臺灣中部北東眼山溫帶常綠闊葉林樹種的組成及分佈類型

Abstract

本研究地點位於臺灣中部北東眼山區的原始常綠闊葉林，樹種組成及分佈類型這兩者與環境變異的關係是研究重點。這個100×300平方公尺的樣區內有50種木本植物（DBH?1 cm，高度?1.3 m），其中41種?喬木，9種?灌木，共有10048棵樹，整個樣區的胸高截面積?78.72 m2/ha。這個森林主要由兩個區域所組成，一是有箭竹出現且樹冠破碎的地區，另一是無箭竹而樹冠完整的地區。由樹種的空間分佈可將森林的組成分成三群。第一群集中分佈在無箭竹，樹冠完整的地區，這些樹種是無法在箭竹中更新的耐陰種，例如：紫珠葉泡花。第二群集中分佈在有箭竹，樹冠破碎的地區，這些樹種是能在箭竹中更新的不耐陰種，例如：南燭。第三群的樹種並無明顯的分佈趨勢，是屬於能在箭竹中更新的耐陰種，例如：長尾栲。 這個原始森林受到自然的幹擾及森林地表的異質性（樹冠的狀況及箭竹的有無）影響很大。因?有不同的影響因數共存著，且不同的種類對這些因數有不同的反應，故而保存了此森林種類的歧異度。

The floristic composition and distribution pattern of an old-growth evergreen broad-leaved forest, partially strong affected by typhoon, in Mt. Peitungyen of central Taiwan. The results were interpreted in terms of the floor and canopy conditions. The 100 m × 300 m plot contained 50 woody species (DBH ? 1 cm, height ? 1.3 m), including 41 trees species, 9 shrub species, and 10048 trees. The total basal area was 78.72 m2/ha. The forest was primarily organized by a group of sites with dwarf bamboo and broken canopy, and sites without dwarf bamboo and with closed canopy. All stems ? 1 cm DBH were mapped on a 3-ha plot and analyses were made of population structure and spatial distribution of major tree species. Species found in the plot were divided into three groups based on spatial distribution patterns. The first group was mainly formed on sites with closed canopy and without dwarf bamboo (Sinobambusa kunishii). It mainly included shade tolerant species, such as Meliosma callicarpaefolia, which regeneration was restricted to sites not covered with dwarf bamboo. The second group was mainly formed on sites with dwarf bamboo and broken canopy, and it mainly included shade intolerant species, such as Lyonia ovalifolia, which could regenerate on sites with dwarf bamboo. Species in the third group did not show any particular habitat preference. The group mainly included shade tolerant species, such as Castanopsis carlessii, which could regenerate on site with dwarf bamboo. It is found that the community of this old-growth evergreen broad-leaved forest is largely organized by natural disturbance and heterogeneous conditions of the forest floor (difference in canopy condition and presence/absense of dwarf bamboo). The existence of these different factors and the different responses of species to them largely contribute to the maintenance of tree species diversity in the forest.