Productivity and nutrient-use efficiency were investigated in plantations of similar age of poplar clone D121 (PopulusdeltoidesMarsh.) that differed mainly in plant density. The plantations were located in the Tarai belt (low-lying area with high water table) of the Indian Central Himalaya. The total net primary productivity of the high-density plantation (4 years old with 666 trees/ha) was conspicuously higher (32.4 tones•ha−1•year−1) than that of the low-density (20 tonnes•ha−1•year−1) plantation (5 years old with 400 trees/ha), while nutrient-use efficiency was similar in these plantations. The net primary productivity/leaf nutrient ratios and percent nutrient retranslocation from senescing leaves were higher in the high-density than in the low-density plantations. In these young plantations leaf litterfall accounted for most of the litterfall (96–97%). The amount of nutrients that returned through litterfall to the soil was distinctly greater in the high-density plantation than in the low-density plantation. The greater nutrient return was due to first, the greater dry weight of litterfall and the lower proportional nutrient retranslocation from leaves during senescence in the high-density plantation. The high-density plantation also showed greater nutrient extraction efficiency from soil. Compared with aEucalyptustereticornisSm. plantation, and with natural forests of the study region, the nutrient use efficiency of poplar, regardless of its density, was lower.