Acorn review: Biochar and its applications in US forestry

Abstract

Biochar derived from woody feedstocks is typically high in carbon, low in ash, and relatively low in nutrients compared with agricultural biochar, making it especially suitable for long-term carbon storage. Current evidence indicates that key functional properties for forestry applications include biochar yield, fixed carbon, pH, nutrient content, and porosity. Across studies, there is broad agreement that these properties are shaped by both feedstock and production conditions, particularly pyrolysis temperature and residence time. Yield and fixed carbon appear to be driven mainly by pyrolysis conditions, whereas pH, nutrient content, and porosity are more strongly linked to feedstock, though still influenced by processing temperature. At the same time, disagreement remains over how consistently wood-based biochar improves tree growth and productivity in forest systems. Reported outcomes range from positive to neutral to negative, reflecting differences in site conditions, application method and rate, and the interaction of biochar traits with forest soil ecosystems. Taken together, the literature suggests that biochar performance is highly context dependent and that benefits are most likely when biochar properties are matched to target species, site conditions, and the time horizon over which responses are evaluated. Overall, wood based biochar should be viewed as a value-added use of low-value woody biomass rather than a universal solution. Its long-term role in forestry will depend on better alignment between biochar properties and site specific management needs, expansion of end uses beyond soil amendment, improved production and distribution economics, and stronger policy support to facilitate broader adoption.

Citation

Dhungel, Gaurav; Baker, Justin; Henderson, Jesse D.; Cook, Rachel. 2026. Acorn review: Biochar and its applications in US forestry. Forest Ecology and Management, 620: 124134. https://doi.org/10.1016/j.foreco.2026.124134