The National Trust is planning to plant twenty million trees over the next decade as part of its efforts to become a net zero carbon emitter by 2030, which it says will cost some £90m- £100m. The organisation made the announcement back in January, to mark its 125th anniversary.
By the end of the decade, it says the new trees and natural regeneration of woods will cover more than 44,000 acres, an area one and a half times the size of Manchester. It will mean that 17% of the land the National Trust looks after will be wooded, up from 10%. This is a big ask and the trees will take decades to bear fruit – thirty to fifty years of growth is realistic to achieve significant reductions of carbon.
The focus will be on planting on farmland – including in upland areas – that the Trust owns, rather than in country estates, but the director general, Hilary McGrady, said the National Trust would be working with farmers to deliver the targets. The use of cultivated farmland would seem counter productive unless it is surplus to requirements.
Keeping global warming below 1.5 °C to avoid dangerous climate change requires the removal of vast amounts of carbon dioxide from the atmosphere, as well as drastic cuts in emissions. No one knows how to capture so much CO2. Forests must play a part – locking up carbon in ecosystems is proven, safe and very affordable if volunteers are involved. Increasing tree cover has the benefit of also increasing biodiversity, but there is a quicker method than traditional planting. The Trust need an innovative approach.
Quick – forests …………….
Tiny, dense forests are springing up around Europe as part of a movement aimed at restoring biodiversity and fighting the climate crisis – Miyawaki forests. Often sited around school playing fields or alongside roads, the forests can be as small as a tennis court. They are based on the work of the Japanese botanist Akira Miyawaki, who has planted more than one thousand such forests in Japan, Malaysia and elsewhere.
Advocates for the method say the miniature forests grow ten times faster and become thirty times denser and one hundred times more bio-diverse than those planted by conventional methods. This result is achieved by planting saplings close together, three per square metre, without plastic tree guards, using native varieties adapted to local conditions. A wide variety of species – ideally thirty or more – are planted to recreate the layers of a natural forest. Birds like the nightingale and partridge, abundant at Ashridge in the fifties and sixties require dense planting for nesting, something which is now sorely missing on the Estate.
Scientists say such ecosystems are key to meeting climate goals, estimating that natural forests can store forty times more carbon than single-species plantations. The Miyawaki forests are designed to regenerate land in far less time than the seventy-plus years it takes for a forest to mature on its own. The recent removal of the coniferous plantations in Rail Copse and Frithsden Little Copse are all very well but replanting will take decades to have any significant effect on carbon reduction – the soil preparation ready for replanting has released significant amounts of stored carbon! Re-planting with single-species like hornbeam does very little to boost biodiversity and store carbon compared with mixed planting.
There are currently some fifty acres of unused land in small patches around Frithsden and Ringshall which would be ideal for small-scale Miyawaki forests. Then there is the one hundred acres of Northchurch open common which is due for upgrading now that the planning restrictions have lapsed. The present twenty year Woodland Management plan has no provision for increasing the woodland cover at Ashridge! Something for the Executive Committee to consider.