
Author(s):  
Guillermo Trincado ◽  
Harold E. Burkhart

A stochastic model to simulate the processes of initiation, diameter growth, death, and self-pruning of branches in loblolly pine ( Pinus taeda L.) trees is presented. Information on whorl formation and branch growth was obtained from destructive sampling of whorl sections from 34 trees growing under 10 different initial spacings. Three different components were modeled and hierarchically connected: whorl, branches, and knots. For each new growing season, whorls and branches are assigned stochastically along and around the stem. Thereafter, branch diameter growth is predicted as a function of relative location within the live crown and stem growth. The branch model was linked to an individual-tree growth model, PTAEDA3.1, to simulate the dynamics of first-order branches arising from the main stem. Information on (i) vertical trend of branch diameter along and around the stem, (ii) volume of knots (live and dead portions), and (iii) spatial location, size, and type (live and dead) of knots can be obtained. In its current stage, the framework allows evaluation of the quality of trees and sawlogs produced, inclusion of additional wood properties, and linkage with industrial conversion processes (e.g., sawing simulation). However, further research is needed to obtain data on branch dynamics to validate the overall performance of the model and improve developed submodels.

2018 ◽  
Vol 65 (3) ◽  
pp. 312-323
Author(s):  
Nicole J Hornslein ◽  
Courtney M Siegert ◽  
Heidi J Renninger

AbstractThe southeastern United States contains extensive loblolly pine (Pinus taeda L.) plantations at risk from bark beetle damage that can change ecosystem biogeochemical cycling. Functional changes in tree physiology have the potential to occur before visual evidence of mortality making them difficult to incorporate into ecosystem models. Therefore, we girdled loblolly pines to simulate bark beetle damage and measured physiological processes including sapflow rates, photosynthesis, litterfall, and needle nitrogen concentrations to determine the physiological changes occurring in trees undergoing mortality. We found that the girdling treatment took 5 months to significantly reduce sapflow rates but visual crown mortality occurred more than one year after girdling. Girdled pines had approximately 2.5 times lower water use than control pines and exhibited greater susceptibility to atmospheric water stress. Girdled and control pines had similar needle nitrogen concentrations and photosynthetic rates measured during the mortality year. However, more litterfall with higher nitrogen concentrations occurred in the mortality year than in the previous year, resulting in redistribution of carbon and nitrogen in the ecosystem. Overall, these data allow for better quantification of the effects of background disturbance levels and individual tree mortality on water, carbon, and nitrogen cycling within a loblolly pine ecosystem.


2021 ◽  
Vol 491 ◽  
pp. 119176
Author(s):  
Michael A. Blazier ◽  
Thomas Hennessey ◽  
Laurence Schimleck ◽  
Scott Abbey ◽  
Ryan Holbrook ◽  
...  

2019 ◽  
Vol 43 (2) ◽  
Author(s):  
Mário Dobner Jr ◽  
Dagoberto Stein de Quadros

ABSTRACT Approximately 1.6 million hectares of southern Brazil are cultivated with pines, and mainly with the loblolly pine (Pinus taeda L.). More than one third of the stands belong to independent log producers, whose aim is to maximize their economic results. In this study, a thinning experiment was evaluated over a production period of 30 years. The stands evaluated were submitted to three different crown thinning intensities, with an unthinned stand used as a control. The aim of the study was to evaluate economic criteria regarding realistic discount rates and production periods varying between 16-30 years. For the circumstances that were evaluated, 'extreme' and early release from competition of pruned loblolly pine trees lead to the best economic performance (land expectation value = ~36,000 US$ ha-1, i = 3% yr-1). Stands subjected to crown thinnings, independently of intensity, produced three times the economic output of unthinned and unpruned stands. Although the optimal harvest ages, according to the internal rate of return, are between 18-22 years for thinned and unthinned stands, from a long-term perspective (land expectation value) and for the current relationship between log price and size, the optimal economic performance requires that production periods are extended (to 24-26 years) from those currently practised in southern Brazil (15-20 years).


1989 ◽  
Vol 13 (4) ◽  
pp. 170-174 ◽  
Author(s):  
Ralph L. Amateis ◽  
Harold E. Burkhart ◽  
Terese A. Walsh

Abstract Individual tree dbh increment and survival equations were developed for predicting annual dbh growth and annual probability of survival of loblolly pine trees in thinned and unthinned plantations on cutover, site-prepared lands. The dbh increment equation predicts dbh increment froma potential dbh growth function multiplied by a modifier function. The survival equations predicts the probability of survival as a function of crown ratio and the tree's competitive position in the stand. When used together, the equations should be useful to foresters interested in predictingfuture dbh and survival values for both thinned and unthinned stand conditions. South. J. Appl. For. 13(4):170-174.


1982 ◽  
Vol 6 (4) ◽  
pp. 215-217 ◽  
Author(s):  
G. L. Wheeler ◽  
F. M. Meade ◽  
M. W. Russell

Abstract A thinning and fertilizing study was established in an 11-year-old loblolly pine (Pinus taeda L.) plantation. Half of the plots were row thinned, removing 50 percent of the trees; plots were split and half were fertilized at a per acre rate of 100 pounds nitrogen, 50 pounds phosphorous and 50 pounds potassium. There was no response of height, d.b.h. or volume growth to fertilizer. Thinning increased diameter growth but decreased volume growth. The trees have shown exceptional growth. At age 17 the height was 49 feet, d.b.h. 7.3 inches and stocking 2,490 cubic feet on the thinned plots. The respective values for the unthinned plots were 48 feet, 6.7 inches, and 3,960 cubic feet.


2005 ◽  
Vol 35 (1) ◽  
pp. 85-92 ◽  
Author(s):  
P D Jones ◽  
L R Schimleck ◽  
G F Peter ◽  
R F Daniels ◽  
A Clark III

Preliminary studies based on small sample sets show that near infrared (NIR) spectroscopy has the potential for rapidly estimating many important wood properties. However, if NIR is to be used operationally, then calibrations using several hundred samples from a wide variety of growing conditions need to be developed and their performance tested on samples from new populations. In this study, 120 Pinus taeda L. (loblolly pine) radial strips (cut from increment cores) representing 15 different sites from three physiographic regions in Georgia (USA) were characterized in terms of air-dry density, microfibril angle (MFA), and stiffness. NIR spectra were collected in 10-mm increments from the radial longitudinal surface of each strip and split into calibration (nine sites, 729 spectra) and prediction sets (six sites, 225 spectra). Calibrations were developed using untreated and mathematically treated (first and second derivative and multiplicative scatter correction) spectra. Strong correlations were obtained for all properties, the strongest R2 values being 0.83 (density), 0.90 (MFA), and 0.93 (stiffness). When applied to the test set, good relationships were obtained (Rp2 ranged from 0.80 to 0.90), but the accuracy of predictions varied depending on math treatment. The addition of a small number of cores from the prediction set (one core per new site) to the calibration set improved the accuracy of predictions and importantly minimized the differences obtained with the various math treatments. These results suggest that density, MFA, and stiffness can be estimated by NIR with sufficient accuracy to be used in operational settings.


2001 ◽  
Vol 31 (5) ◽  
pp. 919-923 ◽  
Author(s):  
Maxine T Highsmith ◽  
John Frampton ◽  
David O'Malley ◽  
James Richmond ◽  
Martesa Webb

Tip moth damage among families of parent pine species and their interspecific F1 hybrids was quantitatively assessed in a coastal planting in North Carolina. Three slash pine (Pinus elliotti var. elliotti Engelm.), two loblolly pine (Pinus taeda L.), and four interspecific F1 hybrid pine families were used. The F1 hybrids were as susceptible to damage by Nantucket pine tip moth (Rhyacionia frustrana (Comst.)), as was their susceptible loblolly pine parent. Their phenotypes support a dominant or partially dominant mode of inheritance for susceptibility. The phenotype of one slash pine family was not statistically different from the phenotypes of the loblolly and F1 hybrid pines. The high susceptibility of that one slash pine family appeared to be intrinsic, even though slash pine is considered resistant to tip moth damage. Tip moth damage on the two other slash pine families was significantly lower.


2002 ◽  
Vol 104 (2) ◽  
pp. 214-222 ◽  
Author(s):  
M. M. Sewell ◽  
M. F. Davis ◽  
G. A. Tuskan ◽  
N. C. Wheeler ◽  
C. C. Elam ◽  
...  

1998 ◽  
Vol 28 (9) ◽  
pp. 1344-1351 ◽  
Author(s):  
Hubert Sterba ◽  
Ralph L Amateis

Crown efficiency was first defined by Assmann (1961. Waldertragskunde. BLV, München) as individual tree volume increment per unit of crown projection area. He hypothesized that within a given crown class, smaller crowns are more efficient because their ratio between crown surface and horizontal crown projection is higher. Data from a loblolly pine (Pinus taeda L.) spacing experiment were used to test if this hypothesis also holds in young loblolly pine stands and, if so, to determine if it explains the increment differences between spacings in the spacing experiment. Using individual tree height relative to plot dominant height to describe crown class, within-plot regression showed that crown efficiency decreased with crown size for trees below dominant height. This relationship was much less pronounced than indicated from Assmann's examples, although the crown surface to crown projection ratio behaved in the same way as Assmann had hypothesized. Crown efficiency as well as the crown surface to crown projection area ratio decreased with increasing density. Basal area increment per hectare increased until total crown closure approached 130% and then stayed constant. This major impact of total crown coverage brings into question the usefullness of crown efficiency as an indicator for unit area growth.


1989 ◽  
Vol 13 (4) ◽  
pp. 181-184 ◽  
Author(s):  
Roger A. Williams

Abstract A previously developed sampling method utilizing randomized branch and importance sampling for the purpose of quickly estimating tree biomass was tested on five loblolly pine (Pinus taeda L.) trees. Results show a wide range of per-tree sampling error, ranging from 5.3 to 28.9%. Largevariation in foliage content among selected branches per treee may be a major source of error. However, the sampling error for the total biomass of the five trees tested was only 3.3%. This sampling method appears to be reliable and efficient in obtaining precise estimates of the total biomassof a population of trees. Increased sampling intensity per tree is necessary to obtain precise estimates of individual tree biomass. South. J. Appl. For. 13(4):181-184.


Sign in / Sign up

Export Citation Format

Share Document