Acorn Production and Tree Growth of Nuttall Oak in a Green-Tree Reservoir

Abstract

SUMMARY Green-tree reservoirs, created by flooding live timber stands, provide resting places and food for wintering waterfowl. The effects of winter flooding in terms of acorn production and growth of Nuttall oaks were studied in a reservoir which had been flooded annually for 15 years and in a nearby un- flooded site. The study, which lasted for 5 years, included four tree sizes and three thinning treat- ments. Acorn production was about half as great in the winter-flooded site as in the control area. Large trees were better mast producers than small trees within the same stand. Thinning had no effect on mast production, but significantly affected diameter growth.' Diameter growth was about the same in flooded and nonflooded areas. Eleven percent of the flooded trees died, while none of the nonflooded trees died. They found that acorn production increased with tree size and stocking. Broadfoot (1967) cited a 50- percent increase in radial growth of timber in stands that were flooded from February to July over a 4- year period. Filer (1975) reported that the, kinds of mycorrhizal fungi present were not altered by win- ter and spring flooding but the concentration of individuals was reduced. Much remains unknown about the benefits and liabilities of fall, winter, and spring flooding. The results of a study of mast pro- duction and growth of Nuttall oak (Quercus nuttalh'i Palmer) in a single, but not atypical, green-tree reservoir are given in this paper.