Abstract:The relationship between leaf traits and environment is an important issue in plant ecology, where leaf traits variation along altitudinal gradient was paid much more attention. However, former studies were failed to consider the integrative effects of topography and soil properties on leaf traits. To improve the understanding on leaf trait variations of Quercus liaotungensis and the integrative effects of topography and soil nutrients on these changes, 119 continuous plots of 10 transects were investigated along altitudinal gradient (1000-1800 m) within the distribution range of Q. liaotungensis in Dongling Mountain near Beijing. Regression analysis showed that leaf morphological and nutritional responses to the altitudinal gradient varied differently. Stomatal density (SD), stomatal length (SL) and leaf area (LA) were non-linear with increasing altitude. Below 1400 m, SL and LA increased with increasing altitude, whereas SD decreased significantly. In contrast, when altitude was above 1400 m, these traits had reverse patterns, but blade length/width ratio (L/W) did not change significantly. Mass basis chlorophyll (a+b) content (ChlC), leaf nitrogen (Nmass), phosphorus (Pmass) and potassium concentration (Kmass) increased with altitude linearly. SD and SL negatively correlated and ChlC had marginally positive relationship with Nmass. Moreover, partial correlation analysis screened out that ChlC significantly correlated with slope position (POS) and Pmass correlated with slope gradient (GRA), but SD, SL and LA did not correlate with POS, GRA and soil nutrient, neither did leaf nutrient concentrations with soil nutrient conditions. Significant differences were found among the ChlC on bottom, middle and top slopes, where ChlC on top slopes was the highest. Although leaf traits of Q. liaotungensis had different variation patterns along the altitudinal gradient, 1400 m might be a critical altitude for most morphological traits.