Trees: why do we plant them?
Over the winter we had hoped to help plant thousands of trees at a variety of sites. We even bought more planting spades! We did manage a few tree planting days before Christmas, but sadly the pandemic scuppered many planned days.
Before conservationists of course, trees re-generated themselves naturally and still do. So as the tree planting season draws to a close, we thought we’d take a look at why we plant trees.
Trees are often practical – whether as a hedge as a wildlife-friendly barrier, a shelter for livestock or as part of a river management plan, often to do with managing flooding. When tree cover connects areas, it can act as a ‘wildlife corridor’ to enable animals to have some cover from predators, for example. They provide homes and a source of food for many animals.
Planting trees increases survival rates as the trees have already got through their vulnerable early stages of life and so are likely to flourish. This is in contrast to natural regeneration in which there are many losses.
Can’t trees re-generate themselves?
Many of Snowdonia’s woodlands have trees all of a similar age. If new trees don’t join their ranks, there will come a time when the old trees decay and die over the same period, leaving little to replace them. There is natural re-generation by trees dropping seeds, but the rate can be slowed by various reasons.
One is animals: if the top of a young tree is nibbled, it can cause its death, when it is small and not yet strong. Wild goats can be a problem in some parts of Snowdonia, where they prevent new trees springing up in woodlands and occasionally sheep get into woodlands too. Mice, squirrels and birds eat many nuts and seeds – though jays and squirrels often forget where they’ve buried their stash and trees re-generate that way.
Rhododendron ponticum is a prolific plant has taken over large areas of Snowdonia woodlands in the past. The thick, waxy leaves shade out young tree saplings and other plants on the woodland floor. A concerted partnership effort has kept on top of the problem. Removing Rhododendron ponticum is a task that Snowdonia Society volunteers often help with.
Native, deciduous trees are best for biodiversity
A significant proportion of the UK’s tree cover consists of conifer plantations, whose needle-like leaves change the pH balance of the soil and not much can grow beneath them. Deciduous trees can support a greater diversity of species over their lifetime, especially as some can live for an extremely long time: oaks can live for centuries. In their older stages, especially, they are brilliant for insects and birds. So some coniferous woodlands that are now owned by conservation organisations are gradually being planted with native deciduous trees as the conifers are harvested.
Many of Snowdonia’s woodlands are remnants of ancient woodlands, which means there has been woodland there since 1600, from which date records are considered accurate. Some flowers, such as wood anemones, are indicators of ancient woodland. Many of Snowdonia’s wet woodlands, classed as ‘Celtic rainforests’, are rich with liverworts, mosses and ferns.
Over the last few years countless ash trees have been affected by a fungus called Hymenoscyphus fraxineus. It weakens ash trees and makes them vulnerable to disease and an early death. The problem has spread rapidly across the country and is comparable in scale to Dutch elm disease some decades ago. So it’s important to have plenty more trees to replace the enormous losses we will see from ash die-back.
Our volunteers’ achievements
Just a few examples of where Snowdonia Society volunteers have helped to plant trees are at Llanrwst, Trawsfynydd, Nebo, Llechwedd, Nant Gwynant, near Penmachno, Maentwrog and at Dyffryn Mymbyr. The latter is the former home of our founder, Esme Kirby. Read this explanation of planting with sheep in mind at Dyffryn Mymbyr, by the National Trust a few years ago.
We’ve helped the Snowdonia National Park Authority’s Afon Eden and LIFE Celtic Rainforests projects, the Woodland Trust, the National Trust including with their Upper Conwy Catchment project and their Hafod Garegog nursery and Pensychnant nature reserve too.
Our Care for Snowdonia visitor engagement scheme will keep us busy over the summer, but we will return to a programme of practical conservation work too in due course, when it is safer to get together. It may not be planting trees (which is seasonal) but it might be maintaining footpaths, removing invasive species such as Himalayan balsam or helping at nature reserves. (We have robust safe ways of working concerning coronavirus.)