In recent years, the conversation around threats to British woodland has understandably centred around climate change, pests, and diseases. However, for those of us working daily in woodlands across Sussex, the more immediate and visible challenge is something closer to ground level: deer.
Fallow deer numbers in the South East have quietly and steadily risen to unprecedented levels, with major consequences. During a recent visit to a fenced site in the New Forest, I witnessed something extraordinary, oak regeneration at a scale rarely seen, tens of thousands of stems per hectare thriving in the absence of deer. Just metres away, outside the exclosure, the contrast was striking. There, browsing pressure had stripped the woodland floor bare. No young trees. No shrub layer. Just a carpet of leaf litter and exposed soil.
A Single Species, a Widespread Impact
Deer, especially fallow, are not inherently destructive. In balanced numbers, they form part of a functioning woodland ecosystem. But the current population densities in the South East have tipped far beyond what our woodlands can absorb. In unmanaged areas, or where control efforts have been inconsistent, we’re now seeing a collapse of regeneration potential.
The effects are not just visual. Where the understorey is removed by constant browsing, the structure needed by many species of birds, invertebrates, and small mammals disappears. Nightingales, for example, rely on dense shrub cover to breed successfully. Many butterflies and ground beetles depend on a diverse field layer, which simply cannot persist when deer consume nearly every green shoot within reach.
And it is not just rare or specialist species that suffer. Common trees such as oak, ash, hazel, and holly fail to regenerate. This gradual failure undermines future canopy development and weakens the ability of woodlands to respond to pests, disease, and changing weather conditions. Without young trees to replace the old, even mature woodlands begin to decline.
Why Now?
The situation has been made worse by several compounding factors. Warmer winters have led to higher survival rates in young deer. Milder springs mean does are producing more fawns, and agricultural margins provide year-round feeding opportunities. Meanwhile, recreational stalking although useful in some settings rarely achieves the consistent control required to reduce populations at the landscape scale.
In many parts of the South East, deer now move freely between estates with no coordinated approach. Some landowners manage them intensively; others not at all. Without fencing, deer simply shift to where there is less pressure. The result is predictable: overbrowsing in the gaps, and little chance for woodlands to recover.
A Hard Look at Regeneration
When woodland owners speak about encouraging natural regeneration, we have to be honest, under current deer pressure, regeneration often doesn’t stand a chance. You can leave an area untouched for ten years and still find not a single sapling above knee height. This is not due to poor soil or climate. It is due to deer.
The fenced plots in the New Forest show what’s possible when deer are excluded. Oak, birch, hawthorn, hazel, and ash all regenerate freely. Shrubs fill in the gaps, supporting butterflies, nesting birds, and ground beetles. And crucially, this regeneration occurs without costly planting or maintenance.
This isn’t just good for biodiversity, it’s good for resilience. Woodlands that can regenerate are more adaptable to climate change. They sequester more carbon, manage water better, and provide a steady supply of future timber. But they cannot do any of this if every shoot is eaten the moment it appears.
So What Can Be Done?
The solution is not a one-size-fits-all policy, but a change in mindset backed by practical support. First, woodland owners must begin with honest assessment. If you can’t see young trees in your wood, if there’s a browse line you can walk under, or if your field layer is dominated by bramble and deer trails, there’s a problem.
From there, several tools are available:
Deer Impact Assessments can provide clear, photographic evidence of the pressure your woodland is under. These are often the first step in accessing financial support through grants like CWS1 (£105/ha/year) and PA7, which fund both management plans and implementation.
Fencing may be required in high-pressure sites, at least temporarily. Grant funding can support the installation of deer-proof exclosures to allow for regeneration within specific compartments.
Structured Cull Plans need to be drawn up. Not just casual stalking, but targeted, consistent population reduction based on evidence. This often requires professional input, and yes, an understanding that deer numbers must be reduced, not just maintained.
Collaboration is key. Deer don’t respect boundaries, and neither should management plans. Neighbours need to work together across the landscape if we are to make a lasting difference.
Deer are now the dominant influence on woodland structure in many parts of the South East. More than pests, disease, or even climate change, they shape what grows and what doesn’t.
We still have time to act, but not indefinitely. If we want to talk seriously about biodiversity, carbon storage, and woodland resilience, we must first address the pressure from deer.
