Stand Structures and Height Growth Patterns in Northern White Cedar Stands on Wet Sites in Vermont

Abstract

Abstract The structure and growth of northern white cedar (Thuja occidentalis) was studied in 16 stands on wet sites in Vermont. White cedar and associate species representing the range in diameter were felled for stem analysis. Height growth curves were constructed. Structure of white cedar stands on wet sites in Vermont is often even-aged with a relatively uniform canopy due to restocking of former agricultural land, or two-aged, or multiaged, depending on degree of harvesting and other disturbances. On bog and swamp sites, cedar may reach less than 25 ft in height in 50 years whereas on upland sites wet only a portion of the growing season, they may reach 50 ft or greater in height. On well-drained upland sites, height growth may be greater, but cedar most likely may be displaced by other conifers and hardwoods. Basal area in pure and well-stocked maturing stands may exceed 300 ft2, and volumes can exceed 12,000 ft3/ac. In high-density stands, there is usually little understory. Very small amounts of cedar regeneration were observed in the stands studied. Some of the stands had a distinct browse line, and deer are presumed to have a major impact on cedar regeneration. All cedar stands are recognized as being of great importance as deer wintering areas. On the low-quality swamp and bog sites, minimal and careful harvest of cedar should be done to maintain deer habitat, integrity of the tree canopy, and associated understory vegetation. On sites with less water restrictions than in swamps and bogs, harvesting practices to maintain wildlife habitat and assure regeneration and thinning and pruning to improve growth rate and value of harvested wood should be considered. North. J. Appl. For. 21(4):173–179.