Use cutting to control problematic large trees/shrubs: freshwater marshes

How is the evidence assessed?
  • Effectiveness
    not assessed
  • Certainty
    not assessed
  • Harms
    not assessed

Study locations

Key messages

  • Two studies evaluated the effects, on vegetation, of cutting down problematic large trees/shrubs in freshwater marshes. One study was in the UK and one was in the USA.

VEGETATION COMMUNITY

  • Overall extent (1 study): One study of a dune slack in the UK reported an increase in total vegetation coverage between one and two years after clearing scrub (by cutting and applying herbicide).
  • Overall richness/diversity (1 study): The same study reported a small increase in total plant richness between one and two years after clearing scrub (by cutting and applying herbicide).
  • Characteristic plant richness/diversity (1 study): The same study reported an increase in the number of slack-characteristic plant species present between one and two years after clearing scrub (by cutting and applying herbicide).
  • Native/non-target richness/diversity (1 study): The same study reported an increase in native plant richness between one and two years after clearing scrub (by cutting and applying herbicide).

VEGETATION ABUNDANCE

  • Individual species abundance (1 study): One study quantified the effect of this action on the abundance of individual plant species, other than the species being controlled. The site comparison study in the USA found that tussock sedge Carex stricta was less dense in a wet meadow restored by removing trees (along with other interventions, including planting sedges) than in nearby natural meadows, after 11–14 years.

VEGETATION STRUCTURE

  • Height (1 study): One site comparison study in the USA reported that sedge tussocks were shorter in a wet meadow restored by removing trees (along with other interventions, including planting sedges) than in nearby natural meadows, after 11–14 years.
  • Diameter/perimeter/area (1 study): The same study reported that sedge tussocks had a smaller perimeter in a wet meadow restored by removing trees (along with other interventions, including planting sedges) than in nearby natural meadows, after 11–14 years.
  • Basal area (1 study): The same study reported that the basal area of sedge tussocks was smaller in a wet meadow restored by removing trees (along with other interventions, including planting sedges) than in nearby natural meadows, after 11–14 years.

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 study in 2005–2007 of a dune slack in England, UK (Smith & Kimpton 2008) reported that after cutting grey willow Salix cinerea scrub (along with applying herbicide), ground vegetation recolonized. In 2006, approximately one year after removing willows, 80% of the site was covered with vegetation (mostly herbaceous). There were 108 vascular plant taxa, including 98 natives. Approximately 54 taxa were characteristic of dune slacks. In 2007, approximately two years after removing willows, 95% of the site was covered with vegetation (still mostly herbaceous). There were 111 vascular plant taxa, including 107 natives. Approximately 65 taxa were characteristic of dune slacks. Twenty-eight taxa recorded in 2006 were not present in 2007, but 31 new taxa had colonized the site. Methods: In November/December 2005, dense grey willow scrub in a dune slack (low-lying area amongst dunes) was controlled. Grey willows were cut at ground level, then herbicide (Roundup® Biactive Plus) was applied to the largest stumps. The study does not distinguish between the effects of these interventions. Cut material was burned on site. Vascular plant taxa and their overall coverage were surveyed in August/September 2006 and 2007.

    Study and other actions tested
  2. A site comparison study in 2008 of five sedge meadows in Illinois and Wisconsin, USA (Lawrence & Zedler 2013) found that a meadow restored by removing trees (and excess sediment, then planting tussock sedge Carex stricta) – contained more but smaller sedge tussocks than nearby natural meadows after 11–14 years. In four of four comparisons, the restored meadow contained a greater density of sedge tussocks (8.4 tussocks/m2) than natural meadows (4.5–5.6 tussocks/m2). Sedge tussocks were also smaller in the restored meadow than in the natural meadows. This was true in four of four comparisons for height (restored: 5 cm; natural: 11–18 cm), perimeter (restored: 39 cm; natural: 51–82 cm) and volume (restored: 560 cm3; natural: 2,342–6,604 cm3). The basal area of tussocks in the restored meadow was only 0.07 m2/m2, compared to 0.12–0.23 m2/m2 in the natural meadows (statistical significance not assessed). Methods: In 2008, sedge tussocks were surveyed in one restored and four natural sedge meadows (15–30 quadrats/meadow, each 1 m2). The restored meadow was formerly a wooded floodplain. Trees and accumulated sediment were removed, then plugs of tussock sedge planted 30 cm apart, between 1994 and 1997. The study does not distinguish between the effects of these interventions on any non-planted sedges.

    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?

List of journals searched by synopsis

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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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