BIOMASS AND PRODUCTION IN THREE CONTIGUOUS FORESTS IN NORTHERN WISCONSIN

Biomass and net primary production were measured in 3 forest communities in north- ern Wisconsin comprised mainly of Populus tremuloides, Betula papyrifera, Acer rubrum, and Acer saccharum. The estimated total aboveground biomass and production for living plants in the 3 stands, designated as (1) aspen, (2) aspen-maple-birch, and (3) maple-birch-aspen types, were 94.8, 95.6 and 119.0 t/ha (= 103 kg/ha) and 10.43, 8.45, and 8.69 t*ha-1tyr-1, respectively. Shrub and ground vegetation accounted for minor portions of the total standing crop. The tree:shrub:ground biomass ratios were 1:.019:.015 for aspen, 1:.009:.006 for aspen-maple-birch, and 1:.003:.006 for maple-birch-aspen. The contribution to stand production by shrubs and ground vegetation ranged from 17% of the total aboveground production in the aspen type to 9W in the other stands. Inputs to the production equation often neglected in stand analysis, i.e., plant losses by death, shedding, and consumption, amounted to a maximum of 4.5% of total aboveground production. A comparison of biomass data from forests in the lake states suggests that 100 to 200 t/ha (above- ground dry weight) is inclusive of most second-growth forests. The upper and lower bounds for mature forests were projected to be -600 and 60 t/ha. Estimates of aboveground productivity for a variety of forest ecosystems within the lake states had a narrow range from 7.1 to 10.4 t ha-1 year-'.