[Responses of radial growth of Quercus mongolica to stand density and climatic factors in a mountainous area of eastern Liaoning Province, China]. / è¾½ä¸œå±±åŒºè’™å¤æ Žå¾„å‘ç”Ÿé•¿å¯¹æž—åˆ†å¯†åº¦å’Œæ°”å€™å› å­çš„å“åº”.

To explore the effects of stand density and climatic factors on radial growth of Quercus mongolica, we used tree ring chronology to examine the radial growth changes in a secondary Q. mongolica forest under different levels of stand density (thinning). The meteorological data combined with the driving factors of Q. mongolica growth were analyzed. The results showed that the radial growth of Q. mongolica was significantly affected by stand density. The mean annual radial growth of Q. mongolica was 3.12 mm in low-density virgin forest, 1.55 and 1.42 mm in the two medium-density secondary forests, respectively, and 0.96 mm in high-density secondary forest. The thinning intensity of 20% had a limited effect on promoting the radial growth recovery of high-density forest (1900 trees·hm-2), but had a significant effect on medium-density forest (1600 trees·hm-2). The radial growth of Q. mongolica was sensitive to the precipitation changes in January and February of the current year. Thinning reduced the sensitivity of Q. mongolica radial growth to climate. Under scenarios of climate warming and drying, density regulation could be beneficial in mitigating the adverse effects of climate change on the growth of Q. mongolica.

[Spatial structure characteristics of the main tree species in a mixed broadleaved Korean pine (Pinus koraiensis)forest in a mountainous area of eastern Liaoning Province, China]. / è¾½ä¸œå±±åŒºåŽŸå§‹é˜”å¶çº¢æ¾æž—ä¸»è¦æ ‘ç§ç©ºé—´ç»“æž„ç‰¹å¾.

Maintaining forest structural diversity is generally considered as an effective way to preserve forest stability and biodiversity. The spatial structure characteristics of the dominant tree species in a climax community were investigated in a primary mixed broadleaved Korean pine (Pinus koraiensis) forest in a mountainous area of eastern Liaoning. Stand spatial structure parameters were determined based on the relationships among neighboring trees. The climax communities were used as a theoretical reference for optimizing the spatial structure of a low-quality secondary forest and monoculture plantation. The diameter distribution of the trees in the pine forest exhibited an inverse J-shape, indicating that understory regeneration was relatively good and with certain proportion of large-diameter trees. The main tree species were randomly distributed across the whole plot (=0.507) and in an intensively mixed state (=0.82). An average DBH comparison of trees in the stand indicated that they were at a intermediate status (=0.506). There was a differentiation among different dominances along the high intensity mixed dimension in the stand, indicating an optimal distribution of understory trees and the rational utilization of resources. Trees in the small diameter category were at a state of complete compression, while canopy trees were at a state of complete dominance in terms of their vertical space. Individuals of each dominant tree species were randomly scattered, with a random pattern of individuals throughout the climax community.