Use grazing to control trees

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

Effectiveness

20%
Certainty

10%
Harms

5%

Calculating overall effectiveness category

Background information and definitions

Livestock can damage and kill tree seedlings as a result of grazing and trampling. This can potentially be used to limit the growth and spread of problematic tree species in shrublands.

Study locations

Key messages

One randomized, controlled, before-and-after study in Italy found that grazing to reduce tree cover reduced cover of common heather and the basal area of trees, but did not alter cover of purple moor grass.

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, controlled, before-and-after study in 2005-2009 in a heathland invaded by aspen Populus tremuloides and silver birch Betula pendula in Italy (Ascoli et al. 2013) found that grazing to reduce tree cover reduced the cover of common heather Calluna vulgaris and the basal area of trees but did not alter the cover of purple moor grass Molinia arundinacea. After five years, the cover of common heather in grazed areas was similar (77%) to than that in areas that were not burned (77%). Purple moor grass cover was similar between grazed (84%) and ungrazed areas (88%). The basal area of trees was lower in grazed (3.2 m²/ha) than in ungrazed areas (4.6 m²/ha). No statistical analyses were carried out in this study. Starting in spring 2006 nine 650 m² plots were grazed by goats for five years, and another six plots were not grazed. Five 2 x 2 m quadrats were placed in each plot and diameter of trees within them measured. Cover of common heather and purple moor grass was estimated using a 10 m transect in each plot along which the presence of both species was noted every 20 cm.
Study and other actions tested
Referenced paper
Ascoli D., Lonati M., Marzano R., Bovio G., Cavallero A. & Lombardi G. (2013) Prescribed burning and browsing to control tree encroachment in southern European heathlands. Forest Ecology and Management, 289, 69-77.

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/mow shrubland to control trees Action Link	No evidence found (no assessment)	0	Synopsis Link
Cut trees and remove tree seedlings Action Link	Unknown effectiveness (limited evidence)	1	Synopsis Link
Apply herbicide to trees Action Link	Unknown effectiveness (limited evidence)	2	Synopsis Link