Influences of provenance and rotation age on heartwood ratio, stem diameter and radial variation in tracheid dimension of Cunninghamia lanceolata

Tracheid dimension, diameter at breast height (DBH) and heartwood ratio can significantly influence wood properties. Information about their variations upon provenance, rotation age and geometric locations within tree is necessary for the scientific cultivation and better utilization of wood materials. For this purpose, the influences of provenance (Chenshan and Rongshui) and rotation age (10, 20 and 30 years) on DBH, heartwood ratio and radial variation in tracheid dimension of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.), one of the major commercial plantation conifer tree species in China, were investigated. Results showed that for all selected variables, provenance was highly significant. Chinese fir from provenance Chenshan generally had the largest DBH, the biggest heartwood ratio, and tracheids with the longest, widest and thinnest dimensions. Besides, tracheid length displayed a radial increase from pith outwards for Chinese fir. It is more accentuated that DBH, heartwood ratio and tracheid length displayed apparent increments with prolonging the rotation age which were probably contributed from the differences in the differentiation of cambium to xylem, cambium age as well as the adaptability to the ecological conditions between two provenances. The results indicated that the rotation age of 20 years is suitable to carry out a clear felling of the stand for both provenances, and provenance Chenshan is preferable to be cultivated and utilized.