ブナ林における傘伐作業試験 : (第II報)種子の落下

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The writers published in the first report that they made the statistical analysis on the stand structure before cutting in experimental area under shelter-wood system of the Buna forest, Iwate pref. The number and volume of the trees in these plots before and after cutting is shown in Table 1. They have since examined the seedlings established there after the heavy crop in 1950.In 1952 the Buna in this region fructified rather better than a average crop, and they surveyed the condition of seed fall from Oct. 1 to Nov. 15,setting 120 zinc vessels on the area to catch seeds. They exmined seeds kept in them every five days, the results being as follows.1) It is generally reported that the heavy crop of Buna occurs periodically, every five to seven years, and that it fructifies little until the next good crop. However, according to their research they came to the conclusion that the period of heavy crop is four to six years and that the amount of seeds of the average crop in alternate years is enough to regenerate.2) The seed starts to fall about the end of September, most heavily from Oct. 15 to Oct. 25,and then less gradually. Perhaps it ends to fall at the end of November.3) Averaging all plots falling seeds are 97 in number per m^2,3,000 per tree of Buna in non-cut area, 10,000 on stand opened by 30-60 %, and 20,000 opened by 80 %. Thus a tree on stand opened heavily fructifies much better than a tree on dense stand.4) It seems that there exists no significant relation between the number of falling seeds and wind velocity per day by period.5) When they estimate on these results, they may conclude that the remaining trees on a cutting area need at least about 50 per ha.
日本森林学会の論文
1953-09-25

ブナ林における傘伐作業試験 : (第II報)種子の落下

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