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Providing evidence to improve practice

Individual study: Effects of small canopy gaps on boreal mixedwood understory vegetation dynamics

Published source details

Grandpré L., Boucher D., Bergeron Y. & Gagnon D. (2011) Effects of small canopy gaps on boreal mixedwood understory vegetation dynamics. Community Ecology, 12, 67-77


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

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

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.

 

Log/remove trees within forests: effects on understory plants Forest Conservation

A before-and-after trial in 1992-2003 in boreal forest in Quebec, Canada (Grandpré et al. 2011) found that conifer cutting increased understory species richness, diversity and cover. Numbers of species/1 m2 plot increased in conifer cut plots (before: 4-9; after: 7-13) and remained similar in uncut plots (before: 5-10; after: 6-12). Species diversity (Shannon's index) increased in conifer cut plots (before: 0.7-1.3; after: 0.9-1.5) and remained similar in uncut plots (before: 0.7-1.3; after: 0.8-1.5). Cover increased in conifer cut plots (before: 70%-80%; after: 100%-170%) and remained similar in uncut plots (before: 90%-100%; after: 90%-120%). In 1992, confer cutting (all conifers cut and removed) 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.

 

Use clearcutting to increase understory diversity Forest Conservation

A before-and-after trial in 1992-2003 in boreal forest in Quebec, Canada (Grandpré et al. 2011) found that clearcutting increased understory species richness, diversity and cover. Numbers of species/1 m2 plot increased in clearcut plots (before: 5-8; after: 9-13) and remained similar in uncut plots (before: 5-10; after: 6-12). Species diversity (Shannon's index) increased in clearcut plots (before: 0.7-1.2; after: 1.4-1.7) and remained similar in uncut plots (before: 0.7-1.3; after: 0.8-1.5). Cover increased in clearcut (before: 70-90%; after: 140-160%), but not uncut plots (before: 90-100%; after: 90-120%). In 1992, clearcut (all trees cut and removed) 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.