Spatial point pattern of coarse woody debris in temperate coniferous forest along an elevation gradient in Wuyi mountain

To investigate the spatial patterns of coarse woody debris (CWD) and their variation along altitudinal gradients in the temperate coniferous forests of Wuyi mountain national park, and to provide a scientific basis for the sustainable management and ecological protection of the forest floor in these mountainous regions.

Taking the temperate coniferous forests located at four altitudinal gradients (1 300, 1 400, 1 500 and 1 600 m) in Wuyi mountain as the research subjects, we conducted a comprehensive survey of Coarse Woody Debris within these forests. Based on this survey, we used point pattern analysis to examine the spatial patterns and spatial associations of CWD with different characteristics (forms of existence, decay stages, and diameter classes) at each altitude.

1) The number of CWD in different diameter classes at all altitudes followed the pattern: diameter class I > diameter class II > diameter class III; 2) The proportion of standing dead wood increased with elevation, whereas the distributions of fallen logs, large dead branches, and stumps did not follow a similar pattern; 3) CWD generally exhibited a clumped distribution within a small scale (0-4 m), and the scale of this clumped pattern expanded with increasing elevation; 4) The spatial association between decay classes I and II of CWD gradually shifted from positive to non-significant with increasing altitude; size classes I and II displayed a positive correlation at small scales, which intensified with elevation.

The CWD in the temperate coniferous forests of Wuyi mountain exhibit an altitudinal dependency in terms of aggregation scale, forms of existence (especially standing dead trees), and spatial associations of different decay stages and diameter classes. The findings of this study not only provide a new perspective for elucidating the response patterns of CWD spatial distribution along altitudinal gradients but also lay the foundation for further research on the altitudinal patterns of CWD carbon storage in the forest floor of Wuyi mountain’s temperate coniferous forests.