PERFORMANCE OF FOUR BROAD-LEAVED TREE SPECIES IN A PINUS ENRICHMENT TRIAL IN CENTRAL HIGHLANDS OF SRI LANKA

Large-scale pine plantations established in the mountainous regions of Sri Lanka cause many environmental and social issues. This paper describes a pine enrichment trial that investigated the potential to convert a Pinus caribaea stand to a mixed species stand using four broad-leaved tree species in Hantana, Sri Lanka. These trees were transplanted under three light treatments (full shade: Pinus understorey, partial shade: three pine rows removed, and full light: open grassland) in 2004. All pine trees were removed in 2010. We compared the performance of these tree species in 2010 and 2015. In 2010, the highest percentage survival (99.0%) was under the partial shade while the highest carbon sequestration (50.2 x 10-4 C t year-1) and carbon stock (0.044 x 10-3 C t ha-1) were under full light by Artocarpus nobilis. In 2015, the highest percentage survival (79.3%) was recorded by Michelia champaca, and the highest relative growth (4.2 x10-3 m year-1), carbon sequestration (56.7 x 10-3 C t year-1) and carbon stock (0.049 x 10-3 C t ha-1) were recorded by A. nobilis. Artocarpus nobilis and M. champaca can be used to convert monoculture pine plantations to mixed species stands in mountainous regions in Sri Lanka.