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Providing evidence to improve practice

Individual study: Restoration treatment effects on the understory of ponderosa pine/Douglas-fir forests in western Montana, USA

Published source details

Metlen K.L. & Fiedler C.E. (2006) Restoration treatment effects on the understory of ponderosa pine/Douglas-fir forests in western Montana, USA. Forest Ecology and Management, 222, 355-369


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 within forests: effects on understory plants Forest Conservation

A replicated, randomized, controlled study in 2001-2004 in temperate coniferous forest in Montana, USA (Metlen & Fiedler 2006) found that thinning increased understory plant species richness. Numbers of species/0.1 ha plot for all species (unthinned: 57; thinned: 66) as well as for native species (unthinned: 53; thinned: 59), exotic species (unthinned: 4; thinned: 7) and forbs (unthinned: 34; thinned: 40) was higher in thinned plots. Numbers of species of grasses graminoids (12-14) and shrubs (9-10) were similar between treatments. Numbers of species/1 m2 was higher in thinned plots for forbs (unthinned: 5.5; thinned: 6.4) and similar between treatments for all species (10.8- 12.2) and for the other plant groups (native species: 10.5-11.8; exotic species: 0.3-0.4; graminoids: 2.4; shrubs: 2.4-2.9). Cover of all plants (28-32%) was similar between treatments. In 2001, ten plots (0.1 ha) were established in each of three replicates of thinned (retaining 11 m2/ha basal area) and unthinned treatment units (9 ha). Species composition was determined in 2004 in 12 quadrats (1 m2) in each plot (total of 720 quadrats).

 

Use prescribed fire: effect on understory plants Forest Conservation

A replicated, randomized, controlled study in 2001-2004 in temperate coniferous forest in Montana, USA (Metlen & Fiedler 2006) found that prescribed fire increased the number of understory exotic species and forbs at the large plot scale and decreased the number of native species at smaller scale. Plot-scale species richness was higher in burned plots for exotic plants (unburned: 4; burned: 6/1,000 m2) and forbs (unburned: 34; burned: 38/1,000 m2). On a smaller scale species richness for native species was lower in burned plots (unburned: 11; burned: 10/m2). For all plants together, plot-scale and a smaller scale were similar between treatments for species richness (plot-scale: 57 -60/1,000 m2; small-scale: 11/m2) and cover (both scales: 26-28%). Three replicates of burned and unburned control treatments (9 ha) were established in 2001. Species composition was determined in 2004 in 12 quadrats (1 m2) in each of ten plots (1,000 m2) within each treatment (total of 1,440 quadrats).