Aspen

Aspen
A Quaking Aspen grove
Scientific classification
Kingdom: Plantae Division: Magnoliophyta Class: Magnoliopsida Order: Malpighiales Family: Salicaceae Genus: Populus Section: Populus
Species
Populus adenopoda Populus alba Populus grandidentata Populus sieboldii Populus tremula Populus tremuloides

Aspens are trees of the willow family (Salicaceae) and comprise one group (section) of the poplar genus, Populus section Populus, with six species. The poplar genus, which is generally divided into six sections includes the cottonwoods and poplars as well, all of which sometimes are called poplars.

As with the poplars, aspens are deciduous, and their leaves turn bright colors before they fall. Like many poplars, the leaves have laterally flattened stems, so the breezes easily cause the leaves to wobble back and forth, giving the whole tree a "twinkling" appearance in a breeze.

Species

There are six species in the section, one of them atypical, and one hybrid.

• Populus tremula - Common aspen, trembling aspen, or Eurasian aspen (northern Europe & Asia)
• Populus tremuloides - Quaking aspen, trembling aspen, or American aspen (northern & western North America)
• Populus grandidentata: Bigtooth aspen (eastern North America, south of P. tremuloides)
• Populus adenopoda: Chinese aspen (China, south of P. tremula)
• Populus sieboldii: Japanese aspen (Japan)
• Populus alba: White poplar (northwest Africa, southern Europe, east to central Asia)
  • Populus × canescens: Grey poplar (hybrid P. alba × P. tremula)

Physical Characteristics and Identification

Aspens are all medium-sized deciduous trees reaching 15–25 meters tall, sometimes even 30 meters.

Aspens (apart from the aberrant White Poplar) are distinguished by their nearly round leaves on mature trees, 4–12 centimeters in diameter with irregular rounded teeth. They are carried on strongly flattened leaf stems, which enable the leaves to twist and flutter in the slightest of breezes.

The juvenile leaves on young seedlings and root sprouts differ markedly from the adult leaves, being nearly triangular, showing here the typical leaf shape of most other poplars. These leafs often are much larger also, being 10–20 cm long.

The five typical aspens are distinguished from each other by leaf size and the size and spacing of the teeth on the adult leaves. White Poplar leaves differ in being deeply five-lobed, covered in thick white down, and having only a slightly flattened leaf stem.

Natural Range and Distribution

File:Aspentreerangeusda.jpg

Range of aspen trees in North America

Aspen trees have the widest distribution of any native tree species in North America (Nix 2007). Worldwide, the only trees with wider natural ranges are 'Populus tremula (European aspen) and Pinus sylvestris (Scotch pine) (Nix 2007).

The five typical aspens are all native to cold regions with cool summers, in the far north of the Northern Hemisphere, extending south only at high altitudes in mountains. Populus Alba (white poplar) by contrast is native to much warmer regions, with hot, dry summers, and is native to Africa and Asia. Quaking aspen also is found in the mountains of Mexico (Nix 2007).

Populus tremloides or quaking aspen extends from Newfoundland and Labrador west acrossCanada.

Growth and propogation

Aspens are dioecious (trees are either male or female).

Aspens typically flower in March and April, prior to the appearance of the leaves (TL 2007). Both male and female trees produce catkins (slim, cylendrical flower clusters), with female catkins, after pollination, ripening in early summer, releasing tiny sees (TL 2007).

Aspen's main reproductive method, however, is vegetative, with new suckers or ramets (vascular bundles, the intra-net system of plants), growing off the roots of mature trees (TL 2007). This method can be very proflific, with numerous new shoots produced, particularly after a major disturbance such as fire (TL 2007).

All the aspens (including White Poplar) typically grow in large colonies derived from a single seedling, and spreading by means of root suckers; new stems in the colony may appear at up to 30–40 m from the parent tree. Each tree only lives for 20–150 years, depending upon the species.

Aspen has an extensive root system (TL 2007). Although trees live less than 150 years, the root system of the colony, on the other hand is long-lived, in some cases for many thousands of years, sending up new trunks as the older trunks die off above ground. One such colony in Utah (United States, given the nickname of "Pando", is claimed to be 80,000 years old, making it possibly the oldest living colony.

Some aspen colonies become very large with time, spreading about a meter per year, eventually covering many hectacres. They are able to survive intense forest fires as the roots are below the heat of the fire, with new sprouts growing after the fire is out. However, aspens do not thrive very well in the shade, and it is difficult for aspen seedlings to grow in an already mature aspen stand. Fire indirectly benefits aspen trees, as it allows the saplings to flourish in open sunlight on account of the burned landscape. Lately, aspen has increased its popularity in forestry, mostly because of its fast growth rate and ability to regenerate from sprouts, which makes the regeneration of the forest after harvesting much cheaper, as no planting or sowing is required.

Pests and Diseases

In the urban landscape, even properly cared-for aspen may not reach 20 years. Life spans can be shortened further by one or more of several insects or diseases that attack aspen. Fungal diseases, such as Cytospora or other cankers which attack the trunk, are common, as are diseases of the foliage such as rusts, or leaf spots. Of the many insects that attack urban plantings of aspen, oystershell scale, aphids and aspen twiggall fly are most prevalent." Remember that aspens are very sensitive to many environmental problems and are host to more than five hundred species of parasites, berbivores, diseases, and other harmfull agents. (ABOUT TREES)

Uses

The wood is white, and soft, but fairly strong, and with very low flammability. It has a number of uses, notably for making matches, where its low flammability makes it safer to use (easy to blow out) than most other woods. Shredded aspen wood is also a popular animal bedding, as it lacks the phenols associated with pine and juniper, which are thought to cause respiratory ailments in some animals. Heat treated aspen is a popular material for the interiors of a sauna. As a commercial wood product, it is of low value.

Cultural Images and Tales

The aspen tree's quivering leaves are, in Christian lore, said to be the result of arrogance at the Crucifixion because the aspen did not tremble like other trees. A German version claims that the aspen was the only tree to refuse to acknowledge the divinity of Jesus. The cross that Christ was crucified on is sometimes said to have been aspen wood.(KIDS NETWORK) As aspens do not occur in Palestine, this legend is improbable. Another old saying was that aspen leaves are made from female tongues, and their quivering is due to women's inability to stop talking.

Emigrant Basque shepherds in the 19th and 20th century carved texts and figures on aspens of the American Southwest to express their loneliness.

Aspen and its leaves have been noted and used by some of the most famous in literature.

"In the Hopkins poem there is a ‘vague fearfulness’ that is associated with tenderness and vulnerability.

In the following exchange between the Hostess and Doll in Shakespeare’s Henry IV Part Two, the extrovert and ‘swaggering’ type is contrasted with the trembling and fearful Aspen type:

• Hostess: But I do not love swaggering, by my troth; I am the worse when one says swagger. Feel, masters, how I do shake, look you, I warrant you.

• Doll: So you do, hostess.

• Hostess: Do I? Yea, in very truth, do I, an ’twere an aspen leaf. I cannot abide swaggerers.

• This is of course humorous, but we can still hear the trembling in the nervous short phrases (‘Feel, masters, how I do shake, look you, I warrant you.’).

Tennyson often refers to Aspens; they contribute to wistful Pre-Raphaelite landscapes as in The Lady of Shalott:

• Willows whiten, aspens quiver,
• Little breezes dusk and shiver . . .

But in his long poem Lancelot and Elaine, Tennyson develops the Aspen association more interestingly. The wounded Sir Lancelot is cared for by a hermit living in a copse of aspen trees:

• Then came the hermit out and bare him in,
• There stanched his wound; and there, in daily doubt
• Whether to live or die, for many a week
• Hid from the wide world's rumour by the grove
• Of poplars with their noise of falling showers,
• And ever-tremulous aspen-trees, he lay.
• Hiding away from ‘the wide world’s rumour’ when the life force is at its lowest ebb seems appropriate for Aspen. But the positive aspect of this *condition is also clearly expressed: it is in this same Aspen copse that Lancelot recovers his strength so that he can return to ‘the wide world’, to the *tragedy of Elaine’s unrequited love for him, and to the eventual transformation anticipated in the poem’s last lines (‘So groaned Sir Lancelot in *remorseful pain, / Not knowing he should die a holy man.’).

Keats is another English poet who uses the Aspen image both lightly and more resonantly. A typical and relatively ‘light’ use may be found in the third book of Endymion where the sage is described as ‘trembling like an aspen-bough’ while performing the momentous act of tearing up a prophetic scroll:

• He spake, and, trembling like an aspen-bough,
• Began to tear his scroll in pieces small . . .

Another of Keats's long poems, Hyperion, opens with a description of ‘gray-hair’d Saturn’, one of the pre-Olympian gods who fell from power when Zeus vanquished the Titans. We meet him as a ‘fallen divinity’ being consoled by the Titaness Thea, to whom he laments

• . . . I have left
• My strong identity, my real self,
• Somewhere between the throne, and where I sit
• Here on this spot of earth.
• When Thea first appears, he is so ‘frozen’ that he fails to see her
• Until at length old Saturn lifted up
• His faded eyes, and saw his kingdom gone,
• And all the gloom and sorrow of the place,
• And that fair kneeling Goddess; and then spake,
• As with a palsied tongue, and while his beard
• Shook horrid with such aspen-malady . . .’

In Tennyson’s Arthurian poem there is an association between Aspen and a wounded hero hiding from the world, but here Aspen (Keats the former medical student writes ‘aspen-malady’) is associated with something far more dislocated: a dethroned god who has ‘left his real self’. If we are haunted by irrational fears, we have surely left our real selves. Is this where the discipline of Bach flower therapy meets the discipline of archetypal psychology? These are provocative remarks which show, I hope, how the associations between flowers and ‘states of being’ made (maybe half-unconsciously) by poets can add to our experience of the conditions with which this therapy deals." (IN LITERATURE)

References

ISBN links support NWE through referral fees

• Trees for Life. 2007. {http://www.treesforlife.org.uk/tfl.aspen.html Species Profile-Aspen] Retrieved March 27,2007

Aspen Tree - One of the 100 Most Common North American Trees From Steve Nix, 2007

About Trees a NY Times Company 2007-Aspen Tree: One of 100 Most Common North American Trees {http://forestry.about.com/od/hardwoods/ss/aspen.htm ABOUT TREES] Retrieved March 27, 2007

• Kids Network Australia-Aspen {http://encyclopedia.kids.net.au/page/as/Aspen KIDS NETWORK] Retrieved March, 27, 2007
• Radboud University (RUVCB) -Virtual Classroom Biology-Vascular Bundles 2006{http://www.vcbio.science.ru.nl/en/fesem/applets/vein/ VCBIO] Retrieved March 27, 2007
• Storhaug, Glenn-Aspen in Literature {http://www.edwardbach.org/creative_Poetry_aspen2ndpiece.htm IN LITERATURE] Retrieved March 27, 2007

Credits

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• WIKICATKIN Retrieved March 27, 2007

External Links

• Aspen Information Resource, U.K.
• Quaking Aspen Forests of the Colorado Plateau
• Arbor Day Foundation
• Trees for Life
• Ecosystem of Aspens
• City of Aspen, Colorado