Initial response of understory vegetation to three alternative thinning treatments

  • Published source details Davis L.R. & Puettmann K.J. (2009) Initial response of understory vegetation to three alternative thinning treatments. Journal of Sustainable Forestry, 28, 904-934.


This study is summarised as evidence for the following.

Action Category

Use group-selection harvesting

Action Link
Forest Conservation
  1. Use group-selection harvesting

    A replicated, controlled, before-and-after study in 1995-2001 in temperate coniferous forest in Oregon, USA (Davis & Puettmann 2009) found that group-selection harvesting increased the change over time in herbaceous and shrub cover. The increase in herbaceous cover (group-selection: 3; uncut: -2%) and in low shrub cover (group-selection: 20%, uncut: -4%) was higher in group-selection than in uncut plots. The increase in bryophyte cover (group-selection: 14%; uncut: 5%) and in tall shrub cover (group-selection: 6%; uncut: 0%) was similar between treatments. Gaps (0.2 ha circular gaps, retaining 250 trees/ha) and uncut treatment units (15-53 ha) were established in each of four sites in 1995-1997. In uncut units about 7.5% of the area was covered using 0.1 ha circular plots. In group-selection units, one 0.1 ha plot was placed in each of ten gaps, ten gap-edges, and ten areas between the gaps. Data were collected before treatments and again in 2001 in 16 subplots of 0.1 m2 in each plot.

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 21

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 ProgrammeRed List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Mauritian Wildlife Supporting Conservation Leaders
Sustainability Dashboard National Biodiversity Network Frog Life The international journey of Conservation - Oryx Cool Farm Alliance UNEP AWFA Bat Conservation InternationalPeople trust for endangered species Vincet Wildlife Trust