Southern Water Biodiversity Grant funded - Hedging Our Future Project
In January we continued with our planting programme and planted over 750 trees making over 170 metres of new hedges. We still need more help so please do join us in February to continue with the planting as the season will soon be finished.
Threats to hedges, small and large
Our hedgerows, a uniquely British feature, are continuing to disappear and since World War Two we have lost 50% of them. Threats to hedges can take many forms and they can be from the smallest insect to government policy.
The Brown-tail moth (Euproctis chrysorrhoea)
These moths are well known to anyone who carries out moth trapping and are quite attractive little creatures with pale wings and a distinctive brown tip to their abdomen that often curls upwards. These moths can be seen in large numbers in hedgerows in their larval form as they create webbed tents that are quite visible. In the spring they can significantly defoliate large sections of hedgerows effectively killing individual trees.
The Brown-tail moth is native to Europe, and countries in Asia, and the north coast of Africa. There are descriptions of outbreaks reported as far back as the 1500s. The life cycle of the moth is atypical, in that it spends approximately nine months (August to April) as larvae (caterpillars), leaving about one month each for pupae, adults and eggs.
The female lays one cluster of 200 to 400 eggs a year, typically on the underside of the host leaf. The larva is very hairy, brown with white markings, and two prominent red spots toward the tail end. The urticating hairs provide protection from predators; the larva incorporates some into the cocoon within which it pupates. The species overwinters communally as larvae within a tough, silken tent constructed around branch-tip leaves and anchored to twigs. In areas where the species is abundant, these tents are a familiar sight, and can be seen on a huge range of plants, especially in late fall and winter when unaffected leaves have fallen. The species feeds on many different species of trees, including oak, hazel, alder, hawthorn, blackthorn, pear, apple, field maple and rowan.
The hairs from the caterpillars are toxic for humans, causing an itchy rash of up to sometimes weeks-long duration due to mechanical and chemical irritation. The hairs are shed and can become windblown so direct contact with larvae is not necessary. Toxins in the hairs remain potent for up to three years. Outdoor activities such as mowing a lawn or raking leaves can be enough to spread these hair onto bare skin. Branch-tip webs can be clipped in winter and very early spring, and either dropped into a bucket of soapy water or burned. Gloves should be worn.
A successful predator of the Brown-tail moth is Compsilura concinnata, a parasitic fly that pierces the brown-tail moth larva and deposits its own larva inside. It over winters in the host larvae and slowly eats it alive in the spring. Not many birds will eat urticating caterpillars but a specialist predator is the Common Cuckoo (Cuculus canorus). Unfortunately their declining numbers in the UK could mean that the Brown-tail moth may get a better foothold in our hedges.
Government Policy - A regulatory gap for hedgerows?
A recent development is that ‘cross compliance’ rules were officially phased out at the end of 2023. Cross compliance provided a link between farm payments and good environmental and animal welfare practice. Farmers receiving payments had to comply with these rules, or risk financial penalties. This included criteria to encourage healthy hedgerows that support birds and other wildlife, including not cutting or trimming hedgerows during the bird nesting season, and maintaining a 2m buffer strip either side of a hedgerow.
While some cross compliance rules are already incorporated into separate legislation, those relating to hedgerows are not. Defra ran a public consultation on 'Protecting Hedgerows' in 2023 and is in the process of considering how to maintain and improve existing protections, but in the meantime this does leave a regulatory gap. Concerns around the ‘hidden threats to hedgerows’ have been raised by environmental charities, including the RSPB, Wildlife Trusts and the National Trust, calling for urgent action to reinstate protection.
Other significant threats
There are many other threats to our native, wildlife rich hedges and they bare varied and numerous. The obvious one is from developers who remove species rich old hedges to make access and building work easier, and replace them with one year old whips of trees that don't thrive. The trees are often planted without stakes and guards and are at risk of being strimmed off by the first landscape contractor on site! These young trees frequently come from overseas, are put in the ground at the wrong time of year and not mulched or watered. These poor trees don't have a chance and are no replacement for what has been lost.
Another threat is the planting of non native species such as laurel or leylandii. These evergreen species are popular as they provide year round screening and are relatively cheap to install. They do not need rabbit guards or stakes and thrive in our tender climate. They do need a lot of management long term and they don't offer much for wildlife. In residential areas laurel has become the hedge of choice but can become invasive and provides little for invertebrates and therefore birds. Nothing beats a lovely native mixed species hedge, full of food opportunities for a wide range of species.
Let's plant more trees and hedges to try and negate the loss, and love and appreciate the trees we have around us. Plant a tree at the back of your garden, in the corner of a playground or recreation ground, or in a gap in a hedge near to you - it all helps.