Sylvatrop, The Technical Journal of Philippine Ecosystems and Natural Resources 13(1&2): 1-30 The importance of forest fragments for birds and local communities in Northeast Luzon, Philippines Merlijn van Weerd, Joeri Strijk, and Denyse Snelder Institute of Environmental Sciences Leiden University, PO Box 9518, 2300 RA Leiden, The Netherlands E-mail: vanweerd@cml.leidenuniv.nl, Joeri.Strijk@wur.nl, snelder@cml.leidenuniv.nl The Philippine islands used to be covered mainly with forest until recent times. Within evolutionary history, the vast majority of flora and fauna species now occurring in the Philippines, colonized or evolved in forest habitats and not in cleared areas. Because of its specific island biogeographical history, the Philippines has a very high number of endemic species. During the last 100 years, most of the original tropical forests in the Philippines have been removed for timber or cleared for crop cultivation. The forest fragments that still remain, usually in areas not suitable for cultivation or timber extraction, harbor remnants of the biodiversity originally found in extensive lowland forest. The species richness of forest fragments is expected to be correlated to fragment size and the distance of the fragments to remaining forest. Local communities often depend on these fragments for their supply of a variety of forest products. We studied forest fragments in the Cagayan Valley of Northeast (NE) Luzon. One series of studies was aimed to describe the vegetation of forest patches. We found that many patches retain some of the tree species usually found in primary forest. Gallery forests along creeks have higher tree to shrub ratios than woody patches surrounded by grassland. Another series of studies was aimed to describe the utilization of forest products by local communities. We found that a variety of “free access” products were derived from forest patches, the most important being fuelwood. Rural and even urban communities in NE Luzon still depend, on a large extent, on the use of fuelwood and the forest patches play a crucial role in providing that. Last, a study was conducted on avian species richness in forest patches in relation to patch size and distance to contiguous remnant forest, of which a large stretch is present in the Sierra Madre Mountains. Species richness and the Keywords: forest fragments, biodiversity, conservation, endemic birds, species-area relationship, nontimber forest products, forest patch utilization, Northern Sierra Madre Natural Park, Northern Sierra Madre, Cagayan Valley, Luzon, Philippines