Canadian Forest Service Publications

Understory plant community resilience to partial harvesting in riparian buffers of central Canadian boreal forests. 2013. Mallik, A.U; Kreutzweiser, D.P.; Spalvieri, C.M.; Mackereth, R.W. Forest Ecology and Management 289:209-218.

Year: 2013

Issued by: Great Lakes Forestry Centre

Catalog ID: 34253

Language: English

Availability: PDF (request by e-mail)

Available from the Journal's Web site.
DOI: 10.1016/forco.2012.09.039

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Abstract

Partial harvesting in riparian buffers has been suggested as a forest management option to emulate natural disturbance patterns in riparian buffers. However, little is known about the effects of canopy gapcreation by partial harvesting in riparian buffers on understory plant communities of boreal forests. We investigated the responses of understory species to gaps created by partial harvesting at up to 50% basal area removal in stream-side riparian buffers of boreal forests in northcentral Ontario,and compared them to nearby un-harvested buffers and riparian reference areas of undisturbed forests. Gap sizes ranged from 10 to 400 m2, but most were between 25 and 125 m2. Gaps created by partial harvesting measurably increased canopy openness, ground-level solar radiation, and shallow soil temperatures proportional to gap sizes, but the changes were small and only consistently higher than the range of these conditions in un-harvested riparian areaswhengapswere >50 m2. Understory plant abundance in gaps tended to be higher than in un-harvested sites but significant differences could not be detected. Richness and diversity were higher among medium and large gaps (>20 m2) than in small gaps, but they were not higher than in un-harvested buffers or reference riparian areas. Multivariate community composition analyses could not detect significant differences between harvested and un-harvested areas. However, gaps created by partial harvesting affected foliar morphology of selected common understory plants. Leaf dry matter content was higher and specific leaf area was lower in harvested gaps than in un-harvested buffers or reference riparian areas, and both were related to gapsize. Based on the unaltered understory community composition coupled with leaf morphological adaptations of selected understory plants to gaps, we conclude that the plant community is resilient to partial harvesting. Implications for riparian forest management under the emulation of natural disturbance paradigm are discussed.

Plain Language Summary

We studied the effects of canopy gap creation on understory plant communities of boreal forests in northcentral Ontario. This was to further knowledge about partial harvesting in riparian buffers as a forest management option to emulate natural disturbance patterns. We compared species in gaps created by partial harvesting (up to 50% basal area removal) in stream-side riparian buffers to nearby un-harvested buffers and to reference riparian areas of undisturbed forests. Gap sizes ranged from 10 to 400 m2, with most between 25 and 125 m2. Understory plant abundance in gaps tended to be higher than in un-harvested sites but significant differences could not be detected. Species richness and diversity were higher among medium and large gaps (greater than 20 m2) than in small gaps, but they were not higher than in un-harvested buffers or reference riparian areas. Measureable changes to leaf morphology were detected in gaps, in response to increased light level s. We conclude that the plant community is resilient to partial harvesting.