Monday, October 25, 2010

A Tree-Spotter's Guide to Fruits and Seeds: Part 4

A really good crop of beech Fagus sylvatica nuts is good news all round for wildlife, providing a food resource that lasts well into the winter. Bramblings are particularly fond of these seeds and in past 'mast years' I've sometimes seen large flocks of these finches in the beech woods at Stanhope Dene in Weardale, feasting on the fallen nuts.
















We have three tree species in the genus Acer that commonly occur in the countryside but only this one - field maple Acer campestre - is native. It grows into a small hedgerow tree. The yellow autumn foliage is attractive and the winged fruits are unmistakeable. In field maple the wings of the fruits (which, botanically, are known as samaras) are held out almost horizontally, unlike .....
... those of the non-native sycamore Acer pseudoplatanus, whose wings are swept back at an angle of about 45 degrees. Sycamore is native to the mountains of central and southern Europe but has spread throughtout Britain since it was introduced in the fifteenth century.


 
The wings on Norway maple Acer platanoides fruits are held at an angle intermediate between field maple and sycamore, at about 30 degrees to the horizontal, and they are larger, broader-winged and altogether more attractive than either of the other species. They are also very efficient fliers - my garden is infested with seedlings that have arrived as an airborne invasion from a tree upwind of us.



 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Sycamore's autumn foliage of often marred by the black spots of tar-spot fungus and simply turns brown and withers in autumn, unlike the leaves of the closely-related Norway maple whose foliage turns a clear, vibrant yellow. This Norway maple tree, photographed at the weekend growing in a crevice in a  quarry wall at Stanhope in Weardale, is testament to the mobility of the winged fruits and the dazzling autumn display that the tree delivers.

Sea buckthorn Hippophae rhamnoides is more of a shrub than a tree, although I know of some specimens of a similar height and stature to large elders. At this time of year it produces a heavy crop of these dazzling orange berries that birds seem to ignore. Sometimes the fruits just decay on the branches and on warm spring days develop a rancid, vinegar-like smell. The underside of the leaves is coated in flat grey scales, that protect the plant against excessive water loss in the windy coastal habitats where it thrives, while its vicious thorns turn it into impenetrable scrub - good nesting territory for birds.

For more posts on tree ID click here

9 comments:

  1. Another fascinating piece, Phil, thank you.

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  2. Beautiful pictures! I loved the maple samaras against the sky .. very interesting the things that you here.
    Saludos

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  3. A lot of work for you but appreciated as usual.

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  4. Great post Phil, so informative. Linda

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  5. Love it! So many things that I didn't know...

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  6. Hello Emma, I find the various ways that plants have evolved to get around fascinating...

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  7. Greetings dejemonos sorprender, we don't have a large number of native tree species here, but there are large numners of introduced trees from other parts of the world, planted in gardens, parks and arboreta.

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  8. Hi Toffeeapple,I'm learning as I go along too..

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