Poplar species such as aspen can be prone to a variety of fungal diseases, including cankers, leaf rusts and poplar scab.
Aspen (Populus tremula)
Trembling, fluttering and shimmering in the slightest breeze. The rippling leaves of this beautiful tree give it its name: quaking aspen.
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This stunning tree has shimmering foliage.
Credit: Derek Mitchell / Alamy Stock Photo
Its leaves turn yellow and red in the autumn.
Credit: SCOTLAND: The Big Picture / naturepl.com
Leaves are round with large, irregular teeth.
Credit: Nature Photographers Ltd / WTML
Mature trees can grow up to 25m in height.
Credit: Daniel Romani / WTML
Aspen twigs are very knobbly in appearance.
Credit: Nature Photographers Ltd / WTML
Its leaves shimmer in the slightest breeze.
Credit: Nature Photographers Ltd / WTML
Catkins appear in March and April.
Credit: Patrick Roper / WTML
The bark is grey and often pitted with diamond-shaped pores, called lenticels.
Credit: Nature Photographers Ltd / WTML
Young leaves are a coppery colour before turning green.
Credit: Daniel Romani / WTML
Twigs are dark brown, thin and shiny.
Credit: Daniel Romani / WTML
Quick facts
Common names: aspen, quaking aspen, common aspen, European aspen
Scientific name: Populus tremula
Family: Salicaceae
Origin: native
Also known as quaking aspen, this is a beautiful tree with shimmering foliage. Mature trees grow to 25m. Older trees may be covered with lichen, which gives the trunk a black appearance, and the bark is grey and often pitted with diamond-shaped pores, called lenticels. The uppermost branches are sometimes bent over horizontally. Twigs are dark brown, slender and shiny.
Look out for: leaf stalks (petioles) which are flattened.
Identified in winter by: its twigs which are very knobbly, especially older ones. Buds spiral around and are closely pressed to the twig.
What does aspen look like?
Credit: Daniel Romani / WTML
Leaves
Round with large, irregular, blunt teeth. The leaf stalks are flattened and flexible near the leaf blade, which is why the leaves flutter so easily. Young leaves are of a coppery colour before becoming green, then turn a vibrant yellow or occasionally red before falling in autumn.
Credit: ImageBROKER / Alamy Stock Photo
Flowers
Aspens are dioecious, meaning that their male and female flowers (catkins) – which appear in March and April – grow on different trees.
Male catkins (pictured here) are brown and around 12cm long, turning yellow with pollen when ripe. Female catkins (below) start out green before developing into fluffy fruits.
Credit: Floral Images / Alamy Stock Photo
Fruits
Once pollinated by the wind, female catkins ripen to release tiny, fluffy seeds in summer.
Aspen can also propagate itself by using suckers – clone shoots produced from the tree’s root system.
Not to be confused with:
Poplar, black
Trees woods and wildlife
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Where to find aspen
Native to cool regions in the northern hemisphere, aspens grow in clonal colonies, particularly in ancient woods and heaths and also on well-drained soil near rivers. It flourishes in open sunlight and moist soil and is intolerant of shade. In the UK, it is most common in the north-west of Scotland.
These trees are most common in the north-west of Scotland.
Credit: Daniel Romani / WTML
Intro to Trees of Indiana: Quaking Aspen
The classic and trusted book “Fifty Common Trees of Indiana” by T.E. Shaw was published in 1956 as a user-friendly guide to local species. Nearly 70 years later, the publication has been updated through a joint effort by the Purdue Department of Forestry and Natural Resources, Indiana 4-H, and the Indiana Department of Natural Resources, and reintroduced as “An Introduction to Trees of Indiana.”
The full publication is available for download for $7 in the Purdue Extension Education Store. The field guide helps identify common Indiana woodlot trees.
Each week, the Intro to Trees of Indiana web series will offer a sneak peek at one species from the book, paired with an ID That Tree video from Purdue Extension forester Lenny Farlee to help visualize each species as it stands in the woods. Threats to species health as well as also insight into the wood provided by the species, will be provided through additional resources as well as the Hardwoods of the Central Midwest exhibit of the Purdue Arboretum, if available.
This week, we introduce the quaking aspen or populus tremuloides.
The quaking aspen, also known as the trembling aspen, is adaptable to a variety of soils, ranging from moist loamy sands and clay, but it is shade intolerant. It is often found on the edge of woodlands or where the site has been disturbed, giving it access to full sunlight.
This species is identifiable by its whitish to grayish bark with dark spots where the branches come out of the trunk. It has small rounded leaves with very small teeth along the margin. Like most aspens, it has long flat leaf steams that are known to flutter in the wind.
Quaking aspen is found int he northern part of the state of Indiana. This species is found from Nefoundland through Alaska in the West, and as far south as Arizona. In the Midwest, it ranges south to northeastern Iowa, northern Illinois and Pennsylvania. It is also found in some scattered areas in the Appalachian Mountains. It is the most widely distributed tree in the United States.
According to the Hardwood Lumber and Veneer Series, aspen is one of our lightest woods with a 12 percent moisture content and a weight of 26 to 27 pounds per cubic foot. It was at one time relegated to the pulp and paper industry as a weed tree, however it is now a favored species for the manufacturer of panel boards.
Full article also can be viewed with Purdue Forestry and Natural Resources News: Trees of Indiana: Quaking Aspen.
Other Resources
Aspen – Hardwood Lumber and Veneer Series
Why Fall Color Is Sometimes a Dud – Purdue Landscape Report
Fifty Trees of the Midwest app for the iPhone
Native Trees of the Midwest, The Education Store, Purdue Extension’s resource center
Shrubs and Woody Vines of Indiana and the Midwest, The Education Store
ID That Tree YouTube playlist
Woodland Management Moment YouTube playlist
Investing in Indiana Woodlands, The Education Store
Forest Improvement Handbook , The Education Store
Wendy Mayer, FNR Communications Coordinator
Purdue University Department of Forestry and Natural Resources
Lenny Farlee, Sustaining Hardwood Extension Specialist
Purdue University Department of Forestry and Natural Resources
