Impacts of post-harvest slash and live-tree retention on biomass and nutrient stocks in Populus tremuloides Michx.-dominated forests, northern Minnesota, USA

Response of the soil microbial community and soil nutrient bioavailability to biomass harvesting and reserve tree retention in northern Minnesota aspen-dominated forests

“…For instance, greater soil disturbance may have occurred from multiple entries during harvest (i.e., backhauling slash from landings onto the site) (Grigal, 2000), or slash piling may have resulted in extreme variation in soil temperature and moisture across a harvest unit (Moroni et al, 2009) and affected the SMC in 20H differently than either BOH or WTH treatments. Additionally, we cannot rule out that the lack of major differences among the slash retention levels may be due to the actual levels of slash retention in the field being more similar to each other than the prescribed levels (Klockow et al, 2013), which may have equalized harvesting treatments to some extent. Finally, because this was a deciduous forest harvested in the winter, nutrient rich leaves were not removed with the harvest, which may have reduced the initial sensitivity to biomass removal treatments.…”

“…These differences in the SMC among slash retention levels were difficult to explain because they were not linearly related to the amount of slash retained. A factor potentially contributing to these trends is the generally higher soil temperatures in WTH (Kurth et al, 2014) due to the lower amount of residual slash left on site (Klockow et al, 2013), which may have lowered AMF, GmP, and actinomycete abundance. It is also possible that the harvesting disturbance associated with 20H is different than other treatments, resulting in a unique SMC response.…”

“…Other tree species present included Betula papyrifera Marshall, Acer rubrum L., Fraxinus nigra Marshall., Abies balsamea (L.) Mill., Picea mariana (Mill.) Britton, and Picea glauca (Moench) Voss, with occasional Thuja occidentalis L. and Pinus strobus L. Further site descriptions can be found in Klockow et al (2013), Slesak (2013), and Kurth et al (2014).…”

“…The frost free growing season is typically 60-100 days. Average air temperature ranged from À16 C in January to 26 C in July and mean annual precipitation ranged from 660 to 710 mm, primarily occurring between May and October (Klockow et al, 2013). Prior to treatment, stands were dominated by 55-to 68-year old aspen originating by spouting of lateral roots following harvest.…”

Legal Harvesting, Sustainable Sourcing and Cascaded Use of Wood for Bioenergy: Their Coverage through Existing Certification Frameworks for Sustainable Forest Management

“…Slash (branches and tops), small trees, and roots are commonly left in the forest as they are unsuitable for industrial processing [8]. On the one hand, with intensive biomass harvesting, sensitive forest soils can suffer from nutrient loss, which may result in lower forest re-growth than with conventional harvesting [11,[15][16][17][18][19]. On the other hand, more intensive harvesting may be beneficial for natural regeneration under certain circumstances.…”