Managing the forest for more than the trees: Effects of experimental timber harvest on forest Lepidoptera

Published source details Summerville K.S. (2011) Managing the forest for more than the trees: Effects of experimental timber harvest on forest Lepidoptera. Ecological Applications, 21, 806-816.
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This study is summarised as evidence for the following.

	Action	Category
	Harvest groups of trees or use thinning instead of clearcutting Action Link
	Use shelterwood harvesting instead of clearcutting Action Link
	Use selective or reduced impact logging instead of conventional logging Action Link

Harvest groups of trees or use thinning instead of clearcutting

A replicated, controlled, before-and-after study in 2007–2009 in three hardwood forests in Indiana, USA (Summerville 2011, same experimental set-up as Summerville 2013) found that timber harvesting method, including group-selection harvesting, did not affect the number of moth species, but all harvested forest stands had fewer moths than unharvested stands. One year after harvesting, there was no significant difference in the number of moth species between stands subjected to group-selection harvesting (40 species), single-tree harvesting (39 species) or shelterwood harvesting and clearcutting (46 species, data not separated), but all harvested stands had fewer species than unharvested stands (56 species). One year before harvesting, all stands had a similar number of moth species (group-selection: 100; single-tree: 85; shelterwood/clearcutting: 96; unharvested: 90 species). In 2008, forest stands (3–5 ha, 150–350 m apart) in three watersheds (500 ha, 10 km apart) were logged. In one watershed, four stands were harvested by group-selection (80% of trees removed) and four stands had random single trees removed. In a second watershed, three stands were shelterwood harvested (15% of trees removed), two stands were clearcut (100% of trees removed), and three stands were unharvested (no trees removed). In the third watershed, all four stands were unharvested. All stands had been clearcut around 60 years earlier. From June–August 2007 and 2009, moths were surveyed every 14 nights (five times/year) from 8pm–7am using a black-light trap placed 2 m above the ground in the centre of each forest stand.

(Summarised by: Andrew Bladon)
Use shelterwood harvesting instead of clearcutting

A replicated, controlled, before-and-after study in 2007–2009 in three hardwood forests in Indiana, USA (Summerville 2011, same study as Summerville 2013) found that timber harvesting method, including shelterwood harvesting, did not affect the number of moth species, but all harvested forest stands had fewer moths than unharvested stands. One year after harvesting, there was no significant difference in the number of moth species between stands subjected to shelterwood harvesting and clearcutting (46 species, data not separated), single-tree harvesting (39 species) or group-selection harvesting (40 species), but all harvested stands had fewer species than unharvested stands (56 species). One year before harvesting, all stands had a similar number of moth species (shelterwood/clearcutting: 96; single-tree: 85; group-selection: 100; unharvested: 90 species). After harvesting, the community composition of shelterwood and unharvested stands in one forest were more similar to an unharvested forest than to two nearby clearcut stands (data presented as model results). In 2008, forest stands (3–5 ha, 150–350 m apart) in three watersheds (500 ha, 10 km apart) were logged. In one watershed, three stands were shelterwood harvested (15% of trees removed), two stands were clearcut (100% of trees removed), and three stands were unharvested (no trees removed). In a second watershed, four stands had random single trees removed, and four stands were harvested by group-selection (80% of trees removed). In the third watershed, all four stands were unharvested. All stands had been clearcut around 60 years earlier. From June–August 2007 and 2009, moths were surveyed every 14 nights (five times/year) from 8pm–7am using a black-light trap placed 2 m above the ground in the centre of each forest stand.

(Summarised by: Andrew Bladon)
Use selective or reduced impact logging instead of conventional logging

A replicated, controlled, before-and-after study in 2007–2009 in three hardwood forests in Indiana, USA (Summerville 2011) found that timber harvesting method, including selective logging, did not affect the number of moth species, but all harvested forest stands had fewer species than unharvested stands. One year after harvesting, there was no significant difference in the number of moth species between stands subjected to single-tree harvesting (39 species), group-selection harvesting (40 species) or shelterwood harvesting and clearcutting (46 species, data not separated), but all harvested stands had fewer species than unharvested stands (56 species). One year before harvesting, all stands had a similar number of moth species (single-tree: 85; group-selection: 100; shelterwood/clearcutting: 96; unharvested: 90 species). In 2008, forest stands (3–5 ha, 150–350 m apart) in three watersheds (500 ha, 10 km apart) were logged. In one watershed, four stands had random single trees removed, and four stands were harvested by group-selection (80% of trees removed). In a second watershed, three stands were shelterwood harvested (15% of trees removed), two stands were clearcut (100% of trees removed), and three stands were unharvested (no trees removed). In the third watershed, all four stands were unharvested. All stands had been clearcut around 60 years earlier. From June–August 2007 and 2009, moths were surveyed every 14 nights (five times/year) from 8pm–7am using a black-light trap placed 2 m above the ground in the centre of each forest stand.

(Summarised by: Andrew Bladon)