求翻译：森林生态系统是陆地生物圈的主体，它不仅在维护区域生态环境上起着重要作用，而且在全球碳平衡中也起着巨大的贡献。这是由于森林生态系统本身维持着大量的植被碳库（约占全球植被碳库的86%以上)，同时也维持着巨大的土壤碳库约占全球土壤碳库的73%。是什么意思？

Forest eco-system is the body of the terrestrial biosphere, it not only plays an important role in the maintenance of regional ecological environment, and also played a tremendous contribution in the global carbon balance. This is because itself maintains a large amount of vegetation of the forest ecosystem carbon pool (about 86% global vegetation carbon pool above), while also maintaining a huge about global soil carbon pool of soil carbon pool 73%.