This article investigates the relationship between net primary production (NPP) of Chinese fir, temperature and precipitation. The spatial–temporal NPP pattern in the potential distribution area of Chinese fir from 2000–2010 was estimated utilizing a MODIS MOD17 product in a geographic information system (GIS) environment. The results showed that the highest NPP value of Chinese fir is in the Fujian province in the eastern part of the study region. The relationship between NPP of Chinese fir and climate variables was analyzed spatially and temporally. On the regional scale, precipitation showed higher correlation coefficients with NPP than did temperature. The spatial variability pattern indicated that temperature was more important in central and eastern regions (e.g. Hunan and Fujian province), while precipitation was crucial in the northern part (e.g. Anhui province). Zonal analysis revealed that the impact of precipitation on the production was more complicate than that of temperature; larger amount of precipitation is not always corresponding with greater NPP value. When compared to natural forests, plantations appear to be more sensitive to the variability of precipitation, which indicates their higher vulnerability under climate change. Temporally, NPP values decreased despite of increasing temperatures, and the decrease was larger in plantations than among other vegetation types.

In this study, a pot experiment was conducted to explore the effects of different levels of N addition (control, low N: 25 kg N ha^-1 yr^-1, high N: 50 kg N ha^-1 yr^-1) on tree growth, leaf nutrient content, foliar P fractions, and root characteristics of two dominant tree species, the pioneer species Salix rehderiana Schneid and the climax species Abies fabri (Mast.) Craib, in a subalpine forest in southwestern China. The results demonstrated that low N addition had a minimal impact on leaf N and P contents. Conversely, high N addition significantly decreased the leaf P content in both species. S. rehderiana exhibited more pronounced increases in specific root length (SRL) and specific root area (SRA) under P deficiency triggered by high N addition when compared with A. fabri. In contrast, A. fabri showed weaker morphological responses to N addition but had a higher proportion of foliar P to metabolic P, as well as higher root exudates rate and root phosphatase activity in response to high N addition. A. fabri employs a synergistic approach by allocating a greater amount of leaf P to metabolite P and extracting P from the soil through P-mobilizing exudates and root phosphatase activity, while S. rehderiana exhibits higher flexibility in modifying its root morphology in response to P limitation induced by high N addition. This study provides insights into subalpine tree species adaptation to N-induced P limitation, emphasizing its significance for guiding forest management and conservation in the context of global climate change.