Use tree guards or shelters to protect planted trees

Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 2
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How is the evidence assessed?

Effectiveness

60%
Certainty

28%
Harms

20%

Calculating overall effectiveness category

Background information and definitions

Tree guards can be used to protect planted tree seedlings from browsing, cold etc. and increase their establishment chances.

Study locations

Key messages

One replicated, randomized, controlled study in the USA found that using light but not dark coloured plastic tree shelters increased the survival rate of planted tree seedlings. One replicated, controlled study in Hong Kong found that tree guards increased treeheight after 37 but not 44 months.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

A replicated, randomized, controlled study in 1996-1997 in temperate coniferous forest in Colorado, USA (Jacobs & Steinbeck 2001) found that tree shelters increased the survival rate of Engelmann spruce Picea engelmannii seedlings. The survival rate of Engelmann spruce was higher with the three light-coloured tree shelters (95-99%) than the controls (70%) and the lowest with the dark brown shelters (5%). Four replicates of each of five treatments were randomly assigned to 20 plots in each of three blocks (0.5 ha): four colours of recycled polyethylene plastic tree shelters (31 cm height and 9 cm diameter), ranging from nearly clear to brown, and a control (using materials from within the site, e.g. logs, stumps, shrubs, rocks, to protect seedlings). In August-September 1996, 25 seedlings were planted in each plot (total of 1,500 seedlings). Data were collected in 1997.
Study and other actions tested
Referenced paper
Jacobs D.F. & Steinbeck K. (2001) Tree shelters improve the survival and growth of planted Engelmann spruce seedlings in southwestern Colorado. Western Journal of Applied Forestry, 16, 114-120.
A replicated, controlled study in 1999-2002 in a degraded tropical forest in Hong Kong (Lai & Wong 2005) found that using tree guards increased the height of thick-leaved oak Cyclobalanopsis edithae seedlings, also covered with weed mats, but only in the first three years. After 37 months, seedling height was greater with tree guards (80 cm) than control (57 cm). However, after 44 months, there was no difference between treatments (control: 85; tree guards: 96 cm). Fifteen oak seedlings were planted in each of four replicate (rows) of each tree guards (45 cm high plastic tree guard) and control treatments. All rows were covered with weed mats (0.4 × 0.4 m hessian cloth around each seeding). Seedlings were planted in June 1999 and observed for approximately 44 months.
Study and other actions tested
Referenced paper
Lai P.C.C. & Wong B.S.F. (2005) Effects of tree guards and weed mats on the establishment of native tree seedlings: implications for forest restoration in Hong Kong, China. Restoration Ecology, 13, 138-143.

Please cite as:

Agra, H., Schowanek, S., Carmel, Y., Smith, R.K. & Ne’eman, G. (2020) Forest Conservation. Pages 323-366 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

This Action forms part of the Action Synopsis:

Forest Conservation

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