Radial growth of Cunninghamia lanceolata and its response to climate in Jiangle National Forest Farm, Fujian Province of eastern China

Objective Cunninghamia lanceolata is a unique timber species in southern China, which has good greening effect and also high economic value. In this article, the relationship between radial growth dynamics of C. lanceolata and climatic factors was investigated at different time scales to provide a basis for scientific management of C. lanceolata in the study area.

Method In this study, the radial growth of C. lanceolata trees was continuously monitored at the Jiangle State owned Forest Farm in Fujian Province of eastern China for 4 years (July 2017−June 2021) using a radial growth meter to analyze their radial growth and determine the growing seasons, while partial and sliding correlation analyses were conducted to investigate the effects of climate factors, such as temperature, humidity, and precipitation on C. lanceolata radial extension.

Result  (1) C. lanceolata had periodic daily radial changes, which were mainly reflected in three stages, the first stage was contraction, the second stage was recovery, and the third stage was growth; the seasonal dynamics of radial changes in C. lanceolata underwent a trough period, a rise period and a stable period; there were interannual differences in radial changes in C. lanceolata, but the time series of diameter growth and cumulative change trends were basically the same. (2) The cumulative radial growth curves of C. lanceolata were combined to determine the growing season of C. lanceolata in Jiangle County, Fujian Province of eastern China, from February to September in each year. (3) The average relative humidity, precipitation, minimum temperature and average temperature were the main influencing factors, and the net increase of C. lanceolata had a significant positive correlation with precipitation. The sliding correlation analysis showed that the correlation coefficient increased and then decreased with the change of growing season time.

Conclusion The radial growth of C. lanceolata is closely related to climate factors, such as relative humidity, precipitation and temperature, therefore, studying the radial variation characteristics of C. lanceolata and its response to climatic factors provides an important technical pathway and reference model for better planning of survival strategies for the target tree species.