文章基本信息

标题：刈払いおよび抑制剤散布を用いた林冠下のササ抑制の効果
本地全文：下载
作者：齋藤智之 ; 酒井武 ; 壁谷大介等
期刊名称：日本森林学会誌
印刷版ISSN：1349-8509
电子版ISSN：1882-398X
出版年度：2021
卷号：103
期号：3
页码：179-185
DOI：10.4005/jjfs.103.179
语种：Japanese
出版社：The Japanese Forest Society
摘要：ササ型林床の森林では，ササの繁茂が樹木の更新阻害要因となり，確実な更新のためにはササ抑制などの更新補助作業が不可欠である.閉鎖林冠下でササを抑制し，前生稚樹を確実に育成してから伐採すれば更新の成功が期待できると考えられる.しかし，伐採前に林冠下でのササ抑制を実施した事例は知る限りにおいてない.そこで，本研究では天然生ヒノキ林の閉鎖林冠下でチマキザサを抑制する野外操作実験を行って，その後伐採しても抑制効果が持続されるササ抑制法について検討した.ササ抑制の方法として，刈払いと抑制剤散布，これらを組合わせた5処理を行った.年一回各処理1 m2のササ地上部・地下部を採取し，現存量，稈数，地下部の貯蔵炭水化物濃度を測定した.刈払いを含む3処理では，チマキザサは最初の刈払いでほぼ再生能力を失い，その後数年で地下部が消耗して現存量が0となった.一方，抑制剤は徐々に地上部現存量を減らしたが，4年後には回復に転じ，地下部は一切抑制効果が表れず，ササを枯殺する効果はなかった.以上のことから林冠下で刈払いを行うことはササ制御に最適な方法と考えられ，前更作業によるヒノキ天然更新施業の可能性が示唆される.
其他摘要：The dense cover of sasa (dwarf bamboo) often inhibits tree regeneration, and silvicultural operations to control sasa are essential so as to ensure natural regeneration of forests. Operations to control sasa are usually conducted following timber harvesting. Controlling sasa under the closed canopy before timber harvesting is expected to ensure the establishment of advanced seedlings and make tree regeneration more successful. However, the effects of operations to control sasa under the forest canopy before timber harvesting have not been previously examined in Japan. In this study, we conducted a field manipulation in stands hinoki (Chamaecyparis obtusa) natural stand, Kiso region, central Japan, to examine the sustainable suppressing effects of the dwarf bamboo, Sasa palmata, under the closed canopy. We conducted five treatments that combined weeding and herbicide application. Every year from 2013 to 2017, in a 1 m² quadrat per treatment, we collected the aboveground and belowground parts of sasa and measured their biomass, number of culms, and carbohydrate concentration belowground. Sasa lost its culm emergence ability immediately after the first weeding practice in the three treatments that included weeding, and in the next few years, its belowground biomass disappeared. In contrast, the herbicide treatment slightly decreased the aboveground biomass of sasa, but caused no effects in the belowground biomass, indicating that this treatment does not eliminate sasa. Weeding under the closed canopy was the most suitable method to control sasa, raising the natural regeneration potential of hinoki from advanced regeneration.
关键词：現存量;野外操作実験;天然更新;貯蔵炭水化物;更新補助作業
其他关键词：biomass##field manipulation##natural regeneration##non-structural carbohydrate##silvicultural operation