No Clinal Variation in Cunninghamia lanceolata Wood Density Sampled from Thirteen Chinese Provinces

Seeds of China-fir were obtained from 42 provenances in 13 provinces of China. Height and diameter were measured at the ages of 11, 16, and 18 years. Wood density samples were taken by increment core at breast height and were assessed by the water displacement method. Isozyme frequencies of PGI, SKDH, and 6PGD were observed from electrophoresis. Wood density ranged from a high of 0.310 in Jiangsu Province to a low of 0.273 in Guizhou Province in southwestern China. The China-fir in these 2 provinces differed from those of their neighboring Provinces. Correlation between density and isozyme frequency was not significant for SKDH and 6PGD; it was weak for PGI. Since there were no linear geographic or climatic trends detected, random variation due to local factors appears to be a suitable description for wood density in China-fir.