Get a spectacular birds-eye view of the tree canopy from the suspended tree top walkway. From the enchanting flaming red Japanese Maples, to the vibrant yellow Black Walnuts, the Arboretum is an utterly magical riot of colour – best seen between the third week in October and first week in November. No leaf peeping list would be complete without the star of the autumnal colours show, Westonbirt Arboretum. To make the most of this colourful season, we’ve put together a guide to Bristol’s best parks for autumn leaf peeping:įor more outdoorsy autumnal inspiration, don’t miss our Bristol’s Best Autumn Walks blog. Under the blanket of snow, the insects that fed off the shrubs were also protected – so the battle with insects continued in these plants, making it necessary for them to color their leaves red, the thinking goes.The leaves have started changing colour and by evening, there’s an unmistakeable whiff of autumn in the air. Unlike trees, dwarf shrubs have managed to survive the ice ages under a layer of snow that covered them and protected them from the extreme conditions above. To back up this theory, the researchers offer an example of the exception that proves the rule: Dwarf shrubs, which grow in Scandinavia, still color their leaves red in autumn. Many tree species that did not survive the severe cold died, and with them the insects that depended on them for survival.Īt the end of the repeated ice ages, most tree species that had survived in Europe had no need to cope with many of the insects that had become extinct, and therefore no longer had to expend efforts on producing red warning leaves. In Europe, on the other hand, the mountains – the Alps and their lateral branches – reach from east to west, and therefore no protected areas were created. Thus the war for survival continued there uninterrupted. And, of course, along with them migrated their insect 'enemies'. In North America, as in East Asia, north-to-south mountain chains enabled plant and animal 'migration' to the south or north with the advance and retreat of the ice according to the climatic fluctuations. Many of these trees also began an evolutionary process of producing red deciduous leaves in order to ward off insects, the researchers say.
Autumn leaf red series#
During this phase, a series of ice ages and dry spells transpired, and many tree species evolved to become deciduous, dropping their leaves for winter. Until 35 million years ago, the idea goes, large areas of the globe were covered with evergreen jungles or forests composed of tropical trees, say Simcha Lev-Yadun of the University of Haifa-Oranim in Israel and Jarmo Holopainen of the University of Kuopio in Finland. It's from this premise that scientists figured out what might be going on. Some scientists have even suggested that the red colors ward off pests that would munch on the leaves if they were a more appetizing-looking yellow. They also act as an antifreeze, preventing leaf cells from freezing easily in the autumn chill. These red pigments act as sunscreen for the trees by blocking out harmful radiation and preventing overexposure to light. The red color comes from anthocyanins, which unlike carotenoids are produced only in the fall. While this process has long been known to scientists, the mechanism that results in red hues has proved trickier to understand, particularly because of the energy the tree must use to produce them at a time when the leaves are about to die anyway.
These pigments were always present in the background of the leaves' color, but can finally shine through as the green diminishes. As the green fades, yellow and orange pigments called carotenoids (also responsible for the orange color of carrots) take over. When the weather begins to turn cool in the fall, chlorophyll, which is sensitive to the cold, stops being produced.
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