Effect of forest thinning on hydrologic nitrate exports from a Nsaturated plantation  

作　　者：Masaaki Chiwa Hirokazu Haga Tamao Kasahara Makiko Tateishi Takami Saito Hiroaki Kato Kyoichi Otsuki Yuichi Onda 

机构地区：[1]Kyushu University Forest,Kyushu University,Fukuoka 811-2415,Japan [2]Faculty of Agriculture,Tottori University,Tottori 680-8553,Japan [3]Faculty of Agriculture,Kyoto University,Kitashirakawa Oiwake-cho,Sakyo-ku,Kyoto 606-8502,Japan [4]Department of Plant Ecology,Forestry and Forest Product Research Institute,Forest Research and Management Organization,Tsukuba 305-8687,Japan [5]Graduate School of Life and Environmental Sciences,University of Tsukuba,Tsukuba 305-8572,Japan

出　　处：《Journal of Forestry Research》2020年第2期387-395,共9页林业研究（英文版）

摘　　要：Although several studies have assessed the effects of thinning on water quality,including nitrogen(N)exports,few have examined N-saturated plantations.This study assessed the short-term effect of thinning on N exports from a N-saturated plantation forest in northern Kyushu,western Japan,that was thinned(43%of basal area)during January-March 2012.Water levels at the gauging station were continually measured,and streamwater baseflow and stormflow samples were collected before(2011)and after(2013)forest thinning.Annual precipitation before(2469 mm)and after(2418 mm)forest thinning differed little,and annual water discharge after thinning(1641 mm)was similar to that before thinning(1609 mm).However,direct flow during stormflow periods was higher after thinning(260 mm)than before(153 mm).The concentrations of major ions in stream water did not differ before and after thinning.As a result,the high annual dissolved inorganic N(DIN)exports differed little before(35.8 kg N ha^-1 a^-1)and after(36.5 kg N ha^-1 a^-1)forest thinning.DIN exports during stormflow periods were slightly higher after(12.2 kg N ha^-1 a^-1)than before thinning(10.5 kg N ha^-1 a^-1)and were proportional to the increased direct flow after thinning(561 mm after vs.470 mm before thinning).We concluded that thinning does not affect annual N exports from the N-saturated plantation forest,but it can increase the proportion of N exported during stormflow periods in proportion to increased water volume of direct flow after thinning.

关 键 词：THINNING Nitrogen saturation Nitrogen export Direct flow BASEFLOW 

分 类 号：S753[农业科学—森林经理学]