地形与栽培模式对轻木生长的影响OA

To investigate the effects of different topographies and cultivation models on the wind-induced breakage rate,diameter at breast height(DBH),tree height,and timber volume of balsa wood,and to provide a theoretical basis for the domestic production of balsa wood in China,a survey was conducted on 3-4 year-old balsa trees(at harvesting age)from 14 demonstration bases in the Xishuangbanna region.The study found that:(1)In pure balsa plantation,trees on flat land and leeward slopes(semi-shady and shady slopes)were almost unaffected by wind damage,while those on windward slopes(sunny slopes)had a wind-induced breakage rate of 8.85%,and riverside areas had a breakage rate exceeding 20%.The average DBH of 3-4 year-old balsa trees in riverside,flat land,leeward slope,and windward slope areas was 26.72 cm,24.86 cm,22.20 cm,and 17.58 cm,respectively,with corresponding tree height was 19.73 m,21.43 m,22.52 m,and 14.67 m.(2)In the balsa/rubber intercropping model,the DBH of balsa trees on leeward and windward slopes was 28.30 cm and 21.14 cm,respectively,with corresponding tree height was 23.79 m and 16.13 m.(3)In pure balsa plantation,leeward slopes,flat land,and riverside areas were conducive to balsa growth,with timber volumes of 131.33 m3·hm-2,123.90 m3·hm-2,and 118.21 m3·hm-2 for 3-4 year-old trees,respectively.Windward slopes were unfavorable for balsa growth,yielding only 40.58 m3·hm-2.In the balsa/rubber intercropping model,the timber volumes on leeward and windward slopes were 85.77 m3·hm-2 and 40.58 m3·hm-2,respectively.Therefore,in Xishuangbanna region,flat land and leeward slopes were suitable for balsa cultivation and the establishment of balsa/rubber agroforestry systems.Windward slopes were unfavorable for balsa growth,as trees were prone to wind damage and should not be used for balsa cultivation or balsa/rubber intercropping.Riverside areas were highly susceptible to wind damage,and unless effective windbreaks were available,balsa cultivation was not recommended in such locations.