scholarly journals Deriving tree growth models from stand models based on the self-thinning rule of Chinese fir plantations

2022 ◽  
Vol 15 (1) ◽  
pp. 1-7
X Zhang ◽  
QV Cao ◽  
Y Qu ◽  
J Zhang
Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 163
Jan Světlík ◽  
Jan Krejza ◽  
Pavel Bednář

Tree growth depends on many factors such as microsite conditions, vitality, and variations in climate and genetics. It is generally accepted that higher growth indicates both an economic benefit and better vitality of any tree. Here we use a modified approach of evaluating tree social area to study mutual tree competition based on the orientation and shape of trees social area. The investigation was performed in nine Norway spruce stands in the Czech Republic. The objective of this study performed from 2008 to 2012 was to quantify relative tree radial increments with respect to the lowest and highest competition found in specific sectors of tree social area (AS). Specific groups of trees (tree classes) were evaluated according to their classes (dominant, co-dominant and sub-dominant) and their composition status in ninety-degree sectors of AS using established classifying rules. The results showed that a spatially-available area (AA) is an inappropriate parameter for predicting tree growth, whereas AS provided robust explanatory power to predict relative radial growth. Tree size was observed as an important indicator of relative radial increments. A significantly positive correlation was found for a radial increment of sub-dominant trees with the lowest competition from western directions; whereas a negative correlation was observed when the lowest competition was observed from eastern directions. For dominant trees, there was an evident growth reaction only when more than 50% of the AS was oriented towards one of the cardinal points. Individual differences in the orientation of tree AS may be important parameters with regard to competition and its spatial variability within an area surrounding a particular tree and deserve more detailed attention in tree growth models and practice.

2014 ◽  
Vol 513-517 ◽  
pp. 3728-3731
Wen Qing Zhang

In order to simulate growth and development process of tree, then provide services for production management and scientific research, all kinds of tree growth models are constructed. The paper firstly considers a variety of factors affecting the growth and development of tree, then studies artificial intelligence knowledge such as neural network and expert system, uses the neural expert system to solve the acquisition and management of tree growth parameters, and design and develop tree growth management and expert system based on growth models, the models combine morphogenesis model of tree and knowledge model to provide comprehensive environmental control and management decision-making. Practice has indicated that the growth models of tree can reflect the growth of trees under different physiological and ecological conditions, and visual effect is very good.

2020 ◽  
Vol 21 (5) ◽  
Narun Nattharom ◽  

Abstract. Nattharom N, Roongtawanreongsri S, Bumrungsri S. 2020. Growth prediction for rubber trees and intercropped forest trees to facilitate environmental services valuation in South Thailand. Biodiversitas 21: 2019-2034.  Tree growth parameters are necessary for valuing ecological services of trees in both natural forest and agroforest. These parameters are difficult to measure annually, and thus often lack the information needed in valuation. This study aimed to use regression analysis to create growth models for diameter at breast height (DBH), total height (TH), and merchantable height (MH) of Hevea brasiliensis Mull-Arg. (rubber tree) and five economic forest trees that are preferred by rubber farmers for intercropping, including Hopea odorata Roxb., Shorea roxburghii G.Don., Swietenia macrophylla King., Dipterocarpus alatus Roxb., and Azadirachta excelsa (Jack) Jacobs. Data were collected from 39 rubber plantations that contain rubber trees and the intercropped tree species at different ages in three provinces in South Thailand. The data were modelled using regression analysis with curve fitting to find the best-fitted curve to a given set of points by minimizing the sum of the squares of the residuals and standard error of the regression of the points from the curve. The results arrived at 21 models for the DBH, TH, and MH growth of rubber and the intercropped trees, in the forms of, power, sigmoid and exponential trends that vary according to the type of trees. The models can be used to predict tree growth parameters, which are useful for determining the value of ecosystem services such as carbon dioxide sequestration, oxygen production, and timber production.

2019 ◽  
Vol 65 (6) ◽  
pp. 776-783 ◽  
Xiongqing Zhang ◽  
Quang V Cao ◽  
Lele Lu ◽  
Hanchen Wang ◽  
Aiguo Duan ◽  

Abstract Stand density index (SDI) has played an important role in controlling stand stocking and modeling stand development in forest stands. Reineke’s SDI (SDI_R) is based on a constant slope of –1.605 for the self-thinning line. For Chinese fir plantations, however, it has been reported that the self-thinning slope varied with site and climate, rendering SDI_R questionable. Remeasured data from 48 plots distributed in Fujian, Jiangxi, Guangxi, and Sichuan provinces were used to develop models for prediction of stand survival and basal area, with SDI_R incorporated as a predictor variable. Also included in the evaluation were growth models based on self-thinning slopes estimated from two groups of sites (SDI_S) or from climate variables (SDI_C). Results indicated that models with climate-sensitive SDI (SDI_C) performed best, followed by SDI_S and SDI_R. The control models without SDI received the worst overall rank. Inclusion of climate-sensitive SDI in growth and survival models can therefore facilitate modeling of the relation between stand density and growth/survival under future climate-change conditions.

2020 ◽  
Vol 66 (3) ◽  
pp. 361-370
Xiongqing Zhang ◽  
Quang V Cao ◽  
Hanchen Wang ◽  
Aiguo Duan ◽  
Jianguo Zhang

Abstract The self-thinning rule has played a critical role in controlling stand stocking and modeling stand development in forest stands. Chinese fir (Cunninghamia lanceolata) is a native and fast-growing tree species used for timber production and is widely grown in southern China. Effective management of this important tree species requires accurate and reasonable predictions of stand growth and survival. Remeasured data from 48 plots distributed in Fujian, Jiangxi, Guangxi, and Sichuan provinces were used to develop models to predict stand survival and basal area based on the self-thinning trajectories. These trajectories were constructed using a self-thinning slope of –1.605, as suggested by Reineke (1933) (Method 1), and the slopes estimated either from two groups of sites (Method 2) or from climate variables (Method 3). Results indicated that the stand growth and survival models using Method 3 performed best, followed by Method 2 and Method 1. In addition, stand growth and survival curves predicted from Method 3 were more similar in shape to those from the observed values, as compared with Method 1. Overall, the models based on the self-thinning lines using climate-sensitive slopes provided reasonable predictions of the stand development dynamics. Therefore, these results facilitate modeling of the relation between stand growth/survival and self-thinning under climate change.

2009 ◽  
Vol 26 (1) ◽  
pp. 15-20
Jeffrey G. Benjamin ◽  
Ying Hei Chui ◽  
John A. Kershaw

Abstract The literature is not consistent in descriptions related to branch location around a stem and, consequently, few models exist to predict distribution of branch azimuth. The objective of this study was to determine if branches in black spruce are uniformly distributed around the stem at the tree, log, and whorl levels with respect to branch size. Branch size limits were selected to reflect the largest branch per whorl and knot size limits were established by visual grading rules for 2 × 3 and 2 × 4 dimension lumber. Using Rayleigh's test of uniformity, branches are considered to be uniformly distributed around the stem for all branch size limits: between 40 and 80% at the tree level, over 70% at the log level, and virtually 100% at the whorl level. The findings of this study indicate that a simple random assignment (from a uniform distribution) of branches around the stem within each whorl is sufficient to properly describe branch location within black spruce tree growth models.

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 344 ◽  
Keiko Fukumoto ◽  
Tomohiro Nishizono ◽  
Fumiaki Kitahara ◽  
Kazuo Hosoda

Understanding the tree growth process is essential for sustainable forest management. Future yields are affected by various forest management regimes such as thinning; therefore, accurate predictions of tree growth are needed under various thinning intensities. This study compared the accuracy of individual-level distance-independent diameter growth models constructed for different thinning intensities (thinning intensity-dependent multiple models: TDM model) against the model designed to include all thinning intensities (thinning intensity-independent single model: TIS model) to understand how model accuracy is affected by thinning intensity. We used long-term permanent plot data of Japanese cedar (Cryptomeria japonica) stands in Japan, which was gathered from four plots where thinning was conducted at different thinning intensities: (1) intensive (41% and 38% of trees removed at 25 and 37 years old, respectively), (2) moderate (38% and 34%), (3) light (32% and 34%), and (4) no thinning. First, we specified high interpretability distance-independent competition indices, and we compared the model accuracy both in TDM and TIS models. The results show that the relative spacing index was the best competition index both in TDM and TIS models across all thinning intensities, and the differences in the RMSE (Root mean square error) and rRMSE (relative RMSE) in both TDM and TIS models were 0.001–0.01 cm and 0.2–2%, respectively. In the TIS model, rRMSE varied with thinning intensity; the rRMSE was the lowest for moderate thinning intensity (45.8%) and the highest for no thinning (59.4%). In addition, bias values were negative for the TIS model for all thinning intensities. These results suggest that the TIS model could express diameter growth regardless of thinning intensities. However, the rRMSE had varied with thinning intensity and bias had negative values in the TIS model. Therefore, more model improvements are required for accurate predictions of long-term growth of actual Japanese cedar stands.

2014 ◽  
Vol 60 (No. 8) ◽  
pp. 307-317 ◽  
H. Ivancich ◽  
G.J. Martínez Pastur ◽  
M.V. Lencinas ◽  
J.M. Cellini ◽  
P.L. Peri

Tree growth is one of the main variables needed for forest management planning. The use of simple models containing traditional equations to describe tree growth is common. However, equations that incorporate different factors (e.g. site quality of the stands, crown classes of the trees, silvicultural treatments) may improve their accuracy in a wide range of stand conditions. The aim of this work was to compare the accuracy of tree diameter growth models using (i) a family of simple equations adjusted by stand site quality and crown class of trees, and (ii) <br /> a unique global equation including stand and individual tree variables. Samplings were conducted in 136 natural even-aged Nothofagus antarctica (Forster f.) Oersted stands in Southern Patagonia (Argentina) covering age (20&ndash;200 years), <br /> crown class and site quality gradients. The following diameter growth models were fitted: 16 simple equations using two independent variables (age and one equation for each stand site quality or crown class) based on Richards model, plus a unique global equation using three independent variables (age, stand site quality and crown class). Simple equations showed higher variability in their accuracy, explained between 54% and 92% of the data variation. The global model presented similar accuracy like the better equations of the simple growth models. The unification of the simple growth models into a unique global equation did not greatly improve the accuracy of estimations, but positively influenced the biological response of the model. Another advantage of the global equation is the simple use under a wide range of natural stand conditions. The proposed global model allows to explain the tree growth of N. antarctica trees along the natural studied gradients. &nbsp; &nbsp;

2012 ◽  
Vol 20 (1) ◽  
pp. 29-42 ◽  
Augustyn Mika ◽  
Paweł Wawrzyńzak ◽  
Zbigniew Buler ◽  
Dorota Konopacka ◽  
Paweł Konopacki ◽  

ABSTRACT Eleven plum cultivars (Prunus domestica L.) for processing grafted on semidwarf rootstock ‘Wangenheim Prune’ and vigorous rootstock ‘Myrobalan’ were densely planted (1000, 1250, 1666, 2500 trees ha-1) and trained to central leader spindle tree. A new training system was applied to obtain trees suitable for mechanical harvesting. The leader was not headed after planting and summer training procedures were performed in May/June. From the third year onwards, renewal pruning was carried out after fruit harvesting. The new training and pruning systems resulted in very fast tree growth, abundant branching, fruit bud formation on young wood and early bearing. The plum trees appeared to be suitable for hand and mechanical harvesting within 3 years from planting. The self propelled straddle combine harvester was able to harvest 2-3 tons of plums per hour compared to 30 kg with hand picking. Harvesting effectiveness was 90-95%. The quality of mechanically harvested plums was a little worse than of those hand picked, but fruits were suitable for processing. The ‘Common Prune’ and the prune type small plums were the most suitable fruit for mechanical harvesting.

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