Tree cavity estimation and verification in the Missouri Ozarks

Missouri forest management guidelines require that cavity trees and snags be provided for wildlife. Missouri Ozark Forest Ecosystem Project (MOFEP) timber inventories provided opportunities to determine if cavity tree and snag densities in a mature second-growth oak-hickory-pine forest meet forest management guidelines, to evaluate the effects of the first-entry harvesting on cavity tree densities in even-aged, uneven-aged, and no-harvest management systems, and to determine if cavity abundance differed among tree species, tree diameter, hole diameter, and location on the tree. We examined 54,452 live trees and snags during two pre-harvest data collection periods and during a third post-harvest data collection period. Pre-harvest cavity tree and snag densities were near or above optimum recommendations specified in the management guidelines. After timber harvests, cavity tree densities were above optimum recommendations in even-aged and no-harvest sites and slightly below optimum recommendations on uneven-aged sites. Snags were well above optimum recommendations on no-harvest and uneven-aged sites and only slightly below optimum on even-aged sites after timber harvests. Blackgum (20%) had the highest occurrence of tree cavities and shortleaf pine (1%) had the lowest, compared to oaks (2-10%) and hickories (7-11%). Basal cavities were the most abundant cavities overall (44%), particularly in trees 26 in. (66 cm) diameter at breast height (d.b.h.). For all tree species, larger diameter classes had a higher proportion of trees with cavities.