Objective  To study the differences in the geographical provenance of Chinese fir (Cunninghamia lanceolata(Lamb.)Hook) in different-aged forest and to screen provenances in the experimental area for the purpose of promoting the long-term genetic improvement of Chinese fir provenance.

Method  A provenance test forest of Chinese fir was established in 1981, and the major growth parameters were measured at the 5th, 10th and 31st years to detect the genetic variation in DBH, tree height and volume index among provenances. The study evaluated the long-term selection effect of good provenance by using juvenile-mature correlation and cluster analysis.

Result  The result showed that there were great significant genetic variation in tree height, DBH and volume. The variation coefficients at the 31th year were 75.86%, 48.55% and 263.76% for DBH, tree height and volume. The variance of traits followed an obvious geographic variation pattern, and latitude played the major role. From the south to north, the increment of Chinese fir increased at first and then decreased, and the provenances from southwestern and southeastern China grew better. The heritabilities of provenance for DBH, tree height and volume varied between 0.75 and 0.85, indicating the three growth traits had high genetic control level. The trait value and the rank based on major traits were correlated significantly and positively among different selection ages. This study showed that the appropriate selection age for Chinese fir provenance test should be about 10 years. Twenty-nine provenances of Chinese fir were selected from 169 provenances, most of which originated from Fujian Province and the others originated from Guizhou, Guangxi and Hu'nan province. Among them the provenances grew the best came from Chong'an, Shunchang, and Youxi of northern Fujian Province. The genetic gains of DBH, tree height and volume were 23.21%-31.45%, 15.60%-20.19%, and 59.94%-89.97%, respectively.

Conclusion  The early selection age has a significant effect on shortening the breeding cycle of Chinese fir. Selection at the 10th year is more conducive to improve the efficiency of Chinese fir genetic improvement. The 29 excellent provenances selected from the 31-year-old mature Chinese fir forests have a larger increase than the local provenances, and are suitable for expanding in the Jiangxi Province and the surrounding areas.