When properly installed and maintained, tree stem protection material provides protection from physical damage. It also modifies air temperature and humidity within the stem.

Use materials to protect

• young trees from deer and rodent damage,
• trees in high-traffic areas from vandalism,
• trees from lawn mowers, weed whips and snow blowers,
• trees from uneven heating of the stem - which may cause sunscald or frost cankers at high elevation, or
• trees in windy sites.

Guards. A guard can be constructed out of common household items, such as hardware cloth. Or purchase it from a lawn and garden store. Install the guard loosely to prevent accumulation of moisture, growth of bacteria and fungi, and damaging-insect habitat. Secure the guard to itself (not to the tree stem) with wire or zip ties. Check the guard frequently for tissue compaction.

Wraps. Wraps are commonly constructed of Kraft™ paper, vinyl spiral wraps, and corrugated tubes. Wraps should be attached from the soil line to the first set of branches. Secure with decomposable materials, like masking tape or twine. Monitor wraps and remove or re-install within one year.

Considerations

• Leaving tightly attached, synthetic or rot-proof wrap on the stem too long may girdle or compress stems, even during the first growing season.
• Thin-barked species, like red maple and linden, have photosynthetic tissue on young stems. Covering this with wrap during the growing season may reduce caliper growth or girth.
• Don't use protectants such as paint or slaked lime. They may chemically damage the stem.
• Light-colored wraps that minimize rapid temperature changes have been reputed to be most helpful in preventing conditions that may cause sunscald or frost cankers at higher elevations. Material that is reflective on the outside and has insulation on the inside will considerably moderate temperature fluctuations.

For more information, consult the Extension publication "Tree Stem Protection," or contact the Department of Forest Resources Extension and Outreach office at 612-624-3020.

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