Comparison of Vertical Distribution of Root Weight between Hinoki Cypress (Camaecyparis obtusa) and Oak (Quercuss crispula)

Research Project

Project/Area Number	12660131
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	林学
Research Institution	Gifu University
Principal Investigator	KOMIYAMA Akira Gifu University, Faculty of agriculture, Professor, 農学部, 教授 (60135184)
Co-Investigator(Kenkyū-buntansha)	KATO Shogo Gifu University, Faculty of agriculture, Research Associate, 農学部, 助手 (20324288) ITO Eiichi Gifu University, Faculty of agriculture, Lecture, 農学部, 講師 (00176322) TOMATSU Osamu Gifu University, Faculty of agriculture, Professor, 農学部, 教授 (50111836)
Project Period (FY)	2000 – 2002
Project Status	Completed (Fiscal Year 2002)
Budget Amount *help	¥2,300,000 (Direct Cost: ¥2,300,000) Fiscal Year 2002: ¥600,000 (Direct Cost: ¥600,000) Fiscal Year 2001: ¥500,000 (Direct Cost: ¥500,000) Fiscal Year 2000: ¥1,200,000 (Direct Cost: ¥1,200,000)
Keywords	artificial forest / broad-leaved tree / root system / vertical distribution / landslide / biomass / oak / cypress / 根密度 / 斜面 / 地下部 / スギ
Research Abstract	Comparison of Vertical Distribution of Root Weight between Hinoki Cypress (Camaecyparis obtusa) and Oak(Quercuss crispula) Individuals Growing in a Hinoki Plantation. It is often said that the shallow rooted characteristic of coniferous tree species such as Hinoki cypress and Japanese cedar leads to the collapse of relatively-young artificial forests when they meet with extraordinary heavy rain. To examine this, we compared the vertical root distribution pattern between Hinoki Cypress (Camaecyparis obtusa) and an oak (Quercuss crispula). In a 48-year-old Hinoki plantation, a Hinoki individual (DBH : 14.28cm, H : 11.9m) and an oak individual (DBH : 12.8cm, H : 12.8m) invaded there were selected. Under each sample tree, a trench was dug of 20cm wide, 100cm long, and 60cm deep, settled for the three directions from stem base, i.e., up-slope, down-slope, and side-ward. The trench was further sub-divided into soil blocks of 10cm deep and 20cm wide. The horizontal distribution pattern of root weight on slope was different by the two sample trees. The oak sample tree developed much root in up-slope direction but the Hinoki one in down-slope direction. The vertical distribution of root weight density decreased exponentially with soil depth. The decreasing rate of root weight density was not different statistically between the two sample trees. The individual root weight was calculated by integration of the exponential equations for the arbitrary soil depth. The individual root weight from soil surface to 30cm depth formed 89% and 94% of total root weight for the oak and Hinoki, respectively. The two sample trees showed similarly the shallow rooted behaviour.