Do climate and human disturbance determine the sizes of endangered Metasequoia glyptostroboides trees in their native range?

Under global change scenarios, climate change and habitat loss or alteration as a result ofhuman activities are regarded as two important factors affecting species’ distributions andin situ conservation. Metasequoia glyptostroboides Hu et Cheng, a living fossil, occursnaturally only in a small region in Central China, with most individuals now growing nearhuman settlements. The climate in the native range is poorly characterized, and little isknown regarding what potential factors (e.g. climate variables) explain variation in thesizes of M. glyptostroboides trees. Here, we found that climate variables were not, or onlyvery weakly, related to three measures of tree sizes: canopy sizes, DBHs (diameter at breastheights) and heights. As elevations increased, tree heights and canopy sizes decreasedsignificantly, but no relationship was found with DBHs.