Influence of climate factors on tree-ring growth in teak (Tectona grandis L. f.) plantations in the Bago Yoma Range, Myanmar.

摘要

The anatomical features of tree rings reflect information about past climatic conditions, and the variation of rainfall patterns from year to year is reflected in tree-ring width pattern. We studied the relationship between tree-ring width of teak (Tectona grandis L. f.) and weather conditions at different age classes of two distinct weather condition areas located in Bago Yoma Range, Myanmar. The sample plot was 1.0 ha of each investigated plantation and we used a computer-compatible tree-ring measuring program (Measure J2X) to measure the tree ring, and the Thornthwaite method for calculating annual moisture index. The average radial increment of 25-, 20- and 15-year-old plantations was 6.2 mm yr-1 while that of the 9-, 10- and 12-year-old plantations was 7.6 mm yr-1. We found that the tree ring was positively correlated with the annual total rainfall in all plantations but was not significant. However, it showed coherent patterns with the chronologies of standardized tree-ring width and annual moisture index in both studied sites. Overall, young age plantations were found to be more highly affected by the changes in the annual total rainfall than older plantations by height. On the other hand, temperature was found to be related negatively to tree ring for mature stage plantations while positively for young plantations.