Action: Increase number of livestock and use prescribed burning to control trees
- One randomized, controlled, before-and-after study in Italy found that using prescribed burning and grazing to reduce tree cover reduced the cover of common heather and the basal area of trees. However, it did not alter the cover of purple moor grass.
Fire may damage or kill trees therefore reducing competition between trees and shrubland vegetation. Combining this with grazing may help to reduce regrowth and recruitment of young trees.
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 using prescribed burning and grazing to reduce tree cover reduced the cover of common heather Calluna vulgaris and 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 areas that were burned and grazed was lower (83%) than that in areas that were not burned (36%). Cover of purple moor grass was similar between burned and grazed areas (89%) and areas that were not burned or grazed (88%). Additionally, the basal area of trees was lower in burned and grazed areas (0.5 m2/ha) than in areas that had not been burned or grazed (4.6 m2/ha). In winter 2005 twelve 650 m2 plots were burned and subsequently grazed by goats for five years, and another six plots were not burned or grazed. No statistical analyses were carried out in this study. 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.