Variation of Growth and Wood Property Traits of Red Heartwood Cunninghamia lanceolata and Its Early Selection

This study concentrated on the assessment of growth and wood property traits in a 6-year grafted clone test of 104 red heartwood Cunninghamia lanceolata. The results indicate that all growth traits of height, diameter at breast height (DBH), stem volume and the wood basic density (WBD) varied significantly among clones. Remarkable clonal differences were also observed for the wood with or without the red heartwood (RHW). Only 40 C. lanceolata clones expressed a notable RHW but each had a different reappear rate and maximum RHW ratio because the RHW ratio varied among ramets of a clone. The growth traits consistently had a high repeatability estimate, and the WBD was 0.37, 14 clones had a notable RHW with reappear rate of ≥50%. Phenotypic correlations for growth traits, RHW with WBD traits were strong and positive. When selection was made for DBH and RHW reappear rate (≥50%), 11 elite clones (cx180, cx200, cx624, cx703, cx710, cx725, cx729, cx735, cx746, cx762, cx797) were identified with an consistently positive realized gain in DBH, WBD and maximum RHW ratio.