DROUGHT AND SITE FERTILITY EFFECTS ON FOLIAR NITROGEN AND PHOSPHORUS DYNAMICS AND NUTRIENT RESORPTION BY THE FOREST UNDERSTORY SHRUB VIBURNUM-ACERIFOLIUM L

The relative importance of site fertility and drought on foliar nutrie nt dynamics and resorption by the forest understory shrub Viburnum ace rifolium L. (maple-leaf viburnum) was determined by sampling leaves mo nthly through 2 growing seasons from plants in three Ohio deciduous fo rest sites which differed in soil nutrient availability. Sampling was done during 1985, a year in which growing season precipitation was nea r the 30-yr average, and during 1991, a year with only ca. 60% of aver age growing season rainfall. Foliar phosphorus (P) and nitrogen (N) co ncentrations were higher during 1991 than 1985. Although there were si gnificant intersite differences in fertility, patterns of foliar P dif ferences did not parallel site fertility. Foliar N was inversely propo rtional to availability in 1985, but not 1991. Resorption of P during senescence was highest at the intermediate fertility site in both year s, and P resorption was significantly reduced during the drought year. At the intermediate fertility site, there were no differences in N re sorption between years. In contrast, at the highest and lowest fertili ty sites, foliar N was significantly higher and N resorption significa ntly lower during the drought year (1991) than the normal precipitatio n year (1985). Overall, there was little indication that resorption be havior correlated strongly with site fertility. The drought year had a strong effect on both foliar nutrient dynamics and nutrient resorptio n.