The government has launched a £ 50 Million campaign to encourage farmers and landowners to plant more trees to help tackle climate change but is this a good idea, and what are the options?
Tree planting is a long term investment, some native species such as Yew can live for thousands of years and even the non-native Sitka spruce commonly grown in commercial forestry may live past six hundred years although in the UK they may be typically harvested between thirty and fifty years of age. If it is intended to produce timber this may follow a clear felling operation on previously forested land, on peat bog moorland or on more productive agricultural land.
If sequestration of carbon is the main objective according to scientific research pasture sequesters 30% more carbon than forestry and this grass land may be grazed by the animals that provide us with dairy products and meat. It would seem to be counter-productive to plant trees in the UK if this merely resulted in forest clearances elsewhere in the world so that food may be grown for us to import instead?
What about the rewilding options, how can they help to fight climate change?
Around ten thousand years ago after the climate had warmed at the end of the Ice Age the tundra habitat that had then prevailed in the UK gave way to the primeval woodland that we consider to be native today, remnants of which may be found in what are defined as ancient woodlands, those deemed to be over four hundred years old. This process occurred through natural regeneration, the spread of both flora and fauna from warmer latitudes.
These woodlands are rich in species diversity containing complex interdependent ecosystems, far better than any man-made creation. They have proved to be resilient in the face of the ongoing post Ice Age climate fluctuations, thriving during the extremes of cold, heat, wet and drought that have occurred since. If allowed to do so these woodlands can expand outwards to regain their former territory through natural regeneration, with the seeds distributed by the wind and in the droppings of wild birds and mammals such as deer.
Nursery grown trees provide an instant visual impact, in the short term is quicker and gives control over what species are planted although the choice may be somewhat limited. If the trees are not local to the area they may bring new plant diseases with them. Planting may be both costly and labour intensive with the trees requiring unsightly stakes and guards, and they may require careful watering and weeding for the first few years until well established.
In the 20th century following the devastating loss of the nation’s Elm trees to the imported Dutch Elm disease the government promoted new tree planting, so what became of it? In short the trees failed to thrive:-
Plant a tree in ‘73
Plant some more in ‘74
Still alive in ‘75
Dead as sticks in ‘76
Natural regeneration can be slower to establish and care must be taken to remove any alien invasive species such as Sycamore, however the emerging scrub will provide valuable, diverse wildlife habitats in which declining species such as nightingales may thrive. Survivability will be good in the long term with the scrub gradually transitioning into mature woodlands from which future generations may benefit. Much of this work is currently being pioneered on the Knepp Castle Estate in Sussex.
Making a choice
Whichever method is used to establish new woodlands there needs to be clearly defined objectives about what this tree planting is supposed to achieve. Is it to be a commercial timber crop that may be used to produce renewable energy wood pellets or is it to be part of a rewilding scheme managed to benefit biodiversity in the future? Each will sequester carbon and both have their advantages and disadvantages, it is however essential to decide which route to follow before embarking on such a project.
Tim Brayford Landscapes were established in 1980 and we are British Association of Landscape Industries National Award Winners for Garden Design & Construction. For more photos, advice & stories about gardening please visit our website email firstname.lastname@example.org phone 07890 869918