Abstract:

Six natural stands of Schima superba with latitude and elevation gradient were selected in Zhejiang and Fujian Provinces to study individual phenotypic variation in stem form,bark morphology and wood properties, as well as effect of latitude and elevation on these traits. The purpose of our experiment was to provide a theoretical basis for the further exploitation and utilization of within-species variation of S.superba. The results revealed various types of bark traits and wood color among natural stands of S.superba. There were significant differences in stem form, bark type and wood basic density, but not in wood texture distortion degree among different stands. In contrast, the largest within-stand variation in wood texture distortion degree and the lesser within-stand variation in stem fullness, stem straightness and wood basic density were observed. Radial analysis in wood property showed that wood basic density decreased from pith to bark gradually. The ring width was increased at first but followed by reduction, and remain constant during 15^th to 25^th rings. Results also demonstrated that natural stands from higher latitudes exhibited higher stem fullness and straightness, thinner bark and lighter wood color relatively, whereas no clear regularity were observed for other characters. The effect of elevation was more significant in comparison with latitude, as increased trunk fullness, thinner and smoother bark, as well as decreased trunk straightness, ring width and wood basic density were observed in natural stands from higher elevation. The individual correlation analysis based on two natural stands from different elevation in the central production region showed that the correlation among traits were quite different and depending on different elevation of stands. In high elevation stands, bark traits could be used as good morphological indicators for wood properties and diameter growth. Individuals with higher stem fullness usually exhibited less wood basic density, as well as bark with lighter color and smooth surface. At the same time, individuals with higher stem straightness and dark bark usually exhibited faster grew speed in diameter. For stands from low elevation, bark thickness was demonstrated to be a good indication on wood basic density and other traits, as decreased wood texture distortion degree and increased wood basic density were observed in individuals with higher stem straightness, lighter bark color and large DBH increment.

Key words: Schima superba, natural stands, individual types, wood properties, phenotypic variation