Rising demand and prices for timber have created economic incentives for upland farmers in the Philippines to incorporate fast-growing timber species into their farming systems. This paper examines the costs and benefits of agroforestry systems that intercrop trees and food crops with a study of the timber species Paraserianthes falcataria. Intercropped trees were 33% thicker at breast height and 21% taller than non-intercropped trees and required half the management costs. Although intercropping depresses food crop yields, the benefits of incorporating the trees exceed the costs. Labor scarcity, limitations on cash inputs, and increased tree value relative to annuals increase the benefits of intercropping.