集约经营雷竹林分结构特征

Structure characteristics of intensive managed Phyllostachys praecon stand

以湖北省崇阳县雷竹林为研究对象,对集约经营雷竹林分结构及各器官生物量分配特征进行了调查与分析,结果表明:集约经营雷竹笋用林立竹在林地上分布均匀,调查的雷竹林分平均胸径为2.55cm,通过胸径计算得到的适宜经营密度约为15 000株/hm2(1 000株/667 m2);林分中立竹处于年青状态,1年生、2年生、3年生及4年生、5年生立竹数依次为3 000、4 660、3 880、460、20株/hm2,所占的百分率依次为24.59%、38.20%、31.80%、3.77%及1.60%;钩梢有利于雷竹林分抗雪压,虽然钩梢后立竹留盘数减少,冠幅减小,但平均每枝叶面积指数增大;生产中每年通过在林地上均匀保留健壮的笋体而形成新立竹,因而林木株数按径阶的分布不符合正态分布规律,出现向右偏态;农事活动使枝下高也发生变异;雷竹林各器官生物量大小依次为杆>竹蔸>竹鞭>叶>枝,钩梢使各器官生物量大小发生变化。

Research had been carried out into the structure and the biomass for different organs of Phyllostachys praecon stands located at Chongyang County, Hubei Province,which were intensive managed,the results showed that bamboo stems were uniform distributed in ground, the average DBH of plots studied was 2. 55 cm,the management density calculated according to the average DBH was 15 000 stems per hm^2 （1 000 stems per 667 m^2）;all stands studied were very young and in good health, stems density for 1,2,3,4 and 5 a were 3 000 stems per hm2,4 660 stems per hm^2,3 880 stems per hm^2,460 stems per hm^2and 20 stems per hm^2 with 24. 59%, 38. 20%, 31.80%, 3.77% and 1.60%, respectively; for anti-snow pressure,although tip hooking made the stem shorted, branch round decreased and crown width dwindled, leaf area index increased. When harvesting bamboo shoots, big and strong shoots were kept uniform in a stand ground which would grow as new stems, so the distribution of DBH was not a normal one,but a rightward. The tending made the stem height under the branch changed as well. The biomass for different Phyllostachys praecon organ was in the following order： eulm〉bamboo stump〉 bamboo rhizome〉leaf〉branch,and tip hooking also made the biomass for organs varied.