本文在閫述臺灣東北角隆隆山次生林之組成及結構。硏究區內計包含241種維管束植物，其中樹木70種、灌木39種、蔓藤48種、草本類45種、蕨類39種。DBH之lcm樹木之歧異度爲： Shannon-Wiener index (3.09)，Simpson index (0.08)及 Equitability index (0.79)。 優勢度一歧異度曲線近似lognormal分佈型。植物社會之铤勢種在樹冠層爲大明橘（Myrsi«e see/uinii)、樹祀（Afdisia siebokiii)、紅楠（Persea thunbefgii)及水金京(Wendhmdia formosana);灌木層爲九節木(Psychotria rubra)及圓葉雞保樹(Lasianthus plagiophyllus) 改良型對應分析及群團分析的結果顯示三類植被型。各植被型樹木大小徑級分佈趨近負指數函數，但 是在上坡稜脊處最小徑級的密度偏低，反映出人爲干擾的跡象。與其他低海拔雨林相比較，隆隆山次生林之總底面積較小，仍屬未成熟之林分。

Floristic composition and structure of a lowland secondary forest was studied in detail on Mt. Lonlon of northeastern Taiwan. The study plot contained 241 species, of which 70 were trees, 39 shrubs, 48 climbers, 45 herbs, and 39 pteridophytes. Diversity of the trees with dbh ^ 1.0 cm was calculated as Shannon-Wiener index (3.09), Simpson index (0.08), and Equitability index (0.79). The dominance-diversity curve seemed to conform to a lognormal species distribution. The community structure was characterized by a relative dominance of Myrsine sequiniiy Ardisia sieboldiit Persea thunbergii、Wendlandia formosanay Gardenia jasminoides, and Schefflera octophylla in the canopy, and Psychotria rubra and Lasianthus plagiophyllus in the understory. Detrended correspondence analysis and cluster analysis led to the recognition of three ecologically meaningful groupings. Diameter distribution curves for vegetation types were observed to fit the negative exponential function. However, slight underrepresentation in the smallest size-class of the upper slope vegetation might be indicative of some minor anthropogenic disturbances. Compared to the mature lowland rain forests of other areas the Lonlon forest showed a lower basal area, and seemed to be indicative of structural immaturity.