November 6, 2025, Tatranská Javorina, Slovakia. In the shadow of the Belianske Tatry, the story of the forest is being rewritten by disturbance. Windstorms, bark beetles, drought, and Armillaria root-rot, once occasional actors in a natural cycle, now interact in ways that challenge the resilience of spruce-dominated ecosystems across Central Europe. During field excursions of the RESDINET project’s final meeting, researchers saw first-hand how these forces converge in the forests of Tatranská Javorina.
A perfect storm for disturbance
The High Tatras have always lived with wind. Periodic storms open clearings and renew growth, but in recent decades, the frequency and severity of windthrow events have increased. Exposed slopes become corridors for bark beetle outbreaks, as fallen and weakened trees provide ideal breeding sites.
“One disturbance rarely comes alone,” noted the RESDINET Coordinator Dr Rastislav Jakuš of the Institute of Forest Ecology, SAS. “When extreme wind meets a warming climate and prolonged drought, the consequences cascade through the entire landscape.”
Hotter summers and milder winters have expanded the window for bark beetle reproduction, allowing up to three generations per year in some parts of the region. Once the beetles gain a foothold, they attack living trees already stressed by drought or root infection, and that is where Armillaria enters the story.
The hidden rot beneath the roots
In the forests near Podspady, researchers observed young spruces, only 10–15 years old, already exuding resin in defence against Armillaria infection. The fungus invades through the roots, decaying the wood from within and weakening the trees’ stability and vitality.
Yellowing needles, a sign of carotenoid build-up as chlorophyll production ceases, mark the slow physiological decline that precedes bark beetle colonisation.
According to Ján Slivinský, long-time forester of Tatranská Javorina, Armillaria used to be a background player in forest dynamics. Today, under warmer and drier conditions and more environmental extremes, it has become a key predisposing factor for bark beetle attacks. “Trees that once recovered after stress now have no chance,” he explained in the field. “The soil is drier, the roots decay faster, and beetles come sooner.”
Climate change as the silent amplifier
Climate extremes are now amplifying every link in this chain. Prolonged drought reduces tree defence mechanisms, while heavy rain events trigger flooding and slope failures in already weakened stands. The recent Monkova dolina landslide, where water and soil rushed down deforested slopes, stands as a dramatic reminder that forest health and mountain stability are inseparable.
RESDINET scientists are combining field ecology, genomics, chemistry, and remote sensing to track these changes from the canopy to the roots. Drone- and satellite-based spectral data help identify early physiological stress, while modelling platforms such as iLand simulate how different disturbance agents interact under future climate scenarios.
From observation to prediction
By integrating biological, climatic, and geomorphological data, RESDINET aims to develop evidence-based tools for early detection and risk forecasting. These insights will support adaptive forest management in Slovakia and across Europe, guiding where intervention is possible and where natural regeneration should lead.
“What we see here is not just forest decline,” said Dr Rastislav Jakuš. “It’s a signal of transition, and an opportunity to rebuild more diverse and resilient forests for the next generation.”
About RESDINET
RESDINET – Network for novel remote sensing technologies in forest disturbance ecology (2023–2025) is a Horizon Europe WIDERA project led by the Institute of Forest Ecology of the Slovak Academy of Sciences, in collaboration with the University of Eastern Finland, the Swedish University of Agricultural Sciences, and the National Land Survey of Finland.
By linking top international expertise in remote sensing and forest ecology, RESDINET strengthens research excellence and delivers innovative tools to help forests adapt to a changing climate.
