Apply herbicide to trees

How is the evidence assessed?
  • Effectiveness
    40%
  • Certainty
    35%
  • Harms
    10%

Source countries

Key messages

  • One replicated, controlled, before-and-after study in South Africa found that using herbicide to control trees increased plant diversity but did not increase shrub cover.
  • One randomized, replicated, controlled study in the UK found that herbicide treatment of trees increased the abundance of common heather seedlings.

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 randomized, replicated, controlled study in 1979–1981 in a heathland in Cambridgeshire, UK (Marrs 1984) found that using herbicide to control silver birch Betula pendula saplings sometimes increased the abundance of heather Calluna vulgaris and birch seedlings while reducing the abundance of silver birch saplings. In one of three cases, plots treated with herbicide had more heather seedlings (64 seedlings/m2) than untreated plots (4 seedlings/m2). In three of three cases, plots treated with herbicide had fewer birch saplings (0–1 saplings/m2) than untreated plots (20 saplings /m2). However, in two of three cases, birch seedlings were more abundant in plots treated with herbicide (24–54 seedlings/m2) than in untreated plots (7 seedlings/m2). The herbicides fosamine, 2,4,5-T, and triclopyr were each applied in four 4 m2 plots in 1979, and in four plots no herbicide was applied. Density of birch and heather plants was estimated annually in 1980-1981 in all plots.

    Study and other actions tested
  2. A replicated, controlled, before-and-after study in 2013–2014 in a fynbos site in Cape Town, South Africa (Krupek et al. 2016) found that spraying invasive orange wattle Acacia saligna trees with herbicide increased plant diversity, but not shrub cover. Plant species diversity was higher in areas treated with herbicide than in untreated areas (data presented as model results). However, shrub cover in areas treated with herbicide (2%) did not differ from untreated areas (5%). In April 2013 herbicide was sprayed on orange wattle saplings in ten 25 m2 plots, while another ten plots were left untreated. The cover and diversity of plant species was assessed using 1 m2 quadrats placed inside each plot.

    Study and other actions tested
Please cite as:

Martin P.A., Rocha R., Smith R.K. & Sutherland W.J. (2019) Shrubland and Heathland Conservation. Pages 493-538 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

Shrubland and Heathland Conservation

This Action forms part of the Action Synopsis:

Shrubland and Heathland Conservation
Shrubland and Heathland Conservation

Shrubland and Heathland Conservation - Published 2017

Shrubland and Heathland synopsis

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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.

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