Hi guys! I hope you all had a brilliant new year. I've been back at college, and just today we were doing something that really captured my imagination. It's something that's come up before in class, but hasn't been really covered in a while. That is the beautiful world of hedgerows.

Hedgerows are a very traditional form of boundary that consists of straight lines of trees being partially felled one over the other in an interlocking pattern in order to form a boundary. By industry standard this is usually done with 80-90% hawthorn trees, followed by 10-15% blackthorn. The rest can be made up of species such as field maple, dog rose, hazel, and crab apple! There is a very persistent effort in Britain to keep the art of hedgelaying alive, and it's a really underrated form of boundary. There's many different methods to arranging a hedgerow that are found in different areas of the UK, such as the double-brush style of southern England, and the sawn-timber stake style of Derbyshire.

Laying a hedge involves felling the trees within the age range of 5-10 years, although 7 years is the most ideal as they will be at the best thickness for sturdiness as a boundary while still being flexible and easy to lay. In order to lay the hedge, you need to cut through the "pleacher" -- this is the stem of the tree -- deep enough that it is easy to bend, but CRUCIALLY you need to maintain the cambium layer on the inside, the hinge of the bend. This is what connects the living tissue of the pleacher to the roots of the tree, and removing this outer layer will kill the tree completely! Our method involves two rows of trees offset to create a zig-zagging pattern when laid, allowing for width and density, as well as a more complex lay better for sturdiness and inhabitability.

There's several reasons for the species selections I described above. Hawthorn is a brilliant species to make up a majority of the hedge for the following reasons:

Mixing in other species comes from a conservation perspective, because the truth is a LOT of different species benefit from a well-laid hedge. Below I will describe some traits of the hedge and how they benefit wildlife!

• Flowering bodies: Hawthorn, blackthorn, field maple, and dog rose all have flowering bodies. A wide variation of flowers, such as the bright pinks of the dog roses compared to the beautiful small white flowers of blackthorn, will be attractive to a wide variety of pollinating insects. A particular quality of blackthorn is that it is the first tree to flower in spring, and including blackthorn in a hedgerow means that it will be valuable to pollinating insects just coming out of hibernation, where the pollen is needed most.
• Fruiting bodies: Due to having a lot of fruit-bearing trees and plants within it, a well-done hedgerow is a great food source for passerine birds who can feast on the blackthorn's sloe berries, the rose hips of the dog rose, and the bright red hawthorn berries.
• Habitat for birds: The hedgerow, being made primarly of hawthorn, will have a dense and tall canopy layer with a short woody component at the bottom. This provides a large and accessible space for passerine birds (songbirds) to shelter safely and nest. The thorns and density of the hedge will prevent birds of prey from being able to see and access the songbirds, too!
• Habitat for bugs: A lot of larvae make great use of the dense leafy component of a hedge. This includes larvae of moths and butterflies, as well as other flies in general. It is a safe habitat for them to feed and grow. The addition of large-leaved plants like field maple to a hedgerow makes it more accessible and appealing to a wider variety of bugs, increasing biodiversity.
• Habitat for mammals: You may have seen holes for rabbits under hedgerows before, and this is because it provides good cover for their homes!
• A wildlife corridor: The term "wildlife corridor" refers to a linear habitat that connects two otherwise isolated habitats to one another. This includes things like woodland rides and hedgerows. A hedgerow is an excellent wildlife corridor due to, first of all, where they usually are found: on agricultural land. These are vast, wide open spaces when used for crops or grazing, and having this corridor cutting through them makes it safer for vulnerable small creatures to cross between habitats, preventing populations from being isolated from each other. The way a hedgerow provides this is through its dense, maze-like woody component toward the ground. It is sheltered and compact, perfect for rodents and small creatures like hedgehogs (which especially favour hedgerows as a habitat)!
• The edge effect: This is the consequence of the ecotone developed on either side of a hedgerow, especially if the hedgerow has a fence on both sides to prevent grazing animals from forcing a stark shift from grassland to hedge. An "ecotone" is the gradient, transitional zone between two forms of habitat, such as a shore between ground and water, or -- in this case -- a slightly taller field layer to transition between short grassland or a crop field and the tall hedge. In this area you can find a wider range of flora, as it acts as a bit of a "crossover" between the two habitats. For instance, the ecotone between a field and a hedge can host a lot of wildflowers that are appealing to butterflies!

One additional thing you can do to enhance the conservation value of a hedgerow is to include standard trees. These are trees left to grow as standard, that will interrupt the understorey-level hedgerow with a taller canopy in regions. One of the benefits of this is it makes the hedgerow more attractive to a wider variety of birds, such as larger birds in general. Additionally, the tree will cast shade on a small portion of the hedgerow that will make the smaller trees have to compete and grow more for access to sunlight. This additional stress on a region of the hedge might give it a weaker or more open canopy, but will in itself create a unique niche microhabitat for different species to capitalise on! Furthermore, the leaf litter from the tree will act as a shelter habitat for some species' larvae, which may hibernate beneath the blanket of leaves. It will also contribute to the population of detritivores who will decompose this leaf litter. It all comes together babey.

The UK government, under Countryside Stewardship regulations, will pay a landowner for the construction of a hedgerow -- particularly as it contributes to the overall tree coverage in the UK. Under this regulation you're also not allowed to remove or destroy a hedgerow once it has been created. Under Higher Level Stewardship (HLS) you can currently be paid up to £22 per metre of hedgerow planted! This is a quantity that has doubled in recent years turning it from a "breaking even" situation into an explicitly profitable venture for any landowner who can create one. At the moment, supply of hedgerow species such as hawthorn can't meet this demand, but in a few years this could be a booming industry.

One of the hardest parts of hedgelaying is getting people on board with the idea, especially farmers who much prefer to flail the canopy without maintaining the hedge's structure. This results in a woody component that is too tall, with a very weak canopy -- the farmer is destroying the part the birds inhabit and nest in! Additionally, there is a recurring issue of people forgetting to come back and actually lay the hedge once it has grown to the appropriate age. This results in a literal row of trees, with no understorey coverage and therefore much less benefit. Not great. One thing that really turns farmers off from hedgerows is how long they take to actually be usable. They need at LEAST five years to be of pleaching age, after all. However, this can be remedied by the construction of a stock fence on both sides of the hedgerow, meaning there is still a physical barrier that doubles in purpose by protecting the young trees from grazing and browsing by creatures such as rabbits, livestock, or deer.