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SPECIALIST TREES

Wetlands

our future needs them

Mark Hinsley reminds us that our countryside is not always natural – and the role of wetlands is essential for balance in nature For thousands of years our countryside was our larder and our DIY store. Just about every last scrap of southern England that was not in a town or village was under some form of production management, be it wood products, foodstuffs or live-stock. One key element of bringing all this lowland into useful production was land drainage, because prehistoric England was a pretty boggy place! Now, all you keen gardeners out there are fully aware that one grows different plants in a wet garden from those one can grow in a dry one; the same is true of the countryside. As more and more land was drained to give a deeper soil for crops or a drier environment for animals, so the wetland plants dwindled in numbers and the dryland plants increased. Ultimately, we ended up with the countryside we have now, populated to a large degree by ‘native’ trees and shrubs, but not necessarily locally indigenous, because the trees and shrubs out there now are growing in an artificial environment with a deeper, drier soil than originally existed before our ancestors came along and installed land drains. Over a long period of time a whole ecosystem of trees, shrubs, ground flora and wildlife has built up to populate these artificial conditions. Artificial conditions that the majority of us consider to be our natural countryside. So why mention this now? I have been doing quite a lot of tree liability and condition surveys on agricultural land recently. In the course of these surveys I have seen a significant number of big old-field boundary oaks looking very sorry for themselves; some have been almost dead and one or two have been blown down. In each case the ground around the trees has been very boggy with reeds showing up amongst the grasses and, when I inspect the edge of the field, completely silted up ditches. 56

These trees had grown strong and healthily for 100 to 200 years in deep well drained soil, created for them by an efficient well-maintained ditch system. However, over the last few decades, ditch maintenance has ceased, and the system has gradually failed. Without functioning land drainage, the ground is returning to its natural marshy state; and oaks don’t survive in wetland. Because of these huge areas of unnaturally dry ground, our ‘dryland’ wildlife is generally quite plentiful, whilst our ‘wetland’ wildlife is scarcer. In my experience, conservationists are usually pretty keen to support schemes that include the creation (or recreation) of wetland, because so many wetland creatures and plants are on endangered species lists. When these wetland schemes are produced and promoted they also receive much public support. Land drainage, by its very function, speeds up the passage of rainwater through the ground and into the river systems, whilst wetland holds it up and slows its progress; this has plus and minus issues for downstream flooding. For the above reasons, wetland can be a ‘good thing’. However, what many people do not understand is that wetland, whilst it may be a ‘good thing’, is also a very different thing. Wetland is the home of willows and alders, not oaks and beeches. With so few people working the land, ditch clearance is an expensive, mechanical task which some landowners of marginal agricultural land are not doing. So, gentle reader, if we do not maintain our land drainage, the countryside we know and love is going to look quite different in the future, but is that a good or a bad thing? Mark Hinsley is from Arboriclture Consultants Ltd. www.treeadvice.info

Country Gardener

Devon Country Gardener April 2018  

The April 2018 issue of Devon Country Gardener Magazine

Devon Country Gardener April 2018  

The April 2018 issue of Devon Country Gardener Magazine

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