DIAMETER GROWTH OF TAXODIUM-DISTICHUM (L) RICH AND NYSSA-AQUATICA L FROM 1979-1985 IN 4 LOUISIANA SWAMP STANDS

Annual diameter growth of baldcypress and water tupelo trees in four swamp stands in S central Louisiana were measured from 1979 to 1985. Seasonal patterns of growth were also monitored during 1979 and 1980 using vernier tree bands. Most growth occurred from late April to early July for both species, with baldcypress exhibiting the greatest growth in all sites. Trees of both species on the site with the least hydrological alteration, had the lowest growth rate. Trees in the crayfish pond (water level managed by pumping) and the impounded area (permanently flooded) had much higher growth rates than the control area. Annual defoliation by the forest tent caterpillar probably accounted for the low water tupelo growth rates compared to baldcypress. It is becoming more difficult to relate annual growth differences to hydroperiod alone in S Louisiana because of changes in tree growth and successional patterns due to increased waterlogging as a result of eustatic sea level rise and subsidence combined with insect herbivory and human manipulation of the environment.