[Responses of soil carbon and nitrogen mineralization to nitrogen deposition in tundra zone of the Changbai Mountain, China.].

The alpine tundra ecosystem, with low soil inorganic nitrogen (N) availability, has a weak buffer against nitrogen and is susceptible to exogenous N enrichment. Here, with a laboratory incubation experiment, we investigated the response of soil carbon and nitrogen mineralization to N deposition with soil samples from the tundra zone on the northern slope of the Changbai Mountain. We set three N levels, control (CK, 0 kg·hm), low N (N, 25 kg·hm), and high N (N, 50 kg·hm), with N being added as NHNO.

[Effect of neighborhood competition on key tree species growth in broadleaved-Korean pine mixed forest in Changbai Mountain, China.].

Competition is the main factor affecting the growth, morphology and death of trees in fore-sts. The analysis of individual competition can reflect the characteristics of interaction among individuals and their interaction ranges, which is important for reducing individual competition and promoting tree growth. To understand the effects of competition on tree growth in broad-leaved Korean pine forest, based on Hegyi single-tree competition index and neighborhood analysis method, we explored the neighborhood radius of competition for five key tree species, i.

[Competition of key tree species with selective cutting at different intensities in broadleaved-korean pine mixed forest in the Changbai Mountain, China.].

Selective cutting changes tree species composition and stand structure, modifies tree competition intensity in the stand, with consequences on tree growth and population dynamics. Key tree species play a crucial role in maintaining community structure and ecosystem function. To clarify the competitive characteristics of three key species (Pinus koraiensis, Tilia amurensis, and Fraxinus mandshurica, which accounted for about 70% of growing stock) of typical forest types in broadleaved-Korean pine mixed forest, Hegyi competition index was used in four permanent 1-hm plots, i.