Characteristics and Use of Cavity Trees and Snags in Hardwood Stands

A 3-year study was conducted to evaluate the availability and use of cavity trees and snags in hardwood stands regenerated using the group selection method. A survey of cavity trees and snags was completed before and after group selection harvest in 16 2.9-ha plots in the Ozark National Forest, Arkansas. Cavity trees and snags were identified to species, and the height, dbh, state of decay, and number of visible cavities recorded. We marked and measured 66 cavity trees and 126 snags with cavities, and observed the use of these cavities by wildlife. Use of cavity trees was observed seasonally and before and after group selection harvest. Plots averaged 12.2 cavity trees/ha and 25.5 snags/ha before harvest. Densities did not vary between plots with northeast and south aspects. Species composition of cavity trees and snags did not reflect overall stand composition. Black gum (Nyssa sylvatica), red maple (Acer rubrum), and black walnut (Juglans nigra) were most likely to develop cavities. Cavity trees and snags declined after group selection harvests to 4.6/ha and 5.3/ha, respectively. Harvesting changed the species composition and relative size of cavity trees. Over 30 species of vertebrates used cavity trees. The percent use of cavity trees dropped from 53% before to 30% after harvest. The 3 species of cavity trees used most frequently by wildlife were black gum (66%), black walnut (63%), and red oak (Quercus rubra, 60%). Large diameter (>45 cm) and tall (>20 m) cavity trees and snags were used most frequently, regardless of the species of tree. Proc. Annu. Conf. Southeast. Assoc. Fish and Wildl. Agencies 50:331-339

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