Coarse root spatial distribution determined using a ground-penetrating radar technique in a subtropical evergreen broad-leaved forest,China  

作　　者：YAN Hui DONG XinLiang FENG Gang ZHANG ShouRen MUCCIARDI Anthony 

机构地区：[1]State Key Laboratory of Vegetation and Environmental Change,Institute of Botany, Chinese Academy of Sciences [2]University of Chinese Academy of Sciences [3]Inner Mongolia Forestry Monitoring and Planning Academy [4]TreeRadar,Inc., Silver Spring, MD 20910, USA

出　　处：《Science China(Life Sciences)》2013年第11期1038-1046,共9页中国科学（生命科学英文版）

基　　金：supported by the National Natural Science Foundation of China(31170457,30710103907)

摘　　要：Coarse roots play a critical role in forest ecosystems and both abiotic and biotic factors affect their spatial distribution.To some extent,coarse root density may reflect the quantity of root biomass and biotic competition in forests.However,using traditional methods(e.g.,excavation)to study coarse roots is challenging,because those methods are time-consuming and laborious.Furthermore,these destructive methods cannot be repeated in the same forests.Therefore,the discovery of non-destructive methods for root studies will be very significant.In this study,we used a ground-penetrating radar technique to detect the coarse root density of three habitats(ridge,slope and valley)and the dominant tree species(Castanopsis eyrei and Schima superba)in a subtropical forest.We found that(i)the mean of coarse root density for these three habitats was 88.04roots m–2,with roots being mainly distributed at depths of 0–40 cm.Coarse root densities were lower in deeper soils and in areas far from the trunk.(ii)Coarse root densities differed significantly among the three habitats studied here with slope habitat having the lowest coarse root density.Compared with S.superba,C.eyrei had more roots distributed in deeper soils.Furthermore,coarse roots with a diameter>3 cm occurred more frequently in the valleys,compared with root densities in ridge and slope habitats,and most coarse roots occurred at soil depths of 20–40 cm.(iii)The coarse root density correlated negatively with tree species richness at soil depths of 40–60 cm.The abundances of the dominant species,such as C.eyrei,Cyclobalanopsis glauca,Pinus massoniana,had significant impacts on coarse root density.(iv)The soil depth of 0–40 cm was the"basic distribution layer"for coarse roots since the majority of coarse roots were found in this soil layer with an average root density of 84.18 roots m–2,which had no significant linear relationships with topography,tree species richness,rarefied tree species richness and tree density.Significant relationships between coarse rCoarse roots play a critical role in forest ecosystems and both abiotic and biotic factors affect their spatial distribution. To some extent, coarse root density may reflect the quantity of root biomass and biotic competition in forests. However, using tra- ditional methods （e.g., excavation） to study coarse roots is challenging, because those methods are time-consuming and labo- rious. Furthermore, these destructive methods cannot be repeated in the same forests. Therefore, the discovery of non-destructive methods for root studies will be very significant. In this study, we used a ground-penetrating radar technique to detect the coarse root density of three habitats （ridge, slope and valley） and the dominant tree species （Castanopsis eyrei and Schima superba） in a subtropical forest. We found that （i） the mean of coarse root density for these three habitats was 88.04 roots m-2, with roots being mainly distributed at depths of 0-40 cm. Coarse root densities were lower in deeper soils and in ar- eas far from the trunk. （ii） Coarse root densities differed significantly among the three habitats studied here with slope habitat having the lowest coarse root density. Compared with S. superba, C. eyrei had more roots distributed in deeper soils. Further- more, coarse roots with a diameter 〉3 cm occurred more frequently in the valleys, compared with root densities in ridge and slope habitats, and most coarse roots occurred at soil depths of 20-40 cm. （iii） The coarse root density correlated negatively with tree species richness at soil depths of 40-60 cm. The abundances of the dominant species, such as C. eyrei, Cyclobalan- opsis glauca, Pinus massoniana, had significant impacts on coarse root density. （iv） The soil depth of 0--40 cm was the ＂basic distribution layer＂ for coarse roots since the majority of coarse roots were found in this soil layer with an average root density of 84.18 roots m-2, which had no significant linear relationships with topography, tree species richness, rarefi

关 键 词：abiotic factors biotic factors coarse root density ground-penetrating radar （GPR） spatial distribution 

分 类 号：S718.5[农业科学—林学]