Monday, July 23, 2007

Preparation of a Management Plan for Small Scale Teak Plantations

K M T S Jayarathne and S M C U P Subasinghe
Department of Forestry and Environmental Science, University of Sri Jayewardenepura
Nugegoda, Sri Lanka

Teak (Tectona gradis) is one of the most valuable timber species in the tropics. It is introduced to Sri Lanka in 1680 by Dutch. At present 45,336.9 ha of teak plantations are maintained by the Sri Lanka Forest Department as homogeneous plantations in dry and intermediate zones. Other than that teak is grown as mixtures with Jak, Margosa, Eucalyptus and Mahogany. The popular methods of establishing teak plantations were Taungya System and PFPs (Participatory Forestry Projects). Teak is maintained as State owned lands, Private lands or Farmers woodlots.

Teak Plantations in Sri Lanka are maintained for productive purposes. Therefore the costs and benefits must be considered economically and ecologically before drawing up proper management plans, especially for the small scale plantations. The yield from properly managed plantations is obtained not only from the final felling but also from silvicultural operations which are applied at regular intervals. In order to manipulate those activities and to maximize the income with minimum environmental impacts comprehensive management plans are required.

With the above considerations, the present study was designed to achieve the following objectives; (i) to identify the maximum extent of a small scale plantation; (ii) to prepare a comprehensive working plan for a selected plantation; (iii) to identify the environmental damages and possible conservation methods in small scale teak plantation management and (iv) to prepare cost and income values at intermediate and final harvestings.

The selected land (12.5 ha) for the present study was initially owned by Rambapokuna Temple in Rambapokuna village in Kurunegala district (309 Kandegedara GN division, Nikaweratiya DS division). It was acquired by the Forest Department in 1999 and given 0.4 ha to each farmer under 25 years lease agreement. The particular block which was used for the data collection was owned by Mrs. W.A. Karunawathi (policy no RP/FW/30/99).

As the plantation is homogeneous the Transect Sampling Technique was applied to collect the necessary data. A transect was demarcated along the diagonal of the land and 0.02 circular plots were demarcated with 5 m intervals. Total height and dbh of the trees were measured from total 04 plots (42 stems) to calculate the basal area and volume.

When the result were analyzed, it was identified that the distribution of dbh is approximately normal. The average tree dbh, height and volume are 11.22 cm, 8.80 m and 0.051 m3 respectively. Pre-commercial thinning has already been done in 2007 without a scientific study. When compared with Provisional Yield Tables published by Forest Department, this site belongs to “height class III”.

The currant volume of the plantation was projected to the future using the appropriate yield table to calculate the income and cost by time series analysis. It is estimated that 48.895m3 of total timber volume which can produce the income of Rs. 3,094,799.00 (assuming 75% timber recovery in harvesting) during the thinnings and final felling which are to be done in 2014, 2024, 2034 and 2049. The total cost of extraction and replanting was estimated as Rs 636,021.08 for the particular teak block. It is calculated that the Net Present Value (NPV) of the total income and total cost will be Rs 162,528.60 assuming the present discount rate of Sri Lanka is 10%.

The above calculations were based only on use values of the plantation. However it is recommended to consider the non-use values such as soil protection, CO2 absorption, O2 emission, climate regulation etc, using an appropriate method. The currant management plan was prepared only for 0.4 ha because of the time and capital constrains. It is strongly recommended to extrapolate this study to different site types covering a vast area of the country in order to obtain the most accurate results so that a precise management plan can be drawn. Otherwise the management guidelines will be less effective.

1 comment:

Anonymous said...

Sri Lanka seems to have lots of valuble teak plantations.
Edwin