Variation on certain morphological characteristics and annual ring growth of Tectona grandis Linn F.

The objectives of the present study were to determine the survival percentages, morphological characteristics and annual growth of teak planted in various Thai Plywood Company plantations, provenance trials, and a seed orchard and clone bank. It was also aimed to provide information on growth and development of teak for future applications. Under plantation conditions, the present study shows the survival percentages of 14 year old teak plantations ranged from 56-96 %; 18 year old teak provenances ranged from 70.0-91.0 % the 25 year old teak seed orchard ranged from 64.53-87.5 % and 8 year old teak clone bank was 86.30 %. In cases of provenances and seed orchards, significant differences in survival percentages were observed. Significant differences in height, diameter at ground level, and diameter at breast height of teak between plantations, among provenances, and among clones were found. Strong relationships between tree characteristics were detected in all cases. For economic consideration, tree volumes per unit area in Huay Tabor were found to be 2.46 times the teak grown in Lad Krating. Variation in tree volume among provenances and clones were reported. Results indicate the need for a tree improvement program, site selection and intensive management practices for teak growing. As regards the annual growth between the two selected plantations, the present study shows that the annual growth at Lad Krating was superior only for the first two years. Higher annual growth of teak was detected at Huay Tabor in the later stages. Concerning the provenance differences in annual growth development, the present study shows high annual growth in the early years and then progressive decrease. In case of the annual growth of clones established in the teak seed orchard and TPC Clone Bank, the average ring growth of teak clones varied considerably. The linear regression equations indicate that each clone responds differently to climatic factors and tree age. Ring indices of all clones are presented separately.