Several methods are available to assess the plantation timber volume at their maturity. However, most of those methods can not be applied to the teak (Tectona grandis L.f) plantations of Sri Lanka, due to different site qualities and different management practices since planting. Therefore it is essential to carry out a comparative study of commercial log production managed under different conditions. For this purpose, the use of height-diameter and relative taper curves for estimation and prediction of planted teak stands in dry and intermediate zones of Sri Lanka were evaluated. Even-age mature plantations which are subjected to clear fell was selected randomly. Standing tree measurements of 164 trees were taken at three sites to build up the height-diameter curve. At the same time, 158 trees were felled and took diameter measurements along the felled log to construct the relative taper curve. The resulted models are useful in generating accurate and localized predictions of standing tree height, total timber volume, commercial timber volume which would eventually lead to better estimations on differently managed teak plantation sites. By measuring the diameter at breast height alone, the developed log diameter-length tables could estimate the commercial log length according to specific diameter values which would finally lead to better commercial log estimation to compete with increasing demand along with different site conditions.