Action: Use grazing to control trees
Key messagesRead our guidance on Key messages before continuing
- 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.
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.
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.