Cut/remove/thin forest plantations: freshwater marshes

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

Study locations

Key messages

  • One study evaluated the effects, on vegetation, of cutting/removing/thinning forest plantations to restore freshwater marshes. The study was in the USA.


  • Characteristic plant richness/diversity (1 study): One replicated, controlled study in the USA reported that the effect of thinning/clearing forest plantations on wetland-characteristic plant species richness depended on soil moisture. After three growing seasons, wetter thinned/cleared sites generally contained more wetland-characteristic plant species than drier thinned/cleared sites or sites that remained afforested.




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 2002–2005 involving 24 pine plantations on a gradient of moist to dry soils in Ohio, USA (Abella et al. 2017) reported that some sites where trees were thinned or cleared contained more wetland-characteristic plant species than sites that remained afforested. Statistical significance was not assessed. After three growing seasons, six thinned or cleared sites developed wetter soils than the others and contained 4–18 wetland-characteristic plant species/0.05 ha. Nine thinned and cleared sites that retained drier soils contained 0–9 such species/0.05 ha. Nine sites that remained fully afforested, and also had drier soils, contained 1–3 such species/0.05 ha. Methods: In early 2002, pine Pinus spp. plantations (47–63 years old; 900 trees/ha) were thinned or cleared from 15 sites (50–100% of trees removed, but many of the remaining trees died). Nine other sites were left fully afforested. Soil moisture varied between sites: the driest, upland sites were not expected to develop wetland vegetation even if trees were removed. Understory vegetation (a mix of herbs and shrubs) was surveyed in summer 2004 in one 20 x 25 m plot in the centre of each site.

    Study and other actions tested
Please cite as:

Taylor N.G., Grillas P., Smith R.K. & Sutherland W.J. (2021) Marsh and Swamp Conservation: Global Evidence for the Effects of Interventions to Conserve Marsh and Swamp Vegetation. Conservation Evidence Series Synopses. University of Cambridge, Cambridge, UK.

Where has this evidence come from?

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Marsh and Swamp Conservation

This Action forms part of the Action Synopsis:

Marsh and Swamp Conservation
Marsh and Swamp Conservation

Marsh and Swamp Conservation - Published 2021

Marsh and Swamp Synopsis

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