Deer: What are the possible solutions to foresters' woes?

IF those who care for woodlands – for commercial, conservation, recreation or multi-purpose ends – agree there are or soon will be too many deer around for comfort, what are the possible solutions? 

One way is to reduce the populations; another to keep them away from the plants; a third is to manipulate the environment; and the fourth is an integrated approach.
Experts advocate putting monitoring and management in place, even though there might be no or little deer impact – so far – and that one should cull even at low densities by concentrating on does or hinds. 

READ PART I: What does the future hold for deer in English woodlands? And what can we learn from Scotland, Wales, and Northern Ireland?

Shooting deer falls under the Deer Act (1961) which imposes close seasons and firearm restrictions. Selective culling can also remove sick, injured or ageing animals and help maintain a healthy population. 
Wild roaming deer in the UK are legally Res nulis (they belong to nobody). While roe, muntjac and Chinese water deer are mainly territorial, the herding fallow, red and sika are far more mobile. 

Often the only practical solution is to cull in collaboration with neighbours and on a landscape scale – when a stumbling block can be managing the human players. A single owner who does not allow shooting can scupper coordinated efforts to reduce numbers as these animals soon learn where they can seek sanctuary.

Culling is an obvious solution, but an expensive one. (Image: FJ)

A seemingly obvious solution is to keep trees and deer apart.

The advent of ‘Tuley tubes’ in the late 1970s heralded a new era in forestry. Millions of such tubes are now deployed across the lowlands each year. 

Of course, besides protecting saplings from hungry herbivores, tree tubes or shelters provide a micro-climate to enhance growth, establishment rates and subsequent care.

Yet planting whips in rows with inadequate protection is offering a self-service cafeteria or buffet bar to deer. 

Serried ranks of regimented 1.2 m tall tubes now criss-cross the countryside. They may seem fine for now, but fast-forward a couple of years. Where there are expanding herds of taller fallow, red or sika, those shelters might prove too short to prevent browsing as the broadleaf foliage emerges over the rims in early summer. More costly 1.5 m ones are advocated by the Forestry Commission.

Long-lasting wire fencing offers economies of scale – expensive, but often the only viable, one-off option in remoter sites. Cheaper, moveable, 1.8 m plastic netting can protect fresh coppice coupes. Yet no fence is ever 100-per-cent deer proof and excluding them may only shift the animals and the associated problems elsewhere.

Chemical and physical repellents are seldom that effective on any serious scale, long term, out in the wide, wet woodland world.

Besides culling, tree shelters and fencing, should managers contemplate modifying silvicultural approaches that can make woodlands more resilient to the attentions of these animals by ‘non-metallic’ means? Are habitat management or diversionary crops considered as part and parcel of woodland expansion from the planning stage or only when it may be too late? 

Growing trees is a long-term game. If selective culling has a future role, then woodland design is vital from the outset to facilitate it. In new plantings, it is essential to plan ahead and incorporate features such as box junctions, lawns, wider rides, sight lines, or diversion and sacrifice crops, all aiding more efficient deer control looking forward. How often is that the case?

Species choice is crucial as well. Certain trees are far more palatable to these herbivores than others. Is it more sensible to establish those matched for a site yet known to be less appetising to deer? When novel saplings are planted – for variety, biodiversity, beauty, commemorative value or resilience – those are a magnet too.

There are 230,000 hectares of Plantations on Ancient Woodland Sites (PAWS) in the UK – about half in England – much still ripe for restoration. Most date from the late 1980s, when tax breaks in the Lawson era encouraged coniferisation. Will well-meaning moves to thin those softwood stands to let light filter in and encourage remnant ground flora to flourish again result in more sustenance for these creatures – and so more of them – with all the associated challenges?

Millions of shelters are deployed across the lowlands each year. (Image: FJ)

A study led by Southampton University investigated how susceptible different locations were to deer damage across Britain. The team launched a free, interactive, predictive tool at https://spake.shinyapps.io/DEERDAMAGETOOL/. Why not try it?

Perhaps surprisingly, the researchers discovered that more deer does not always result in greater damage. A wide range of factors come into play, from climate, tree type and density to roads, surrounding low cover and the amount of forest nearby. Unmanaged, broadleaved, mixed-age woodlands with low numbers of stems and several age classes were especially vulnerable. 

Their findings highlight how establishing additional woodlands might have a knock-on effect on deer impacts in existing ones, plus the need to consider new schemes within a broader landscape context and not in isolation. And at a landscape scale, things get complicated.

Modelling work in eastern England discovered that while local targeted culling of 50–60 per cent of the population can work for smaller territorial species such as roe and muntjac, far larger management units across many kilometres are called for to make a lasting impression on mobile herding stocks of red or fallow.

LOOKING FORWARD

Managing deer appears an essential and growing part of successful woodland creation and stewardship. So, what might be the drivers for the long term? 

Most players agree that more needs to be done to manage cervid populations to protect new and existing woodland in England. In August – the peak holiday season – a month-long consultation on the Forestry Commission’s proposed deer management strategy gleaned views on their key proposals being mooted. The results of the consultation are due out before Christmas. 

All the present focus seems to be on areas where these beasts are deemed out of control, but that leaves them free to cause problems in other areas quite soon.

The present expansion of woodland is a great concept – driven largely through carbon sequestration goals, offsetting, incentives and boosting biodiversity, and underpinned by a suite of grants and incentives. 

A concerted drive on expanding tree cover is not new, of course. After WWI, the Forestry Commission was founded, heralding an expansion in plantations from an all-time low of five per cent – motivated by timber production before locking up carbon, biodiversity and ecosystem services became buzz words. 

The present boom in planting additional lowland, broadleaved woods appears set to continue with the government’s aspirational target figures for England still way over the horizon. Additional lowland plantings this century have been overwhelmingly mixed native broadleaved – a trend likely to continue as softwood timber production is a low priority, despite the UK off-shoring 80 per cent of its needs.

Extending woodland through both natural regeneration or rewilding and agroforestry is gaining ground. Letting nature recover is a long process that might be hampered by disproportionate deer densities. 

So we have more woodland cover, mostly young broadleaves, and a greater carrying capacity for the ever-expanding deer numbers in the foreseeable future – plus the need to manage them to establish, maintain or enhance both new and existing woodlands. 

Or are woodland managers fighting a losing battle? Should they just learn to live with more deer, or ring-fence sensitive sites? After all, heavily browsed scrub is one valuable wildlife habitat.

Deer management has associated costs. Can it ever pay its way? Over 185,000 people across the UK hold firearms certificates permitting a rifle for taking deer. Some pay for the privilege of woodland stalking. Trophy hunting for roe bucks can be a useful money spinner on larger lowland estates by clients from mainland Europe, but that concentrates on males and has little bearing on overall numbers. Charged-for deer-watching safaris do take place in the UK. Is commercial wildlife watching here an untapped market? 

Efforts to up the cull and boost consumption and sales of local venison have met with limited success. COVID lockdown also curtailed shooting and the sale of venison to the restaurant market.

Deer pose a tremendous problem for the country’s young trees. (Image: FJ)

On the property it manages, Forestry and Land Scotland has this year contracted a professional cull of 200,000 over the next five years – around a fifth of the herds.
Reintroducing top predators is mooted, with Eurasian lynx to roam large commercial forests in Kielder or Galloway. One pivotal argument in their favour is that they would return a natural balance in stocks and disrupt smaller deer. Wolves are mooted too.  

Are there alternatives besides or as well as reducing the cervid populations, protecting the trees and modifying the habitats? Any wild cards?

ALTERNATIVES AND UNKNOWNS

Resistant trees: Some trees contain natural phytochemicals that make their foliage or bark less attractive to deer. If modern tree breeding can select for bigger, better, disease-resistant plants, could it conjure up clonal trees that are less palatable for deer and then bulk up material through micropropagation? Would such genetically engineered trees be economically viable and socially acceptable? 

Contraception: Hormonal or immunocontraception has been trialled in deer in North America. Technically it can work, but how to expand those trials to wild woodland deer in the UK appears a major stumbling block.
Work on immunocontraception with grey squirrels under the UK Squirrel Accord shows promise. 

Ash dieback: Various alien pests and diseases are decimating trees across the UK. ADB drifts inexorably on and will change the structure of many broadleaf woodlands – and their carrying capacity for deer.

Diseases: Deer in the UK are generally healthy, yet – as with trees – the menace of novel diseases alighting on these shores poses a wild card for the Cervidae. Blue tongue, foot and mouth and chronic wasting disease have ravaged stocks abroad. White tails in North America are reservoirs for COVID, although in central Europe, local deer were given a clean bill of health. 

Deer-proof exclosures allow vegetation to regrow. (Image: FJ)

Lyme disease can be spread from wildlife to humans by ticks, but is not a major cause of mortality in deer in the UK, nor is TB.   

Climate change: With higher temperatures the new norm, how might this affect both lowland woodlands and the deer stocks they harbour? Milder winters and longer growing seasons could be a bonus for these mammals.

A PERFECT STORM?

My article asks more questions than it provides answers. I do not have the proverbial ‘silver bullet’. They say if you ask two foresters the same question you will get three differing answers. The same holds true for wildlife management, which is both a science and an art. But as a neutral, semi-retired observer who knows a thing or two about deer, maybe I am in a privileged position to flag up concerns here that others in employment may share but cannot openly express.  

In my humble opinion, everything appears in the deer’s favour in the UK lowlands. They have never had it so good, will prosper and continue to be a major challenge to both woodland creation and sustainable management of treed ecosystems here.