CONVERSION OF THE Pinus caribeae PLANTATIONS IN UPCOUNTRY INTERMEDIATE ZONE WITH OTHER POSSIBLE TREE SPECIES

Abstract

Pine plantations in the upcountry are now in their rotation end. These plantations has beenplanted in comparatively degraded patana lands. At present, as a policy it was decided not toreforest the second rotation lands again with pines. Therefore the conversion of pineplantations with other suitable tree species has become priority area for study in the ForestDepartment.

A research project was initiated in 1994 to investigate the possibility of converting theavailable pine plantations to other broad leaved species. As the first phase, nine timberspecies. nitrogen fixing soft wood species, woody herbal species and non-woody herbalspecies were tested under different thinning levels (Basal area 10 m2 ha,l , 15 m2 ha'. 20 m2ha I and control). As the second phase the selected timber species from phase one (Micheliachampaca. Swietenia macrophylla) and some other possible tree species (Artocarpus[raxinifollus, Ecucalvptus grandis, Eucalyptus microcorys, Acacia melanoxylon and Kyayascnagalensisv were established under different levels of gap openings (4 m, 6 m and 20 rn).

The initial tree growth assessment of the second phase experiment was done after 15 monthsof planting. The fast growing exotic species E. grandis, E. microcorvs and A. melanoxvionshowed the highest height growth 3.0 m, 2.8 m and 1.2 m respectively under the heavythinning level (20 m gap). Other than S. macrophylla and K. senagalensis all other treeshowed a significantly higher tree height growth under the heavy canopy openingconditions.