华北沙地小黑杨林生物量及其与树冠关系的研究

A Study on Biomass and Productivity of Populus × xiaohei Plantation on Sandy Land in North China

应用相对生长法和典型样方调查法对华北沙地不同密度、不同年龄的小黑杨人工林生物量和生产力进行了估算，同时对树冠与生物量的关系进行了研究。结果表明：密度为1000株·hm^-2、500株·hm^-2、250株·hm^-2的小黑杨林分（27年生）的生物量分别为85．31t·hm^-2、102．60t·hm^-2、86．74t·hm^-2；生产力分别为3．16t·hm^-2·a^-1、3．80t·hm^-2·a^-1、3．21t·hm^-2·a^-1，密度500株·hm^-2为华北沙地小黑杨的合理密度。不同密度小黑杨不同器官生物量所占的比例差异不明显，地上部分生物量在83％～86％之间，其中干57％～62％，枝11％～16％，叶2％～3％，皮8％～10％；地下部分生物量在14％～17％之间。对不同年龄小黑杨的生物量和生产力研究表明，27年生的比23年生的分别高59．74％和36．20％。同时，23年生小黑杨的根、叶所占比例明显高于27年生的根、叶比例，但是干生物量所占比例低于27年生小黑杨，反映了23年生小黑杨的生物量和生产力处在快速生长期，小黑杨的轮伐期应在27年以后。小黑杨生物量与树冠之间存在极显著的相关关系，其中树干生物量与树冠指数之间可以用线性模型Y=ax＋b描述，利用遥感技术可以反映小黑杨林树干生物量，为进一步利用遥感预测小黑杨木材材性提供了重要的基础数据。

The underground and aboveground standing biomass and productivity of Populus x xiaohei plantation with different densities and stand ages were measured by the methods of sampling typical plot and allometric dimension analysis in Xuejiazhuang Forest Farm in Shanxi Province. It showed that the rationale density of Populus x xiaohei plantation was 500 trees per hectare. The biomass of 29 years old Populus x xiaohei plantation with 1 000,500,250 trees per hectare was 85.31 t · hm^-2, 102.60 t· hm^-2 , and 86.74 t· hm^-2 , respectively. The productivity of Populus xxiaohei plantation was 3.16 t·hm^-2·a^-1, 3.80 t·hm^-2·a^-1 , and 3.21t·hm^-2·a^-1 , respectively. The proportion of tissue biomass had little difference in the 29 years old stand. The proportion of aboveground biomass ranged from 83% to 86% , the proportion of stem ranged from 57% to 62% ,the branch ranged from 11% to 16% ,the leaf ranged from 2% to 3% , and the bark ranged from 8% to 10% ; the proportion of underground biomass ranged from 14% to 20%. The biomass and productivity of 27 years old Populus x xiaohei plantation was higher than the that of 23 years old Populus x xiaohei plantation. The biomass increased by 59.74% in 27 years old plantations, and productivity increased by 36.20%. The proportion of leaf and root in the 23 years old plantations was significantly higher than that of 27 years old plantations, but the proportion of stem biomass in the 23 years old plantations was lower than that of 27 years old plantation, which showed that the 23 years old plantation was in rapid growth period. Therefore, the rotation of Populus x xiaohei plantation should be longer than 27 years. There was a very significant correlation between the biomass of Populus x xiaohei and the canopy indexes. The relationship between tree stem biomass and tree canopy indexes could be described as y = ax ＋ b. Applying remote sensing techniques in biomass estimation was practicable, and it could provide the basis data for remote sensing techniques in wood properties estimation.