Bat activity is low in thinned and unthinned stands of red pine

  • Published source details Tibbels A.E. & Kurta A. (2003) Bat activity is low in thinned and unthinned stands of red pine. Canadian Journal of Forest Research, 33, 2436-2442.


This study is summarised as evidence for the following.

Action Category

Thin trees within forest and woodland

Action Link
Bat Conservation
  1. Thin trees within forest and woodland

    A replicated, paired sites study in 2001 in 13 managed red pine Pinus resinosa forests in Lower Michigan, USA (Tibbels & Kurta 2003) found that thinned tree stands had similar bat activity to unthinned stands. Overall bat activity (of at least five bat species) did not differ significantly between thinned (16 bat passes, 0.3 feeding buzzes) and unthinned stands (8 bat passes, 0.5 feeding buzzes). At all sites, bat activity was higher in nearby openings within the forests (thinned: 788 bat passes, 5 feeding buzzes; unthinned: 725 bat passes, 5 feeding buzzes) than within tree stands. Thirteen paired tree stands (one thinned: 12 stems/100 m2: one unthinned: 22 stems/100 m2) were surveyed on two occasions. All stands were >10 ha and 52 years old on average. Thinned stands had been thinned 5–11 years prior to the study. Openings in stands were either cleared for wildlife or sites used by loggers. Bat surveys were carried out simultaneously at groups of four sites (interior and openings in a pair of thinned and unthinned stands). Bat detectors recorded bat activity for one full night/site in May–June and July–August 2001. Bats were captured using mist nets during six nights in May–August 2001 at half of the thinned sites and half of the unthinned sites.

    (Summarised by: Anna Berthinussen)

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