Drought related losses in growth efficiency, the increase in intensity and frequency of threats (e.g. wildfires, wind-storms) and the subsequent exponential increase in biological risks (e.g. bark beetle outbreaks) (Figure 2) are just a few of the most perceptible effects across forests in Europe and worldwide. The relevance of forests in terms of climate protection is not doubted. However, it is complex to determine how much and how the forest carbon sink and reservoir can be managed to mitigate atmospheric CO2 build-up.
Moreover, modern forestry should also consider and minimize carbon release by monitoring, modelling and managing relationships between carbon sequestration from forest and carbon emission due to forest operations. Thus, an innovative, integrated forest management system is vital to make forests and forestry adaptive to immanent environmental changes and increasing risks is urgently needed. Drought, together with the increasing susceptibility of European forests to
other abiotic (e.g. wild fires in Croatia and Portugal 2017, extreme wind events in Poland in 2017, ‘Friederike’ storm in Germany and ‘Vaia’ storm in Italy in 2018) and biotic (e.g. bark beetle outbreaks such as in Central Europe in 2017, 2018, 2019,
2020, 2021 and in the Southern Alps 2020, 2021) risks, can compromise the resilience of forests and reduce the efficiency of removing anthropogenic carbon through growth (del Rio et al. 2016). Consequently, losses in productivity and lower carbon
sequestration rates are expected. One of the aims of forest management strategies should be to improve water use efficiency on trees and forest stand scales to enhance forest resilience. For example, differently sized trees within a stand show an
unequal response to water limitation, with smaller trees being less vulnerable. Conversely, there are still many uncertainties about how stand structure is modifying resource partitioning between trees of a stand and within a tree and how wood density, forest growth and the carbon storage may be affected.
The effective implementation for adjusted forest management strategies depends largely on forest operations, which can account for a substantial amount of carbon emissions. The need to set intervention protocols that consider the adaptation of silvicultural practices through an eco-efficient use of harvesting systems is an existing challenge. The carbon emission rate is related to silvicultural treatments, harvesting systems and operational conditions. In particular, the shift to more complex stand structures of close to nature forest stands requires higher sophistication of forest operations than those applied in mono-layered or even-aged stands. Consequently, there are challenges in terms of harvesting criteria and harvesting methods.
The lack of comprehensive information on the appropriateness of forest ecosystems concerning their resilience and resistance against biotic and abiotic risks also produces further uncertainness for forest management in terms of financial returns, carbon dynamics and climate change mitigation. Therefore, there is a strong need to develop applied models to optimise carbon balance and financial performance.
Along a wide spectrum of climate zones and a gradient of forest management intensities, the general objectives and challenges of the ETN Skill-For.Action are to generate a clearer knowledge about: i) the dynamics of carbon sequestration and enhancing forest resilience against biotic and abiotic stressors acknowledging site and stand characteristics; ii) the potential to reduce carbon emissions generated from forest operations; iii) provide forest managers with innovative approaches to optimise smart forest management by linking biological and technical production to cope with climate changes.
