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Providing evidence to improve practice

Action: Thin trees by girdling (cutting rings around tree trunks) Forest Conservation

Key messages

  • One before-and-after trial in Canada found that thinning trees by girdling (cutting rings around tree trunks) increased understory plant species richness, diversity and cover.

 

Supporting evidence from individual studies

1 

A before-and-after trial in 1992-2003 in boreal forest in Quebec, Canada (Grandpré et al. 2011) found that thinning trees by girdling increased understory species richness, diversity and cover. The number of species increased following girdling (before: 5-9; after: 7-12/1 m2 plot) and remained similar in uncut plots (before: 5-10; after: 6-12). Species diversity increased following girdling (Shannon's index before: 0.8-1.1; after: 1.2-1.7) and remained similar in uncut plots (before: 0.7-1.3; after: 0.8-1.5). Plant cover increased following girdling (before: 80%; after: 100-120%) and remained similar in uncut plots (before: 90-100%; after: 90-120%). In 1992, girdling (cutting >1 cm deep cuts around the trunks of all conifers) and uncut treatments (100 m2) were replicated in three blocks (>625 m2) at each of two sites. Data were collected before (1992) and after treatments (2003) in 5-12 plots (1 m2) in each treatment.

 

Referenced papers

Please cite as:

Agra H., Schowanek S., Carmel Y., Smith R.K. & Ne’eman G. (2018) Forest Conservation. Pages 285-328 in: W.J. Sutherland, L.V. Dicks, N. Ockendon, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2018. Open Book Publishers, Cambridge, UK.