Long-term effects of forest fires on soil greenhouse gas emissions and extracellular enzyme activities in a hemiboreal forest

Fire is the most important natural disturbance in boreal forests, and it has a major role regulating the carbon (C) budget of these systems. With the expected increase in fire frequency, the greenhouse gas (GHG) budget of boreal forest soils may change. In order to understand the long-term nature of the soil–atmosphere GHG exchange after fire, we established a fire chronosequence representing successional stages at 8, 19, 34, 65, 76 and 179years following stand-replacing fires in hemiboreal Scots pine forests in Estonia. Changes in extracellular activity, litter decomposition, vegetation biomass, and soil physicochemical properties were assessed in relation to carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) emissions. Soil temperature was highest 8years after fire, whereas soil moisture varied through the fire chronosequences without a consistent pattern. Litter decomposition and CO2 efflux were still lower 8years after fire compared with pre-fire levels (179years after fire). Both returned to pre-fire levels before vegetation re-established, and CO2 efflux was only strongly responsive to temperature from 19years after fire onward. Recovery of CO2 efflux in the long term was associated with a moderate effect of fire on enzyme activity, the input of above- and below-ground litter carbon, and the re-establishment of vegetation. Soil acted as a CH4 sink and N2O source similarly in all successional stages. Compared with soil moisture and time after fire, soil temperature was the most important predictor for both GHGs. The re-establishment of overstorey and vegetation cover (mosses and lichens) might have caused an increase in CH4 and N2O effluxes in the studied areas, respectively.Peer reviewe

Metsanduse arengukava 2030 arengustsenaariumite mõju analüüs : lõpparuanne

Metsanduse arengukava (MAK 2030) on laiapõhjaline dokument metsade jätkusuutliku majandamise ja metsanduse suunamiseks, arvestades nii sotsiaalseid, majanduslikke, keskkonnakaitselisi kui ka kultuurilisi aspekte. Kokkuleppe aluseks on piisavalt lahti kirjutatud strateegilised arengustsenaariumid, mis luuakse metsanduse arengukava koostamise käigus koostöös teadlastega huvirühmade aruteludest tulnud ettepanekute põhjal. Metsanduse arengustsenaariumeid arutatakse juhtkogu kohtumistel 11., 12., 17. ja 18. detsembril 2019. aastal ning valitakse välja sobivaim stsenaarium või nende kombinatsioon, mille põhjal koostatakse metsanduse arengukava terviktekst. Juhtkogu koosneb huvirühmade, riigi- ja uurimisasutuste esindajatest ning selle on kokku kutsunud keskkonnaminister

How Time since Forest Fire Affects Stand Structure, Soil Physical-Chemical Properties and Soil CO2 Efflux in Hemiboreal Scots Pine Forest Fire Chronosequence?

We compared the changes in aboveground biomass and initial recovery of C pools and CO2 efflux following fire disturbances in Scots pine (Pinus sylvesteris L.) stands with different time since stand-replacing fire. The study areas are located in hemiboreal vegetation zone, in north-western Estonia, in Vihterpalu. Six areas where the last fire occurred in the year 1837, 1940, 1951, 1982, 1997, and 2008 were chosen for the study. Our results show that forest fire has a substantial effect on the C content in the top soil layer, but not in the mineral soil layers. Soil respiration showed a chronological response to the time since the forest fire and the values were lowest in the area where the fire was in the year 2008. The respiration values also followed seasonal pattern being highest in August and lowest in May and November. The CO2 effluxes were lowest on the newly burned area through the entire growing season. There was also a positive correlation between soil temperature and soil respiration values in our study areas.Peer reviewe

Forest Multifunctionality

To meet all demands and challenges that we, as a society, exert on our forests, knowledge-based cross-sectorial interdisciplinary research is needed to move forward. Areas are becoming scarce; stakeholders are in conflict, but, multiple use approaches point at integration and synergy opportunities. Accordingly, there is an increasing need for science-based policy support for EU decision-making concerning multiple uses of forests. In the end, future-proofing Europe’s forest is an aspiration we all share

Trilemma of Nordic–Baltic Forestry—How to Implement UN Sustainable Development Goals

Forests are the dominant land cover in Nordic–Baltic countries, and forestry, the management of forests for improved ecosystem-service (ES) delivery, is an important contributor to sustainability. Forests and forestry support multiple United Nations Sustainability Goals (UN SDGs) and a number of EU policies, and can address conflicting environmental goals. Forests provide multiple ecosystem services and natural solutions, including wood and fibre production, food, clear and clean water and air, animal and plant habitats, soil formation, aesthetics, and cultural and social services. Carbon sequestered by growing trees is a key factor in the envisaged transition from a fossil-based to a biobased economy. Here, we highlight the possibilities of forest-based solutions to mitigate current and emerging societal challenges. We discuss forestry effects on forest ecosystems,focusing on the optimisation of ES delivery and the fulfilment of UN SDGs while counteracting unwanted effects. In particular, we highlight the trilemma of (i) increasing wood production to substitute raw fossil materials, (ii) increasing forest carbon storage capacity, and (iii) improving forest biodiversity and other ES delivery

Patterns of Carbon Sequestration in a Young Forest Ecosystem after Clear-Cutting

A large area of Estonian hemiboreal forest is recovering from clear-cut harvesting and changing carbon (C) balance of the stands. However, there is a lack of information about C- source/sink relationships during recovery of such stands. The eddy covariance technique was used to estimate C-status through net ecosystem exchange (NEE) of CO2 in two stands of different development stages located in southeast Estonia in 2014. Measured summertime (June–September) mean CO2 concentration was 337.75 ppm with mean NEE −1.72 µmol m−2 s−1. June NEE was −4.60 µmol m−2 s−1; July, August, and September NEE was −1.17, −0.77, and −0.25 µmol m−2 s−1, respectively. The two stands had similar patterns of CO2 exchange; measurement period temperature drove NEE. Our results show that after clear-cutting a 6-year-old forest ecosystem was a light C-sink and 8-year-old young stand demonstrated a stronger C-sink status during the measurement period.publishedVersio

Importance of scale and process in forest disturbance legacies

Ecological memory is the information and material legacies—the adaptations, individuals, and materials that persist after disturbance—that guide ecosystem response to disturbances. Resilience is directly related to ecological memory, and because resilience is desired in forest management, it is important to consider how ecological memory works. We propose that six spatial scales are needed to characterize ecological memory and its interactions with disturbance. These scales are: micro, tree, neighborhood, stand, meso and landscape. The nested hierarchy of microsites-tree-stand-landscape is well known, with widespread recognition of the need for diverse microsites, tree species and ages, and stand ages to create a managed landscape that harbors biodiversity. However, roles of the neighborhood and meso scales have been considered less often and have not been well integrated into overall legacy theory and its application to forest management. Here we show the key role of processes at these scales and their interactions with disturbance to maintain ecological memory, using cold-temperate and boreal forests from Minnesota, USA as a case study.peerReviewe