scholarly journals Predicting the growth response to thinning for Scots pine stands using individual-tree growth models.

Silva Fennica ◽  
1995 ◽  
Vol 29 (3) ◽  
Author(s):  
Jari Hynynen
2010 ◽  
Vol 260 (10) ◽  
pp. 1735-1753 ◽  
Author(s):  
Sonja Vospernik ◽  
Robert A. Monserud ◽  
Hubert Sterba

2015 ◽  
Vol 45 (8) ◽  
pp. 1006-1018 ◽  
Author(s):  
Sonja Vospernik ◽  
Robert A. Monserud ◽  
Hubert Sterba

We examined the relationship between thinning intensity and volume increment predicted by four commonly used individual-tree growth models in Central Europe (i.e., BWIN, Moses, Prognaus, and Silva). We replicated conditions of older growth and yield experiments by selecting 34 young, dense plots of Norway spruce (Picea abies (L.) Karst.), Scots pine (Pinus sylvestris L.), and European beech (Fagus sylvatica L.). At these plots, we simulated growth, with mortality only, to obtain the maximum basal area. Maximum basal area was then decreased by 5% or 10% steps using thinning from below. Maximum density varied considerably between simulators; it was mostly in a reasonable range but partly exceeded the maximum basal area observed by the Austrian National Forest Inventory or the self-thinning line. In almost all cases, simulated volume increment was highest at maximum basal area and then decreased with decreasing basal area. Critical basal area, at which 95% of maximum volume increment can be achieved, ranged from 0.46 to 0.96. For all simulators, critical basal area was lower for the more shade-tolerant species. It increased with age, except for Norway spruce, when simulated with the BWIN model. Age, where mean annual increment culminated, compared well with yield tables.


2019 ◽  
Vol 65 (6) ◽  
pp. 784-795
Author(s):  
Jeffrey S Ward ◽  
Jessica Wikle

AbstractSix study areas were established in 80–125-year-old upland oak stands on average sites to compare stand and individual tree growth response following two active treatments (B-level thinning, crop tree) with an unmanaged control. Initial stocking of 104 percent was reduced to 62 percent and 60 percent on the B-level and crop-tree-management plots, respectively. Approximately 7,200 board feet per acre (International ¼) were harvested on the actively managed plots with upland oaks accounting for 81 percent of pre- and 86 percent of residual stand. Eleven-year diameter and volume growth of oak sawtimber trees was greater on actively managed plots. Growth response increased with degree of release and was maintained for the length of the study. Because of the increased individual tree growth of oaks in response to release, stand volume growth of oak sawtimber did not differ between treatments. In contrast to an 11-year decline of poletimber stocking on unmanaged plots, poletimber stocking increased on managed plots as diameter growth increased in response to partial release. This may increase difficulty of regenerating oak in the future. For those mature red oak stands where traditional regeneration prescriptions will not be implemented or will be delayed, commercial harvests can be conducted without compromising stand volume growth of oak.


Trees ◽  
1998 ◽  
Vol 13 (1) ◽  
pp. 19 ◽  
Author(s):  
W. Oberhuber ◽  
M. Stumböck ◽  
Werner Kofler

1995 ◽  
Vol 25 (1) ◽  
pp. 69-80 ◽  
Author(s):  
P.W. West ◽  
G.H.R. Osier

The factors determining individual tree growth response are examined during the 4 years following thinning in experiments in even-aged, 8- or 12-year-old regrowth Eucalyptusregnans F. Muell. forest at two sites in southern Australia. At one site, a vigorous understorey dominated by a sedge developed after the thinning. At that site, light-use efficiency by the trees was unaffected by thinning and the aboveground biomass production by the trees in the thinned stand was substantially less than that in the unthinned stand. At the other site, little understorey developed, light-use efficiency by trees in the thinned stand was greater than that in the unthinned stand, and aboveground biomass production was unaffected by thinning even though the leaf weight of the thinned stand was far below that of the unthinned stand. Where the understorey developed, it was concluded that it competed successfully with the trees for water, thereby reducing production in the thinned stand when compared with the unthinned stand. The individual tree growth response that occurred in the thinned stand at that site appeared to be due soley to the extra light available to individual trees following the canopy opening. Where the understorey did not develop, it was concluded that individual tree growth response was due not only to the extra light available to individual trees but also to the increased availability of belowground resources, most probably soil water. Application of a pre-existing stand growth model suggested that at that site the tendency for increased growth resulting from extra water availability in the thinned stand was just balanced by decreased growth due to lower radiation absorption by the reduced canopy, so that net production was unaffected by thinning.


2001 ◽  
Vol 154 (1-2) ◽  
pp. 261-276 ◽  
Author(s):  
Julian C. Fox ◽  
Peter K. Ades ◽  
Huiquan Bi

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 187 ◽  
Author(s):  
Qiangxin Ou ◽  
Xiangdong Lei ◽  
Chenchen Shen

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.


Trees ◽  
1998 ◽  
Vol 13 (1) ◽  
pp. 19-27 ◽  
Author(s):  
W. Oberhuber ◽  
M. Stumböck ◽  
Werner Kofler

2011 ◽  
Vol 130 (5) ◽  
pp. 829-839 ◽  
Author(s):  
Timo Pukkala ◽  
Erkki Lähde ◽  
Olavi Laiho

1985 ◽  
Vol 15 (1) ◽  
pp. 18-22 ◽  
Author(s):  
T. M. Ballard ◽  
N. Majid

The use of pretreatment increment can lead to improved estimates of individual and average tree growth response to fertilization, by helping to adjust for site as well as stand structure differences between fertilized and control areas. It has applications in research using either single-tree or plot fertilization, and also in estimating responses to operational fertilization. Particularly useful equations are R = Af − (Bf)av(Au/Bu) and I = av(Af/Bf) − av(Au/Bu), where R is an estimate of the absolute magnitude of individual tree growth response to fertilization; A and B are increment after and before fertilization, and f and u denote fertilized and unfertilized trees, respectively; av signifies the average of several replicates; and I is an index of whether response has occurred. Equations were evaluated by examining branch length increment data from foliar spray application of iron and copper to Pinuscontorta Dougl. (lodgepole pine) and of nitrogen and iron to Pseudotsugamenziesii (Mirb.) Franco (Douglas-fir).


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