Module 3 — Stand level components
of biodiversity
British Columbia
Ministry of Forests
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Module 3, Part B — Wildlife trees — continued
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Characteristics of wildlife trees

icon  What organisms inhabit wildlife trees?
 
How do these organisms use wild life trees?

 

  One or more of the following characteristics may determine if a wildlife tree is a valuable habitat:
  • Large size (diameter and height-greater than 15 metres in height preferable; greater than 30 cm dbh preferable (interior); and greater than 70 cm dbh preferable (coastal)

  • Condition and age (decay stage, see Figure 8)

  • Wildlife tree class — tree classes 2-6 most valuable 

  • Location and surrounding habitat features

  • Windfirm

  • Sound root system

  • Broken top

  • Some large branches

  • Abundance and distribution

  • Cause of tree mortality

  • Evidence of wildlife use (feeding, nesting, roosting or denning)

     

 

 

icon How is being cognizant about the life stages of wildlife trees useful in your work?

  Large, live trees provide:
  • A future source of standing dead trees and coarse woody debris

  • Foraging sites for many insectivorous birds (woodpeckers, nuthatches, chickadees)

  • Large, well-branched structures for platform nesting birds (eagles, osprey, herons, hawks)

  • Broad, deep canopies that intercept snow and modify microclimates

  • Substrates for mosses and lichens

  • Some intact bark with space behind loose bark

     
    Wildlife treeIn addition, standing dead trees and dying trees provide: 
  • Cavities for nests, roosts and dens (especially in trees with extensive heartrot)

  • Perching sites 

  • Foraging sites for insectivorous birds

  • In thick barked species (for example, Douglas-fir and ponderosa pine), cracks and fissures, and spaces behind loose bark provide feeding and nesting/roosting opportunities for bats and some birds such as the Brown Creeper 

  • A source of coarse woody debris 

Although different animals prefer trees with various characteristics, some trees stand out as being particularly valuable to wildlife. Generally, the following characteristics indicate the relative habitat value of a wildlife tree. 

See Figure 8: British Columbia's wildlife tree classification system  

     
Wildlife Tree Value Characteristics
High — A high value has a least two of the characteristics listed below and, where possible, is within the upper 10-15% of the diameter range distribution
Internal decay (heart rot or natural/excavated cavities present) 

A sound, firm outer stem shell

Crevices present (loose bark or cracks suitable for bats) 

Large brooms present 

Active or recent wildlife use (feeding, nesting, denning)

Tree structure suitable for wildlife use (e.g., large nest, hunting perch, bear den) 

Largest trees for site (height and/or diameter) and veterans

Locally important wildlife tree species 

Favourably located for use by wildlife

Medium
Large, stable tree that will likely develop two or more of the above attributes for High
Low
Trees not covered by High or Medium 
For further information https://www.for.gov.bc.ca/hfp/values/wildlife/WLT/index.htm
 
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Next: Categories of wildlife tree users
 
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