Forestry and Environment Sympoisum 1998, Sri Lanka

Fourth Annual Symposium organized by Department of Forestry and Environment Science, University of Sri Jayewardenapura, Sri Lanka.

Sunday, October 08, 2006

STUDY OF GROWTH PATTERN AND PHENOLOGY OF Dipterocarpus zeylanicus FROM TWO FOREST RESERVES OF SRI LANKA

M P de Silva
Department of Botany,
University of Ruhuna.

Dipterocarpus zeylanicus is an endemic emergent tree which grows in the wet evergreen forests of Sri Lanka. Usually it grows up to height of about 45 m, A study of the growth pattern and phenology was carried out at two forests reserves viz. Kottawa Forest Reserve located in the wet zone and Ellakanda forest reserve located in the intermediate zone of Sri Lanka. Both zones receive rain through the year but the intensities of rainfall received during the North Eastern (NE) and South Western (SW) monsoons in the two zones are different, SW being the most prominent in the wet zone of Sri Lanka and NW monsoon is equally intense as SW in the intermediate zone. Monthly growth increments were studied using dendrometer bands and phenological events were observed monthly. The growth intensity varied during the year, though there was a least some growth throughout the year. There was higher growth with an average diameter increment of about 3 mm/ month in the trees growing in the intermediate zone while in the wet zone, the average was around 1 mm. In the wet zone higher growth was recorded during the SW monsoonal period (i.e. From May to July) whereas growth of equal intensities was recorded during SW and NE (i.e. From October to December) monsoons in the intermediate zone. For phenological observations, period of leaf growth / greening, leaf fall, flowering, seed ripening / fruiting, and number of growth periods were recorded.

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