Module 3 — Stand level components
of biodiversity
British Columbia
Ministry of Forests
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Module 3, Part B — Wildlife trees — continued
Figure 8. British Columbia's wildlife tree classification system. 
LIVE DEAD DEAD FALLEN
Decay class
1 2 3 4 5 6 7 8 9
graphic graphic graphic graphic graphic

approx. 2/3
original height

graphic

approx. 1/2
original height

graphic

approx. 1/3
original height

graphic
graphic
Description
Live/healthy;
no decay; tree has valuable habitat characteristics such as large, clustered or gnarled branches, or horizontal, thickly moss-covered branches.*
Live/unhealthy;
internal decay or growth deformities (including insect damage, broken tops); dying tree.*
Dead;
needles or twigs may be present; roots sound.
Dead;
no needles/twigs; 50% of branches lost; loose bark; top usually broken; roots stable.
Dead;
most branches/bark absent; some internal decay; roots of larger trees stable.
Dead;
no branches or bark; sapwood/ heartwood sloughing from upper bole; decay more advanced; lateral roots of larger trees softening; smaller ones unstable.
Dead;
extensive internal decay; outer shell may be hard; lateral roots completely decomposed; hollow or nearly hollow shells.
Debris;
downed trees or stumps.
Uses and users

Nesting (e.g., Bald Eagle, Great Blue Heron colonies, Marbled Murrelet); feeding; roosting; perching.

Nesting/roosting 1—strong PCEs2 (woodpeckers); SCUs3; large-limb and platform nests (Ospreys); insect feeders. Nesting/roosting— strong PCEs; SCUs; bats. Nesting/roostin g—PCEs; SCUs; insect feeders. Nesting/roosting— weak PCEs (nuthatches, chickadees); SCUs; bats; insect feeders. Weaker PCEs; SCUs; insect feeders; salamanders; small mammals; hunting perches. Insect feeders; salamanders; small mammals; hunting perches; occasionally used by weak cavity excavators such as chickadees. Insect feeders; salamanders; small mammals; drumming logs for grouse; flicker foraging; nutrient source.

1 Large witches' brooms provide nesting/denning habitat for some species (e.g., fisher, squirrels).
2 PCE = primary cavity excavator
3 SCU = secondary cavity user
* This classification system does not recognize root disease trees specifically. Such trees become unstable at or before death.

 

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