Summer 2010 TREE Fund Report: New John Duling Research projects underway


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An overview of current research being conducted by John Z. Duling Grant recipient Michael Arnold of Texas A&M University:

Does Propagation Method Impact Survival and Growth of Below Grade Planted Trees?
Several researchers have investigated responses with different taxa of trees planted below grade around the country. Although many report adverse responses to below grade planting, these growth and physiological responses vary considerably among sites even with them using the same species. One potential explanation for some of this variability may be the method of propagation, seedlings versus cuttings. Trees propagated from cuttings would have a larger portion of stem tissue planted below grade than a seedling given the same planting depth. Our work will investigate the responses of both seedlings and cutting propagated trees from species with reported mild to severely adverse responses to below grade planting to determine the importance of this tree propagation decision on landscape establishment.

Cutting Baldcypress Off At The Knees?
Baldcypress, varieties of Taxodium distichum some of which are also known as Montezuma cypresses or pondcypresses, are graceful, long-lived, durable trees with numerous aesthetic and architectural qualities that make them highly desirable urban and suburban trees. Recent selection work has also yielded clones with improved tolerance to alkaline soils, salinity exposure, and drought. However, one maintenance objection sometimes cited by Arborists and Urban Planners is the development of unwanted knees. These root protuberances are often formed in wet soils or in other locations with suspected low oxygen containing root zones. Anecdotal reports suggest variable tendencies in populations of seedlings to develop knees. Our work will center on developing methods to screen populations of seedlings and advanced clonal selections in the hope of obtaining “kneeless” baldcypresses for urban landscapes.

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