Aspen is a common name for certain tree species; some, but not all, are classified by botanists in the section Populus, of the Populus genus. [1]
Aspen is a common name for certain tree species; some, but not all, are classified by botanists in the section Populus, of the Populus genus. [1]
These species are called aspens:
Aspen trees are all native to cold regions with cool summers, in the north of the northern hemisphere, extending south at high-altitude areas such as mountains or high plains. They are all medium-sized deciduous trees reaching 15–30 m (50–100 ft) tall. In North America, the aspen is referred to as quaking aspen or trembling aspen because the leaves "quake" or tremble in the wind. This is due to their flattened petioles which reduce aerodynamic drag on the trunk and branches.
Aspens typically grow in environments that are otherwise dominated by coniferous tree species, and which are often lacking other large deciduous tree species. Aspens have evolved several adaptations that aid their survival in such environments. One is the flattened leaf petiole, which reduces aerodynamic drag during high winds and decreases the likelihood of trunk or branch damage. Dropping leaves in the winter (like most but not all other deciduous plants) also helps to prevent damage from heavy winter snow. Additionally, the bark is photosynthetic, meaning that growth is still possible after the leaves have been dropped. The bark also contains lenticels that serve as pores for gas exchange (similar to the stomata on leaves).[ citation needed ]
Aspens are also aided by the rhizomatic nature of their root systems. Most aspens grow in large clonal colonies, derived from a single seedling, and spread by means of root suckers; new stems in the colony may appear at up to 30–40 m (100–130 ft) from the parent tree. Each individual tree can live for 40–150 years above ground, but the root system of the colony is long-lived. In some cases, this is for thousands of years, sending up new trunks as the older trunks die off above ground. For this reason, it is considered to be an indicator of ancient woodlands. One such colony in Utah, given the nickname of "Pando", has been estimated to be as old as 80,000 years, [3] if validated, this would be making it possibly the oldest living colony of aspens. Some aspen colonies become very large with time, spreading about 1 m (3 ft) per year, eventually covering many hectares. They are able to survive forest fires, because the roots are below the heat of the fire, and new sprouts appear after the fire burns out. The high stem turnover rate combined with the clonal growth leads to proliferation in aspen colonies. The high stem turnover regime supports a diverse herbaceous understory.[ citation needed ]
Aspen seedlings do not thrive in the shade, and it is difficult for seedlings to establish 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, devoid of other competing tree species. Aspens have increased in popularity as a forestry cultivation species, mostly because of their fast growth rate and ability to regenerate from sprouts. This lowers the cost of reforestation after harvesting since no planting or sowing is required.
Recently, aspen populations have been declining in some areas ("Sudden Aspen Death"). This has been attributed to several different factors, such as climate change, which exacerbates drought and modifies precipitation patterns. Recruitment failure from herbivory or grazing prevents new trees from coming up after old trees die. Additionally, successional replacement by conifers due to fire suppression alters forest diversity and creates conditions where aspen may be at less of an advantage.
In contrast with many trees, aspen bark is base-rich, meaning aspens are important hosts for bryophytes [4] and act as food plants for the larvae of butterfly (Lepidoptera) species—see List of Lepidoptera that feed on poplars.
Young aspen bark is an important seasonal forage for the European hare and other animals in early spring. Aspen is also a preferred food of the European beaver. Elk, deer, and moose not only eat the leaves but also strip the bark with their front teeth.
Aspen wood is white and soft, but fairly strong, and has low flammability. It has a number of uses, notably for making matches and paper where its low flammability makes it safer to use than most other woods.[ citation needed ] Shredded aspen wood is used for packing and stuffing, sometimes called excelsior (wood wool). Aspen flakes are the most common species of wood used to make oriented strand boards. [5] It is also a popular animal bedding, since it lacks the phenols associated with pine and juniper, which are thought to cause respiratory system ailments in some animals. Heat-treated aspen is a popular material for the interiors of saunas. 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).
Populus is a genus of 25–30 species of deciduous flowering plants in the family Salicaceae, native to most of the Northern Hemisphere. English names variously applied to different species include poplar, aspen, and cottonwood.
Populus section Populus, of the Populus (poplar) 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 contrast, is native to warmer regions, with hot, dry summers. These trees are all medium-sized deciduous trees ranging 15–30 metres (49–98 ft) tall.
A clonal colony or genet is a group of genetically identical individuals, such as plants, fungi, or bacteria, that have grown in a given location, all originating vegetatively, not sexually, from a single ancestor. In plants, an individual in such a population is referred to as a ramet. In fungi, "individuals" typically refers to the visible fruiting bodies or mushrooms that develop from a common mycelium which, although spread over a large area, is otherwise hidden in the soil. Clonal colonies are common in many plant species. Although many plants reproduce sexually through the production of seed, reproduction occurs by underground stolons or rhizomes in some plants. Above ground, these plants most often appear to be distinct individuals, but underground they remain interconnected and are all clones of the same plant. However, it is not always easy to recognize a clonal colony especially if it spreads underground and is also sexually reproducing.
Larix laricina, commonly known as the tamarack, hackmatack, eastern larch, black larch, red larch, or American larch, is a species of larch native to Canada, from eastern Yukon and Inuvik, Northwest Territories east to Newfoundland, and also south into the upper northeastern United States from Minnesota to Cranesville Swamp, West Virginia; there is also an isolated population in central Alaska.
The balsam poplars are a group of about 10 species of poplars, indigenous to North America and eastern Asia, distinguished by the balsam scent of their buds, the whitish undersides of their leaves, and the leaf petiole being round in cross-section. They are large deciduous trees, 30–60 m tall, with leaves with a rounded base, pointed apex, and a whitish waxy coating on the underside of the leaf; this latter distinguishes them from most other poplars. The name is derived from the pleasant balsam smell of the opening buds and leaves in spring, produced by a sticky gum on the buds which also helps protect the buds from insect damage. The balsam poplars are light-demanding trees that require considerable moisture. Balsam poplars are tolerant of very cold conditions, occurring further north than other poplars except for the aspens. The poplars in Southern California are tolerant of 100 plus degree heat. They grow along dry washes and dry riverbed's. The dry washes and dry riverbeds will have flowing water when it rains sufficiently. Their leaves hang down and are at an edge to the sun. This may be another factor why they can take the high heat. Their leaves tremble in the slightest breeze like the quaking aspen
Populus alba, commonly called silver poplar, silverleaf poplar, or white poplar, is a species of poplar, most closely related to the aspens. It is native to a region spanning from the Atlas Mountains of Africa, through most of South and Central Europe, into Central Asia; it has been introduced to many temperate, moist regions worldwide. It grows in moist sites, often by watersides, in regions with hot summers and cold to mild winters.
White poplar is a common name used to refer to several trees in the genus Populus, including:
Betula papyrifera is a short-lived species of birch native to northern North America. Paper birch is named after the tree's thin white bark, which often peels in paper-like layers from the trunk. Paper birch is often one of the first species to colonize a burned area within the northern latitudes, and is an important species for moose browsing. Primary commercial uses for paper birch wood are as boltwood and sawlogs, while secondary products include firewood and pulpwood. It is the provincial tree of Saskatchewan and the state tree of New Hampshire.
Diamond willow is a type of tree with wood that is transformed into diamond-shaped segments with alternating colors. Salix bebbiana, the most common, is a species of willow indigenous to Canada and the northern United States, from Alaska and Yukon south to California and Arizona and northeast to Newfoundland and New England. Among common names are beaked willow, long-beaked willow, gray willow, and Bebb's willow. This species is also called red willow by Native Americans according to The Arctic Prairies Appendix E by Ernest Tompson Seton.
Betula populifolia, known as the gray birch, is a deciduous tree in the family Betulaceae. It is native to eastern North America and is most commonly found in the northeast United States as well as southern Quebec, New Brunswick, and Nova Scotia. The tree is a pioneer species that is commonly found in sites following disturbance, such as fire or logging. Gray birches don't have as much economic value as other birch species but are still commonly used as ornamental trees.
Populus tremuloides is a deciduous tree native to cooler areas of North America, one of several species referred to by the common name aspen. It is commonly called quaking aspen, trembling aspen, American aspen, mountain or golden aspen, trembling poplar, white poplar, and popple, as well as others. The trees have tall trunks, up to 25 metres tall, with smooth pale bark, scarred with black. The glossy green leaves, dull beneath, become golden to yellow, rarely red, in autumn. The species often propagates through its roots to form large clonal groves originating from a shared root system. These roots are not rhizomes, as new growth develops from adventitious buds on the parent root system.
Populus trichocarpa, the black cottonwood, western balsam-poplar or California poplar, is a deciduous broadleaf tree species native to western North America. It is used for timber, and is notable as a model organism in plant biology.
Populus tremula is a species of poplar native to cool temperate regions of the Old World.
Populus grandidentata, commonly called large-tooth aspen, big-tooth aspen, American aspen, Canadian poplar, or white poplar, is a deciduous tree native to eastern North America.
Pando, the world's largest tree, is a quaking aspen clone in central Utah. The tree, an individual male clonal organism, has an estimated 47,000 stems (ramets) that appear as individual trees, but are connected by a root system that spans 106 acres. Pando is the largest tree by weight and landmass, and is the largest known aspen clone. Pando was identified as a single living organism because each of its stems possesses identical genetic markers. The massive interconnected root system coordinates energy production, defense and regeneration across its expanse. Pando is in the Fremont River Ranger District of the Fishlake National Forest along the transition zone between of the Colorado Plateau and Basin and Range in south-central Utah, United States, Pando is 0.43 miles west of Fish Lake, the largest natural mountain freshwater lake in Utah.
Ectoedemia argyropeza is a moth of the family Nepticulidae. It is a widespread species, with a Holarctic distribution.
Aspen trunk rot is a fungal disease that causes stem decay heart rot of living aspen trees. The pathogen that causes this disease is the fungus Phellinus tremulae. Most of the symptoms of this disease are internal, with the only external signs of a diseased aspen being fruiting bodies called conks. A single conk found on an aspen can indicate advanced decay of up 82% of the tree volume. Internal decayed wood of freshly cut aspens is spongy, yellow/white colored, surrounded by black zones of discoloration, and contains a distinct wintergreen smell. The fungus is spread via airborne spores released from the fruiting body which can infect through dead branches, branch stubs, or wounds in the tree. Although no direct management control is known, harvesting aspen stands that have been damaged or harvesting stands before decay becomes advanced minimizes tree loss. Aspen wood is white, malleable but strong, and heat-tolerant and therefore has many commercial uses including matches, packing paper, lumber, plywood, pulp, and animal beds. Aspen trees diseased with aspen trunk rot decrease the economic value of the lumber.
Fire adaptations are traits of plants and animals that help them survive wildfire or to use resources created by wildfire. These traits can help plants and animals increase their survival rates during a fire and/or reproduce offspring after a fire. Both plants and animals have multiple strategies for surviving and reproducing after fire. Plants in wildfire-prone ecosystems often survive through adaptations to their local fire regime. Such adaptations include physical protection against heat, increased growth after a fire event, and flammable materials that encourage fire and may eliminate competition.
Rivière-du-Moulin Ecological Reserve is a strictly protected ecological reserve in the province of Quebec, Canada. It contains a stand of mature eastern hemlock trees, with some white pines, a combination that was once common in Quebec but has almost disappeared due to forestry and farming.
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