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Providing evidence to improve practice

Individual study: 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


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Use group-selection harvesting Forest Conservation

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.