STUDY ON FOREST ECCKTSTTMS IN LONG-TERM RESEARCH PLOTS

对森林动态进行分析和讨论，必然要建立较大规模的研究样地。除了在东京大学森林的三个地区建立的地块外，1998年在东京大学森林的其他地区新建立了四个研究地块。1998年和1999年，在7个样地上测量了每一样地中胸径大于4~5 cm的所有树木的胸径。各林分样地及其面积特征如下：1.北海道日本冷杉、条斑云杉、兴安落叶松为主的混交林36.25公顷样地，池池部山地天然林以日本水曲柳、铁杉、铁杉为主的山地天然林6.0ha样地，赤松、锯缘栎混交林次生林0.42公顷样地4.75年生兴安落叶松人工林0.25ha样地。山奈子林场落叶阔叶林混交林，千叶林场以冷杉、铁杉、锯缘栎为主的次生混交林5.a样地1.845公顷，伊豆树业研究所以赤松、锯缘栎林、木兰林、山茶林、麻栎林为主的次生混交林6.a样地，43年生次生常绿阔叶林样地7.1.0ha。在这7个样地中，千叶林、千叶林和北海道的3个样地已经进行了2-4次调查，为分析各林分的区系和结构变化提供了重要数据。这些数据将用于保护和综合利用日本不同气候条件下的森林生态系统。

To analyze and discuss about forest dynamics, it is inevitable to establish relatively large-scale research plot. In addition to the plots having in established in three regions of Tokyo University Forests (TUF), four research plots were newly established in other regions of TUF in 1998. Diameter breast height (DBH) of all the trees larger than 4-5cm A DBH in each plot was measured at seven plots in 1998 and 1999. The characteristics of each stand in a plot and its area are as follows: 1.a 36.25 ha plot in mixed natural forest mainly dominated by Abies sachalinensis, Picea yezoensis and Tilia japonica in TUF in Hokkaido, 2.a 6.0 ha plot in montane natural forest dominated by Fagus japonica, F. crenata and Tsuga sieboldii in TUF in Chichibu, 3.a 0.42 ha plot in secondary forest dominated by Pinus densiflora and Quercus serrata mixed with planted trees of Chamaecyparis obtusa and Quercus myrisinaefolia in Experimantal Station at Tanashi, 4.a 0.25 ha plot in ca. 75 year-old plantation of Larix leptolepis, mixed with deciduous broad leaved trees in TUF at Yamanakako, 5.a 1.845 ha plot in mixed natural forest dominated by Abies firma, Tsuga sieboldii and Quercus serrata in TUF in Chiba, 6.a 2.76 ha plot in secondary mixed forest dominated by Pinus densiflora, Quercus serrata, Magnolia obovata, Camellia japonica, Quercus acuta in TUF in Aichi and 7.a 1.0 ha plot in 43 year-old secondary evergreen broad leaved forest dominated by Shiia siebldii, Eurya japonica and Neolitsea aciculata in Arboricultural Research Institute at Izu, repectively. Among these seven plots, three plots in Chiba, Chichibu and Hokkaido have already been investigated 2-4 times, therefore, important data for analyzing the floristic and structural change of each stand have been obtained. These data will be available for the conservation and multiple uses of forest ecosystems in different climatic conditions in Japan.