Abstract:

The species composition, DBH(diameter at breast height) class, existing form, decay class of coarse woody debris (CWD) were studied in a large permanent plot (9 hm²) of a typical mixed broad-leaved korean pine forest in Xiaoxing’an Mountains. All CWDs with DBH ≥2 cm were tagged, mapped, measured (girth) with species identified. Important findings: a total of 3 418 CWD individuals with DBH ≥2 cm were recorded in the 9 hm² plot among which the species of 864 CWD individuals were not able to be identified due to serious decay, accounted for 25.3% of the total samples recorded. The CWD density, basal area and volume were 380 indivadual·hm^-2, 15.80 m²·hm^-2and 90.1 m³·hm^-2, respectively. Acer ukurunduense and Betula costata were the major broad-leaved tree species while Pinus koraiensis and Abies nephrolepis were the major coniferous tree species. The basal area (9.12 m²·hm^-2) and volume (57.68 m³·hm^-2) of CWDs from coniferous tree species accounted for 57.7% and 64% of the total basal area and volume, respectively. The density of different types of CWDs decreased as increase of DBH class, and followed the inverse J-shape. The CWD existing forms was mainly composed of standing die, breakage at rootstock and breakage at trunk. Density of conifer stump CWDs increased with the DBH class. The decay classes of CWD followed normal distribution with a focus of decay class Ⅱ and Ⅲ, suggesting that the input and output of CWD was largely balanced in the mixed broad-leaved korean pine forest. Except the CWD of coniferous tree species with decay class V, the decay class of the rest of CWDs decreased with increase of DBH class.

Key words: mixed broad-leaved korean pine forest, coarse woody debris, exiting types, decay class, Xiaoxing&rsquo, an Mountains