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Effects of Light Regimes on 1-Year-Old Sweetgum and Water Oak Seedlings

Informally Refereed

Abstract

Light regimes vary significantly within small forest openings, ranging from full sunlight to total shade. This may affect establishment, early growth, and competitive status of hardwood seedlings. We used modified shadehouses to simulate light conditions within forest openings and to test the effects of daily photosynthetically active radiation and time of direct light exposure on growth of sweetgum (Liquidambar sfyraciflua L.) and water oak (Quercus nigra L.) seedlings. The study was a split-plot design in a completely randomized block layout with four replicates. The five light regime treatments representing the time of exposure to direct sunlight were NO, NOON, MORNING, AFTERNOON, and FULL. Green-house-raised sweetgum and water oak seedlings were planted in the treatment plots at a 0.3 x 0.3 meter spacing in early May 2000. Height, groundline diameter, and leaf surface area were determined at the end of the first growing season. Growth for both species generally increased with the amount of direct sunlight received. For treatments receiving some direct sunlight, sweetgum and water oak were the same height at the end of the growing season. However, sweetgum was 35 percent taller than water oak in the fully shaded treatment. For sweetgum, surface area of the average leaf was significantly larger in the fully shaded treatment than in other treatments, but no treatment differences occurred or surface area in water oak. Results suggest that sweetgum seedlings are more adaptive to low light levels than water oak seedlings during the first year of development.

Parent Publication

Citation

Guo, Yanfei; Shelton, Michael G.; Zhang, Hui. 2002. Effects of Light Regimes on 1-Year-Old Sweetgum and Water Oak Seedlings. Gen. Tech. Rep. SRS–48. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. pp 373-376
https://www.fs.usda.gov/research/treesearch/3144