| "Planting conifer and conserving broad-leaved" Korean pine forest nearly 30 years in Mt. Changbai, Mt. Zhangguangcailing, Mt. Xiaoxing'anling were selected as study objects, the effect of different crown thinning intensity was analyzed quantitatively by means of simple transect method and important value, diversity index and other index, so as to provide scientific basis for the management and restoration of secondary forest. The results showed that:①The different crown thinning intensity had influence on trees composition structure of "Planting conifer and conserving broad-leaved" Korean pine forest in forest region northeast China. The important value of Korean pine in Mt. Changbai plots gradually increased (94.04%-43.83%), formed broad-leaved Korean pine dominated by Korean pine and codominated by Tilia amurensis, Ulmus davidiana. As the crown thinning intensity increasing, the position of Korean pine in Mt. Zhangguangcailing plots increased gradually(45.8%-62.9%), formed broad-leaved Korean pine which Korean pine was in a preponderant position and the broad-leaved tree (Quercus mongolica, Betula dahurica, Tilia amurensis) was in a subordinate position. The importance of Korean pine in Mt. Xiaoxing'anling plots increased observably(24.6%-51.8%), formed broad-leaved Korean pine which Korean pine was dominant species, Quercus mongolica and Betula dahurica were codominant species, Populus davidiana, Betula platyphylla or Tilia amurensis were auxiliary species.②Korean pine diameter distribution had difference as canopy density changing. The smaller diameter class of Korean pine in Mt. Changbai plots reduced gradually (94.04%-43.83%);median diameter class increased gradually (5.96%-56.17%). As the crown thinning intensity increasing, the smaller diameter class of Korean pine in Mt. Zhangguangcailing plots showed decreasing tend (92.71%-69.90%); median diameter class showed increasing tend (7.29%-30.10%). The smaller diameter class of Korean pine in Xiaoxing'anling plots decreased gradually (89.9%-81.4%); median diameter class increased gradually (10.1%-18.6%).③Korean pine community volume productivity showed regular change as crown thinning intensity changing, showed increasing tend as the crown thinning intensity increasing. Volume productivity of broad-leaved Korean pine under tree in Mt. Changbai plots were 0.95,1.43,2.60m3/a·hm2; as the crown thinning intensity changing, volume productivity of broad-leaved Korean pine under tree in Mt. Zhangguangcailing plots were 0.88,1.39,2.84m3/a·hm22; volume productivity of broad-leaved Korean pine under tree in Xiaoxing'anling plots were 1.57,1.89,2.83 m3/a·m2.One-Way ANOVA showed that volume productivity difference was significant; there was significant difference among different crown thinning intensity by LSD test. ④Korean pine diameter and height annual growth had a close correlation with crown thinning intensity, showed increasing tend as canopy density decreasing. Diameter and height annual growth of Korean pine in Mt. Changbai plots were 0.20,0.29,0.39cm/a and 0.16,0.23,0.29m/a; as crown thinning intensity increasing, diameter and height annual growth of Korean pine in Mt. Zhangguangcailing plots were 0.27,0.33,0.39cm/a and 0.28,0.30,0.36m/a; diameter and height annual growth of Korean pine in Xiaoxing'anling plots were 0.24,0.29,0.32cm/a and 0.25,0.30,0.33m/a. One-Way ANOVA showed that diameter and height annual growth difference were significant; there was significant difference among different crown thinning intensity by LSD test.⑤Korean pine plant diversity showed regular change as crown thinning intensity increasing. Plant diversity of Korean pine in Mt. Changbai plots reached the highest value in canopy density 0.4; tree layer, herb layer and herb layer all had difference as canopy density changing. Plant diversity of Korean pine in Mt. Zhangguangcailing plots, the moderate crown thinning intensity was highest, weak was higher, strong was lowest, tree layer, herb layer and herb layer showed the same tend. Plant diversity of community layer, tree layer, herb layer and herb layer in Xiaoxing'anling plots showed canopy density 0.4>0.6>0.2 change tend. |
