Aspen
Populus tremulaAspen is a slender tree that usually grows in a close group of stems from the same roots. Its nearly round leaves hang on flattened stalks and tremble in the lightest breeze.
How to identify aspen →
Jens-Christian Svenning, CC BY 4.0
Ben Wallace, CC BY 4.0
Lookalikes
Aspen or black poplar?
Both hang their leaves on a stalk flattened side to side, so both turn in a breeze.
The quickest check
The quickest check is the leaf shape and tip. Aspen: nearly round, wider than long. Black poplar: triangular to diamond, a long fine tip. No leaves on the tree? Check the older trunk.
At a glance
| Look at | Aspen | Black poplar |
|---|---|---|
| Leaf shape and tip | Nearly round, wider than long | Triangular to diamond, a long fine tip |
| Older trunk | Cream, banded with small black diamonds | Dark, deeply cracked, with knobbly woody lumps |
Two ways to tell them apart
Leaf shape and tipLeaves
Older trunkBark
The two trees
Black poplar
Populus nigraBlack poplar is a huge, broad tree on a short trunk that nearly always leans. Its heavy branches arch out and down. The trunk is covered in burrs, woody lumps that grow out of the bark.
How to identify black poplar →
In the app
See them side by side in Treely
- Both trees, part by partLeaves, bark, buds, flowers and fruit, photographed through the year
- Every lookalike side by sideThe checks that settle it, for every pair people mix up
- A short round each dayUntil you can tell them apart at a glance
- The full GuideBoth trees written up in full, with where to find them
Free to download.
Every fact on this page is checked against the Collins Tree Guide, last in November 2026. Spotted something that looks wrong in front of a real tree? Tell us. How we check.
Photographs: Jens-Christian Svenning (CC BY 4.0), Ben Wallace (CC BY 4.0), Barry Walter (CC BY 4.0), olly_morgan (CC0), jamie-aa (CC BY 4.0), Zeke Marshall (CC BY 4.0). With thanks to everyone who shares their photographs on iNaturalist and Wikimedia Commons.