Data on the net production of oven-dry organic matter from 28 temperate angiosperm herbaceous species and 4 temperate arboreal species were analyzed to determine the relationship between below-ground and above-ground yearly increment. Mean yearly net herbaceous production (t/ha) was 3.9 for below-ground parts, 5.9 for above-ground parts, and 9.8 total. Mean yearly net arboreal production (t/ha) was 1.9 for below-ground parts, 8.9 for above-ground parts, and 10.8 total.The mean below-ground/above-ground ratio and mean below-ground production was significantly higher for herbaceous species. Mean above-ground production was significantly higher for arboreal species. There was no significant difference between total herbaceous and total arboreal production. Productivity comparisons based only upon above-ground parts are likely to be biased in favor of arboreal species.In herbaceous species, root production decreased with age and increased from fruit crops to root and tuber crops and the below-ground/above-ground ratio increased from moist to mesic to xeric species. Arboreal species were uniform in below-ground/above-ground ratios.