Ecosystem analysis of montane natural forest within a large scale research plot in Chichibu Mountains

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From a research on seed production of beech trees in a plot (50m*50m) by seed traps for three years (1994-'96). Fagus japonica had a good seed year in 1995 and F.crenata had a normal seed year in 1996, respectively. The seed production of two beech species did not occur in a same year in these three years (Kaji). Based on the data of complete enumeration of trees (DBH>5cm) in a large scale research plot (5.0625ha), correlation between physiognomical characteristics of stands and topographic factors and spatial distribution of tree species in relation to the topographic factors were analyzed. The distribution of several groups of tree species intimately correlated with topoghraphic factor (Ohkubo & Kaji). Seasonal and spatial change of species and population density of arthropods on F.japonica and F.crenata trees were investigated. Vertical distribution of arthropods on beech trees was largely different among taxa. The density of herbivorous insects was different between two kinds of beech trees. From bird research within a large scale research plot and its surroundings, 70 bird species were recorded, among which 37 species breeded. Shannon's diversity index of breeding birds in a research area showed a high value (5.04), However, this value was not so high in comparison with the high diversity of vegetation structure in the research area (Ishida). From observation of temperature and insolation in several different height on a tower (23m high), dates of defoliation in beech stand were estimated at Nov.7th-9th.in 1995 and at Nov.2nd.-6th.in 1996, respectively. It is also estimated that flushing occurred at ca.May 17th.in 1996. Diurnal range of air temperature was the largest above forest canopy, and it was getting smaller near ground surface. From comparison of mean diurnal temperature between defoliation and foliation periods, the latter period is more effective to moderate forest climate (Kabaya & Shibano).