Individual-tree diameter growth models for quantifying within-stand response to nitrogen fertilization

1990 ◽  
Vol 20 (8) ◽  
pp. 1149-1155 ◽  
Author(s):  
Bahman Shafii ◽  
James A. Moore ◽  
James D. Newberry
Keyword(s):  
Growth Models ◽  
Stand Density ◽  
Simulation Models ◽  
Diameter Growth ◽  
Individual Tree ◽  
Diameter Increment ◽  
Prognosis Model ◽  
Using Data ◽  
Individual Trees ◽  
Northern Idaho

Diameter-increment models for nitrogen-fertilized stands were developed using data from permanent research plots in northern Idaho. The equations partially resembled PROGNOSIS model diameter growth formulations. Results indicated that both initial tree size and initial stand density produced significant interactions with treatment to explain an individual tree's response to fertilization. Larger trees in a stand showed more fertilization response than smaller trees. Furthermore, individual trees in low-density stands showed more fertilization response than those growing in high-density stands. These diameter increment predictive equations were formulated to be compatible with individual-tree distance-independent simulation models.

scholarly journals Effect of thinning on the diameter increment in black locust (Robinia pseudoacacia L.) stands

2000 ◽  
Vol 65 ◽  
Author(s):  
K. Redei ◽  
H. Meilby
Keyword(s):  
Black Locust ◽  
Robinia Pseudoacacia ◽  
Stand Density ◽  
Control Plot ◽  
The Other ◽  
Diameter Growth ◽  
Diameter Increment ◽  
The Past ◽  
Robinia Pseudoacacia L ◽  
Individual Trees

Black  locust is one of the most important stand forming species in Hungary,  covering    approximately 20% of the forested land (340 thousand ha) and providing 25%  of the annual    timber cut of the country. Hence, during the past two decades several  experiments with this    species have been carried out. This paper investigates the influence of  thinning on the diameter    increment in an experiment including four plots. One plot was left as an  unthinned control plot    and three plots were thinned with various thinning intensities at age 22.  The experiment was    measured at ages 22, 27, 32, and 36. Apparently the thinning intensities  applied on two of the plots did not come up to the intensity required to influence the diameter growth of the remaining    upper-storey trees. Therefore, for a given tree size the growth of the  trees on these two plots did    not differ significantly from the growth of similar trees in the unthinned  plot. By contrast,    significant thinning effects on the diameter increment of individual trees  were observed on the    most heavily thinned plot. Here the diameter increment was enhanced for  trees with diameters of    less than 20 cm, whereas the largest trees of the stand exhibited reduced  growth. Apparently a    stand density corresponding to the heavy thinning treatment (Fw values of 22-23) is  required to    get a significant thinning response. On the other hand, to avoid thinning  shocks, it may be    recommendable to apply two moderate thinning treatments instead of a single  heavy one.

scholarly journals Precommercial Thinning Increases Spruce Yields in Boreal Mixedwoods in Alberta, Canada

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 412
Author(s):  
Ivan Bjelanovic ◽  
Phil Comeau ◽  
Sharon Meredith ◽  
Brian Roth
Keyword(s):  
Growth Models ◽  
Growth And Yield ◽  
Diameter Growth ◽  
Growth Responses ◽  
Projection System ◽  
Precommercial Thinning ◽  
Thinning Intensity ◽  
Boreal Mixedwoods ◽  
Using Data ◽  
Mixedwood Stands

A few studies in young mixedwood stands demonstrate that precommercial thinning of aspen at early ages can improve the growth of spruce and increase stand resilience to drought. However, information on tree and stand responses to thinning in older mixedwood stands is lacking. To address this need, a study was initiated in 2008 in Alberta, Canada in 14 boreal mixedwood stands (seven each at ages 17 and 22). This study investigated growth responses following thinning of aspen to five densities (0, 1000, 2500, 5000 stems ha−1 and unthinned (control)). Measurements were collected in the year of establishment, and three and eight years later. Mortality of aspen in the unthinned plots was greater than in the thinned plots which were not significantly different amongst each other. Eight years following treatment, aspen diameter was positively influenced by thinning, while there was no effect on aspen height. The density of aspen had no significant effect on the survival of planted spruce. Spruce height and diameter growth increased with both aspen thinning intensity and time since treatment. Differentiation among treatments in spruce diameter growth was evident three years from treatment, while differentiation in height was not significant until eight years following treatment. Yield projections using two growth models (Mixedwood Growth Model (MGM) and Growth and Yield Projection System (GYPSY)) were initialized using data from the year eight re-measurements. Results indicate that heavy precommercial aspen thinning (to ~1000 aspen crop trees ha−1) can result in an increase in conifer merchantable volume without reducing aspen volume at the time of harvest. However, light to moderate thinning (to ~2500 aspen stems ha−1 or higher), is unlikely to result in gains in either deciduous or conifer merchantable harvest volume over those of unthinned stands.

scholarly journals Individual-Tree Diameter Growth Models for Mixed Nothofagus Second Growth Forests in Southern Chile

Forests ◽  
2017 ◽  
Vol 8 (12) ◽  
pp. 506 ◽  
Author(s):  
Paulo Moreno ◽  
Sebastian Palmas ◽  
Francisco Escobedo ◽  
Wendell Cropper ◽  
Salvador Gezan
Keyword(s):  
Growth Models ◽  
Diameter Growth ◽  
Southern Chile ◽  
Individual Tree ◽  
Tree Diameter ◽  
Second Growth ◽  
Diameter Growth Models

Incorporating intertree competition into an ecosystem model

1995 ◽  
Vol 25 (3) ◽  
pp. 413-424 ◽  
Author(s):  
R.L. Korol ◽  
S.W. Running ◽  
K.S. Milner
Keyword(s):  
Process Model ◽  
Basal Area ◽  
Stand Density ◽  
Tree Height ◽  
Ecosystem Model ◽  
Growth And Yield ◽  
Maintenance Respiration ◽  
Tree Diameter ◽  
Diameter Increment ◽  
Individual Trees

Current research suggests that projected climate change may influence the growth of individual trees. Therefore, growth and yield models that can respond to potential changes in climate must be developed, TREE-BGC, a variant of the ecosystem process model FOREST-BGC, calculates the cycling of carbon, water, and nitrogen in and through forested ecosystems. TREE-BGC allocates stand-level estimates of photosynthesis to "each tree using a competition algorithm that incorporates tree height, relative radiation-use efficiency, and absorbed photosynthetically active radiation, TREE-BGC simulated the growth of trees grown in a dense and an open stand of interior Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) near Kamloops, B.C. The competition algorithm dynamically allocated stand estimates of photosynthesis to individual trees, and the trees were grown using an allometric relationship between biomass increment and height and diameter increment. Asymptotic height growth and the changes in the height–diameter relationship with competition were also incorporated in the model algorithms. Sapwood and phloem volume were used to calculate maintenance respiration. Predicted reductions in diameter growth with stand density were similar to those observed in the study stands. Although the carbon balance of individual trees was not tested, simulated tree diameter increments and height increments were correlated with the actual measurements of tree diameter increment (r2 = 0.89) and tree height increment (r2 = 0.78) for the 5-year period (n = 352). Although the model did not work well with trees that had diameters <5 cm, the model would be appropriate for a user who required an accuracy of ± 0.03 m3•ha−1 for volume, ± 0.02 m2•ha−1 for basal area, or ± 0.4 m for tree height over a 5-year period.

scholarly journals Individual Tree Diameter Growth Models of Larch–Spruce–Fir Mixed Forests Based on Machine Learning Algorithms

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 187 ◽  
Author(s):  
Qiangxin Ou ◽  
Xiangdong Lei ◽  
Chenchen Shen
Keyword(s):  
Machine Learning ◽  
Tree Growth ◽  
Growth Models ◽  
Tree Size ◽  
Diameter Growth ◽  
Individual Tree ◽  
Mixed Forests ◽  
Tree Diameter ◽  
Individual Tree Growth ◽  
The Individual

Individual tree growth models are flexible and commonly used to represent growth dynamics for heterogeneous and structurally complex uneven-aged stands. Besides traditional statistical models, the rapid development of nonparametric and nonlinear machine learning methods, such as random forest (RF), boosted regression tree (BRT), cubist (Cubist) and multivariate adaptive regression splines (MARS), provides a new way for predicting individual tree growth. However, the application of these approaches to individual tree growth modelling is still limited and short of a comparison of their performance. The objectives of this study were to compare and evaluate the performance of the RF, BRT, Cubist and MARS models for modelling the individual tree diameter growth based on tree size, competition, site condition and climate factors for larch–spruce–fir mixed forests in northeast China. Totally, 16,619 observations from long-term sample plots were used. Based on tenfold cross-validation, we found that the RF, BRT and Cubist models had a distinct advantage over the MARS model in predicting individual tree diameter growth. The Cubist model ranked the highest in terms of model performance (RMSEcv [0.1351 cm], MAEcv [0.0972 cm] and R2cv [0.5734]), followed by BRT and RF models, whereas the MARS ranked the lowest (RMSEcv [0.1462 cm], MAEcv [0.1086 cm] and R2cv [0.4993]). Relative importance of predictors determined from the RF and BRT models demonstrated that the competition and tree size were the main drivers to diameter growth, and climate had limited capacity in explaining the variation in tree diameter growth at local scale. In general, the RF, BRT and Cubist models are effective and powerful modelling methods for predicting the individual tree diameter growth.

Modelling growing space requirement for Alnus nepalensis D. Don in Nepal

1970 ◽  
Vol 16 (2) ◽  
pp. 30-36 ◽  
Author(s):  
Ram Prasad Sharma
Keyword(s):  
Prediction Models ◽  
Growth Models ◽  
Basal Area ◽  
Individual Tree ◽  
Area Density ◽  
Space Requirement ◽  
Space Model ◽  
Alnus Nepalensis ◽  
Crown Diameter ◽  
Individual Trees

Relationship between crown diameter and stem diameter of individual trees can be translated into mathematical model, and used to generate information of growing space requirement for individual trees and crown competition index for growth models. Nine different crown diameter prediction models were developed using inventory data of Alnus nepalensis trees from a part of Parbat and Syanja districts in Nepal. Among those developed, a non-linear three parameter-based model (W = β0 {1 – exp( - β1D)}β2) explained the greatest proportion of variations of crown diameter (R2adj = 0.78), and showed desirable behaviour of flexibility and robustness. An individual tree growing space model was then derived from crown model to generate important information of shocking limits and stand basal area density for monoculture plantation or natural stands of Alnus nepalensis. Because of its flexibility, crown model is seemed potentially useful for extrapolation purpose also. However, the model cannot be applied for buttressed, wolfed and malformed trees. Key words: Alnus nepalensis; crown model; growing space model; stocking limit; basal area density Banko Janakari Vol.16(2) 2006 pp.30-36

Performance and comparison of stand growth models based on individual tree and diameter-class growth

1979 ◽  
Vol 9 (2) ◽  
pp. 231-244 ◽  
Author(s):  
Alan R. Ek ◽  
Robert A. Monserud
Keyword(s):  
Growth Model ◽  
Growth Models ◽  
Stand Density ◽  
Diameter Class ◽  
Tree Model ◽  
Individual Tree ◽  
Clear Cut ◽  
Individual Tree Model ◽  
The Individual ◽  
Stand Conditions

A distance-dependent individual tree based growth model (FOREST) was compared with a diameter-class growth model (SHAF) for describing changes in stand density and structure. Projections of Lake States' northern hardwood stand development were made by each model for 5–26 years over a range of stand conditions and harvest treatments. Results from numerous performance tests and comparisons of actual and predicted diameter distributions, basal areas, and numbers of trees, indicate the individual tree model was considerably more sensitive to harvest treatments and reproduction response than the diameter-class model. Conversely, the latter was much less expensive to operate. Prediction of species and individual tree growth with the individual tree model appeared to provide sensitivity nearly equal to that observed for predictions of the stand as a whole. Long-term projections (120 years) for reserve (no cut) and clear-cut stand conditions further suggest the potential and limitations of the models for management analyses.

scholarly journals Precommercial Thinning in a Ponderosa Pine Stand Affected by Armillaria Root Disease in Central Oregon: 30 Years of Growth and Mortality

1999 ◽  
Vol 14 (3) ◽  
pp. 144-148 ◽  
Author(s):  
Gregory M. Filip ◽  
Stephen A. Fitzgerald ◽  
Lisa M. Ganio
Keyword(s):  
Ponderosa Pine ◽  
Tree Mortality ◽  
Basal Area ◽  
Stand Density ◽  
Root Disease ◽  
Diameter Growth ◽  
Individual Tree ◽  
Precommercial Thinning ◽  
Tree Diameter ◽  
Armillaria Root Disease

Abstract A 30-yr-old stand of ponderosa pine was precommercially thinned in 1966 to determine the effects of thinning on tree growth and mortality caused by Armillaria root disease in central Oregon. After 30 yr, crop tree mortality was significantly (P = 0.02) less in thinned plots than in unthinned plots. Tree diameter growth was not significantly (P = 0.17) increased by thinning. Crop-tree basal area/ac growth was significantly (P = 0.03) greater in thinned plots. Apparently, from a root disease perspective, precommercial thinning of pure ponderosa stands significantly decreases the incidence of crop-tree mortality after 30 yr and significantly increases basal area/ac growth but not individual tree diameter growth. Recommendations for thinning based on stand density index (SDI) are given. West. J. Appl. For. 14(3):144-148.

Stand structure and growing space efficiency following thinning in an even-aged Douglas-fir stand

1988 ◽  
Vol 18 (7) ◽  
pp. 859-866 ◽  
Author(s):  
K. L. O'Hara
Keyword(s):  
Stand Structure ◽  
Volume Growth ◽  
Basal Area ◽  
Stand Density ◽  
Douglas Fir ◽  
Stem Volume ◽  
Projection Area ◽  
Individual Tree ◽  
Space Efficiency ◽  
Individual Trees

The growth of individual trees from four thinning treatments in a 64-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stand was analyzed to determine desirable residual stand structures after thinning. Dominant and codominant trees had the highest individual tree stem volume growth rates over the previous 5 years, and accounted for most stand volume growth in thinned and unthinned stands. Two measures of growing space, crown projection area and sapwood basal area (a surrogate for leaf area), were used to measure how efficiently individual trees used their growing space. Crown classes were useful in characterizing growing space efficiency (volume growth per unit of growing space) only in the unthinned treatment. In thinned treatments, tall trees with medium-sized crowns were most efficient, while in the unthinned treatment, tall trees with relatively large crowns were most efficient. A large crown in an unthinned stand was comparable in size to a medium-sized crown in a thinned stand. Results suggest growing space is not limiting individual tree growth in thinned stands and that thinning to a particular stand structure is more appropriate than thinning to a particular level of stand density.

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