Natural and Management-Related Variation in Cypress Domes

Abstract

Fifteen cypress domes located within an extensively managed slash pine plantation were characterized according to the presence and nature of ditches and berms. Mean water depth and hydroperiod for the year 1978-79 were generally greater in the domes without these alterations. Cypress importance values were significantly higher in the unaltered, wet domes whereas hardwood importance values and shrub density were higher in the altered, drier domes. The abundance of grasses and sedges in the domes was more closely correlated with the amount of light reaching the dome floor than with the degree of wetness. Acid-extractable phosphorus, iron, and aluminum concentrations in the dome soils were pos- itively correlated with mean water depth. Carbon concentration in the dome soil was positively correlated with hardwood importance value. Cypress tree growth rates increased significantly following ditching in four domes. This was probably the result of increased soil aeration and increased nutrient inputs from ditch inflow. Cypress growth rates in other altered and unaltered domes were not significantly different before and after intensive forest management of the study site. Although dome alterations sometimes increased cypress tree growth, the associated changes in hydrological conditions, vegetation com- position, and soil parameters may inhibit cypress regeneration. FOREST SCI. 29:627--640. CYPRESS DOMES are small forested wetlands that commonly occur in shallow depressions within the pine flatwoods of the southeastern coastal plain. The dom- inant tree in these wetlands is the deciduous conifer, pondcypress (Taxodium distichurn var. nutans (Ait.) Sweet). Cypress domes are normally open, ponded areas with little understory, and are dominated by cypress with swamp blackgum (Nyssa sylvatica vat. bifiora (Wait.) Sarg.) occurring occasionally and pines (Pinus spp.) occurring rarely (Harper 1914, Mattoon 1915, Gano 1917). In Florida, slash pine (Pinus elliottii Engelm.) is being intensively managed for pulp and paper production on approximately 10 million hectares. Swamps comprise about 33 percent of these commercial forest lands, with half of that area in cypress domes (Anonymous 1978). Although commercial use ofpondcypress has generally been restricted to mulch, railroad crossties, and fenceposts, recent advances in chipping have made it more attractive, and interest in long-term management has increased. Moreover, the potential use of cypress domes for wastewater recycling (Ewel and Odum 1978), for water conservation (c.f., Burns 1978, Brown 1981), and for