Data from the Philippines are used to measure impacts of technical progress in lowland agriculture on upland forests. Irrigation development, labor demand, and employment are studied. Total annual labor use increased following irrigation. Employment of household members living along forest margins increased also. Time allocation data from the uplands show that increases in employment among households living along the forest margin were accompanied by reductions in forest clearing and forest-degrading activities. Empirical findings show irrigation-induced increases in agricultural employment can reduce pressure on tropical forests. Implications for policies and trends in use of labor saving methods that could undermine the observed changes are discussed.