Cut/remove/thin forest plantations: freshwater marshes

Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
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How is the evidence assessed?

Effectiveness

58%
Certainty

38%
Harms

0%

Calculating overall effectiveness category

Background information and definitions

This action includes clear cutting (felling and removing all trees) and thinning (removal of only some trees) to address the threat from forest plantations (i.e. areas where trees have been deliberately planted, usually after drainage). Large wetland areas have been drained and afforested in the Paraná River Delta, South America (Ceballos et al. 2013) and the Sanjiang Plain, China (Zhang et al. 2014). Removing trees may increase light intensity at the ground surface allowing herbaceous plants to grow (Aschehoug et al. 2015), and may allow the water table to rise somewhat, since water is no longer intercepted or taken up by the trees).

^{Aschehoug E.T., Sivakoff F.S., Cayton H.L., Morris W.F. & Haddad N.M. (2015) Habitat restoration affects immature stages of a wetland butterfly through indirect effects on predation. Ecology, 96, 1761–1767.}

^{Ceballos D.S., Frangi J. & Jobbágy E.G. (2013) Soil volume and carbon storage shifts in drained and afforested wetlands of the Paraná River Delta. Biogeochemistry, 112, 359‒372.}

^{Zhang B., Chang L., Ni Z., Callaham M.A., Sun X. & Wu D. (2014) Effects of land use changes on winter-active Collembola in Sanjiang Plain of China. Applied Soil Ecology, 83, 51‒58.}

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.

VEGETATION COMMUNITY

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.

VEGETATION ABUNDANCE

VEGETATION STRUCTURE

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, 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
Referenced paper
Abella S.R., Schetter T.A. & Walters T.L. (2017) Restoring and conserving rare native ecosystems: a 14-year plantation removal experiment. Biological Conservation, 265-273.

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?

List of journals searched by synopsis

All the journals searched for all synopses

This Action forms part of the Action Synopsis:

Marsh and Swamp Conservation

Related Actions

Actions	Effectiveness	Category
Cut/remove/thin forest plantations: brackish/salt marshes Action Link	No evidence found (no assessment)	Synopsis Link
Abandon plantations: allow marshes or swamps to recover without active intervention Action Link	No evidence found (no assessment)	Synopsis Link
Cut/remove/thin forest plantations: freshwater swamps Action Link	No evidence found (no assessment)	Synopsis Link