Effects of forest harvesting and biomass removal on soil carbon and nitrogen: Two complementary meta-analyses

FOREST ECOLOGY AND MANAGEMENT

卷:485

Article

James, Jason¹  Page-Dumroese, Deborah²  Busse, Matt³  Palik, Brian⁴  Zhang, Jianwei⁵  Eaton, Bob⁶  Slesak, Robert⁷  Tirocke, Joanne²  Kwon, Hoyoung⁸ 

[1] Exponent Inc, Bellevue, WA 98007 USA

[2] US Forest Serv, Rocky Mt Res Stn, Moscow, ID 83843 USA

[3] US Forest Serv, Pacific Southwest Res Stn, Davis, CA 95618 USA

[4] US Forest Serv, Northern Res Stn, Grand Rapids, MN 55714 USA

[5] US Forest Serv, Pacific Southwest Res Stn, Redding, CA 96002 USA

[6] US Forest Serv, Southern Res Stn, Res Triangle Pk, NC 27709 USA

[7] Univ Minnesota, Dept Forest Resources, St Paul, MN 55108 USA

[8] Argonne Natl Lab, Energy Syst Div, Syst Assessment Ctr, Lemont, IL 60439 USA

关键词: Long term soil productivity;    Soil carbon;    Soil nitrogen;    Meta-analysis;    Bioenergy production;    Whole tree harvest;   

DOI  :  10.1016/j.foreco.2021.118935

来源: Elsevier

【 摘 要 】

Forest residues and logging slash from pre-commercial forest thinning and regeneration harvests are a potential feedstock for bioenergy production but there has been a concern about the impact of residue removal on forest soil C and N. This study aimed to address such by conducting two meta-analyses using the data available from published literature and an independent dataset compiled from the North American Long-Term Soil Productivity (LTSP) study. For the meta-analysis using literature, we categorized forest harvesting and biomass removal into i) no harvest control, ii) bole-only (BO, partial or clearcut) regular harvests, iii) BO with partial removal of logging slash and/or O horizon (BO+Removal), iv) whole tree harvests (WTH), and v) WTH with slash and O horizon removal (WTH+Removal). Accordingly, we compiled soil C and N data and key statistics (e.g., standard deviation) from 142 scientific articles published since 1979. We compared the results from this meta-analysis with data from 22 installations of the LTSP study where three levels of organic matter removal - BO, WTH, and WTH plus forest floor (+FF, O horizon) removal - as well as an additional vegetation control (+VC) were measured for two decades in either completely randomized or randomized block design. In the literature meta-analysis, BO+Removal (-19.2%), WTH (-15.4%) and WTH+Removal (-24.9%) contained significantly less soil C than no-harvest controls across combined soil depths, while BO had no difference. Within individual mineral soil horizons, only BO+Removal and WTH+Removal treatments contained significantly less carbon than controls. There was a high degree of heterogeneity in treatment response between studies in the literature. The analyses from the LTSP dataset showed no significant difference in combined soil depths for WTH or WTH+VC relative to BO harvest, but there was significantly less soil C in BO+VC (-3.6%), WTH+FF (-8.5%) and WTH+FF +VC (-15.3%). These treatment effects declined over time since harvest, particularly the most intensive treatments. Soil N results largely mirrored soil C in both meta-analyses with smaller estimated effects for most treatments at equivalent depths (except for WTH+Removal and WTH+FF +VC, which remain about the same). There were no significant differences in soil N for combined soil depths between WTH and no-harvest control (in the literature analysis) or BO harvest (for both analyses). Since the most severe losses of soil C and N involved FF removal, WTH that accounts for modest removals (<80%) of harvesting residues may provide a sustainable source of biomass for bioenergy production without additional soil impacts compared to BO harvesting practices.

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