Threats to our hedgerows
Although the rates of direct hedge removal have been reduced, we are still seeing the loss of hedges through mismanagement. With many farmland species now marginalised to hedgerows, we take a look at the issues that are threatening them.
Lack of rejuvenation
Lack of rejuvenation is probably the biggest direct threat to existing hedgerows. Traditionally, hedges were routinely laid or coppiced to keep them stockproof. Although containing livestock is not always a requirement today, rejuvenation remains essential for the long-term condition and survival of hedges. Understandable changes to this rotational rejuvenation system occurred after the war, as farming practices, national priorities and farm labour capacity changed. Periodic hedge laying was often no longer a priority, or even feasible. At the same time, mechanised hedge trimming became increasingly popular, making routine hedge management easier and allowing rejuvenation to be delayed.
But rejuvenation can only be delayed for so long. We are now witnessing the continued decline of hedge condition and extent as a result. Bringing back laying and coppicing, alongside gapping up and re-stocking where needed, as part of our hedge management systems is the only way to halt and reverse this decline.
When a hedge isn’t rejuvenated, it often falls into one of two main management traps: over-trimming or lack of management altogether.
Over-trimming
Sensitive hedge trimming can be used to maintain branching density and slow a hedge’s progress through its natural lifecycle, but hedges cannot be trimmed indefinitely. Trimming too frequently, always at the same height, or for too many years without a periodic reset can weaken a hedge over time and eventually lead to the gradual loss of stems.
Over-management causes stem health to deteriorate, reducing the number and density of healthy stems and eventually leading to gaps in the hedge. This affects the hedge’s value as a wildlife corridor. An over-trimmed hedge may also lose its valuable branching structure at the base and develop a knuckle of dense growth at the trimming line.
Cutting hedges every year can also significantly reduce the number of flowers and fruits available to wildlife, as many of Britain’s native berry-bearing species only flower on growth that is two years old or older.
How to prevent over-trimming: Try not to cut hedgerows at the same height each year. Instead, cut them slightly higher each time, or trim them on a two- or three-year rotation. Allow hedges to gradually grow over time and, once every 20–40 years, lay or coppice them to reset the hedge cycle.
Lack of management
Lack of any management also threatens hedgerows. Although short periods without trimming can benefit wildlife, long periods without management can eventually allow hedges to develop into lines of trees. These can become increasingly gappy and may eventually be lost altogether. The 2007 UKCEH Countryside Survey showed a 9% increase in the number of hedges lost through under-management over the previous decade, and the 2023 update showed this trend continuing.
Hedgerows are succession habitats, made up of trees and shrubby woody species, that naturally change over time. They require management to maintain the valuable mid-succession stage of bushy, low growth and prevent them developing into lines of trees.
Without browsing or trimming, hedges grow upwards and the low, shrubby cover needed by wildlife for shelter, food and movement along the landscape is gradually lost. Whilst standard trees in hedges can offer wildlife and farm benefits when well placed, this is very different from allowing the entire hedge to grow into a line of trees. Once a hedgerow has become a line of trees, it can be very difficult to restore the shrubby hedgerow structure beneath it. It is therefore important to prevent this happening.
How to prevent hedges growing into a line of trees: Sensitive trimming can slow the rate at which a hedge matures into a tree line by removing the tip buds (apical meristems). This prevents the hedge from racing upwards and can encourage branching lower down. It can extend the period before laying or coppicing is needed to around 40 years.
However, where hedge trimming is not appropriate or possible, hedges can instead be managed on a shorter cycle, with no trimming at all, but laying taking place every 10–20 years.
Both over-trimming and lack of management are symptoms of the main cause of hedge decline: failure to rejuvenate hedges at the right time. Rejuvenation resets the hedge lifecycle, allowing it to regenerate from ground level and begin a new lifecycle.
Ploughing
Ploughing too near a hedge destroys the herbaceous vegetation that usually grows at the hedge base. It can also damage the roots of the shrubs and hedgerow trees that make up the hedge structure. If the root systems are no longer able to support them, this can sometimes kill the trees which leads to the loss of parts of the hedge. This is especially the case in times of drought.
Direct removal
Although the rates of direct removal have slowed in recent years, hedgerows can still be removed, with council permission, for agriculture or development. Any removal reduces how well connected the hedgerow network is for birds, bats, butterflies and other wildlife that use hedges as foraging and commuting habitats.
Spraying
Over 500 native plant species have been recorded as being supported by hedgerows. Herbicides sprayed too close to a hedge or in windy conditions, can kill off plant diversity, especially at the base. Similarly, fertilizers can cause a change in the type of plants growing at the hedge base. Many wildflowers do not thrive in enriched soils. This is because enrichment causes the rapid growth of nutrient-loving plants such as nettles and docks, which then dominate the ground vegetation.
Over 1,500 different insect species have been found feeding on or living in hedgerows. Pesticides can cause a decline in the number and diversity of these insects. This can have a knock-on effect on the wildlife that they feed, such as birds, bats and other mammals.
Health-check your hedgerows
The Healthy Hedgerows survey provides instant feedback about the health of the hedge and bespoke management advice. The data that you contribute helps us to understand the overall health of hedgerows at a national scale so that we are able to direct our conservation work. Learn more: