调查了青檀( Pteroceltis tatarinowii Maxim .) 人工林不同经营措施对林分地上部分生物生产力及檀皮产量的影响。 结果表明:( 1) 在密度及墩龄相同条件下, 单位面积檀皮产量与年龄成正比, 出皮率与年龄成反比;( 2) 单位面积檀皮产量年增长以第 3 年为最高, 分别是第 2 年和第 4 年年增长量的 1.58 倍和 4.12 倍;( 3) 在密度、留萌数及萌发年龄相同条件下, 单位面积檀皮产量以条墩年龄 12 年为最高, 分别是 6 年生和 9 年生的 3.32 倍和 1.11 倍;( 4)四种造林密度类型( 2 500 、3 333、4 200 和 5 350 墩 hm2) 中, 檀皮产量大小顺序为 4 200>3 333 >5 350>2 500。 4 200墩 hm2 ( 株行距 1.4m ×1.7m) 的林分檀皮产量是 2 500 墩 hm2 ( 株行距 2m ×2m) 林分檀皮产量的 1.68 倍;( 5) 在密度、墩龄相同条件下, 每墩留萌数为 10 时, 单位面积檀皮产量最高。 从收获经济生物量( 檀皮) 的角度考虑, 青檀人工林密度应在 3 333～ 4 200 墩 hm2之间, 轮伐期为 3 年;在条墩年龄为 9 年以上的人工林中, 留萌数以 10 条为好。
 

Based on the investigation of 33 plots in Jing County and Qingyang County, the effects of management practice on above-ground biomass and phloem yields were analysed. The results indicated that: ( 1) In the Pteroceltis tatarinowii Maxim. plantations with same density and same stump age, pholem production ( kg /hm² ) increased, but the rate of phloem to above-ground biomass ( % ) decreased with the increasing of sprout age. ( 2) For the sprouts with different age, the highest annual increment of phloem to above-ground biomass occurred in the third year, which is 1. 58 times of the second year, 4. 12 times of the fourth year. ( 3) In the same density but different stump age, the phloem production ( kg /hm² ) of P. tatarinowii plantations increased with the increasing of stump age and the highest productivity of phloem occurred in the stands with 12-year-old stump, which is 3. 32 times of the stand with the 6-year-old stump, and 1. 11 times that of the 9-year-old stump . ( 4) Within four planting densities ( 2 500, 3 333, 4 200 and 5 350 stumps/ hm²) , the highest production of phloem took place in the stand with 4200 stumps hm², reaching 3 765 kg/ hm², which is 1. 68 times of the stand with 2 500 stumps hm² . The ranking of phloem production was in the order 4200>3 333>5 350>2 500 stumps hm² . ( 5) In the stands with 3 333 stumps hm² and 9year-old stump, the highest production of phloem was achieved in the stand with 10 sprouts on each stumps. On the basis of the results, we suggest that 3 333～ 4200 stumps hm² should be chosen as a planting density, 3 years should be chosen as a harvesting cycle and 10 sprouts on each stump should be an option for the stands with over 9-year-old stumps in the practice so that high phloem production can be obtained.