The mutual-belt selective cutting was conducted in the secondary poplar-birch forests. The changes of environmental factors after cutting were observed. The environmental factors of effect belts(cutting belts) of 15m ...The mutual-belt selective cutting was conducted in the secondary poplar-birch forests. The changes of environmental factors after cutting were observed. The environmental factors of effect belts(cutting belts) of 15m in width had great changes. 10-m effect belts had unnoticed changes in environmental factors. The reserved belts with 10-m effect belts had a greater increase in DBH growth rate and volume growth rate. The reserved belts for 6-m and 8-m effect belts had lower increase in DBH and volume. The environmental factors of 6-m and 8-m effect belts did not change much. comparing with their reserved belts. Cluster analysis and principal component analysis for environmental factors between each two belts were also made. and the results proved that 10-m cutting belt is the best way for management of the secondary poplar-birch forests.展开更多
The basic principle of life table method is deseribed, and the method of tree height instead of tree age in static life table is suggested, and it is also discussed that the possibility of natural poplar -birch forest...The basic principle of life table method is deseribed, and the method of tree height instead of tree age in static life table is suggested, and it is also discussed that the possibility of natural poplar -birch forest recover to broad-leaf Korean pine forest on low pitches in the Xiaoxing’an Mountains by this method. If there is no particular situation, Korean pines after high than 5m under natural Poplar-birch forest will basically survive and make their way into dominant callopy accompanied by climax broad-leaf species.展开更多
The community ecology of Poplar-Birch forest in China was studied. It includes the distribution, classification. structure. growth.regeneration, succession and forest management. Research direction of community ecolog...The community ecology of Poplar-Birch forest in China was studied. It includes the distribution, classification. structure. growth.regeneration, succession and forest management. Research direction of community ecology and forest management for PoplarBirch forest was pointed out. Further studies should be made on the relation between stand and ecological environment. the structure and dynamics. nursery role to needle leave trees,target cultivation and classification management. management of the second generation forest and the third generation forest.展开更多
Data from a survey in the Hasi Mountain areas of Jinyuan County in Gansu province of China showed that 83.3% white birch(Betula platyphylla) stand was infested by the Asian longhorned beete,Anoplophroa glabripennis.Th...Data from a survey in the Hasi Mountain areas of Jinyuan County in Gansu province of China showed that 83.3% white birch(Betula platyphylla) stand was infested by the Asian longhorned beete,Anoplophroa glabripennis.The longevity of the beetles was(41.2±11.5) days for a male and(39.1±13.1) days for a female when twigs of white birch were used as a sole source of food for the adult beetles.The area of twig barks consumed by a pair of beetles in their life time was(9.93±8.15) cm2.A female can make(12.4±12.1) egg pits in average during the period when they were alive and caged.If removal of the infested tree is used as a management measure,it must be excuted consecutively for two years to be effective.Field tests were conducted in 2005 and 2006 to treat infested trees with imidacloprid through trunk injection,soil injection,and soil drench.The results showed that the number of dead adults under the treated trees was 6.3 times for trunk injection,5.1 times for soil injection,and 4.9 times for soil drench more than that under the untreated control.The number of live larvae decreased by 95.8% for trunk injection,83.3% for soil injection,and 85.5% for soil drench in comparison with larva mortality in control.The number of egg pits made on tree trunks by an adult was decreased by 87.1%、77.4%and 82.6%for imidacloprid trough trunk injection,soil injection,and soil drench,respectively,compared with the untreated control.展开更多
文摘The mutual-belt selective cutting was conducted in the secondary poplar-birch forests. The changes of environmental factors after cutting were observed. The environmental factors of effect belts(cutting belts) of 15m in width had great changes. 10-m effect belts had unnoticed changes in environmental factors. The reserved belts with 10-m effect belts had a greater increase in DBH growth rate and volume growth rate. The reserved belts for 6-m and 8-m effect belts had lower increase in DBH and volume. The environmental factors of 6-m and 8-m effect belts did not change much. comparing with their reserved belts. Cluster analysis and principal component analysis for environmental factors between each two belts were also made. and the results proved that 10-m cutting belt is the best way for management of the secondary poplar-birch forests.
文摘The basic principle of life table method is deseribed, and the method of tree height instead of tree age in static life table is suggested, and it is also discussed that the possibility of natural poplar -birch forest recover to broad-leaf Korean pine forest on low pitches in the Xiaoxing’an Mountains by this method. If there is no particular situation, Korean pines after high than 5m under natural Poplar-birch forest will basically survive and make their way into dominant callopy accompanied by climax broad-leaf species.
文摘The community ecology of Poplar-Birch forest in China was studied. It includes the distribution, classification. structure. growth.regeneration, succession and forest management. Research direction of community ecology and forest management for PoplarBirch forest was pointed out. Further studies should be made on the relation between stand and ecological environment. the structure and dynamics. nursery role to needle leave trees,target cultivation and classification management. management of the second generation forest and the third generation forest.
文摘Data from a survey in the Hasi Mountain areas of Jinyuan County in Gansu province of China showed that 83.3% white birch(Betula platyphylla) stand was infested by the Asian longhorned beete,Anoplophroa glabripennis.The longevity of the beetles was(41.2±11.5) days for a male and(39.1±13.1) days for a female when twigs of white birch were used as a sole source of food for the adult beetles.The area of twig barks consumed by a pair of beetles in their life time was(9.93±8.15) cm2.A female can make(12.4±12.1) egg pits in average during the period when they were alive and caged.If removal of the infested tree is used as a management measure,it must be excuted consecutively for two years to be effective.Field tests were conducted in 2005 and 2006 to treat infested trees with imidacloprid through trunk injection,soil injection,and soil drench.The results showed that the number of dead adults under the treated trees was 6.3 times for trunk injection,5.1 times for soil injection,and 4.9 times for soil drench more than that under the untreated control.The number of live larvae decreased by 95.8% for trunk injection,83.3% for soil injection,and 85.5% for soil drench in comparison with larva mortality in control.The number of egg pits made on tree trunks by an adult was decreased by 87.1%、77.4%and 82.6%for imidacloprid trough trunk injection,soil injection,and soil drench,respectively,compared with the untreated control.
