ブナ林の上層木がもたらす散光環境と下層木の分布
Distribution patterns of understory trees and diffuse light under the canopy of a beech forest

Shogo KATO, Akira KOMIYAMA
1999 Nihon Seitai Gakkaishi  
Science , Gifu Unlversity , Yanagido , Gifu 501 − 1193, Japan) , Japanese/ournal ρ プ Ecotogy 49 : 1 − 10 ( 弖 999 ) We studied the relationship between the llght environment and distribution patterns of understory woody species ln a natural beech f ( )rest in Japan. Stem Iocations and diameter at breast height ( dbh)of 2 , 039 understory trees comprising of 30 species ( 】cm ≦dbh 〈 5 じm ) were inves − tigated in a O, 4 − ha plot . Relative photosynthetic photon Hux density( rPPFD ) at O, 2and 4 m
more » ... FD ) at O, 2and 4 m above ground was measured at I 89 points inthe plot 重 n September and November . The understory vegetation was covered with heavy snow unt 三 l early June , when the overstory trees had already leaf ヒ d ou し Using the rPPFD data at 4 m height in September , the light condition above each stem was eyaluated fbl ' the understory trees . The rPPFD value varied within a wide range , 5, 4 -65, 7%. Higher rPPFD values were related to the presence of canopy gaps of ≧ 100 m2 , Two types of understory species were recognized ffom their distribution patterns , according to the relationship between stem locations and rPPFD distribut 重 on . The 1 ) runus g 厂 α ア 砌 α type was distributed widely throughout the plot withQut any change in its local densi 宅 y, irrespective ofthe rPPFD leveL The Co1 ッ lus sieboldia type showed an aggregated distribution at sites with a high rPPFD value , although it also appeared throughout the pEot . These results suggest that the varied light environment resulting from a heterQgeneous canopy structure is an important factor a 牙 recting loca】 density f( )r some components of the understory community ,
doi:10.18960/seitai.49.1_1 fatcat:ymjs57uexrecxe33zwgbeup46m