Total nonstructural carbohydrate (TNC percent dry weight) of various tissues was monitored over winter in four aspen (Populus tremuloides Michx.) clones in central Colorado. Midwinter TNC was highest in root phloem, followed by bark, small roots, root xylem and stem sapwood respectively. Photosynthates were not immediately translocated to roots with the onset of dormancy, but persisted in bark, possibly due to photosynthetic activity, throughout the fall before being transferred to root phloem tissue in mid to late winter. Small roots and woody tissue do not appear to play a significant role in carbohydrate storage. These TNC allocation patterns may help explain seasonal aspen herbivory, particularly the stripping of bark by deer, elk and moose in winter.
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