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Estimation of change of taper with age for Tectona grandis L. f. (Teak)
By hiran | December 10, 2007
M A Nafees, Divisional Forest Office, Ampara and
S M C U P Subasinghe, Department of Forestry and Environmental Science, University of Sri Jayewardenepura, Sri Lanka.
Taper is the change of diameter over a specified length along the tree stem, which varies not only by species and site type, but also by diameter at breast height (dbh), height and other tree growth parameters. Taper is important for the foresters to estimate the upper stem diameters especially in volume calculations. The main objective of the present study was to find out the variation of taper with different ages for Tectona grandis L. f. (teak). For this reason, three teak plantations of 22, 27 and 35 years of age were selected from the Block 01 in Kotagoda plantation, Ampara Forest Division. Selection of these three plantations from a single Block was done to minimise the effect of the site quality on tree growth. Data were collected from randomly laid out 14 circular plots of 0.05 ha. The trees in sample plots were measured for dbh, total height and sectional diameters at 5m and 10m along the stem. In order to estimate the taper variation, the equation developed by Kozak et al (1969) for Douglas fir in Western Colombia was used. This equation is given below and it is considered as one of the best models developed to estimate the upper stem tree diameters. (Equation)
; where d = diameter at height h and H = total height
At the first stage, the data were fitted to the selected equation separately for each age and the regression parameters were estimated separately without changing the basic structure of the original equation. It was observed that the parameter b0 and b2 were positive values and increased from age 22 to 27 and then decreased from that to age 35. The parameter b1 was a negative value which decreased from age 22 to 27 and then increased from that to age 35. When the results were examined further, it was observed that the taper is decreasing with the age proving that the teak tree stems become more conical with the age, i.e., the diameter difference increases with age for a fixed length along the stem.
Topics: Forest Management, symposium 2006 |
August 29th, 2008 at 9:25 pm
Dear Sir,
Is it possible to get a PDF copy of your entire paper entitled “Estimation of change of taper with age for Tectona grandis”?
I am involved with teak plantations in Brazil and would very much appreciate to know your work better.
Thank you for your attention,
Kind regards,
Fernando Torres