Tree Stem Protection

Benjamin K. Cooper, Undergraduate Research Assistant *
Gary R. Johnson, Associate Professor, Urban and Community Forestry *

Tree stem protection, commonly referred to as tree wraps, can serve two basic functions:

  • stem protection from physical (mechanical) damage and
  • modify the stem’s ambient environment. Physical or mechanical protection may protect the stem from equipment, animal, vandalism and herbicide damage. The stem-ambient conditions that potentially may be modified by protection materials are air temperature and humidity.

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Facts And Myths: What Information Is Research-Based?


Secured incorrectly, any tree wrap can be a detriment. Most problems occur due to three common situations:

Figure 1: Stem girdled by wire.
Figure 1: Stem girdled by wire.
  • the wrap is applied too tightly to the stem, allowing no airspace between the material and the stem,
  • the material is left on too long, and
  • the material is attached to the stem with another material that does not decompose soon enough to avoid stem girdling (constriction) [Fig.1].

    Figure 2: Overly moist bark.
    Figure 2: Overly moist bark.

Any material that is applied directly to stem tissues may trap moisture, which may lead to more cases of stem diseases, decay, and infestations of certain insects that can damage stem tissues [Fig. 2]. Most commonly, the insects that prefer tightly wrapped stem conditions are woodborers and wasps with wood-boring larvae. It has also been observed that tightly wrapped stems have larger lenticels, which may or may not be a health issue. Leaving a tightly attached, synthetic or rot-proof wrap on the stem for too long, or using synthetic materials to attach the wrap to the stem may girdle the stem [Fig. 3].

As the stem expands during growing season – even the first growing season – the rigid materials may compress (girdle) the stem tissues. This compression may restrict water, nutrients and/or photosynthates from normal movement within the stem, or weaken the stem physically. Other protectants such as paint and slaked lime may chemically damage the stem tissues.

Figure 3: Nylon cord attached for too long and girdling the stem.
Figure 3: Nylon cord attached for too long and girdling the stem.

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Figure 4a: The start of a frost canker
Figure 4a: The start of a frost canker

A wrap that minimizes temperature changes within the stem environment should be the most helpful in preventing sunscald or frost cankers [Fig. 4a-c]. Studies have been conducted that indicated that wrapping tree stems with paper wraps provided no more benefit than leaving the stems bare. Research has also shown that wraps with reflective material on the outside and insulation on the inside considerably moderated temperature fluctuations in the air surrounding the stem as well as the stem tissues.

Wraps should not be left on tree stems for more than one year. Never attach wraps to stems with materials (synthetic twine, plastic, wires) that will not decompose within a year.

Materials Available

Numerous materials have been used to protect tree stems. The most commonly used materials include:

  • paper wrap (kraft paper)
  • latex paint
  • commercial plastic guards

    Figure 4b: Intermediate stage.
    Figure 4b: Intermediate stage.
  • Foylon
  • burlap
  • homemade guards
  • cardboard

Guards and wrapping materials may be purchased at lawn and garden centers. For larger orders, contact Ben Meadows Company (1-800-241-6401) or Forestry Suppliers (601-354-3565).

Figure 4c: Resulting frost canker.
Figure 4c: Resulting frost canker.

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Figure 5: Plastic guards protect stems during transport.
Figure 5: Plastic guards protect stems during transport.

Plastic guards can be used to prevent physical damage to trees [Fig. 5]. They can prevent the bark from animal, lawnmower and string trimmer damage [Fig. 6, 7]. Seemingly small mechanical injuries can eventually be the demise of the tree when decay fungi or disease pathogens enter through the wounds. A simple alternative to guards is the installation of a mulch ring around the base of the tree [Fig. 8]. Mulch has other benefits, too, but does eliminate the need to mow or trim around the base of the tree.

Figure 6: Rabbit damage to tree.
Figure 6: Rabbit damage to tree.
Figure 7: This tree has twice the protection with wire cage outside and plastic tubing on the inside.
Figure 7: This tree has twice the protection with wire cage outside and plastic tubing on the inside.
Figure 8: Mulch rings benefit trees in many ways.
Figure 8: Mulch rings benefit trees in many ways.

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Wraps. Stems should be wrapped from the bottom (near soil line) to the top (first set of branches) to keep water from seeping in between the wrap and stem. The top should be attached with a stretchable material, such as masking tape or light twine, that will decompose naturally within a year [Fig. 9a & b]. Never use fiber-reinforce tape, nylon cord or wires to attach the wrap to the stem. They could girdle the stem. Wraps may be installed any time but they must be removed within a year.

Figure 9a: Start wrapping at soil line.
Figure 9a: Start wrapping at soil line.
Figure 9b: Wrap to first set of branches with masking tape.
Figure 9b: Wrap to first set of branches with masking tape.

Guards should be loose enough to allow air to flow through the space between the stem and the guard [Fig. 10]. This will allow the guard to better moderate the ambient stem conditions, especially temperature and humidity. Many guards have holes in them to aid in this process. Like wraps, guards may be installed any time, but may cause girdling and excess stem moisture conditions if left on for too long. Guards, like wrapping materials, should be removed within a year or at least before the stem out-grows the guard diameter [Fig.11-13].

Figure 10: Arborjacket (left) and tree shelter (right).
Figure 10: Arborjacket (left) and tree shelter (right).
Figure 11a: Start a spiral wrap.
Figure 11a: Start a spiral wrap.
Figure 11b: Finished spiral wrap.
Figure 11b: Finished spiral wrap.
Figure 12a: Arborjacket before installation.
Figure 12a: Arborjacket before installation.
Figure 12b: Arborjacket being installed and inserts connected.
Figure 12b: Arborjacket being installed and inserts connected.
Figure 13a: Tube guard being installed - note: be careful not to scrape bark with sharp edges of tube.
Figure 13a: Tube guard being installed - note: be careful not to scrape bark with sharp edges of tube.
Figure 13b: Plastic tie connecting tube guard together.
Figure 13b: Plastic tie connecting tube guard together.
Figure 13c: Installed tube guard.
Figure 13c: Installed tube guard.

Any use of guards or other stem protection materials can best be summed up by a statement made by Bonnie Appleton, who has researched and authored several articles on stem protection: “Regardless of the reason for using a trunk protective material, there is no point in providing protection at planting if the material used may eventually damage the tree because of improper material selection, or nonremoval. Timely readjustment or removal is mandatory, for both tree growth and aesthetic reasons.” [Fig. 14-15]

Figure 14: Chicken-wire guard left unattended for too long.
Figure 14: Chicken-wire guard left unattended for too long.
Figure 15: This stem has outgrown its protection, notice mower damage.
Figure 15: This stem has outgrown its protection, notice mower damage.

Research Referenced

Appleton, B.L. 1995. Use and misuse of tree trunk protective wraps, paints and guards. Florida Urban and Community Forestry Newsletter 1995(Spr): 2.

Appleton, B.L. and S. French. 1992. Current attitudes toward and uses of tree trunk protective wraps, paints and devices. Journal of Arboriculture 18(1): 15-20.

Harris, R.W. 1999. Arboriculture: Integrated Management of Landscape Trees, Shrubs and Vines. Prentice Hall, Englewood Cliffs, NJ 687 pgs.

Hart, J.H. and G.K. Dennis. 1978. Effect of tree wrap on the incidence of frost crack in Norway maple. Journal of Arboriculture 4:226-227.

Litzow, M. and H. Pellett. 1983. Materials for potential use in sunscald prevention. Journal of Arboriculture 9(2): 35-38.

Owen, N.P., C.S. Sadof and M. Raupp. 1991. The effect of plastic tree wrap on borer incidence in dogwood. Journal of Arboriculture 17(2): 29-31.

Watson, G.W. and E.B. Himelick. 1997. Principles and Practice of Planting Trees and Shrubs. Savoy, IL: International Society of Arboriculture. 199 pgs.

Emily Hanson deals with natural resources of urban areas. She is based in St. Paul.

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5 Comments

  1. What is the best wrap to use on my autumn blaze maple that is two years old? Last year my tree had sun scold in the spring. I had it wrapped with a natural colored tree wrap not paper wrap. Any suggestions for this fall? best way to wrap the tree and how tight? Thank you

    1. Hi Kelly. Good questions. From the text above, you’re probably aware of what you’re trying to accomplish: To reduce the likelihood of sunscald and a frost canker, you’re looking for a wrap that will moderate the temperature (in other words minimize or reduce temperature extremes) at the bark surface. The text recommends a wrap that has a reflective outer surface and some insulating properties. I can’t recommend a particular brand, but if you go to a good garden store, you should see several options.

      Once you’ve selected the wrap, be sure to read the advice above about installing it: You want it to be well enough secured that it’ll stay in place, but it needs to allow moisture to escape and air to flow either through or inside (from the top or bottom) to avoid excessive moisture, which can lead to decay.

      Hope this helps! We’d love to hear what you decide to go with and how it works.
      -eli

  2. i left the protective tubing on my young trees too long. there are spots on the truck where the bark has fallen off. what can i do before the upcoming winter to protect them?