Loss of species from deciduous forest understorey immediately following selective tree harvesting

  • Published source details Reader R.J. (1987) Loss of species from deciduous forest understorey immediately following selective tree harvesting. Biological Conservation, 42, 231-244.


Selective tree harvesting (removal of selected trees rather than clear-cutting) is undertaken in some areas in an attempt to manage forests for both timber production and species conservation. This Canadian study evaluated the effect of selective harvesting operations on understorey plants of mature deciduous forest in the Haldimand-Norfolk Region of southern Ontario (42°30'N, 80°30'W).

The study was undertaken in two areas with mature forest (generally oak Quercus spp. dominated) scheduled to be selectively cut. The experiment comprised removal of 0, 33 or 66% of the basal area of canopy trees from plots 12.5, 25 or 50 m in diameter. Three replicates of the nine treatments (i.e. 3 cutting intensities x 3 plot diameters) were established at one site and two replicates of the nine treatments at the other.
Trees were cut in winter (November-April) and commercially valuable trunks removed using a mechanical skidder. Unwanted trunks and tree tops were left. Before and after trees were cut, understorey vegetation in the plots was surveyed along two (2-m wide) transects. The presence of newly exposed soil and tree slash was also recorded when spring-flowering forbs were resurveyed in May. Surveys were also repeated later in the growing season (July-August).

The percentage of species lost from plots before and after cutting increased with cutting intensity; the most heavily cut plots lost significantly more species than plots cut at an intermediate level or uncut (average percentage of species lost per plot ranged 3 to 19% for the nine treatments).
There was no statistically significant difference in the percentage of species lost according to plot diameter. Ground surface disturbance increased with cutting intensity and appeared to account for most species loss. Understorey woody plants (damage to above ground parts) were more affected than herbs (underground perennating organs protected below ground during harvesting).
Herbs and woody species present at low density (i.e. 1-8 stems/plot) were more likely to be lost than more frequent species. To reduce losses of uncommon species during harvesting, the authors suggest that it would be more effective to minimise surface disturbance than cutting intensity or the area cut.
Note: If using or referring to this published study, please read and quote the original paper, this can be viewed at:

Output references
What Works 2021 cover

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 19

Go to the CE Journal

Discover more on our blog

Our blog contains the latest news and updates from the Conservation Evidence team, the Conservation Evidence Journal, and our global partners in evidence-based conservation.

Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape Programme Red List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Bern wood Supporting Conservation Leaders National Biodiversity Network Sustainability Dashboard Frog Life The international journey of Conservation - Oryx British trust for ornithology Cool Farm Alliance UNEP AWFA Butterfly Conservation People trust for endangered species Vincet Wildlife Trust