Reverse casting Taiwan red cypress distribution in central Taiwan from topographic sheltering effects of Taiwan fir in Hohuan Mountains

Ecological niche modeling (ENM) coupled with 3S has become increasingly important for environment monitoring. Chamaecyparis formosensis (Taiwan red cypress, TRC) only grows in Huisun´s Shou-Cheng Mountain. We used GIS to overlay physiographic variables and vegetation index with TRC samples. We developed ENMs by using generalized linear model (GLM), maximum likelihood (ML), maximum entropy (MAXENT) and BIOCLIM. Results indicated that the accuracies of four models increased linearly with the sample size and also the mean kappa value of SPA methods (0.95) was better than that of SPO methods (0.85) for predicting the suitable habitat of TRC forests in the study. The variables used except elevation could not reflect the relationship between humidity and topographic sheltering characteristics (wind). Hence, we proposed a hypothesis: northeastern seasonal wind with humidity cannot fully blow into Huisun due to its topographic sheltering effects. We will attempt to incorporate proxy indicators of wind and humidity into models.