STUDY ON FOREST ECCKTSTTMS IN LONG-TERM RESEARCH PLOTS

要对森林动态进行分析和探讨，就必须建立比较大规模的研究基地。1998年，除了在东京大学森林（TUF）的3个区域新建立的样地外，在TUF的其他区域新建立了4个研究样地。1998年和1999年在7个样地测量了每个样地所有大于4-5cm A DBH的树木的胸径高（DBH）。样地各林分及其面积的特征如下：1。1 .北海道TUF地区以冷杉、云杉和椴为主的混交林36.25 ha样地。2 .在赤父市TUF以日本Fagus japonica， F. crenatata和Tsuga sieboldii为优势的山地天然林6.0 ha样地。4.在田西试验站以密松和锯齿栎为主要树种的次生林中，混种了黄柏和黑栎。在山中子TUF约75年树龄的leptolepis落叶松人工林中，混有落叶阔叶树，0.25公顷的样地。6.千叶TUF以冷杉、三叶松和锯齿栎为主的混交林面积为1845 ha。以密松、锯栎树、白玉兰、山茶、尖栎树为主要树种的次生混交林面积2.76 ha。以伊豆树木研究所43年次生常绿阔叶林为研究对象，分别以希伯叶、日本Eurya japonica和新石海acaculata为主要优势种。其中，千叶、秩父和北海道的3个样地已经进行了2 ~ 4次调查，获得了分析各林分区系和结构变化的重要数据。这些数据将用于日本不同气候条件下森林生态系统的保护和多种利用。

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.