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Wind disturbance is an important factor that can affect the development of the forests of the Central Hardwood Region of the United States. However, there have been few long-term studies of the recovery of these systems following wind damage. Long-term studies of protected forest systems, such as Dinsmore Woods in Northern Kentucky, within the fragmented forest of this region are valuable as they provide a resource to document and understand the effect of both abiotic and biotic challenges to forest systems. This study is a 40-year analysis of both overstory and understory changes in the forest system at Dinsmore Woods as the result of damage caused by severe winds in the spring of 1974. The forest was surveyed before and immediately following the windstorm and then at 10-year intervals. Although the windstorm had an immediate effect on the forest, the pattern of damage was complex. The forest canopy (diameter at breast height (DBH) ≥ 30 cm) experienced an irregular pattern of damage while in the subcanopy (DBH ≤ 30 cm) there was a 25% reduction in total basal area. However, the major effects of the windstorm were delayed and subsequently have altered forest recovery. Ten years following the disturbance declines were seen in total density and basal area in the canopy and subcanopy of the forest as a consequence of windstorm damage. In the past 20 years the total basal area of the canopy has increased and exceeds the pre-disturbance total basal area. In contrast, the subcanopy total basal area continued to decline 20 years post-disturbance and has not recovered. Further openings in the canopy and subcanopy due to the delayed windstorm effects helped to establish a dense understory of native shrubs and sugar maple which have affected tree regeneration and is reflected in the continual decline in species diversity in the subcanopy and sapling strata over the 40-year period.

Abs~ract. Fiber tracheids of first-year seedlings of Liquidambar styraciflua from geograph-Ically diverse seed sources grown under controlled conditions differed in length. The longest tracheids were found in seedlings from Mexico populations; tracheids in plants from New Jersey, North Carolina, and Texas were shorter and showed a latitudinal trend the shortest being northernmost. Cell lengths varied with the environmental conditions, i.bose of the United States populations being more reduced in length under short day-lengths, cooler temperatures, and low light intensity. Populational differences in specific gravity of wood were evident in seedlings grown under controlled conditions. Lower specific gravity was correlated with decrease in latitude of origin. A possible relationship between fiber tracheid length cell diameter, and latitude of origin is suggested.'

Laboratory germinated seedlings of Acer negundo grown under controlled environmental conditions showed patterns of decreasing cell length (tracheids) with decrease in length of growing season of parental tree's habitat. Populations tested represented a range in latitude of 15 degrees (Texas to Canada) and the results indicate populational response to shorter growing seasons being reflected in xylem development.