Enhancing gap model accuracy by modeling dynamic height growth and dynamic maximum tree height

2012 ◽  
Vol 232 ◽  
pp. 133-143 ◽  
Author(s):  
Livia Rasche ◽  
Lorenz Fahse ◽  
Andreas Zingg ◽  
Harald Bugmann
2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Wuming Zhang ◽  
Shangshu Cai ◽  
Xinlian Liang ◽  
Jie Shao ◽  
Ronghai Hu ◽  
...  

Abstract Background The universal occurrence of randomly distributed dark holes (i.e., data pits appearing within the tree crown) in LiDAR-derived canopy height models (CHMs) negatively affects the accuracy of extracted forest inventory parameters. Methods We develop an algorithm based on cloth simulation for constructing a pit-free CHM. Results The proposed algorithm effectively fills data pits of various sizes whilst preserving canopy details. Our pit-free CHMs derived from point clouds at different proportions of data pits are remarkably better than those constructed using other algorithms, as evidenced by the lowest average root mean square error (0.4981 m) between the reference CHMs and the constructed pit-free CHMs. Moreover, our pit-free CHMs show the best performance overall in terms of maximum tree height estimation (average bias = 0.9674 m). Conclusion The proposed algorithm can be adopted when working with different quality LiDAR data and shows high potential in forestry applications.


2015 ◽  
Vol 45 (8) ◽  
pp. 970-977 ◽  
Author(s):  
Y.H. Weng ◽  
P. Lu ◽  
Q.F. Meng ◽  
M. Krasowski

Developing resistance to western gall rust (WGR) is important for maintaining healthy and productive jack pine plantations. In this study, we estimated genetic parameters of resistance to WGR and its relationship with tree height growth, based on data collected from three second-generation full-sib progeny testing series of jack pine planted in New Brunswick, Canada. Results indicated that (i) resistance to WGR in jack pine was controlled by both additive and dominance gene effects, with the latter playing a greater role; (ii) narrow-sense heritability estimates for resistance to WGR were low (mean = 0.05; series range = 0.00∼0.09), and broad-sense heritability estimates were moderate on an individual-tree basis (mean = 0.53) and considerably higher on the full-sib family mean basis (mean = 0.87); (iii) additive genetic correlation between tree height growth and WGR incidence was low (≤0.06) in two series and only slightly higher and favorable (–0.19) in one series, suggesting that selection on growth traits would not negatively affect WGR resistance; and (iv) mid-parental additive genetic and dominance effects on WGR were empirically correlated (>0.65), indicating that incorporating breeding for WGR resistance into current jack pine tree improvement programs with a seed orchard approach could partly capture the benefit from dominance effects. Although genetic gains in WGR resistance could be realized through various breeding and deployment schemes, it appeared that rapid improvement could be achieved through backward selection on full-sib family means.


2020 ◽  
Vol 27 (1) ◽  
pp. 177-189
Author(s):  
Eric B. Gorgens ◽  
Matheus H. Nunes ◽  
Tobias Jackson ◽  
David Coomes ◽  
Michael Keller ◽  
...  

1964 ◽  
Vol 40 (3) ◽  
pp. 298-307 ◽  
Author(s):  
K. J. Mitchell

Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) plantations on the east coast of Vancouver Island, British Columbia, were examined to determine the effect of animal feeding upon height growth.Length of internodes and evidence of past leader damage were recorded and cumulative average height-age growth curves compared for undamaged trees and for trees suffering various intensities of damage.The average reduction in tree height attributable to animal feeding in heavily browsed plantations varied from one-half to two feet over a period of 8 to 10 years. It is unlikely that either tree volume or quality at rotation age would be seriously affected.Exposed trees were browsed more heavily than those protected by vegetation or logging slash.


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