Partial and clear-cut harvesting of high-elevation spruce-fir forests: implications for small mammal communities

Published source details Klenner W. & Sullivan T.P. (2003) Partial and clear-cut harvesting of high-elevation spruce-fir forests: implications for small mammal communities. Canadian Journal of Forest Research, 33, 2283-2296.
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This study is summarised as evidence for the following.

	Action	Category
	Fell trees in groups, leaving surrounding forest unharvested Action Link
	Clear or open patches in forests Action Link
	Use selective harvesting instead of clearcutting Action Link

Fell trees in groups, leaving surrounding forest unharvested

A replicated, controlled study in 1994–1997 of Douglas-fir Pseudotsuga menziesii forest in British Colombia, Canada (Klenner et al. 2003) found that felling groups of trees within otherwise undisturbed stands increased southern red-backed vole Myodes gapperi abundance in some years relative to clearcutting but did not increase abundances of three other small mammal species. There were more southern red-backed voles in the third and fourth year after felling in group cut stands (7–14/stand) than in clearcuts (0.3–0.7/stand) but similar numbers between treatments in the first two years (group cut: 27–51/stand; clearcut: 13–34/stand). There were no differences between treatments for deer mouse Peromyscus maniculatus (group cut: 2–13/stand; clearcut: 6–21) or northwestern chipmunk Tamias amoenus (group cut: 1–8/stand; clearcut: 0.3–6/stand). There were fewer meadow voles Microtus pennsylvanicus in 20% group cut stands (1–3/stand) than in 50% group cut stands (0.8–4/stand) or clearcut stands (3–14/stand). Forest stands (20–25 ha) were partially harvested in winter 1993/94. Two each had 20% volume removed by cutting patches of 0.1–1.6 ha and 50% volume removed by cutting patches of 0.1–1.6 ha. Abundances across these stands were compared with that in two clearcuts of 1.6 ha. Small mammals were sampled by live-trapping at 2–4-week intervals, from May–October in 1994, 1995, and 1996 and from April–May 1997.

(Summarised by: Nick Littlewood)
Clear or open patches in forests

A replicated, controlled, before-and-after study in 1994–1998 of a coniferous forest in British Colombia, Canada (Klenner & Sullivan 2003) found a greater abundance of one small mammal species when forest was harvested in small patches, relative to clearcutting, but not of three other species. Populations of all species did not differ between treatment plots in the pre-treatment year. After harvesting, there were more southern red-backed voles Clethrionomys gapperi in patch harvesting plots (0.1-ha patches: 18.7–49.7/ha; 1-ha patches: 18.0–38.1/ha) than in clearcuts (0.1–10.8/ha). Long-tailed voles Microtus longicaudus were less abundant in patch harvesting plots than clearcut plots (0.1-ha patches: 0.4–4.5/ha; 1-ha patches: 0.2–2.6/ha; clearcuts: 2.6–16.2/ha). Abundances were similar between treatments for northwestern chipmunk Tamias amoenus (0.1-ha patches: 2.9–3.4/ha; 1-ha patches: 2.2–2.4/ha; clearcuts: 3.7–6.0/ha) and deer mouse Peromyscus maniculatus (0.1-ha patches: 0.4–5.1/ha; 1-ha patches: 2.0–4.5/ha; clearcuts: 0.8–5.0/ha). Forest stands were c.30 ha. There were three replicate stands each harvested in winter 1994/95, with 0.1-ha patches, 1-ha patches and 10-ha clearcuts. Each involved removing 30% volume of timber. Small mammals were live-trapped in 1994–1998, over two consecutive nights, at 3-week intervals, from June or July to August or September.

(Summarised by: Nick Littlewood)
Use selective harvesting instead of clearcutting

A replicated, controlled, before-and-after study in 1994–1998 of a coniferous forest in British Colombia, Canada (Klenner & Sullivan 2003) found that when forest was harvested by single tree selection, one of four small mammal species was more abundant relative to clearcutting. Populations of all species did not differ between plots assigned for different treatments in the year before harvesting. After harvesting, there were more southern red-backed voles Clethrionomys gapperi in single tree selection plots (20.8–44.0/ha) than in clearcuts (0.1–10.8/ha). Long-tailed vole Microtus longicaudus was less abundant in single tree selection than clearcut plots (0.0–3.4 vs 2.6–16.2/ha) as was northwestern chipmunk Tamias amoenus (0.8–1.4 vs 1.9–6.0/ha). Deer Mouse Peromyscus maniculatus numbers were similar between treatments (single tree selection: 0.4–4.0/ha; clearcuts: 0.8–5.0/ha). Forest stands were c.30 ha. There were three replicates each of single tree selection (removing 33% of timber volume) and 10-ha clearcuts, harvested in winter 1994–1995. Small mammals were live-trapped in 1994–1998, over two consecutive nights, at 3-week intervals, from June or July to August or September.

(Summarised by: Nick Littlewood)