What is a wood? Most people would probably answer a large group of trees. But let’s think about the other layers, a wood should contain a mix of trees, shrubs and other plants that combine together and allow other species to associate with that mix that would not normally occur where the individual tree species are found in isolation. Or alternatively a wood is a habitat with four basic layers - canopy, understorey, ground layer and soil, with associated species. What layer is most important?

What is important or what makes that woodland resilient? With ancient woodlands it is not just about the canopy trees, it’s largely about the soil and groundflora. Take a Plantation on Ancient Woodland Site (PAWS), all the native canopy trees and understorey could have been replaced with non-native trees, but that woodland could still be restored because the soil retains the fungus, invertebrates and seedbank that are irreplaceable and can’t just be recreated by planting a few trees. Many species that are found in ancient woodlands just require the continuous cover of damp, shaded habitat, but others may specialise in wood in various stages of decay, some species cannot tolerate the ground disturbance, or they require symbiotic or parasitic relationships with other woodland species. Most often the soil biodiversity is forgotten, but it is vital to the functioning and resilience of a woodland. New woodlands may not have good soil or groundflora, but by creating suitable connections with old woodlands (ancient and long established) we can provide the link to the right soils, fungi, invertebrates and groundflora that so many woodlands lack. Creating locally native, low density, non-modular woodlands with diverse structure along watercourses, boundaries, high input/low output corners of fields could also provide vital connections between these fragmented old woodlands.

Although we will never see a return of the areas of woodlands that once covered much of Britain, we are seeing an increase in woodland cover. Woodlands are being planted for various reasons, whether it’s commercial crops, shelter belts, flood management, soil stability, wildlife conservation or all of these and more. There should always be space for locally native species, they’ve evolved in our climate, they have adapted to our weather, however erratic it is, and they have evolved together and alongside other local wildlife, including the soils they grow in. Species like our native oaks (Quercus robur and Q. petraea) can support over 3300 species, hundreds of which are obligate oak species. So, they are microhabitats not just individual trees. Our locally native canopy trees also come in to leaf later, so woodland groundflora and the soils have that vital sunlight in the spring for just that bit longer. Northumberland has very little ancient woodland left, much of it is along our river valleys, and lowland woodlands are largely ash, oak, elm canopies, with wetter woodland mixes of alder, birch, willow. While wych elm persists as more of an understorey species now, and ash is clinging on with resistant individuals, there is more talk of replacement large tree species and woodland resilience. Many woodlands are often so dense with canopy trees there’s no room or light for understorey and the groundflora is usually absent or limited to secondary woodland species such as brambles and common grasses.

Before you plan your woodland, always check what is there before you plant, avoid species-rich grasslands, fens, deep peat, or any habitat that supports important species or features. Think about what makes a woodland. Don’t just focus on the canopy! Plan your species mix according to the soil and locality. Look at the woodland communities in your area, choose species like grey willow, goat willow, eared willow, alder, downy birch for damper/wetter areas; or pedunculate oak, silver birch, wild cherry, hazel and hawthorn for lowland sites. Ash is still clinging on and may make a comeback as a dominant canopy species, but this will take time. Alternatives to ash could include small-leaved lime or wild cherry, or an increase in oak, with less canopy trees and more understorey to create a more open canopy woodland. Aspen could also be included. A resilient woodland is about all of the layers, supporting healthy soils, diverse groundflora, species that work together and connectivity. It’s not about cramming as many tree species into a planted area as possible. Think about native pinewoods, where the main or only canopy tree is Scots pine, but they can have a phenomenally diverse range of species within these woodlands.

While species such as beech is a UK native it is not naturally found in Northumberland and can be a huge threat to the groundflora and understorey of our locally native woodland. It has a large, dense canopy causing shade and the heavy, persistent leaf litter smothers groundflora. The shallow roots dry out the surface layer, making it less suitable to many plants and beech favours beech, growing happily under its own shade and dryness.

Where there’s no room for a woodland, think about connectivity through species-rich hedgerows. 

Below is a list of woody species native to Northumberland, the list is not exhaustive. Many species will tolerate different soil types. Some of the species are localised in Northumberland. Rarer species, e.g. gangrenous willow, have not been included. 

• Ash
• Alder
• Aspen
• Bird cherry
• Blackthorn
• Broom
• Crab apple
• Dog rose
• Downy Birch
• Field Maple
• Gorse
• Guelder rose
• Hazel
• Hawthorn
• Holly
• Honeysuckle
• Juniper
• Pedunculate oak
• Rowan
• Sessile birch
• Silver birch
• Small leaved lime
• Spindle
• Wild cherry
• Wych elm
• Yew
• Almond willow
• Bay willow
• Eared willow
• Goat willow
• Grey willow
• Purple willow
• White willow

One final note don’t forget about the importance of dead and decaying wood!