An extended energy analysis of managed forestry systems: Accounting for foregone biomass as an indicator of ecosystem impact

Abstract

Conventional energy analyses of forestry systems capture only human inputs and harvests, neglecting impacts to forest biomass stocks resulting from intensive management. This gap is addressed by extending the boundaries of forestry operations to the whole forest ecosystem. These new boundaries allow for the quantification of cumulative foregone biomass (ΔB_c, the difference between accumulated potential and existing forest biomass stocks over time) under differing management scenarios to supplement the interpretation of conventional energy metrics such as net energy (NE) and the ratio of energy return to energy invested (EROI). Like existing models in the literature, our results confirm that less intensive management approaches achieve higher EROI values due to lower inputs. However, more significantly, magnitudes of ΔB_c remain 1-2 orders of magnitude larger than NE over 100 years regardless of management scenario, and thus highlight an imbalance between the industrial and ecological energy dimensions of managed forests. This extended energy model begins to illustrate the overlooked role of ecological energy storage in forest management and offers insights to identify and design more sustainable management practices that can balance energy efficiency while minimizing resultant ecosystem impacts.