Good Forestry in the Granite State:
Recommended Voluntary Forest Management Practices for New Hampshire
Table of Contents >> 6.1 Mast << 6.2 Cavity Trees, Dens and Snags >> 6.3 Dead and Down Woody Material

6.2 CAVITY TREES, DENS AND SNAGS

BACKGROUND

Retaining snags (dead or partially dead standing trees) and den trees (live trees with existing cavities) helps maintain populations of wildlife that require cavities.

Ten species of New Hampshire forest birds excavate cavities for nesting and roosting. Another 15 birds and 18 mammals use natural or excavated cavities in forests for nesting, roosting, or denning. In addition, the brown creeper nests under loose flaps of bark, attached at the top, on standing dead trees. Meeting the needs of these many different species requires a variety of cavity-tree sizes (Table 1). While cavity trees of any size have value for smaller-bodied wildlife such as the black-capped chickadee and tufted titmouse, trees larger than 18 inches in diameter at breast height (DBH) accommodate larger-bodied animals and are used by more species. Due to past agricultural and timber harvesting practices, cavity trees larger than 24 inches in diameter are uncommon.

Table 1: Minimum Tree Diameters for Cavity-Using Species

6- 8"
Downy woodpecker*
Black-capped chickadee*
Boreal chickadee*
Tufted titmouse
House wren
Winter wren
Eastern bluebird

6-12"
Northern saw-whet owl
Hairy woodpecker*
Yellow-bellied sapsucker*
Red-breasted nuthatch*
White-breasted nuthatch
Brown creeper
Chimney swift
Southern flying squirrel
Northern flying squirrel
Ermine

12-18"
Eastern screech-owl
Three-toed woodpecker*
Black-backed woodpecker*
Northern flicker*
Great crested flycatcher
Northern long-eared bat
Indiana myotis

> 18"
Wood duck
Common goldeneye
Hooded merganser
Common merganser
Turkey vulture
Barred owl
Pileated woodpecker*
Silver-haired bat
Gray squirrel
Red squirrel
Porcupine
American marten (pine marten)
Fisher
Long-tailed weasel

> 24"
Little brown bat
Big brown bat
Gray fox
Black bear
Raccoon

* = primary cavity excavators

OBJECTIVE

Maintain cavity and den trees, particularly trees with diameters exceeding 18 inches.

CONSIDERATIONS

RECOMMENDED PRACTICES

CROSS REFERENCES

2.2 Forest Structure; 4.2 Wetlands; 4.3 Forest Management in Riparian Areas; 6.1 Mast; 6.3 Dead and Down Woody Material; 6.4 Overstory Inclusions.

ADDITIONAL INFORMATION

Elliott, C.A. 1988. A Forester's Guide to Managing Wildlife Habitats in Maine. University of Maine Cooperative Extension, Orono, Maine.

USDL Occupational Safety and Health Administration. http://www.osha.gov/SLTC/etools/logging/userguide/safety_health/treeharvestingplan/treeharvestingplan.html Accessed February 22, 2010.

6.1 Mast << 6.2 Cavity Trees, Dens and Snags >> 6.3 Dead and Down Woody Material

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