The Soil Environment of Abandoned Charcoal Kiln Platforms in a Low-Altitude Central European Forest

Abstract

This study examines the soil environment of eight charcoal kiln platforms and the neighboring soil in Czech and Bohemian low-altitude forest stands. Both mixed and undisturbed soil samples were used to assess the hydrophysical soil properties, nutrient content, cation exchange capacity, enzyme activity, and soil active carbon content, while soil color, stoniness, root density, and horizon thickness were estimated in the field. Charcoal-rich horizons had high total organic carbon concentrations and total nitrogen content (about 150% and 40% higher than in the organomineral horizons of the control plot, respectively), with total carbon stocks being higher than those in neighboring forest soils. Fine root density was highest in the charcoal-rich horizons, encouraged by high soil porosity, aeration, and favorable chemical properties. Enzyme group activity differed between individual soil horizons and kiln and control plots, with depolymerization enzyme activity highest in charcoal-rich horizons and humification enzyme activity highest in mineral horizons. Phosphatase, chitinase, and phenoloxidase activity were highest in charcoal-rich horizons, while β-glucosidase activity remained similar across horizons. After long-term abandonment, kiln sites shift from inhospitable sites to localized hotspots for plant and microbial growth, having more favorable physical, enzymatic, and chemical soil properties than the surrounding areas. This study confirmed that kiln production platforms act as microhabitat hotspots, also providing information on a wide spectrum of soil properties linked with soil microorganisms and root growth.