Manage woody debris before tree planting

How is the evidence assessed?
  • Effectiveness
  • Certainty
  • Harms

Study locations

Key messages

  • One replicated, randomized, controlled study in Canada found that removal of woody debris increased the survival rate of planted trees.
  • One replicated, controlled study in the USA found mixed effects of removing, chopping and burning woody debris on the size of planted trees.


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

  1. A replicated, controlled study in 1988-1994 in temperate coniferous forest in Washington state, USA (Zabowski et al. 2000) found that removing, chopping or burning woody debris had mixed effects on the growth of planted Douglas-fir Pseudotsuga menziesii and lodgepole pine Pinus contorta seedlings. The average total height growth of both species was lower in cleared than control plots and highest following a spring burn (piled: 61 cm; autumn burn: 66; chopped: 71; pulled off site: 71; piled and burned: 72; control: 75; spring burn: 90). In 1989, seven treatment plots (0.3-3.2 ha) were established in each of four sites: control (untreated); woody debris pulled off site (using a cable system); chopped (debris mechanically chopped); debris piled and burned; debris piled; spring burn (low intensity spring broadcast-burn); autumn burn (low-to-medium intensity autumn broadcast-burn). All plots were clearcut in 1988 and planted with Douglas-fir or lodgepole pine seedlings in 1990. The height of 100 seedlings in each plot was measured at the end of the first and fifth growing seasons.

    Study and other actions tested
  2. A replicated, randomized, controlled study in 2001-2006 in temperate coniferous forest in Alberta, Canada (Landhäusser 2009) found that woody debris removal decreased the mortality of planted lodgepole pine Pinus contorta seedlings. Mortality of planted seedlings was lower in removal (3%) than control plots (11%). Twelve removal (woody debris removed in winter 2001) and 12 control (woody debris not removed) plots (30 × 30 m) were planted with lodgepole pine (2,000 seedlings/ha) in 2002. The mortality of 20 planted seedlings/plot was monitored in 2003-2006.

    Study and other actions tested
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

Forest Conservation

This Action forms part of the Action Synopsis:

Forest Conservation
Forest Conservation

Forest Conservation - Published 2016

Forest synopsis

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