Tips for Creating Snags

• Snags may be created from living trees if there is a shortage of safe natural snags. Created snags can be expected to last for a long period of time. Poor quality or deformed trees, such as those with broken tops or large branches, make excellent snags.
  
• Snags can be dangerous so locate them well away from trails, roads, buildings, and other structures.
  
• Select both conifers and deciduous trees for snag creation. Snag trees should be at least 14" in diameter.
  
• Top or girdle trees at or above the first whorl of branches, but at least 14 feet high (ideally, much higher). Smaller trees may be useful for some cavity nesters, as are stumps which are at least 3 feet high.
  
• A jagged top will decay faster and supply more habitat than a smooth-topped tree.
  
• Large branches, extending at least 2 feet out from the trunk can be cut to create foraging habitat on live trees not intended to be used as snags.
  
• Roosting slits and cavity starts may be added to created snags at the time of topping or girdling. However, do not put these features, or bird boxes, on existing snags.
  
• Roosting slits may be used by most bats and some birds. The slits should be at least 8" deep and 2" wide, and angled sharply upward into the cambium layer.
  
• Cavity starts all allow decay-causing fungus to enter the tree wound. These cavities may be used by flying squirrels, swallows, kestrels, and small owls. They should be at least 6" deep and 4" high. In time, as rot progresses, these cavities may be used by a large variety of cavity nesters, such as pileated woodpeckers, nuthatches, and chickadees.
  
• Bird boxes of varying sizes will host many species, such as wood ducks and swallows. They can be erected in most forest stands depending on target species and stand characteristics. Bird boxes, however, do not replace the need for snags.

-adapted from Backyard Forest Stewardship from the Washington State Dept of Natural Resources

See also Dead & Dying Trees: Part of a Healthy Forest