REGENERATION DYNAMICS O F SILVICULTURALLY ASSISTED DRY ZONE SCRUB VEGETATION AT DAMBULLA ARBORETUM

Abstract

Regeneration dynamics of silviculturally assisted scrub vegetation is described for a three year period between 1993 and 1995 in Dambulla Arboretum. The tree flora based on an enumeration of all trees above 3.1 cm girth at breast height (1cm dbh) in a plot of 1352 m2 were tabulated and analyzed. The diversity recorded in 1995 was 45 species, 42 genera and 19 families. The most diverse families were Euphorbiaceae (Relative Diversity [RD]-8.9 ) and Sapindaceae (RD-8.9) in 1993; and Euphorbiaceae (RD-13.3), Rubiaceae (RD-13.3) and Rutaceae (RD-11,1) in 1995. The most abundant families in all size classes were Euphorbiaceae (Relative Frequency [RF] -12.9) and Mimosaceae (RD-13.9) in 1993, whilst those in 1995 were 10.6 and 6.5 respectively. The most abundant species, Phyllanthus polyphyllus (Euphorbiaceae) accounted for 57.4% of the total number of trees in 1993, and 37.6% in 1995. The common species of canopy and emergent trees in the Dry Zone primary forest are not common at this stage. Six emergents (2 from root suckers), six pioneers, eight main canopy species and 25 understorey species were recorded in 1995. On this floristic evidence, it is too early to predict which species will prevail on the study plot in the regeneration process in future. Long-term studies should provide further information.