アカマツ林における間伐強度の違いが林床とクヌギ・コナラ植栽苗の成長に与える影響(平成11年度 日本造園学会研究発表論文集(17))

Although Red-pine forest composes a typical and popular Japanese forest landscape, it widely spreads as a result of over coppicing in suburban areas especially in the Kansai region, in Japan. Then it is effective to convert a part of Red-pine forest to a deciduous oak forest or the mixture forest from the viewpoint of enhancing the bio-diversity and creating the amenity landscape every seasons. This study aims to ascertain the optimum light condition for growth of deciduous oak seedlings planted in the Red-pine forest floor. In 1993, within the Nishigohri park forest of Osaka Prefecture, the experimental plots of 4 different light condition were prepared with tree thinning and scrub removing, and Quercus acutissima and Q. serrata seedlings were planted. The results are as follows: The heavy thinned stand of half-shaded condition showed the best growth among the 4 stands, whereas in the open stand, the seedlings were stunted by direct sunshine, and showed half-growth in height and diameter compared with the half-shade stand. On the other hand, it become apparent that the growth was seriously damaged in the light-thinned stand and the none-thinned stand caused by light shortage. According to the results, it is considered that forest clearance should be avoided, and heavy thinning would be recommended for considerable growth of the planted seedlings in the Red-pine forest floor.