THE EFFECT OF WIND ON THE VEGETATION OF THE DUMBARA HILLS (KNUCKU=S RANGE)
DOI:
https://doi.org/10.31357/fesympo.v0i0.1626Abstract
The Dumbara Hills are in the Kandy and Matale districts. They straddle between 7° 18' and 7°34'N and 80° 41' and 80° 55'E, covering some 28,000 ha. The range extends along a NW-SEaxis for about 20 km. This massif, gradually rising over the NE of Kandy plateau slopesprecipitously to the eastern Dry Zone plain. There several high peaks in the Dumbara Hills,Gombaniya (l904m) Knuckles (1863m) and Dotalugala (1574m).
Dumbara Hills make an impregnable barrier to the NE and SW monsoon rains and arecharacterized with four major forest formations, namely; Lowland Dry Semi-Evergreen, Mid-Elevational Wet Evergreen, Mid-Elevational Dry Evergreen and Montane Wet EvergreenForests or cloud forests.
Deformed trees develop under the influence of severe environmental factors. The 'pigmy forest'and wind-shaped trees in other parts of the range are examples of theses. In such habitats thetrees are stunted (stature 1-2 m) despite that they ar:! hundreds of years old. Moreover, they aregnarled and twisted. The barks are covered with lichens and mosses, and support many epiphyticferns as well as angiosperms. Wind shaped trees abundant on peaks of the Dumbara Hills areuseful indicators to study dendrological effects of wilds.
This study was done by visual observation of wind- shaped trees in the field to estimate thedominant wind direction. The wind conditions were inferred by observing the wind shaped-treesin and around the Dumbara Hills. Considering the position of the wind-shaped trees, mean windvelocity was estimated based on the ranks mentioned by the following equation.WS = 1.6 + 0.95 GSL WS is the mean wind velocity (mJsec) observed at the meteorologicalstation in summer. GSL is the grade of wind-shaped trees,
The observations were made at fourteen points in the Dumbara Hills and, outside in the vicinity.In then sample were silver oak tGrevillea robusta) and gum (Eucalyptus sp.) trees. There arethree locations identified with strong winds; Lakegala, Asgirikanda and Ovilikanda, Asgirikandaand Ovilikanda are a few km north of the range and Lakegala is on the east. In the first twolocations are NW winds and in the third are SW winds.
The second area includes Bambarella on the western slope (middle) of the range with SW winds,Looloowatta, on the eastern on the eastern slope of the range with NNE winds andHunnasgiriya, in the southern end of the range, with winds from SW direction.
The third area is Kirimetiyakanda near the northern end of the range, where the prevailing windsare from SSW and Katuattamada, on the western slope range where there are winds from SWdirection. Wind-shaped trees are rarely found in the eastern lowlands (Wilgamuwa) northeast ofthe range. Hence it was not possible to continue streamlines up to the eastern low lands.
