執行成果摘要
The purpose of this year is to explore the self-thinning of various cypress stands. The man-made forest after clear cut and natural regeneration forest, we investigate the plots that the tree mortality rate or self-thinning reach 5%, and using the plot data that the number trees of per hectare (ρ) and the mean stem volume per tree (v) to fit equation the maximum size-density curve applying the least square method to obtain the experimental equation. The man-made forest and natural regeneration forest which slope value were -1.70700 and -2.122, intercept value were 4.787 and 5.615 in log scale, respectively. With respect to the estimates of total species diversity, the effective number of species was 17.3 for the ground-layer vegetation and only 6.9 for the natural regeneration seedlings. There were significant differences on the diversity of ground-layer vegetation among the four different cypress forest stands. The snags-and-logs-cleaned stand held the highest species richness, followed by the undisturbed natural stand, the plantation stand, and the natural regeneration stand. The situation was different for the diversity of natural regeneration seedlings, and the rank order changed as: the undisturbed natural stand ＞ the plantation stand ＞ the snags-and-logs-cleaned forest ＞ the natural regeneration stand.
On the monitoring of larger mammals, we achieved 310 independent camera-trapping samplings, and retrieved 2710 mammal images. Among 3 forest types, i.e. virgin forest, managed forest and plantation, the managed forest was the most mammalian speciose. The major part of the mammal images was Reeve’s Muntjac in each of all 3 forest type. Occurrence frequency of Formosan Serow was distinctively different (ANOVA, p=0.01) within 3 forest type, yet it showed no difference for both Reeve’s Muntjac and Formosan Macaque. A principle component analysis (PCA) plot shows no segregation between virgin forests and managed forests. Virgin forest site N4 is isolated from other virgin forest sites, which may relate to higher occurrence frequency of Reeve’s Muntjac and Formosan Wild-boar. On the whole, plantations are more or less group together.