(1) Litterfall in an age sequence (7, 17, 30, 46 and 56 years) of Alnus nepalensis D. Don plantation stands in the Kalimpong forest division of the Eastern Himalaya was compared over two years for quantity and temporal distribution. (2) Average annual litter production in the plantations ranged from 3.2 t ha-1 (7-year stand) to 5.8 t ha-1 (46-year stand). Litterfall showed marked seasonal distribution and peaked in dry winter. (3) Seasonal rates of decomposition were distinct, with the highest rate in the first three months (warm rainy season) followed by subsequent seasons of the year. Among different stands decomposition rate was highest in the 30-year stand, i.e. at the time of canopy closure. The pattern of nutrient release (K > Ca > P > N) was the same in all the stands and the actual amount of nutrient release (30 > 17 gtrless 46 > 7 > 56-year stands) was related to mass loss. The energy-content loss in twenty-four months per unit area was highest (3098 kJ m-2) in the 30-year stand. (4) The quantities of nutrients released per unit area in twenty-four months were highest in the 30-year stand (nitrogen, 5 g m-2; phosphorus 0.14 g m-2; potassium, 1.17 g m-2; and calcium, 0.59 g m-2). The release of nitrogen (70-85 mg), phosphorus (4-5 mg), potassium (32-44 mg), calcium (16-20 mg) and energy loss (35-44 kJ) were maximum in the first three months and declined gradually with time. (5) Ash-free mass of decomposing litter remaining at different retrieval dates was associated with a narrowing of the C/N ratio. Decomposition of litter was related to mineral element concentrations in litter and environmental factors.
