Abstract:

Response and adaptation of tree growth characteristics of sapwood and heartwood to climate changes are essential to exploring mechanisms of tree water relation and carbon metabolism, developing tree growth yield models, effectively using timber, etc. In this study, we compared the growth of sapwood and heartwood and allometric relationships of 26yearold Larix gmelinii trees growing under same environmental conditions but originated from seven provenances (Tahe, Mangui, Genhe, Xinlin, Sanzhan, Wuyiling, Heibei), representing significantly different geographical and climatic conditions, to examine effects of climatic conditions of origins on the growth characteristics of sapwood and heartwood. There were significant differences in such growth parameters as diameter at breast height (DBH), sapwood width (SW), sapwood area (SA), heartwood radius (HR) and mean sapwood growth rate (MSGR) among the provenances. The mean values of the parameters from the most southern provenance: Heibei were the greatest, whereas those from Sanzhan were the least. Provenances also significantly influenced the relationships between SA, heartwood area (HA) and MSGR, but did not affect the allomteric relationships of the parameters against DBH, and the ratio of heartwood area to sapwood area (HSR). The SW, HR, HSR and SGR were significantly correlated to DBH; and SA and HA were related to DBH as a power function. The mean annual air temperature and precipitation of the origins significantly affected the SA and MSGR of the larch trees except for the Sanzhan provenance. We concluded that significant changes in the growth characteristics of sapwood and heartwood of L. gmelinii due to the longterm adaptation to changes in temperature and precipitation of the origin, which were presented in terms of changes in growth rates instead of growth patterns.

Key words: Larix gmelinii , provenance, sapwood, heartwood, growth, adaptation