Action: Reduce the intensity of livestock grazing in forests
Key messagesRead our guidance on Key messages before continuing
- One replicated study in the UK found that reducing grazing intensity increased the number of tree saplings.
- One replicated, randomized, controlled study in Greece found that reducing grazing intensity increased understory biomass.
Complete removal of livestock by fencing tends to promote regeneration, mainly in the early stages after removal. This is due to the removal of the disturbance effect of animals, which commonly provides ‘niches’ for seedling establishment. Reducing grazing intensity rather than complete removal may allow continued income from livestock.
Supporting evidence from individual studies
A replicated study in 1986-1993 in temperate woodland in the UK (Hester, Mitchell & Kirby 1996) found that reducing the intensity of sheep grazing increased the numbers of tree saplings. The number of saplings/100 m2 was higher in low-intensity (0.54-0.66) than in high- and medium-intensity grazing plots. Four plots for each grazing intensity: high (2.1-3.8 sheep/ha); medium (1.2-2.0 sheep/ha) or low (0.6-1.2 sheep/ha) were established in 1986. Saplings (>30 cm diameter at breast height) were monitored in 2003 in 20 quadrats (10 × 10 m) within each plot.
A replicated, randomized, controlled study in 1991-2005 in a Mediterranean oak forest in central Macedonia, Greece (Ainalis, Platis & Meliadis 2010) found that reducing grazing intensity increased understory plant biomass . Understory production (kg/ha dry matter) was higher in non- and lightly-grazed (~4,500) than in moderately-grazed (~2,800) and heavily-grazed sites (~1,000). A study area of 2,000 ha was divided into six forest segments, each was divided into three areas with different stocking densities (goats and cattle): heavy (15 animals/ha), moderate (5 animals/ha) and light (0.2 animals/ha). Sixty plots (1 m2) were randomly placed in every grazing treatment in all stands and protected from grazing at the end of 2004. Similar size plots with grazing close to protected (control) plots were sampled for comparison. Overall understory (herbage and browse) production was measured in 1991 and in September 2005.
- Hester A., Mitchell F. & Kirby K. (1996) Effects of season and intensity of sheep grazing on tree regeneration in a British upland woodland. Forest Ecology and Management, 88, 99-106
- Ainalis A.B., Platis P.D. & Meliadis I.M. (2010) Grazing effects on the sustainability of an oak coppice forest. Forest ecology and management, 259, 428-432