Diversity of Trees in Two Mountain Sites of Arak.an Valley, North Cotabato

Abstract

The study was conducted from April 23 to May 8, 2008 in l\ilt. Sinaka and :Mt. Mahuson, Arakan, North Cotabato in order to assess the abundance and diversity of trees present along the two study sites using quadrat and transect methods. In Mt. Sinaka, Salasang, Arakan, North Cotabato, a total of 97 identified and 17 unidentified tree species in 69 genera and about 39 families were collected and recorded along the three sampling sites corresponding to the three elevation gradients. Across the three sampling sites, Shorea negrosensis Foxw. is the most dominant, followed by Shorea contorta Vid. Calculations using Shannon-Weiner Diversity Index (H') reveals that the tree vegetation on this site can be
classified as highly diverse. A total of 79 identified and 16 unidentified tree species in 50 genera and 34 families were recorded along the three sampling sites in Mt. Mahuson, Ganatan, Arakan, North Cotabato where Lithocarpus
apoensis (Elm.) Rehd. is the most dominant and is of the highest value. The diversity value of trees in l\1t. Mahuson is considered as moderately diverse. Three species are classified as critically endangered species, 3 endangered, 13 tree species are vulnerable, and 1 species is under the wildlife species category based on the DAO 2007·01 List of Threatened
and Wildlife Species.