四川长宁毛竹林碳储量与碳汇能力估测

利用生物量法研究了四川长宁毛竹林(Phyllostachys edulis)碳密度、碳储量及其空间分配格局,并对毛竹林碳汇能力进行了估算。结果表明:(1)毛竹立竹各器官的平均含碳率波动范围为462.37—480.68 g/kg,不同龄级毛竹各器官含碳率差异不显著。土壤有机碳含量为15.77 g/kg,不同土层差异极显著;(2)毛竹立竹碳储量为40.92 t/hm2,其中竹竿碳储量所占比例为51.49%,竹杆、竹枝、竹叶地上部分碳储量为26.76 t/hm2,占立竹碳储量的65.39%,地上碳储量为地下碳储量的1.89倍;(3)毛竹林总碳储量为156.57 t/hm2,其中土壤是其最大的碳库,为113.54 t/hm2,占总碳储量的72.52%,立竹碳储量所占比例为26.14%,林下植被碳库最小,为0.52 t/hm2,只占总碳储量的0.33%,可忽略不计;(4)毛竹林年生产量为20.28 t/hm2,年固碳量为9.43 t/hm2,相当于每年固定CO2量34.57 t/hm2,固碳能力较强。

Carbon stock and sequestration of a Phyllostachys edulis forest in Changning, Sichuan Province

Accurate estimation of carbon stock and sequestration of forests is a key in evaluating forest function in CO₂ mitigation in responding to the climatic change because it holds the largest carbon in terrestrial ecosystems. The complex biological and ecological characters of bamboo hinder such an effort, yet there exists an urgent need doing so due to its widespread, fast growth, high productivity, and multiple uses in Southern China. Here we report a comprehensive study on carbon production and storage, with systematic and accurate accounting of carbon density, storage and spatial distribution in a bamboo (Phyllostachys edulis) forest in Sichuan province using the biometric approach. We found that: (1) difference in carbon density among ages and organs in stumpage bamboo was not significant, with a mean of 472.82 g/kg. The range of carbon density of bamboo organs varied from 462.37 to 480.68 g/kg, with a descending order of sheath, rhizome, branch, stem, leaf, root. The soil carbon density was 15.77 g/kg, but varied significantly among layers. The carbon density was 379.96 g/kg and 377.66 g/kg, respectively, in the understory vegetation and the litter. (2) Carbon storage of the bamboo stand was 40.920 t/hm², with 21.07 t/hm² (51.49% of the total). The bamboo leaves contained the smallest amount (1.78 t/hm², or 4.35%). At our study site, the three-year old bamboo had higher proportion than the other aged stems, accounted for 19.91%. Above and belowground carbon accounted for 65.39% and 34.61%, respectively. The carbon storage of stumpage bamboo had the same distribution among various ages and organs. (3) The carbon storage in the top 30 cm was 113.54 t/hm² (69.02%). (4) The total carbon storage of the stand was 156.57 t/hm², which is partitioned into 113.54 t/hm² (72.52%), 40.92 t/hm² (26.14%) and 0.52 t/hm² (0.33%) in the soil, stumpage bamboo and understory, respectively. Although there is great differences in carbon storage between P. edulis and the other bamboos, the spatial distribution seemed similar. (5) Carbon sequestration of P. edulis stand was 9.43 t · hm² · a^-1, which is equivalent to 34.57 t/hm² of CO₂.