Variation was investigated in forage production, in sacco dry matter (DM) and nitrogen (N) degradation, and in vitro gas production characteristics of 3 Albizia species/provenances (A. lebbeck N 864, A. procera N 865, A. saman N 825) and Paraserianthes falcataria (N 783) obtained from the Nitrogen Fixing Tree Association. One year after establishment on a site at IITA, Ibadan, SW Nigeria, forage production was assessed by harvesting trees at 0.5 m above ground in the main wet (April-August) minor wet (September-November) and dry (December-March) seasons. Forage samples from the main wet and dry seasons were incubated for 6, 12, 48, 72 and 96 h in rumen fistulated cattle to estimate in sacco DM and N degradation characteristics. In vitro gas production was estimated over 3, 6, 12, 24, 48, 72 and 96 h of incubation. Forage production of A. procera was significantly higher than the other species in all seasons. Cell-wall components were comparatively higher in A. procera than in the other species. Values for potential DM and N degradation of A. lebbeck and A. saman were significantly higher than those for P. falcataria and A. procera. The results suggest that A. lebbeck and A. saman provenances used in this study have relatively higher feed value than A. procera and P. falcataria. (CAB Abstract)