Aspen
Overview
 
Populus section
Section (botany)
In botany, a section is a taxonomic rank below the genus, but above the species. The subgenus, if present, is higher than the section, and the rank of series, if present, is below the section. Sections are typically used to help organise very large genera, which may have hundreds of species...

 Populus
, of the Populus (poplar) genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

, includes the aspen trees
Aspen
Populus section Populus, of the Populus genus, includes the aspen trees and the white poplar Populus alba. The five typical aspens are all native to cold regions with cool summers, in the north of the Northern Hemisphere, extending south at high altitudes in the mountains. The White Poplar, by...

 and the white poplar Populus alba. The five typical aspens are all native to cold regions with cool summers, in the north of the Northern Hemisphere
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...

, extending south at high altitudes in the mountains. The White Poplar, by contrast, is native to warmer regions, with hot, dry summers. These trees are all medium-sized deciduous
Deciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...

 trees ranging 15 – tall.

All of the species in section Populus typically grow in large clonal colonies
Clonal colony
A clonal colony or genet is a group of genetically identical individuals that have grown in a given location, all originating vegetatively from a single ancestor. In plants, an individual in such a population is referred to as a ramet...

 derived from a single seedling, and spreading by means of root suckers
Basal shoot
A basal shoot, root sprout, adventitious shoot, water sprout or sucker is a shoot or cane which grows from a bud at the base of a tree or shrub or from its roots. This shoot then becomes, or takes the form of, a singular plant. A plant that produces suckers is referred to as surculose...

; new stems in the colony may appear at up to 30–40 metres from the previous trees.
Encyclopedia
Populus section
Section (botany)
In botany, a section is a taxonomic rank below the genus, but above the species. The subgenus, if present, is higher than the section, and the rank of series, if present, is below the section. Sections are typically used to help organise very large genera, which may have hundreds of species...

 Populus
, of the Populus (poplar) genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

, includes the aspen trees
Aspen
Populus section Populus, of the Populus genus, includes the aspen trees and the white poplar Populus alba. The five typical aspens are all native to cold regions with cool summers, in the north of the Northern Hemisphere, extending south at high altitudes in the mountains. The White Poplar, by...

 and the white poplar Populus alba. The five typical aspens are all native to cold regions with cool summers, in the north of the Northern Hemisphere
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...

, extending south at high altitudes in the mountains. The White Poplar, by contrast, is native to warmer regions, with hot, dry summers. These trees are all medium-sized deciduous
Deciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...

 trees ranging 15 – tall.

All of the species in section Populus typically grow in large clonal colonies
Clonal colony
A clonal colony or genet is a group of genetically identical individuals that have grown in a given location, all originating vegetatively from a single ancestor. In plants, an individual in such a population is referred to as a ramet...

 derived from a single seedling, and spreading by means of root suckers
Basal shoot
A basal shoot, root sprout, adventitious shoot, water sprout or sucker is a shoot or cane which grows from a bud at the base of a tree or shrub or from its roots. This shoot then becomes, or takes the form of, a singular plant. A plant that produces suckers is referred to as surculose...

; new stems in the colony may appear at up to 30–40 metres from the previous trees. Each individual tree can live for 40–150 years above ground, but the root
Root
In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...

 system of the colony is long-lived, sending up new trunks as the older trunks die off above ground, spreading about a metre per year, sometimes eventually covering many hectares. They are able to survive forest fires
Wildfire
A wildfire is any uncontrolled fire in combustible vegetation that occurs in the countryside or a wilderness area. Other names such as brush fire, bushfire, forest fire, desert fire, grass fire, hill fire, squirrel fire, vegetation fire, veldfire, and wilkjjofire may be used to describe the same...

 because the roots are below the heat of the fire, and new sprouts can grow from the roots. One such colony of American aspen (P. tremuloides) in Utah, given the nickname of "Pando", is estimated to be 80,000 years old, making it possibly the oldest living colony of aspens.

Species

Some of the species in the section are:
  • Populus alba: white poplar (northwest Africa, southern Europe, east to central Asia)
  • Populus adenopoda: Chinese aspen (China, south of P. tremula)
  • Populus davidiana
  • Populus grandidentata
    Populus grandidentata
    Populus grandidentata — the large-tooth, or big-tooth, aspen — is a deciduous tree native to eastern North America.-Name:...

    : bigtooth aspen (eastern North America, south of P. tremuloides)
  • Populus ningshanica
  • Populus qiongdaoensis
  • Populus rotundifolia
  • Populus sieboldii: Japanese aspen (Japan)
  • Populus tomentosa, Chinese white poplar (China)
  • Populus tremula
    Populus tremula
    Populus tremula, commonly called aspen, common aspen, Eurasian aspen, European aspen, trembling poplar, or quaking aspen, is a species of poplar native to cool temperate regions of Europe and Asia, from the British Isles east to Kamchatka, north to inside the Arctic Circle in Scandinavia and...

    : Eurasian aspen (northern Europe and Asia)
  • Populus tremuloides
    Populus tremuloides
    Populus tremuloides is a deciduous tree native to cooler areas of North America, commonly called quaking aspen, trembling aspen, American aspen, and Quakies,. The trees have tall trunks, up to 25 metres, with smooth pale bark, scarred with black. The glossy green leaves, dull beneath, become golden...

    : American aspen (northern and western North America)
  • Populus wulianensis


Natural hybrids between species in the section include:
  • Populus × canescens: grey poplar, P. alba × P. tremula
  • Populus × hopeiensis: P. davidiana × P. tomentosa
  • Populus × pseudotomentosa: P. adenopoda × P. tomentosa

Ecology

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, since it allows the saplings to flourish in open sunlight in the burned landscape. Lately, aspens have an increased popularity in forestry, mostly because of their fast growth rate and ability to regenerate from sprouts, making the reforestation
Reforestation
Reforestation is the natural or intentional restocking of existing forests and woodlands that have been depleted, usually through deforestation....

 after harvesting much cheaper, since no planting or sowing
Sowing
Sowing is the process of planting seeds.-Plants which are usually sown:Among the major field crops, oats, wheat, and rye are sowed, grasses and legumes are seeded, and maize and soybeans are planted...

 is required.

In contrast with many trees, aspen bark
Bark
Bark is the outermost layers of stems and roots of woody plants. Plants with bark include trees, woody vines and shrubs. Bark refers to all the tissues outside of the vascular cambium and is a nontechnical term. It overlays the wood and consists of the inner bark and the outer bark. The inner...

 is base-rich, meaning that aspens are important hosts for bryophytes and act as food plants for the larvae
Larvae
In Roman mythology, lemures were shades or spirits of the restless or malignant dead, and are probably cognate with an extended sense of larvae as disturbing or frightening...

 of butterfly (Lepidoptera
Lepidoptera
Lepidoptera is a large order of insects that includes moths and butterflies . It is one of the most widespread and widely recognizable insect orders in the world, encompassing moths and the three superfamilies of butterflies, skipper butterflies, and moth-butterflies...

) species—see List of Lepidoptera that feed on poplars.

Young aspen bark is an important seasonal forage for the european hare
European Hare
The European hare , also known as the brown hare, Eastern Jackrabbit and Eastern prairie hare, is a species of hare native to northern, central, and western Europe and western Asia. It is a mammal adapted to temperate open country. It is related to the similarly appearing rabbit, which is in the...

 and other animals in early spring. Aspen is also a tree of choice of the european beaver
European Beaver
The Eurasian beaver or European beaver is a species of beaver, which was once widespread in Eurasia, where it was hunted to near extinction both for fur and for castoreum, a secretion of its scent gland believed to have medicinal properties...

.

Uses

Aspen wood
Wood
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...

 is white and soft, but fairly strong, and has low flammability. It has a number of uses, notably for making match
Match
A match is a tool for starting a fire under controlled conditions. A typical modern match is made of a small wooden stick or stiff paper. One end is coated with a material that can be ignited by frictional heat generated by striking the match against a suitable surface...

es and paper
Paper
Paper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....

 where its low flammability makes it safer to use than most other woods. Shredded aspen wood is used for packing and stuffing, sometimes called excelsior (wood wool)
Excelsior (wood wool)
Wood wool, known primarily as excelsior in North America, is a product made of wood slivers cut from logs and is mainly used in packaging, for cooling pads in home evaporative cooling systems known as swamp coolers, for erosion control mats, and as a raw material for the production of other...

. It is also a popular animal bedding, since it lacks the phenol
Phenol
Phenol, also known as carbolic acid, phenic acid, is an organic compound with the chemical formula C6H5OH. It is a white crystalline solid. The molecule consists of a phenyl , bonded to a hydroxyl group. It is produced on a large scale as a precursor to many materials and useful compounds...

s associated with pine
Pine
Pines are trees in the genus Pinus ,in the family Pinaceae. They make up the monotypic subfamily Pinoideae. There are about 115 species of pine, although different authorities accept between 105 and 125 species.-Etymology:...

 and juniper
Juniper
Junipers are coniferous plants in the genus Juniperus of the cypress family Cupressaceae. Depending on taxonomic viewpoint, there are between 50-67 species of juniper, widely distributed throughout the northern hemisphere, from the Arctic, south to tropical Africa in the Old World, and to the...

, which are thought to cause respiratory system
Respiratory system
The respiratory system is the anatomical system of an organism that introduces respiratory gases to the interior and performs gas exchange. In humans and other mammals, the anatomical features of the respiratory system include airways, lungs, and the respiratory muscles...

 ailments in some animals. Heat-treated aspen is a popular material for the interiors of a sauna
Sauna
A sauna is a small room or house designed as a place to experience dry or wet heat sessions, or an establishment with one or more of these and auxiliary facilities....

. While standing trees sometimes tend to rot from the heart outward, the dry timber weathers very well, becoming silvery-grey and resistant to rotting and warping, and has traditionally been used for rural construction in the northwestern regions of Russia (especially for roofing, in the form of thin slats).

Aspens and other members of the Populus genus contain salicylates, compounds related to aspirin
Aspirin
Aspirin , also known as acetylsalicylic acid , is a salicylate drug, often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication. It was discovered by Arthur Eichengrun, a chemist with the German company Bayer...

. Leaves and leaf buds of aspens have been used to treat burns, irritations, aches, and swollen joints. Bitter herbal tea from bark and leaves has been used to treat mild urinary tract inflammations. The Ojibwe used the inner bark of the trunk as a poultice
Poultice
A poultice, also called cataplasm, is a soft moist mass, often heated and medicated, that is spread on cloth over the skin to treat an aching, inflamed, or painful part of the body. It can be used on wounds such as cuts...

, and the Cree
Cree
The Cree are one of the largest groups of First Nations / Native Americans in North America, with 200,000 members living in Canada. In Canada, the major proportion of Cree live north and west of Lake Superior, in Ontario, Manitoba, Saskatchewan, Alberta and the Northwest Territories, although...

ate the inner bark in the spring as a mild purgative.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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