Projeto Educa??o: professor responde quest?es sobre polaridade e química organica
Leaves_turn_brown_early_as_drought_impacts_Yorkshires_woodlands.txt
'The gaiola bingoimpact of drought can be felt in woodlands'4 days agoShareSaveFiona CallowBBC News, YorkshireShareSaveBBCThorp Perrow Arboretum was showing signs of autumn in AugustAfter one of the warmest and driest summers since records began in 1884, trees in Yorkshire's woodlands have started to show signs of stress.Browning leaves were spotted as early as mid-August as the impact of the long drought began to become apparent.Dave Powell, living landscapes officer at Yorkshire Wildlife Trust, explained that extended periods of hot, dry weather have serious ramifications for woodland wildlife which is already "under tremendous pressure"."The unpredictability of our weather over the past few years has given wildlife far less opportunity to bounce back from periods of more extreme weather," he said.The charity looks after more than 100 regional nature reserves and reported numerous examples of nature displaying signs of strain after the long dry spell.Mr Powell is also the reserve manager at Askham Bog in York and said its ditches, normally full of water, have been almost completely dry all summer."Normally, being a bog the water table needs to be just below the surface or at surface level year round," he explained."This year, the ditches have completely dried out, to the point where you could walk along the ditches in a pair of trainers, you wouldn't even need wellies."The main pond which is the lowest point of the reserve is completely dry, and obviously this causes issues for any wildlife that might survive the summer in the wet areas."Yorkshire Wildlife Trust also manages Moorlands Nature Reserve, a seven-hectare (17 acres) woodland located five miles north of York city centre.Volunteers have witnessed trees exhibiting signs of survival including limb drop, when a tree sheds healthy branches to conserve energy. "We've lost a few large oak branches - it's to sustain the life of the tree in the long term, but it's not good for them this year," Mr Powell said."There's a risk that if it loses a branch, disease or fungus can get into the wound."Yorkshire Wildlife TrustWet wooded reserves like Askham Bog should retain moisture all year roundHe added that a lack of moisture in summer meant that trees would enter the winter months more brittle and less flexible, making them less able to withstand wind and more prone to snapping."Oak trees alone support 2,300 species, but they are at risk from a changing climate and require constant care to keep them as healthy habitat and beautiful places to visit," he added.On the edge of the Dales near Bedale, the trees at Thorp Perrow Arboretum have been displaying similar signs of stress, according to its curator Faith Douglas."The first thing we've noticed is a browning, almost like a scorched affect [on the leaves] - they look burnt, to be honest," she explained."The trees are going dormant because they need to, to preserve their energy to concentrate on their roots, to focus on the branches."This year, she noticed the effect of the hot summer across numerous species of trees on the family-owned estate, including drooping acers and conifers dropping more needles that usual.Fruit trees have also produced a lower yield than normal, impacting the wildlife that use them as a food source.Faith Douglas, curator at Thorp Perrow Arboretum, said nature is resilientHowever, Ms Douglas said that she was hopeful that the specimens in the arboretum could find a way to adapt and autumn could progress as usual."Nature's amazing, I think it's resilient and it knows what it's doing," she added.Experts are warning that the chance of a hot, dry summer in the UK is increasing.The top five warmest summers on record have happened since 2003, according to Paul Hudson, BBC Look North's climate correspondent. "This year, we've now had the warmest spring on record, now the warmest summer on record and never before have we had two seasons following each other, both of which were record-breaking," he said."It's even more evidence of a warming climate."Wetter weather over autumn and winter won't necessarily be the solution for a prolonged period without rainfall either.According to Mr Powell, although wildlife "may have struggled through", next year could be when more issues present themselves.He noted that one repercussion can be that plants will have had less chance to reseed and repopulate, giving them a disadvantage when spring arrives.This can also leave soil exposed and more susceptible to erosion, especially in reserves with open spaces, such as Allerthorpe Common near Pocklington or Dearne Valley Country Park in South Yorkshire.The country has just experienced one of the warmest summers since records began according to the Met OfficeHis advice was that people should explore ways to play their part, however small, in supporting nature to thrive."Nature can cope, but it's when it starts getting really sustained, but anything anyone can do to help the environment is good," he said."It's that patchwork effect, if we all do our little bit, everything is going to add up."Yorkshire Wildlife Trust's autumn appeal seeks to raise awareness about the management needed to maintain its woodland, and mitigate some of the risks. The charity takes care of combined area of woodland that spans nearly twice the size of Sherwood Forest, and provides a home for rare species including lesser-spotted woodpeckers, Nathusius' pipistrelle bats and pied flycatchers."A lot of people really connect with woodlands, and they are a really important habitat, especially in dry times as they provide shade for wildlife," Mr Powell added. "Yorkshire's woodlands are already struggling from lack of mixed and older habitat, disease, and minimal management. Now is a good time to get the message across." Listen to highlights from North Yorkshire on BBC Sounds, catch up with the latest episode of Look North.Related Internet LinksThorp PerrowYorkshire Wildlife TrustMore on this storyLeaves falling, berries ripe, but it's hot. Is autumn coming early?Reservoir level fall exposes bridge for first timeYorkshire seas set to break temperature recordsAskham RichardBedaleClimate
