Woodland Trust : Preserve Ancient Forests
The Woodland Trust and Climate Change
The Woodland Trust's remit includes working to preserve ancient woodland, land continuously wooded for at least 400 years and often much longer. It is home to more threatened species than anywhere else in the UK, and is of great cultural and environmental importance. In 80 years nearly 50% of our ancient woodland has been replanted with conifers or lost for ever to agriculture or development. Today it accounts for only around 2% of the UK’s land, and most (85%) has no legal protection. Bluebells are typical of ancient woodland. Britain’s bluebell woods are internationally important, accounting for about 50% of the planet’s entire population of this beautiful flower.
Each week the Woodland Trust and Ancient Tree Forum hear of ancient woods and trees being severely damaged or destroyed by road schemes, new housing, industry and other development. These woods are shown on an online map at www.woodsunderthreat.info. The site provides advice for campaign groups.
The Trust sees climate change as the single greatest threat to the remnants of our ancient woodland. Many of its rare and threatened species are strongly attached to a small locality, so it is hard for them to move from one wood to another in a highly fragmented and inhospitable landscape. With rapid climate change predicted, the future looks bleak for many rare woodland creatures. More than 232 threatened species depend on native woodland, trees and hedgerows to survive. The plants are the backbone of their food chain, while native insects, birds and other animals have evolved with native trees and are struggling to survive without the food and shelter they provide.
Over the past 30 years Nature’s calendar has provided clear evidence that spring is arriving earlier. Trees have been coming into leaf sooner, migrant birds are arriving earlier, frogspawn is being spotted before Christmas across the UK, while comma and holly blue butterflies have been sighted as early as March.
Phenology studies the timing of natural, seasonal events. It already provides some of the longest written biological records in Britain. If we continue to collect this information we can show how climate change is affecting our wildlife. It faces three major problems with climate change:
Competition between species, which may change as some respond more quickly to changing temperatures;
Synchrony between species: predator-prey links are broken as species respond differently to changing temperature e.g. great tit, winter moth and oak leaves;
Life cycles, as abnormal temperatures induce unseasonal activity that stops when normal conditions resume: for example frogspawn may not survive a return to cold weather.
Oak could come to dominate most ash-oak woodland. In the last 50 years oak leafing has advanced by three weeks, and in southern England leaves now start to emerge in late March.
Beech is particularly sensitive to summer droughts, partly because of its relatively shallow, wide-spreading root system. By the 2050s the "climate space" of beeches may be lost in East Anglia and parts of southern England, affecting other plants and wildlife that live in beech woods. But climate change could also make areas further north and west more suitable for beech.
Sycamore is responding fastest to climate change, and its large leaves shade out later-leafing native species. Hawthorn and hornbeam are coming into leaf earlier, while others like ash, beech and maple show only a small change. Some species will thrive, meaning changes in woodland composition over the next 50 to 100 years. Other species such as small-leaved lime, once a major component of woodlands, may make a comeback as the climate warms up.
The UK Phenology Network (www.naturescalendar.org.uk), a partnership between the Woodland Trust and the Centre for Ecology and Hydrology, has over 11,500 members recording signs of the changing seasons. It monitors climatic changes to find out more about its probable effect on the natural world. We need more people to do the recording to build up a picture of how Nature is responding. The Nature Detectives Club gives primary school children the chance to discover nature throughout the seasons. For more information visit www.naturedetectives.org.uk
Changes in the seasons affect more than wildlife. They also affect us. Grass pollen is the biggest trigger for hay fever, the main allergy in the UK. Many flowers are now flowering earlier and the beginning of the pollen season can alter by up to a month, depending on early spring temperature. Species flower at slightly different times, and for slightly longer, so the total pollen season is longer. Pollen production itself increases in warmer years and some plants will flower more than once, so hay fever sufferers will face even longer periods of misery.