At the edge of a country road, in a city square, or deep inside an old park, there is sometimes a tree that looks different from its neighbours. Its bark is cracked and twisted, one of its branches was broken by a storm decades ago, and its trunk is so thick that two people cannot wrap their arms around it. This may be a veteran tree — a living witness to history that, for the local ecosystem, matters more than an entire young plantation. At the One More Tree Foundation we plant hundreds of thousands of new trees every year, but we believe just as strongly that protecting the trees that have already been growing for decades or centuries is part of the very same mission. This article explores what veteran trees actually are, why their ecological role is so unique, and what each of us can do to help them survive for future generations.
What Veteran Trees Are and What Defines Their Special Status
The term “veteran tree” describes a tree that, due to its age, size, or state of decay, has reached an advanced stage of biological development — a stage often associated with tree senescence, sometimes preceding or overlapping with the “hollowing tree” or “standing deadwood” phase. In practice, it is not only about the number of rings — an oak may become a veteran at 200 years old, while a birch reaches a comparable status much sooner because its natural lifespan is shorter. What matters most is the point in the organism’s life cycle it has reached, and the ecological structures it has managed to develop along the way.
Age Alone Is Not the Whole Story
Arborists and ecologists typically identify three features that define a veteran tree: the presence of microhabitats such as cavities, deadwood, and cracked bark; visible signs of decay and regeneration occurring simultaneously within the same crown; and a size disproportionate to the species and location, indicating decades of growth without major disruption. A veteran tree, then, is less a “very old tree” in the everyday sense, and more a complex, self-contained ecosystem within a single organism — something no sapling can replace for many decades, no matter how carefully it is tended.
Underground and Above-Ground Microhabitats – Biodiversity That Cannot Be Transplanted
What makes veteran trees so valuable from a conservation standpoint is the richness of microhabitats that develop in their crowns, trunks, and root systems over decades. Scientists estimate that a single ancient oak can be home to several hundred species of invertebrates, fungi, lichens, and mosses — populations that cannot simply be “moved” to a younger tree, because they arise only through long-term processes of wood decay and the formation of deadwood.
Among the most important microhabitats are:
- Cavities and bark fissures — shelter for bats, owls, woodpeckers, and saproxylic insects.
- Heartwood decay inside the trunk — habitat for beetle larvae, including rare and protected species such as the hermit beetle.
- Bracket fungi and epiphytic lichens — indicator organisms that appear only on bark with a specific structure and moisture level, built up over years.
- Dead branches within a living crown — a valuable habitat that, despite looking like a sign of disease, actually reflects the tree’s natural life cycle.
This kind of biodiversity is often called “hidden,” because most of these organisms are invisible to a passer-by, yet together they form the foundation of local food chains. This is why felling a single ancient tree can mean losing a habitat that would take another century to recreate — even if ten new saplings are planted on the very same spot.
The Climate and Landscape Role of Ancient Trees
Beyond their biological value, veteran trees perform functions that are hard to overstate in the context of climate change. Large, mature trees sequester significantly more carbon dioxide than young saplings — research shows that a single old tree can store as much carbon in its biomass as several dozen young trees combined, simply because its root system and trunk have already reached their maximum wood volume. The broad canopy of a veteran tree also provides shade and cooling on a scale unmatched by young plantings, which matters increasingly in cities struggling with heatwaves.
The landscape role is equally important. Solitary old trees — especially those growing along field boundaries, roadsides, or farmland edges — act as windbreaks and orientation points for animals migrating through fragmented agricultural landscapes. Their deep root systems stabilise soil on slopes and along watercourses, reducing erosion far more effectively than the shallow roots of young trees. In this way, a single veteran tree can shape the ecosystem around it across a radius of many metres.
Why Veteran Trees Disappear Faster Than New Ones Are Created
Despite their value, ancient trees are today one of the most threatened categories of nature in Europe. The main problem is a lack of generational succession — trees that are 200 to 400 years old today often have no younger successors aged 50 to 100 years in many regions, because throughout the twentieth century the priority was agricultural intensification and urbanisation rather than preserving old-growth trees. This means that in a few decades a generational gap may appear that cannot be quickly filled, no matter how fast new trees are planted.
The most significant threats to veteran trees include:
- Felling for development — roads, car parks, and construction often treat a single old tree as an obstacle rather than an asset.
- “Tidying up” green spaces — removing dead branches and hollow trunks for aesthetic reasons or a misplaced sense of safety.
- Changes in groundwater levels and soil compaction around the trunk caused by road and pavement construction.
- Disease and invasive pests, to which weakened old trees are often more vulnerable than young, vigorous specimens.
- Fires and extreme weather events, increasingly frequent as the climate changes.
It is worth highlighting the paradox: a tree that has survived two hundred years of shifting climate, wars, and epidemics can be lost in a single afternoon because of an administrative decision made without full awareness of its ecological value.
Legal Protection for Ancient Trees Across Europe
Fortunately, nature conservation law recognises the uniqueness of veteran trees. In many European countries, the oldest and most valuable specimens can be granted the status of a protected natural monument, which prohibits felling, damage, or earthworks in the immediate vicinity of the tree without approval from the relevant authority. The decision to grant such status is usually made by local government, often at the request of a resident, an NGO, or a forester.
At the European level, additional initiatives exist, such as registries of trees of European heritage (the European Tree of the Year contest) and national databases of ancient trees maintained by scientific institutions and environmental organisations. These registries not only document the location and health of the most valuable specimens but also support spatial planning — developers and municipalities can check whether a planned investment would conflict with a protected tree.
How to Register a Tree for Protection
Nominating a tree for protection is simpler than it might seem, and virtually any resident can do it:
- Photograph the tree and measure the trunk circumference at 130 cm above ground level (breast height).
- Check with the local municipal office which size and age criteria apply to the species in question.
- Submit an application to the local council requesting protected status, including a description of the location and an ecological justification.
- Contact a local environmental organisation, which can support the application with a professional arboricultural assessment.
Such an application, while it requires patience, can effectively protect a tree from felling for decades to come.
What Each of Us Can Do to Protect Old Trees Nearby
Protecting veteran trees is not reserved for officials and scientists alone. The everyday decisions of residents, farmers, and businesses have a real impact on whether an ancient tree survives to the next generation. It is worth starting with a simple observation: is there a tree in your neighbourhood that looks unusually old or impressive? If so, the first step toward its protection has already been taken — now it just needs to be safeguarded from disappearing unnoticed.
Practical actions anyone can take include:
- Avoiding soil compaction around the trunk — do not park vehicles or store building materials within the tree’s canopy area.
- Reporting planned felling of old trees to local environmental organisations before the decision becomes irreversible.
- Educating neighbours and children about the value of ancient trees — public awareness often determines whether a tree is seen as a “hazard” or as a treasure.
- Supporting local initiatives that carry out inventories and ecological education about ancient trees in your municipality.
Planting New Trees and Protecting Old Ones – Two Sides of One Mission
A question sometimes arises: if we are planting thousands of new trees, does protecting individual old specimens even matter? The answer is yes, for several reasons. First, no number of new saplings can quickly replace the ecological functions performed by a veteran tree — the microhabitats described earlier take decades, and often centuries, to form at all. Second, the young trees we plant today have the potential to become future veterans — but only if we ensure the conditions for them to survive the next hundred or two hundred years, including protection from felling down the line.
This is exactly why, at the One More Tree Foundation, we treat planting and protection as two elements of one coherent strategy for building ecosystem resilience. When we plant a tree with a local community, we choose native species suited to local conditions and try to involve residents in caring for young plantings — precisely so that, half a century from now, they have a chance of becoming the next generation of veteran trees in their region. At the same time, we support initiatives that inventory and protect existing ancient trees, because they form the foundation of biodiversity on which the entire forest and landscape ecosystem depends.
Looking at an ancient tree in a park or along a field boundary, it is worth remembering that it is not just a landscape feature, but a living record of natural history whose value cannot be recreated within a single human lifetime. Protecting such trees, alongside planting new ones, is an investment in a future that will benefit generations to come — both people and the hundreds of species for which an old tree is home. Join our efforts and help us build a landscape where young plantings and ancient veterans will coexist for centuries to come.
