Simulating the impacts of wind damage on stand structure and dynamics of plantations: A case study of long-term cryptomeria japonica experimental plots with two spacing trials [風害對人工林的林分結構與動態影響之模擬：以兩個不同栽植距離的柳杉長期試驗地為例]
Journal
Taiwan Journal of Forest Science
Journal Volume
36
Journal Issue
1
Pages
51-67
Date Issued
2021
Author(s)
Abstract
Wind damage often causes unexpected risks and losses for forest managers. The impacts of catastrophic wind damage can lead to considerable disturbances in forest management plans. In this study, we analyzed the effects of wind damage on 2 long-term experimental plots of Japanese cedar (Cryptomeria japonica D. Don) with 2 spacing trials (CJ3000 with an original density of 3000 trees ha-1 and CJ5400 with an initial density of 5400 trees ha-1) in 1944 (from Typhoon B174; T1) and 1955 (from Typhoon Iris; T2). These 2 experimental plots are located next to each other in the Xitou area of central Taiwan and were established via 2-yr-old seedlings in 1929. The objective was to simulate the impact of typhoons on the stand structure in terms of the present and long-term dynamics. First, the 3-parameter Weibull probability density function was used to fit and compare the diameter at breast height (DBH) distribution before and after wind damage occurred. Second, under an assumption of a self-thinning slope, a switching regression was used to simulate the number of trees between the 2 plots over time. Interventions by typhoons in 4 scenarios were assumed: plots suffered T1, plots suffered T2, plots suffered both T1 and T2, and simulated plots experienced no intervention. Results showed that (1) more trees with medium and smaller DBHs were removed than larger ones in both plots, (2) the 3-parameter Weibull probability density function effectively fitted and described the DBH-class structure of plots before and after the disturbance, with the patterns of DBH distribution after the interventions being more concentrated and similar to the consequences of low (or light) thinning, (3) the switching regression with dummy variables effectively estimated changes due to the typhoon intervention and reductions in the number of trees in the 2 plots, in particular, the number of trees in CJ3000 were higher than those in CJ5400 after 50 yr of age, and (4) the impact of wind damage could change the original density structure, which would lead to long-term changes in stand structure and stock. ? 2021 Taiwan Forestry Research Institute. All rights reserved.
Subjects
Intervention analysis
Switching regression
Weibull distribution
Wind damage
Hurricanes
Probability density function
3-parameter weibull
Cryptomeria japonica
Density structures
Diameter-at-breast heights
Forest management plans
Japanese cedar (Cryptomeria japonica D. Don)
Long term dynamics
Switching regressions
Forestry
Type
journal article