GROWTH-RESPONSE OF BALDCYPRESS [TAXODIUM-DISTICHUM (L) RICH] TO AN ALTERED HYDROLOGIC REGIME

Altering the hydrologic regime of a wetland forest may result in changes in tree growth, as hydrology is a primary factor influencing the growth of wetland trees. Road construction, a common cause of altered hydrologic regimes, modified the hydrology of a permanently flooded southeastern backwater swamp and resulted in significantly higher water levels upstream of the road. Following construction, upstream water levels averaged 85 cm, whereas downstream water levels were believed to be relatively unchanged at 22 cm. Study areas were selected upstream and downstream of the road. Increment cores were taken from canopy baldcypress trees Taxodium distichum (L.) Rich., to determine if the change in hydrologic regime was reflected in the annual growth rings. Before road construction, annual growth patterns were similar at the two sites. Following construction, annual growth patterns in trees below the road were unchanged; however, growth of trees in the upstream area was accelerated for several years followed by a long-term decline.