Monitoring and climate-smart management of European forest soils
Forest soils are teeming with life and biodiversity. Their processes and highly diverse biota (living organisms) drive nutrient cycling, carbon and greenhouse gas (GHG) fluxes, and other soil-related ecosystem services. Forest soils are currently insufficiently considered in computational models, climate scenarios, forestry decision-making and climate policy. The EU-funded HoliSoils(opens in new window) project filled important gaps in the effects of forest management and natural disturbances on soil functioning and resilience. The outcomes will support more effective modelling, decision-making and policies to mitigate climate change and keep ecosystem services functioning well.
Harmonised soil monitoring framework for pan-European inventories
“We developed harmonised protocols for microbial analyses and tested their performance across different forest types in Europe,” explains project coordinator Raisa Mäkipää of the Natural Resources Institute Finland(opens in new window). In extensive field experiments, the team analysed microbial community composition and soil microbial biomass, enzyme activity and respiration (rate at which soil releases CO2 into the atmosphere) across European forest types and forest management practices. Among key outcomes, the results showed that both bacteria and fungi had site-specific community compositions. However, according to Mäkipää, “Soil microbial biomass seems to be a more important explanatory variable to soil respiration than microbial community.”
Identifying and validating effective forest soil management practices
In Europe, forest soils are heavily affected by management practices and harvesting, which means that climate-smart decisions on forest use are needed to maintain soil health. Soil organisms are also sensitive to drought and disturbances – the larger the organism, the more sensitive it is. Boreal forests are the world’s largest biome, characterised by dense coniferous forests found in high-latitude regions with cold winters. HoliSoils found that in boreal forests nitrogen fertilisation increases fungal biomass as well as both soil carbon stabilisation and soil respiration. Continuous-cover forestry on peatland sites can improve hydrology that controls aerobic/anaerobic soil microbial processes. Stand thinning may increase soil biological activity if it favours vegetation growing beneath the forest canopy and enhances ‘litter’ production, the principal source of organic matter for forest soils. HoliSoils also found that, in Mediterranean forests, fire risk can be reduced by slash burning (cutting and burning trees); this practice decreases the total carbon stored in the soil but creates more stable ‘soil organic carbon fractions’ (distinct carbon pools) that store carbon for a longer time.
Climate-sustainable forest management and soil organisms
HoliSoils studied soil health on the test sites located in different parts of Europe ranging from boreal peatlands to Mediterranean forests. While European forest soils are generally healthy; the major challenges were seen in degraded peatland soils, acidified forest soils in central Europe and soils affected by forest fires in southern Europe. “Based on our tests of climate-smart forest management approaches, these can be addressed by practices that include mixed stands over monocultures, modest thinning that can reduce drought risks, and continuous-cover forestry on peatland sites,” Mäkipää concludes. This wealth of information(opens in new window) contributed to the GlobalFungi(opens in new window) database that shows variation of fungal diversity at the global scale. “We also developed soil property maps(opens in new window) that can be used for decision-making and integrated in vulnerability modelling and climate-change scenarios at continental scale,” notes Mäkipää. The protocols for soil microbial analyses can be used by EU Member States in addressing the proposed EU soil monitoring law. Furthermore, the developed and tested methodologies for soil carbon and GHG assessment serve experts of the GHG reporting of the ‘Land Use, Land-Use Change, and Forestry’ sector in the EU. HoliSoils has made a significant contribution to a healthy future for Europe’s forest soils.
