Aspen trees are a well-known tree type in certain regions of Canada and North America, particularly popular for elevating the appearance of the already naturally beautiful landscapes of these areas. These trees can be identified by their beautiful white bark and autumn-turned yellow colored leaves.
Scientifically speaking, Aspens trees belong to the genus populous, which is the same genus that is shared by tree types such as poplars and cottonwoods. Trees of this particular genus are easily identifiable because of their triangular, toothed leaves.
Furthermore, these trees are known to grow rather quickly, but do not live very long. Once dead, the roots of these dead-looking aspen trees keep on growing out new plants by means of root suckering. Botanists have recently discovered aspen groves sprouting from a basal rootstock dating over 10,000 years old.
Most Aspen trees don’t live longer than 5-15 years after which their roots start developing new aspen sprouts. These new suckers often grow into large trees with defined trunks, as long as they can get the required space and sunlight for growth.
Aspen trees are of numerous different types. Some of the most common ones are as follows:
- Quaking Aspen (Populus tremuloides)
- Korean Aspen (Populus davidiana)
- Common/European Aspen (Populus tremula)
- Japanese Aspen (Populus sieboldii)
- Chinese Aspen (Populus adenopoda)
- Bigtooth Aspen (Populus grandidentata)
Source: Gardening Knowhow
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Related: All types of trees
Quaking or Trembling Aspen (Populus tremuloides)
Quaking, also known as trembling aspen trees, are the most popular among their kind. These aspens are scientifically referred to as Populus tremuloides and have earned this particular name because of how they appear to flutter or tremble on windy days, even in the lightest of breezes.
These aspens, unlike most of their fellow genus species, have round edged leaves instead of the usual pointed ones with the characteristic single teeth pointing outwards. The trembling aspens are regarded as tall and quick growing trees. With a total length of around 65–80 feet when fully grown, the trunk alone can reach 8 inches to 2 feet 7 inches in diameter. The tallest quaking recorded was about 119 feet 9 inches in length and 4 feet 6 inches in diameter.
These aspens’ barks are fairly smooth and greenish-white to gray in color with wide, black horizontal markings and dense black knots across them.
The Populus tremuloides trees are indigenous to both of the two American coasts, and because of their habitat, these trees can withstand severe cold weathers, so much so that they can even grow in the harsh climate of northern Canada.
The leaves change color with the change in seasons, turning from a rich summer green to yellow in the fall. Although these trees are strikingly beautiful, they do pose a serious threat to footpaths, drainage pipes, and sewers because of their extensive root network and recurrent root suckering.
Korean Aspen (Populus davidiana)
The Korean aspen trees are scientifically known as Populus davidiana. They stand at a height of 25 m with a trunk of a diameter of 60 cm. These trees have greenish gray to white barks that are smooth for the most part of the trunk with just the basal part being rough. While their barks have a light color usually, their branches are of much darker hues, like red or brown. Korean aspens have the traditional triangular, sharp edged, toothed leaves that make them easily identifiable.
Eurasian aspen (Populus tremula)
Populus tremula, or better known as the European aspen, is one of the most spotted species of this genus. These trees cover a wide global area in terms of distribution, stretching from the Arctic region to northern Africa and ranging from Western Europe to Japan. Similar to the trembling aspen trees, the European aspen too have rounded, fluttering leaves with curvy margins. Their foliage appears to have copperish brown hues in the spring and turns to green or at times yellow in the autumn.
These aspen trees exercise quick root suckering, with new shoots and groves sprouting out of the roots of old and dead trees frequently. They also act as fodder for wild animals such as elk, deer, moose, bears, and beavers and as shelters for birds like the woodpecker.
Japanese Aspen (Populus sieboldii)
Populus siebodlii, or more commonly known as Japanese Aspen, are deciduos trees that grow at a fairly fast rate. These trees are commonly found growing on mountains all over Japan. Japanese Aspen trees grow to height of about 20m and are grown easily in a soil that is heavy and damp. These trees prefer growing in a soil that is well-drained. Japanese Aspen does not perform very well in exposed upland regions.
Japanese Aspen trees have numerous uses. The extract from the shoots is used as a rooting hormone for cuttings of all types. The wood of Japanese Aspen is soft and woolly in texture, and tasteless and odourless, having low-flammability. The wood is resistant to abrasion.
Chinese Aspen (Populus adenopoda)
The Chinese aspen, or Populus adenopoda, is a species from the genus populous. These aspen trees predominantly originate from China, and this is where they are found in most abundance, hence the name Chinese Aspen. The Populus adenopoda aspen trees are noted for being able to reach total heights of almost 30 meters, despite their growing locations, which are mostly mountainous slopes that are elevated at 300–2500 meters.
Chinese aspens offer numerous uses, with the most prominent ones being supplying wood for construction and furniture making. The timber from these trees also helps in the manufacturing of farm tools, carts, and wood pulp.
Bigtooth aspen (Populus grandidentata)
The bigtooth aspen, or Populus grandidentata, are deciduous trees with limited growth and distribution region compared to the other aspen species. These trees are chiefly found in parts of northeastern and north-central America, as well as in southeastern Canada. Populus grandidentata also goes by other names such as the large-tooth aspen, American aspen or white poplar.
This species gets its name “bigtooth” from its relatively larger teeth on the leaves as compared to the teeth on the leaves of other aspen species’ trees. The name Populus in the species’ genus is in Latin and means poplar in English, while grandidentata refers to the uneven and rough teeth on the leaves, where grandis means “large “and dentata means “toothed.” The barks of these trees are thin, olive-green colored, and smooth when they are young. On fully developing, after 30–40 years, the barks turn gray, thick and rough with knots and grooves.
The wood from these trees is light-shaded, fine-grained, straight-textured, and soft. It is mostly used for wood pulp, but is also seldom used for making particle boards and structural panels. Other, less common uses include pallets, log homes, boxes, chopsticks, match splints, hockey sticks, cricket bats and ladders. The bark is also often pelletized for fuel and additional cattle supply.
Habitat-wise, these trees prefer to grow in sandy soils and flooded plains. It is in such circumstances that this species grows to its full potential height and width. Bigtooth aspen trees grow predominantly in areas where they can find other species of aspens and poplars. Their foliage, as well as twigs and shrubs, feed the local wildlife. If the trees are removed from their favored habitat or location in a forest, they are quick to re-colonize the area.
Habitat and Endurance
Most of these aspen species’ trees are accustomed to cold climates and regions where even the summers are relatively cooler than in other parts of the world. They are chiefly found in the north of the Northern Hemisphere, stretching to the south in high-altitude areas such as mountains or high floodplains. These deciduous trees are mostly medium-sized aspens growing to heights of 49 to 98 ft. Some of these aspen types are identified by their unique characteristics, like the fluttering and trembling of the leaves of the Populus tremuloides trees in soft breezes. This happens because of the flattened petioles of the leaves that consequently minimize the aerodynamic drag on the trunk and branches, thus making the leaflets flutter frequently.
Poplars normally cultivate in areas that are typically dominated by species of coniferous trees, where large deciduous tree species are absent or insufficient. These aspen trees are able to thrive in such conditions because of the evolutionary adaptations that help them in surviving in such settings. One such adaptation is the flattened leaf petioles; these petioles decrease the overall aerodynamic drag on the trunks of these trees during strong winds and reduce the chances of branch or trunk breaking. Another example of their evolutionary adaptations is how these trees drop their leaves in the winters, thus helping to prevent any damages to the trees or the leaves by the heavy snowfall. Moreover, the barks of aspens are photosynthetic, which means that the trees can still grow and develop even if the leaves have been damaged or shed. Additionally, the barks also feature small pores called lenticels, like the stomata on leaves that serve as apertures for gaseous exchanges.
Aspen trees boast another unique feature – their root systems possess a rhizomatic behavior. Most of the aspen species tend to grow in large colonies of cloned and identical trees, all originating from one single seedling, spread by the root suckering technique. New stems and groves in these colonies can grow at distances as far as 98 to 131 ft from the original tree. Each of these individual trees can thrive for as long as 40 to 140 years above the surface. However, the extensive root network lives for an even longer time.
An important fact about these trees is that they cannot survive in the shade both as seedlings as well as root sprouting. Seedlings find it difficult to grow in the absence of sufficient sunlight. Another important key fact is that aspen trees can indirectly benefit from forest fires because these enable the fresh saplings to grow well in the open sunlight of the cleared landscape due to the burnt trees.
Aspens have made a name for themselves because of their immensely fast growth rate and sprout regeneration ability. This aspect of the aspen trees reduces the plantation and cultivation costs of these trees, thus making them the ideal species for reforestation since little to no planting or sowing is required for these trees.
Aspen trees and barks are considered base-rich plants because of how they are hosting grounds for bryophytes. This allows them to act as feeding grounds for larvae such as the butterfly larvae.
Aspen trees’ wood appears to be light colored in most instances, usually being white or gray and very soft but incredibly strong. This wood boasts low flammability and because of this, proves to be a very useful kind of wood. Among its many uses, matches and paper production continue to be the most dominant ones where its low combustibility makes this wood a safer option to use when compared to the other wood types.
Similarly, shredded aspen wood pieces also referred to as excelsior (wood wool), serve packing and stuffing purposes. These trees also produce flakes called the aspen flakes, which are the most widely used wood species used for making strand and structured boards as well as animal bedding. Dried out aspen woods sheets are a popular construction alternate in rural areas for rural building, particularly famous for roof thatching.
These are all the common types of aspen trees that are found around the globe. After reading this article, we are sure you will be able to identify your aspen trees easily. Happy planting!