EN
Morphological traits of conifer species are known to vary adaptively with the geographic and climatic variables, but little is known about intra- and inter-population variation and impact of associated climate factors on the morphological variation. Chinese hard pine (Pinus tabulaeformis Carr) is a major and widespread component of coniferous forests in the temperate and semi-humid zone in northern China. Here we investigated 12 life history traits involving cone length (CL), width (CW) and dry weight (CDW), cone length to width ratio (CLW ), seed length (SL ), width (CW) and total weight (STW ), seed length to width ratio (SLW ), seed wing length (SWL), width (SWW) and total weight (SWTW ), seed wing length to width ration (SWLW ) at 12 sites between longitudes (102oE to 122oE) and latitudes (32oN to 43oN) covering an altitude range of 125–2581 m. Our results showed that each morphological character presented a large variation both within and among populations. Moreover, we found that proportion of phenotypic variation (i.e. Vst, %) of the all cone traits except for the cone width was over 50% among populations, indicating that the variation of these traits was mainly controlled by the environmental variables. Although the mean proportion of phenotypic variation of all measured traits was only about 28% among populations of this species, it was much higher than those of other conifers, which further suggested that this species held the higher adaptive phenotypic variation or stress-tolerance ability under varying environmental conditions. Furthermore, the phenotypic variation presented a general pattern that almost all measured traits were negatively correlated with the potential evapotranspiration which reflected the synthetic effects of multiple factors such as the temperature and rainfall, rather than a single environmental or climatic factor. In conclusion, according to the relationship between phenotypic variation and climate factors, it will undoubtedly provide important information for the reforestation and genetic conservation for this species in the changing climate.