Action

Use cutting to control problematic large trees/shrubs

How is the evidence assessed?
  • Effectiveness
    60%
  • Certainty
    30%
  • Harms
    15%

Source countries

Key messages

  • Two studies evaluated the effects on peatland vegetation of cutting and removing problematic large trees/shrubs. Both studies were in fensN.B. Cutting trees/shrubs in historically disturbed peatlands is considered as a separate action.
  • Plant community composition (2 studies): Two studies (one replicated, controlled, before-and-after) in fens in the USA and Sweden reported that the plant community composition changed following tree/shrub removal, becoming less like unmanaged fens or more like undegraded, open fen.
  • Characteristic plants (1 study): One study in a fen in Sweden found that species richness and cover of fen-characteristic plants increased following tree/shrub removal.
  • Vegetation cover (2 studies): One study in a fen in Sweden found that moss and vascular plant cover increased following tree/shrub removal. One replicated, controlled, before-and-after study in fens in the USA found that shrub removal (along with other interventions) could not prevent increases in shrub cover over time.
  • Overall plant richness/diversity (2 studies): One study in a fen in Sweden found that moss and vascular plant species richness increased following tree/shrub removal. However, one replicated, controlled, before-and-after study in fens in the USA found that shrub removal (along with other interventions) prevented increases in total plant species richness.

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, before-and-after study in 1986–2000 in two shrub-invaded fens in Ohio, USA (Barry et al. 2008) found that cutting shrubs (along with burning and herbicide application) altered plant community composition and prevented increases in plant species richness, but had no effect on shrub cover. The overall plant community composition changed significantly over time along transects with and without shrub control, but they accumulated different sets of species (data reported as a graphical analysis). Plant species richness was stable in the fen with shrub control (before: 12.8; after 14 years: 12.7 species/m2) but increased in the fen without shrub control (before: 12.5; after 14 years: 14.6 species/m2). Woody plant cover increased similarly in fens with shrub control (before: 46%; after 11 years: 62%) and without shrub control (before: 20%; after: 28%). From 1986, encroaching shrubs were managed using ad hoc cutting, burning and herbicide application. The study does not distinguish between the effects of these interventions. Three of four transects were managed in one fen (‘with shrub control’). Only one of four transects were managed in the other fen (‘without shrub control’). In summer 1986 (before shrub control began), 1999 and 2000, vegetation cover was estimated in 1 m2 quadrats along the eight transects. Shrub cover was estimated from aerial photographs.

    Study and other actions tested
  2. A site comparison study in 1995–2001 in an overgrown rich fen in Sweden (Sundberg 2011) found that following shrub/tree removal, the plant community composition became more like a natural fen, and plant species richness and vegetation cover increased. Between one and six years after shrub removal, the overall plant community composition became more like an open fen (data reported as a graphical analysis). Where shrubs were removed, species richness increased for vascular plants (from 15 to 18 species/m2), mosses (from 7 to 9 species/m2) and fen-characteristic plants (from 8 to 10 species/m2). Cover of these groups also increased (vascular plants: from 18 to 24%; mosses: from 9 to 31%; fen-characteristic plants: from 7 to 15%), as did cover of common cottongrass Eriophorum angustifolium (from 0.3 to 0.6%) and three of eight Carex sedge species. Cover of five other sedge species, purple moor grass Molinia caerulea and common reed Phragmites australis did not change. In 1995, shrubs (mainly juniper Juniperus communis) and trees (conifers) were manually cut and removed from a 30 x 50 m area of overgrown fen. The fen was grazed by 7–12 cows every summer, both before and after shrub removal. Cover of every plant species was estimated in August 1996 and 2001: in nine 1 m2 quadrats across the managed area and three quadrats in another part of the fen that had not become overgrown.

    Study and other actions tested
Please cite as:

Taylor N.G., Grillas P. & Sutherland W.J. (2019) Peatland Conservation. Pages 375-438 in: W.J. Sutherland, L.V. Dicks, N. Ockendon, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2019. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

Peatland Conservation

This Action forms part of the Action Synopsis:

Peatland Conservation
Peatland Conservation

Peatland Conservation - Published 2018

Peatland Conservation

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence in synopses. Subjects covered so far include amphibians, birds, terrestrial mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read latest volume: Volume 17

Go to the CE Journal

Subscribe to our newsletter

Please add your details if you are interested in receiving updates from the Conservation Evidence team about new papers, synopses and opportunities.

Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape Programme Red List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Bern wood Supporting Conservation Leaders National Biodiversity Network Sustainability Dashboard Frog Life The international journey of Conservation - Oryx British trust for ornithology Cool Farm Alliance UNEP AWFA Butterfly Conservation People trust for endangered species Vincet Wildlife Trust