Apply herbicide to trees

Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 2
Share Tweet Email

View assessment score

How is the evidence assessed?

Effectiveness

40%
Certainty

35%
Harms

10%

Calculating overall effectiveness category

Background information and definitions

Application of herbicide can be used to control problematic trees and may aid recovery of shrubland vegetation.

Study locations

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

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
Referenced paper
Marrs R.H. (1984) Birch control on lowland heaths: mechanical control and the application of selective herbicides by foliar spray. Journal of Applied Ecology, 21, 703-716.
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
Referenced paper
Krupek A, Gaertner M., Holmes P.M. & Elser K.J. (2016) Assessment of post-burn removal methods for Acacia saligna in Cape Flats Sand Fynbos, with consideration of indigenous plant recovery. South African Journal of Botany, 105, 211-217.

Please cite as:

Martin, P.A., Rocha, R., Smith, R.K. & Sutherland, W.J. (2020) Shrubland and Heathland Conservation. Pages 483-525 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, 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:

Shrubland and Heathland Conservation

Related Actions

Actions	Effectiveness	Studies	Category
Cut trees Action Link	Unknown effectiveness (limited evidence)	3	Synopsis Link
Cut trees and use prescribed burning Action Link	Unknown effectiveness (limited evidence)	3	Synopsis Link
Use grazing to control trees Action Link	Unknown effectiveness (limited evidence)	1	Synopsis Link