Every Forest Has a Past: Why History Holds the Key to Saving Them

Every forest on Earth carries a hidden archive. Beneath the canopy of even the most remote-looking woodland lie the traces of centuries of human activity: stumps from long-abandoned logging, fire scars etched into ancient trunks, boundary earthworks swallowed by moss, and soil chemistry still shaped by practices that ended generations ago. A new perspective paper in the journal Ambio, authored by Matthias Bürgi of the Swiss Federal Research Institute WSL and Lars Östlund of the Swedish University of Agricultural Sciences, argues that reading this archive is not a nostalgic luxury but a scientific prerequisite for tackling some of today’s most urgent environmental questions, from biodiversity loss to climate change mitigation.

The authors’ central claim is deceptively simple: forests always have a history. There are specific reasons why they exist where they do and how they came to look the way they do, and the legacy of that past remains embedded in the ecosystem today. Ignoring it, they contend, has tangible consequences for society, for our understanding of forest ecology, and for forest management. Most ecosystems on Earth are now anthropogenically modified, whether through the diffuse fingerprints of climate change and altered soil chemistry or through complete transformation, as in plantations and urban forests. Because ecosystems are not in equilibrium with present conditions alone, their current state reflects superimposed past and present impacts, some of which act with long delays.

These so-called legacy effects can be striking. The authors point to research showing that soil carbon pools in Swiss forests still bear the imprint of historical litter raking, a practice of collecting forest floor material for animal bedding that ceased long ago. Interpreting forest change purely as a response to current management or a warming climate risks misreading signals that actually reflect recovery from abandoned land uses. Knowing more about past impacts allows ecologists to assess the degree and direction of human influence on forests and to better predict future trajectories, a point the authors illustrate with the classic work of Oliver Rackham on English ancient woodlands and G.F. Peterken on natural woodlands.

The relevance extends to disturbance regimes, one of the most consequential areas of modern forest science. Forest fires can be of natural or human origin, and people interfere with fire regimes in many ways: through arson, firefighting, fuel removal by logging, grazing, and litter collection. Analyzing past fire events alongside historical management practices provides the tools to disentangle the drivers of changing fire regimes, and forms the basis for informed decisions about when and how to use fire in restoration or to protect forests from burning. With a recent review indicating that European forests face more frequent and destructive disturbances from wildfire, windstorm, drought, and bark beetles under climate change, this historical baseline has never been more valuable.

So how do researchers actually reconstruct a forest’s past? The paper provides a systematic tour of the main source types, spanning both the humanities and the natural sciences. Field surveys remain foundational: by analyzing tree age, forest density, growth patterns, recruitment, and traces of disturbance, researchers can reconstruct historical development. Fieldwork is also essential for detecting living trees bearing evidence of past human activity, including logging stumps, old roads, fire scars, and archaeological remains. Old-growth forests are especially precious in this regard, because their ancient living and dead trees preserve long-term evidence of human-forest interactions. The method is labor-intensive and poorly suited to very large areas, but national forest inventories can help contextualize smaller-scale studies.

Tree rings offer a second powerful window. Dendrochronology and dendroecology exploit the annual record of growth encoded in ring widths, anatomical features, and wood chemistry. By extracting cores and cross-dating samples, scientists can reconstruct forest dynamics over centuries or even millennia, and rings record environmental shifts from climate variation to pollution and drought. Fire scars allow precise dating of both natural and human-caused fires, while other scars reveal logging damage, animal browsing, and wind events. The limitations are real: some species lack clear annual rings, decay and harvesting destroy records, and sampling effort constrains spatial coverage.

For deeper time, paleoecology takes over. Pollen and macrofossils preserved in lake and bog sediments survive for thousands of years, allowing reconstruction of past vegetation composition, clearing events, grazing pressure, and fire activity through microscopic identification and radiocarbon dating. Recent advances in automated pollen classification using deep learning have improved analytical efficiency, and the authors expect sedimentary ancient DNA to further transform the reconstruction of local and regional vegetation change. Documentary evidence, meanwhile, brings the human perspective: local histories, letters, travel reports, court records, maps, and diaries all illuminate past relationships between people and forests, provided researchers read them critically for bias and context. Forest management plans deserve special mention. Originating in Germany in the eighteenth and early nineteenth centuries and typically revised every ten to twenty years, these standardized documents allow researchers to reconstruct long-term changes in forest structure, species composition, and management strategy, though unofficial uses are often omitted.

Remote sensing, oral history, and pictorial sources round out the toolkit. Aerial photography, available since the early 1900s, reveals changes in forest extent, composition, and disturbance, while satellite imagery has monitored deforestation since the 1980s. LIDAR creates detailed three-dimensional models that can expose hidden cultural features such as hunting pits, charcoal kilns, and ancient monuments, directly linking present forest structure to past land use. Historical paintings and photographs, including repeat photography retaken from identical viewpoints, document change visually, and oral history interviews capture firsthand accounts of forest use, often preserving the voices of marginalized communities absent from official archives.

The real power, the authors argue, lies in combining these sources. In the Swiss Rhone valley, pairing forest management plans with oral history interviews revealed the full picture of traditional non-timber forest uses: the plans recorded the administration’s view, while farmers’ narratives explained the extent, intensity, and daily-life context of practices like woodland pasture and litter collection. In northern Scandinavia, researchers combined court, tax, and church records dating to the seventeenth century with detailed field inventories and dendrochronological analysis of Scots pine and Downy birch to decipher centuries of Sámi indigenous forest use, revealing subtle resource areas created by bark harvesting, reindeer lichen cutting, and settlements within what is today protected old-growth forest. The study concluded that the designation and management of protected forests should incorporate these cultural dimensions.

The authors’ recommendation is clear: ecologists should incorporate retrospective methods into broader studies, and important forest landscapes deserve historical analysis as a distinct component of ecological research. Fostering exchange between scholars of cultural forest history and ecological forest history, they argue, will deepen our understanding of the interrelationship between ecosystems and humans. Disregarding history, they warn, is not merely incomplete science; it is perilous, because without understanding the longer trajectory of change we cannot truly know what a forest is, what it once was, or what it might become.

Subject of Research: Interdisciplinary methods for studying forest history and their relevance to forest ecology and management

Article Title: Bridging forest history and forest ecology: Why it is important to understand the history of forests and what are the main sources and methods

Article References: Bürgi, M., & Östlund, L. (2026). Bridging forest history and forest ecology: Why it is important to understand the history of forests and what are the main sources and methods. Ambio. https://doi.org/10.1007/s13280-026-02502-y

Image Credits: AI Generated

DOI: 10.1007/s13280-026-02502-y

Keywords: forest history, forest ecology, dendrochronology, pollen analysis, legacy effects, oral history, remote sensing, forest management plans, old-growth forests, interdisciplinary research, historical ecology, biodiversity conservation