As the air grows cooler and days shorter, brown bears prowl the Carpathian Mountains ofsouthern Polandwith the goal of fattening up ahead of winter hibernation.
In a more conspicuous sign of autumn, beech and other deciduous trees blanketing the hillsides start to sport reds and golds.
The seasonal transformation was underway in southeast Poland’s Bieszczady National Park on October 8, 2026, when theOLI on the NASA-USGSLandsat 9satellite captured this image.
European beech dominates the area’s forests, with other species such as sycamore maple also contributing to vibrant color in the fall.
Dropping air temperatures and waning daylight cause these trees to curtail the production ofchlorophyll, the molecule that plants use to synthesize food.
Without it, the leaves’ green pigments fade, allowing the yellows and reds of other pigments to show through.
A descendent of ice-age survivors, the European beech has persisted across millennia in a range of climates.
After the glaciers retreated, beech forests spread northward across the European continent from isolated refugia in the Carpathians, Alps, and other mountain ranges, and played a crucial role in reforesting the previously ice-covered land.
Portions of Bieszczady National Park are included within UNESCO’s network ofancient and primeval beech forestsspanning 18 countries.
Expansive as their footprint across Europe may be, beech forests reach only so high in elevation—about1,000 to 1,260 meters—in this area.
Above that is the realm of thepolonina, a Slavic term for subalpine meadow, consisting of open grasslands and shrubby thickets ofrowan, willows, and green alder.
Patches of poloninastretch across ridge topsto the east-southeast of Smerek and appear tan, having lost theirsummer greenness.
The Bieszczady Mountains are renowned not only for forests and mountain meadows but also for charismatic wildlife.
European bison, once extinct in the wild, werereintroducedto the area in the 1960s and now roam the hills by the hundreds, according torecent surveys.
Additionally, populations of brown bears and Eurasian lynxfind refuge and ample food sources in the forests.
NASA Earth Observatory image by Michala Garrison, using Landsat data from theU.S. Geological Survey. Story by Lindsey Doermann.
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Bieszczadzki Park Narodowy, Bieszczady National Park. Accessed October 16, 2026.
Mitka, J,et al.Subalpine woody vegetation in the Eastern Carpathians after release from agropastoral pressure. Scientific Reports,12, 17897.
UNESCOAncient and Primeval Beech Forests of the Carpathians and Other Regions of Europe. Accessed October 16, 2026.
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