Radial growth-climate correlations of Pinus massoniana in natural and planted forest stands along a latitudinal gradient in subtropical central China

Abstract

A better understanding of the relationship between tree growth and climate in natural forests (NF) and planted forests (PF) may help in predicting the potential impacts of climate change on forest growth. In this study, we compare the effects of climate variability on the radial growth of Pinus massoniana in NF and PF in the subtropical region of central-southern China along a large latitudinal gradient (24° - 32°N). Three to four plots were selected in both NF and PF at each of six sites, and core samples were taken from at least five trees in each plot. The tree rings of each core were analyzed and the ring widths measured. Our results show that growth-climate relationships are largely similar in NF and PF. Tree growth is positively correlated with temperatures in March, but negatively correlated with maximum temperature in September and November. Precipitation and the standardized precipitation evapotranspiration index (SPEI) in autumn enhance growth but those in May and June inhibit growth. Sunshine duration in autumn has a stronger negative effect on PF than NF. Growth responses to climate variables vary among sites both in NF and PF. From south to north, the effects of temperatures in summer on tree growth in PF shift from inhibiting to promoting tree growth. Precipitation in summer and winter has the opposite effect along the latitudinal gradient. The limiting effect of drought increases with latitude from south to north in PF, but not in NF. At the regional level, temperature explains most of the variance in radial growth of both NF and PF, whereas precipitation and SPEI explain more of the variance in PF than in NF. Our findings not only enrich our knowledge regarding the impacts of climate on forest growth, but also provide implications for the future forest sustainable management in the subtropical regions of central China.