Growth of Teak (Tectona grandis L.f.) in Unthinned Plantations

Abstract

The objectives of this study were to measure the diameter and basal area growth of teak in unthinned plantations of the Forest Industry Organization, Lampang province, including Mae Chang, Mae Mai and Mae Moh  plantations. Samples of 72 cores from 36 trees were analyzed using dendrochronological techniques (tree ring analysis) to measure tree diameter and basal area growth.

The study results indicated that the average tree diameter of 23-24 year old unthinned teak trees ranged from 15.03 to 18.65 cm. Diameter growth trends in plantations spaced at 2×4 m and 4×4 m spacing plantations decreased in years 10-12 and years 5-9, respectively. Tree diameter growth varied from 0.418 to 0.715 cm per year and the basal area growth was 7.470×10^-5-8.580×10^-4 m2 per year.

The appropriate period for the first thinning should be when the diameter and basal area growth rates start to decline, when the teak was aged 10-12 y and 5-9 y at spacing of 2×4 m and 4×4 m spacing, respectively. The first thinning scheduled during the corresponding period could promote the growth in these teak stands.

Keywords:  growth, teak, thinning, tree ring analysis