Earlywood-Latewood Features of Red Pine Grown Under Simulated Drought and Irrigation
Authors: Zahner, Robert; Lotan, James E.; Baughman, William D.
Source: Forest Science, Volume 10, Number 3, 1 September 1964 , pp. 361-370(10)
Publisher: Society of American Foresters
Abstract:Six Pinus resinosa Ait. trees, 20 years old and 21 feet in height, on a sandy Podzol in northern lower Michigan, were subjected to controlled soil moisture treatments. Three were irrigated to maintain soil at field capacity, and three subjected to artificial drought by confining their roots under sheds. Terminal growth and cambial activity were measured in detail throughout one season of treatment. Annual rings in upper and lower boles were analyzed for gross anatomical features at the end of the season. In lower boles, approximately 100 percent more xylem was formed in irrigated trees than in drought trees, both in wood volume and in numbers of tracheids. In the upper bole about 50 percent more xylem was formed in irrigated trees. Mork's definition latewood was greater in size of cells and in number at all stem positions in irrigated trees, but percentage of latewood was equal in both treatments at comparable stem positions. Initiation of flattened latewood cells began in late July at breast height for trees under drought, but not until late September for irrigated trees. Cessation of needle elongation was not well correlated with time of cell size changeover at breast height, but was correlated in the crown portion of the stem. Rates of needle elongation, however, could be related to tracheid flattening. The relationships are discussed in terms of modern theories of wood formation, and both direct and indirect effects of water are considered.
Document Type: Journal article
Publication date: 1964-09-01
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