西双版纳农田弃耕后橡胶园的建立对碳的固存作用

 由于温室气体的大量排放引起的全球气候变暖等环境问题日益严重，近年来人们开始考虑通过植被和土壤的碳固存，以缓解大气中CO2浓度的升高速度，减缓温室效应的影响。有研究表明，热带原始森林的保护和人工林的建立能有效地固存大气中的碳。但是，在建立热带种植园和人工林以固存大气CO2的可行性及其碳的固存潜力大小等方面还存在较大争议。云南省西双版纳自治州是我国重要的热带地区之一，目前橡胶(Hevea brasiliensis)园的面积为1.3×105 hm2，约占该地区林地面积的14%。在本研究中，选择11块在弃耕后的农田上建立的橡胶园（定植年限为3至38年），初步探讨了橡胶园建立后植被和土壤中碳的固存规律。两个生物量模型（唐建维等的模型和Brown模型）的模拟结果显示，橡胶园建立后植被中生物量的平均增长速率分别为10.2×103和9.4×103 kg·hm-2·a-1，40和100 cm表层土壤碳的平均固存速率分别为0.61×103和0.72×103 kg C·hm-2·a-1，植被和100 cm表层土壤中碳的平均固存速率为5.82×103和5.42×103 kg C·hm-2·a-1，而定植40年后植被和100 cm表层土壤碳的固存潜力为232.8×103和216.8×103 kg C·hm-2。对两个模型的比较结果显示，唐建维等的模型生物量计算结果明显高于Brown模型，尤其是在对中幼龄橡胶园生物量估算时更是如此。

CARBON SEQUESTRATION IN RUBBER TREE PLANTATIONS ESTABLISHED ON FORMER ARABLE LANDS IN XISHUANGBANNA, SW CHINA

The ability for vegetation and soil organic matter (SOM) to sequester atmospheric CO2 has receiveda lot of attention recently. Two management options being considered for enhancing C sequestration from the atmosphere include tropical forest conservation and establishment of plantations; however, there is still considerable debate regarding the appropriateness of using plantations and the sequestration potential of tropical plantations. There are 1.3×105 hm2 of rubber trees ( Hevea brasiliensis ) plantations in Xishuangbanna, southwest China, which account for approximately 14% of the forest lands in this region. In this study, eleven plantations of different ages were selected to investigate C sequestration in the vegetation and soils following the establishment of rubber tree plantations on former arable lands. The results indicated that the average biomass growth rates of the rubber trees, calculated according to two different biomass growth equations, were models. When comparing the two models, our results showed that the biomass calculated based on the equation of Tang et al. was higher than that based on the equation of Brown, especially in young- and middle-aged rubber tree plantations.