title: Reconciling Harvest Intensity and Plant Diversity in Boreal Ecosystems: Does Intensification Influence Understory Plant Diversity?
abstract: Overall demand for forest products in the boreal forest is increasing to supply growing bio-energy demands in addition to traditional forest products. As a result, there is a need to refine current forest policies to reconcile production and ecosystem function within the context of ecologically sustainable management. This study assessed understory plants' richness, evenness, and diversity in six harvested boreal black spruce-dominated stands situated on loam, sand, and peat site types 15 years after the application of four harvest treatments of increasing biomass removals. Treatments included uncut, stem-only harvest, full-tree harvest, and full-tree harvest + blading of O horizon. Following canopy removal, species richness and diversity (Shannon's and Simpson's indices) increased on all soil types. The more than doubling of slash loading on the stem-only treatment plots compared to the full-tree plots led to significantly lower species diversity on loam sites; however, the reverse was observed on peat sites where the slash provided warmer, drier microsites facilitating the establishment of a broader array of species. Preexisting ericaceous shrub and sphagnum components continued to dominate on the peat sites. Compositional shifts were most evident for the full-tree + bladed treatment on all soil types, with increases in herbaceous cover including ruderal species. The results suggest that the intensification of harvesting on plant diversity varies with soil type, and these differential results should be considered in the refinement of forest biomass-harvesting guidelines to ensure ecological sustainability and biodiversity conservation over a broad suite of soil types.
authors.affiliation: Ontario Forest Research Institute, Ontario Ministry of Natural Resources and Forestry, 1235 Queen Street East, Sault Ste. Marie, ON, P6A 2E5, Canada.
authors.forename: H Maureen
authors.initials: HM
authors.lastname: Kershaw
authors.affiliation: Centre for Northern Forest Ecosystem Research, Ontario Ministry of Natural Resources and Forestry, c/o Lakehead University, 955 Oliver Road, Thunder Bay, ON, P7B 5E1, Canada. dave.m.morris@ontario.ca.
authors.forename: Dave M
authors.initials: DM
authors.lastname: Morris
authors.affiliation: Natural Resources Canada, Canadian Forest Service, 1219 Queen St. E., Sault Ste. Marie, ON, P6A 2E5, Canada.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Fleming
authors.affiliation: Faculty of Natural Resources Management, Lakehead University, 955 Oliver Road, Thunder Bay, ON, P7B 5E1, Canada.
authors.forename: Nancy J
authors.initials: NJ
authors.lastname: Luckai
mesh_terms: D044822:Biodiversity; D056804:Biofuels; D018533:Biomass; D003247:Conservation of Natural Resources; D016468:Forestry / Q000379:methods*; D010944:Plants; D012987:Soil; D066188:Taiga
chemical_list: D056804:Biofuels; D012987:Soil
keywords: Boreal forest; Harvest impacts; Management intensification; Plant diversity