Burning forest biomass for energy: Not a source of clean energy and harmful to forest ecosystem integrity

Abstract

The climate crisis is driven mainly by the extensive use of fossil fuels but also by the emissions from widespread deforestation and degradation, plus other factors including cement production (Mackey and Lindenmayer 2014, Masson-Delmotte et al. 2021). In response, a rapid transition toward renewable energy is underway to decarbonize economies globally (IEA 2021). Some commentators have proposed that a necessary component of this transition is to burn forest biomass for energy production, including pushing for the use of energy from forest biomass burning in the generation of hydrogen through hydrolysis, claiming this as “green hydrogen” (IRENA 2020). While the Land Use Land Use Change and Forestry (LULUCF) sector has been functioning as a net sink, there has been a significant increase in the intensification of logging in many regions (Ceccherini et al. 2020, Angelstam et al. 2021). Studies have projected a reduction in the amount of carbon stored in this sector by 2030 due to projected future increased harvest rates caused in part by greater demand for bioenergy, as well as age-class shifts in EU forests and climate change (Körner et al. 2007, Nabuurs et al. 2013, Böttcher and Graichen 2015, Jiang et al. 2020). Conversely, there can be a major turnaround in carbon accounts when there are changes in the LULUCF sector such as occurred in the Australian State of Tasmania when there was a marked reduction in wood production from natural forests (Mackey et al. 2022b). Here we argue that a major shift to using forest biomass burning for energy comes with grave risks of highly perverse outcomes, including increased CO2 emissions and negative impacts on forest integrity. A rethink of the role of forest biomass burning for energy in national decarbonization policy is therefore urgently needed. Our focus here is on naturally regenerating forests and not plantations (sensu (FAO 2018)). There is growing body of scientific evidence that burning forest biomass for energy will greatly increase the amount of carbon in the atmosphere for decades and have harmful impacts on forest integrity (Holtsmark 2013, Ter-Mikaelian et al. 2015, Searchinger et al. 2018) countering claims that forest biomass energy provides positive mitigation benefits (Favero et al. 2020, IRENA 2020). International and national policies and programs for decarbonization and forest management should be informed by a scientific understanding of the key factors determining the emissivity of burning forest biomass for energy, the role of forest ecosystems in the carbon cycle, and the climate mitigation benefits of forest protection. We first review current and projected use of and demand for forest biomass energy and then consider five critical issues which challenge commonly held views regarding the benefits of burning forest biomass for energy. Studies which conclude that logging forests for fuel results in climate benefits tend to make highly specialized assumptions that may not be met in actuality. We then examine the impacts on, and risks to, forest ecosystem integrity and some of the consequences for the conservation of forest-dependent biodiversity. We argue that a global ban on using forest biomass for industrial scale bioenergy is urgently needed given its negative effects on climate mitigation and forest integrity.