Comparative Biomass and Growth of Cypress in Florida Wetlands

Tree biomass and increase in biomass were determined for cypress (Taxodium distichum) in different systems in Florida. Ten trees were harvested to determine biomass regressions. Lowest biomass and tree growth rates were found in cypress-pine associations indicative of low water, in monospecific stands of cypress which are indicative of high water levels, and in a poorly drained cypress dome. Increases in individual tree growth ranged from 1.0 to 3.5 kg/y-1 in these groupings. Highest cypress tree growth rates were found in cypress-tupelo systems and cypress-hardwood systems. The latter are less dominated by cypress, however, so individual tree growth is greater (7.7 kg/y vs. 4.0 kg/y). Cypress-hardwood associations are known to be generally better drained than cypress-tupelo systems. Two experimental cypress domes currently receiving treated sewage effluent and groundwater showed high individual tree growth (5.0 and 4.2 kg/y, respectively), but little difference was noted between the two domes. Tree diameter increase showed normal cypress tree growth to be 1.0-2.0 mm/y with higher values of 2.8-3.3 in cypress-hardwood associations and the experimental cypress dome. Cypress in the poorly drained dome increased by only 2.0 mm/y.