Forestry

Forest Health Protection

Invasive Species

Powerline

Defects commonly observed on forest trees native to Wisconsin

TREE SPECIES (Average life expectancy, yrs.) DEFECTS
Ash (black) Weak unions

Uprooting – black ash is most abundant in moist locations and along low banks of streams where uprooting is more likely to occur.
Ash (green & white) Weak unions Dead branches in the upper and outer crown.
Aspen (big-toothed and quaking) (60-90) Extensive decay from canker-rot Phellinus tremulae.
Stem breakage due to infection by Hypoxylon and other cankers.
Rapid decay .1
Basswood (150-200) Weak unions from both branch unions and stump sprouts.
Birch (white & yellow)
(white – 70-110)
(yellow – 150-250)
 Extensive decay from canker-rot Inonotus obliquus.
Stem breakage due to the presence of Nectria canker.
Rapid decay.
Box Elder Weak unions
Butternut Branch breakage due to the presence of butternut canker.
Cherry (black) (120-150) Dead branches throughout crown.
Cottonwood (eastern) Dead branches throughout crown.
Rapid decay.
Fir (balsam)
(70-100)
 Uprooting or lower stem breakage may occur as a result of root rot or decay of the root collar region. Balsam fir frequently has a shallow root system.
Rapid decay.
Maple (red & sugar)
(red – 80-140)
(sugar – 150-250)
 Weak unions.
Dead branches.
Stem breakage due to the presence of Eutypella and Nectria cankers.
Cracks.
Oak (black & northern pin)
(black – 150-200)
 Extensive decay from canker-rot Phellinus everhartii.
Weak unions.
Cracks.
Dead branches in lower crown from natural branch mortality and upper crown from several factors causing dieback.
Dead trees may be common due to oak wilt and two-lined chestnut borer.
Oak (red) Dead branches (see black oak).
Dead trees (see black oak).
Oak (white) Extensive decay (see black oak).
Dead branches (see black oak).
Pine (jack)
(60-100)
 Extensive decay from canker-rot Phellinus pini.
Rapid decay.
Pine (white)
(200-300)
 Extensive decay from canker-rot Phellinus pini.
Dead branches in lower crown due to natural branch mortality.
Dead tops due to presence of white pine blister rust canker.
Spruce (white & black)
(white – 100-200)
(black – 150 – 200)
 Uprooting – particularly true on wet sites; spruces tend to be shallow rooted
1 Rapid decay denotes species that are likely to decay quickly if in a state of decline from numerous other initiating factors.
Last Revised: Monday July 30 2007