近期，中科院华南植物园科学家发现，我国人工林与天然林的生产力及其多样性与年龄相关。相关研究结果已发表于《全球生态学与生物地理学》。

鉴于过去植物科学界较少研究全国尺度上同一气候带下人工林与天然林的生长表现，华南植物园植被与景观生态学研究组研究员任海携手美国林业署研究员郭勤峰，利用中国森林生态系统生物量和生产力的数据库，分析了中国热带雨林、亚热带常绿阔叶林等六个气候带的植被信息。

研究发现，在同一气候带内，虽然人工林的生物多样性低（常是单一种纯林），但有相似生物量的人工林比天然林的生产力更大。因而，其固碳速率更大。

与人工林相比，天然林乔木的生物量、生产力等数据显示了较强的纬度和海拔变化趋势。在人工林中，一个树种的纯林或两个树种的混交林的生产力没有显著不同。而天然林中，生物多样性高的森林，生产力更高。

结果表明，人工林与天然林生长表现出不同的主要原因是年龄、海拔和物种选择造成的，这些结果可为国家林业规划和管理提供重要参考。此研究得到中科院战略先导专项资助。（来源：中国科学报 李洁尉）

Productivity as related to diversity and age in planted versus natural forests

Abstract  Aim Little is known about the performance of plantations relative to natural forests of the same climate zone and age. China has more plantations than any other country as a consequence of massive afforestation efforts. We use data from China to comparatively examine tree biomass and productivity of planted and natural stands in relation to climate zone, latitude, elevation, age and species diversity (richness). Location Six forest climate/vegetation zones in China. Methods We used a database completed in 2007 and then updated in 2013 that contained extensive records of forest stands (10 m × 10 m plots) across China. The database records included a total of 6153 forest stands (1716 planted forests aged 0–80 years and 4437 natural forests of aged 0–400 years), located from 18.1 to 53.2° N and 75.53 to 131.8° E, and between elevations of 7 and 4240 m above sea level. These forests were grouped into six climate zones for comparisons. Results Under generally similar physical conditions (climate zones) to those in natural forests and despite having low diversity (i.e. often a single tree species), plantations aged 0–80 years already had similar biomass but much higher productivity, and thus much higher carbon sequestration rates, than natural forests. Tree biomass, productivity and their above/below ground ratios showed stronger latitudinal and elevational trends in natural forests than in planted forests. No difference in productivity was observed between the planted forests with one or two species; in natural forests, however, high diversity usually led to high productivity. Main conclusions The differences in performance between planted and natural forests were mainly explained by: (1) age (the plantations were in early succession), (2) elevation (plantations were located at lower elevations), and (3) species selection (only highly productive species were planted). As the plantations were all still young, closer monitoring of their performance is needed.

原文链接：http://onlinelibrary.wiley.com/doi/10.1111/geb.12238/pdf