Clarification of Factors Inhibiting Regeneration of Yezo Spruce (Picea jezoensis) at the Initial Stage of Natural Regeneration

研究是关于抑制Yezo Spruce的自然再生的因素的研究（Picea Jezoensis）：当覆盖雪的时候，真菌攻击种子;土壤层的水含量中的变化，其中可能会损害种子在从土壤中去除过程中从土壤到生根的过程中;在年轻种子生长期的增长期间，事件光线的数量和增长率之间的关系，Racodium Therryanum被定义为Yezo Spruce种子上的真菌;这种真菌大多在L， F和H层中找到（例如，L层infection rate -70%; in the A层， the quan\of the fungi decreased with soil depth。在0 ° C的温度下，健康种子的百分比在90天内变成零。两年多来，土壤层中含水量的测量显示，它在上层最大的部分中流动， L，范围从20 - 70%;特别是，在六月期间，它在20%，非常干燥。所以，它包含了一个典型的干燥层是一个重要的因素，伴随着真菌的损伤，它抑制了种子再生。生长率之间的关系和年轻种子在生长期跟随生长期的光照数量：生长率低于43 KWH/m^2 （17.5%的未构建天空），1.9厘米低于21 KWH/m ^2 （1.9厘米）。

Investigations were conducted on factors that inhibit the natural regeneration of Yezo spruce (Picea jezoensis): fungi attacking seeds when covered with snow; changes in the water content of the soil layers which might damage seeds by dehydration during the period from germination to rooting; the relationship between the amount of incident light and growth rate during the growth period of young seedllings, etc. Racodium therryanum was indentified as a fungus which damages Yezo spruce seeds; this fungus was found mostly in the L, F and H layers (e.g., L layer infection rate - 70%); in the A layer, the quantity of the fungi decreased with soil depth. At a temperature of 0゜C, the percentage of healthy seeds became zero in 90 days. Measurements of the water content in the soil layers over two years showed that it fluctuated widely in the uppermost layer, L, ranging from 20 to 70%; especially, in June during germination, it was at 20%, extremely dry. Thus, it was concluded that an excessively dry L layer was an important factor, along with the fungi damage, that inhibited seed regeneration. The relatonship between the growth rate and the amount of light incident on young seedlings during their growth period was as follows: the growth was 2.6cm under an incident light level of 43 KWH/m^2 (17.5% of unobstructed sky) and 1.9cm at 21 KWH/m^2.