Ice / Snow / Hail damage,  

Conifers
Fig. 257  Hail-caused lesions on upper surface of branch.	Fig. 258  Broken and bent stems caused by heavy snow pack.	Fig. 259  Crown deformity and branch stripping caused by snow or hail.
Broadleaves
Fig 396  Tree has collapsed under weight of snow.	Fig 397  Snapped branch from weight of ice.	Fig 398  Snow damage to aspen.

Distribution:  Throughout B.C. wherever the incidence of snow, ice or hail is significant.

Tree Species Affected: All conifers are susceptible. Douglas-fir is more readily damaged than true fir, pine, or hemlock species.

What to Look For:  Branches and main stems that are bent, broken, or deformed.  

Signs & Symptoms: Snow damage consists of temporarily or permanently bent main stems, depending upon duration and movement of the snow pack, and branch stripping or breakage, stem breakage, or uprooting. Symptoms are concentrated in small groups or are seen on scattered individual trees in affected stands. Older trees can suffer top breakage. Windblown ice crystals abrade portions of the main stem above the snowline. Affected areas of the stem have a smooth appearance. Hail damage symptoms can be seen over a broader area and consist of stripped branches, stem lesions, scars and bruises on the upper surface of branches, or tattered, ragged crowns with missing foliage and buds. Damage symptoms are aligned in one direction. Buds, foliage, and branches litter the ground. Larger seedlings and saplings show more symptoms than smaller trees.

Damage: Heavy snowfall or hail can cause significant mortality in young plantations. Losses occur in patches or as scattered individual trees. Growth is reduced when foliage and buds are removed. In younger trees, deformity results from permanently bent main stems or broken tops due to snow press. Deformity of older trees is caused by top breakage. Hail-related branch or stem scars and top breakage act as entry points for disease.

Similar Damage: Broken or uprooted trees can be symptomatic of stem weakening diseases such as rusts, heartrots, or root rots. These may occur in conjunction with snow press. Investigate the stems and roots for signs of diseases. Old hail damage can be confused with other agents such as old insect feeding. However, hail damage always occurs on only one side of the tree, while damage from other causes usually occurs on all sides of the tree.

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Contact Tim Ebata if you have comments on the presentation of this information.

BC Ministry of Forests
Forest Practices Branch
P.O. Box 9513 Stn. Prov. Gov.
Victoria, BC
V8W 9C2

Section phone: (250) 387-8739
Section fax: (250) 387-2136

Last updated March 04, 2002