The timber industry provides benefits to local communities and is an important component of Canada's economy, but intensive forestry can also reduce the complexity of a landscape on which biodiversity depends. In an attempt to mitigate this harm, many forestry practitioners have adopted retention harvesting, in which the spatial patterns of harvest resemble those of wildfire. To emulate this natural pattern, foresters leave small remnants of intact forest within clear-cuts, called retention. Understory plants are critical to supporting forest biodiversity but few studies have examined the plant  communities of forest remnants. We investigated the relationships between forest structure, microclimate and plant community composition in forest remnants to test the hypothesis that remnants maintain forest-interior-like conditions, and that the function of retention patches and wildfire skips is comparable.

Air and soil temperatures were significantly lower in remnants of both types, and forest remnants had similar microclimates to reference forest. Remnant edges had higher temperatures than reference edges, but temperatures equalized 15m into the forest. Results of perMANOVA and divisive cluster analysis showed that plant community composition responded to microclimate and edge effects with composition driven by proportion of moss, litter and ericaceous shrubs as well as disturbance-adapted species such as fireweed (Chamaenerion angustifolium) and  hairy wildrye (Leymyus innovatus). We also found evidence for variation in plant community composition between remnants and reference forests which we hope to determine in a future analysis. 

Our results support our hypothesis that remnants can act as refugia for interior-adapted species and potential sources for seed and animal dispersal as the adjacent disturbance recovers. As climate change and habitat fragmentation continue to threaten biodiversity in forests worldwide, the role of forest remnants should be given increasing consideration in forest management decisions.