Heartwood, Calcium and Silica Content in Five Provenances of Teak (Tectona grandis L.) 1

Heartwood percent and content of silica and calcium were estimated in a 17 year old provenance trial of teak (Tectona grandis L.). Large variation were found both within and between the five tested provenances. Average contents of silica was significantly different between provenances ranging from 0.27% to 0.66%. Percent of heartwood and content of calcium were also significantly different between provenances and significantly correlated to tree size. Large trees had the