Ecosystem metabolism data from White Clay Creek, southeastern PA, were examined for long-term trends and responses to riparian zone management. Land use in the rural watershed has not changed appreciably. Metabolism was measured using chambers during 1971-1975 and 1985, and using the open-system approach between 1997-2006. Gross Primary Productivity (GPP) has remained relatively constant in a permanently forested reach, averaging 475, 427 and 436 g O₂^.m^-2.y^-1 in 1971-1975, 1985, and 1997-2006, respectively. Ecosystem Respiration (ER) increased from 410 and 405 to 981g O₂^.m^-2.y^-1, respectively, because open-system measures included greater hyporheic activity. GPP and ER in a meadow reach averaged 1781 and 998 g O₂^.m^-2.y^-1, respectively during 1973-1975. Following reforestation (R) in 1990, it was compared with a different meadow reach (M2) and the forested reach (F) in May 2005 and July 2006. In May, GPP (g O₂^.m^-2.d^-1) in R was greater (7.87) than in M2 (5.94) and F (3.17), while ER was 3.13, 5.01, 7.90, respectively. In July, however, GPP in R (1.78) was similar to F (1.53) and lower than in M2 (4.38), while ER was 2.32, 2.99, and 4.38, respectively. While metabolism was similar, R had not attained the wide, shallow channel typical of forested reaches.