川西山地主要人工林种群根系生物量与生产力

Studies on root biomass and productivity in dominant plantation populations in the mountainous land in western Sichuan

采用标准地法,对四川西部山地主要人工林的根系进行了研究,结果表明:(1)用D2H估测单株林木根系生物量的适合模型均以幂函数模型为最佳,所筛选统计模型的相关系数较高,在0.94～0.99之间;(2)根系总生物量大小排序为日本落叶松>峨眉冷杉>四川红杉>川西云杉,分别为37.832、24.907、18.320thm2和15.982thm2,各级根的生物量占总根量的比例各不相同;(3)根系生物量集中在分布土层0.00～40.00cm,川西云杉占97.88%,四川红杉占96.78%,峨眉冷杉占95.65%,日本落叶松占99.72%;尤其在0.00～20.00cm土层分布的根最多,分别占77.13%,77.13%,65.02%和80.66%;在0.00～20.00cm,20.00～40.00cm和40.00～60.00cm的各层根系生物量分配比例,川西云杉为34∶12∶1,四川红杉为24∶6∶1,峨眉冷杉为15∶7∶1,日本落叶松为63∶14∶1;(4)川西云杉、四川红杉、峨眉冷杉和日本落叶松人工林种群根系的生物量密度分别为10.782t(hm2·m),8.230t(hm2·m),14.546t(hm2·m)和13.211t(hm2·m);(5)川西云杉、四川红杉、峨眉冷杉和日本落叶松人工林种群根系生产力分别为0.57、0.83、0.71t(hm2·a)和1.64t(hm2·a)。

This study investigated root biomass and productivity in dominant plantation populations in western Sichuan, China. A total of 4 plots （Pieea balfouriana plantation population for 28 age in Maerkang, 9 trees, mean DBH of population for 10.4cm and height for 10.5m; Larix maxteriana plantation for 22 age in Wolong, 9 trees, mean DBH of population for 17.0cm and height for 13.8m; Abies fabri plantation for 35 age in Ebian, 18 trees, mean DBH of population for 14.1cm and height for 11.9m; Larix kaempferi plantation for 23 age in Miyaluo, 8 trees, mean DBH of population for 17.4 cm and height for 14.5m; a 20 m×25 m plot located on each of the 4 types in western Sichuan, China） were randomly selected and excavated to a depth of 60cm for each of the 4 plantation population types. To estimate the root biomass of an individual tree using D^2H, an exponential model was selected with the highest coefficient ranging from 0.94 to 0.99. The total root biomass per hm^2 varied among plantation population types following the order： Larix kaempferi （37. 832 t/hm^2 ） 〉 Abies fabri （24.907t/hm^2 ） 〉 Larix maxteriana （ 18. 320 t/hm^2 ） 〉 Picea balfouriana population（ 15.982t/hm^2 ）. The biomass fractions of a given root size class compared to the total root biomass differed among plantation population types. For all 4 studied plantation types, the majority of the roots were distributed in the top 40 cm of soil, e.g. 97.88 % for Picea balfouriana population, 96.78 % for Larix maxteriana, 95.65 % for Abies fabri, and 99.72% for Larix kaempferi population. The root biomass fractions distributed in the top 20 cm of soil were 77.13% for Picea balfouriana,77.13% for Larix maxteriana, 65.02% for Abies fabri and 80.66% for Larix kaempferi, respectively. The root allocation in the 0 - 20, 20 -40, and 40 -60 cm soil layers gave ratios of 34 ： 12 ： 1 for Picea balfouriana, 24 ： 6 ： 1 for Larix maxteriana, 15 ： 7 ： 1 for Abies fabri, and 64： 4 ： 1 for Larix kaempferi populations. The root biomass density of dominant plantation population was 10.782 t/（hm^2·m） （for Picea balfouriana） ,8. 230 t/（ hm^2·m） （ for Larix maxteriana ）, 14. 546 t/（ hm^2·m） （ for Larix maxteriana）,, 13.211 t/（hm^2·m） （Larix kaempferi population）, respectively. The root biomass productivity was found to be 0.57 t/（hm^2·a） （for Picea balfouriana）, 0.83 t/（hm^2·a） （for Larix maxteriana）, 0.71 t/（hm^2·a） （for Abiesfabric） and 1.64 t/（ hm^2·a） （ Larix kaempferi population）, respectively.