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.