Methods to estimate the amount of snowmelt in forested areas with use of heat balance models have been presented including a convenient method. The amount of snowmelt is calculated from the meteorological data over the forest and forest density. It was found that, in general, as the forest density increased the snowmelt decreased. However, with conditions of high air temperature, weak winds, and large snow albedo, a greater degree of snowmelt occurred under a dense forest due to infrared radiation from the leaves than under a sparse forest. Moreover, it was investgated how the leaf distribution influenced the transmittance for solar radiation. It was shown that it was not necessary to consider the effect of leaf distribution when the solar zenith angle was large (low elevation).

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[in Japanese]

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Structure and dynamics of an old-growth Chamaecyparis forest in the Akasawa Forest Reserve, Kiso district, central Japan, were investgated in four stands with different species composition in the canopy: a pure C. obtusa stand, two stands dominated by C. obtusa with a few Thujopsis dolabrata, and a stand dominated by C. pisifera mixed with C. obtusa and hardwoods. C. obtusa had its dominant dbh class around 50-60cm in the C. obtusa stands, but the distribution of C. pisifera showed an L-shape in the C. pisifera stand. Stilt -rooted canopy trees of C. obtusa were found. The understory layer of the pure C. obtusa stand was dominated by small trees or shrubs of hardwood species, and that of stands with C. obtusa and T. dolabrata in the canopy was dominated by T. dolabrata saplings. There were no saplings of C. obtusa in stands in which it was a canopy dominant. C. pisifera saplings dominated and few C. obtusa saplings occurred in the understory layer of the C. pisifera stand. For five years during 1985-1990, mortality of canopy trees occurred only in the C. obtusa stands; the rate was one to three percent. Mortality was absent in the C. pisifera stand. Mean annual dbh growth of canopy trees ranged 0.3-1.2cm. Mortality rate of stems in the understory layer of each stand ranged 8-23% during this period. The rate was 11.1% for C. pisifera and 12-21% for T. dolabrata, but there was no mortality for C. obtusa saplings.

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Sprouts of beech (Fagus crenata) on various site condition were studied to clarify patterns of the sprouts in "high beech forest type" and "dwarf beech forest type". The ecological importance and the relationships between the sprouts patterns and site conditions were discussed. There are few sprouts of beech (Fagus crenata) in closed stands of "high beech forest type". But within a few years after mast year, there are many seedlings, which were classified into seedlings and "seedling sprouts". The seedlings were died within a few years under the closed canopy. Under small canopy gaps, a few seedlings can survive to recover up to sapling stage and young tree stage and they repeat die-back and recovery by sprouts. Sprouting activities of the beech maintain below 10-15cm in D.B.H. and decrease above the size. Some beech "seedling sprouts" can survive under the open canopy like Fagus japonica. Consequently, the growth of sprouts in the styands of "high beech forest type" depends on the light condition under the canopy. On the other hand, the beech sprouts in "dwarf beech forest type" were depended on topographical condition, such as summit phenomena. The beech trunks were broken by physical damage of deep snow caused by prevailing wind up to the size below 10-20cm in trunk diameter and after recovered by sprouts. The "dwarf beech forest type" was maintained by repetitions of trunk broken and sprouting. Such a sprouting ability of the beech is very important to survive under severe condition like heavy snow area.

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