Meg C's Idaho: Aspens: Facts and how to identify an Aspen tree

3 April 2020
Backyard Exploration: Aspens!

Good Day Everyone!

Todays topic of exploration was Aspen trees! Aspens are a deciduous tree species. Deciduous means to "fall off" or to "shed". In the case of Aspens they loose their leaves in the fall and winter. As opposed to Evergreen trees which keep their needles and stay green all year. A major way to identify an Aspen is to look at its bark. The bark will often be white or grayish in color and will sometimes possess a powdery substance on its surface. There are also dark linings (similar to eye shapes) at the base of branches that can be a quick identifier.

Aspen tree bark consists of layers - From the inside out: Cork Cambium (the first layer of "Bark"), Photosynthetic Chlorenchyma (Photosynthetic Cells), and another layer of dead/ dying cells.

The last layer of cells you see are typically the white powdery substance shown in the video link below. The powdery layer on the outside of the tree is formed by dead and dying cells from the layer(s) below. There are many questions surrounding this white substance and why the aspens have evolved with it rather than developing the corky, woody and thicker bark that is seen on most tree species. Although, thicker bark does develop around the base of older Aspens and in areas the tree has been damaged. A possible explanation for the powdery substance on the bark of Aspens could be to prevent sun scorch (damage to the plant from the suns radiation). Research is ongoing.

Clones and Individuals!

Aspen trees have dense underground root systems that promote shoots that turn into trees later. These shoots are genetically identical to their parent tree. Clone stands can be distinguished by their different characteristics. Ex: Difference of leaf color between aspen stands throughout the year, leaf shape and size, when leaf drop occurs, disease resistance, and bark characteristics (Ex. color may be - greenish-white, yellowish-white, yellowish-gray, or gray to almost white in color.)

Fun Fact: Pando, which means "I spread", refers to large stands of identical Aspens! How neat is that?!

Aspens can also be spread to new areas by their seed!Aspen trees are dioecious which means there is a male tree and a female tree! How cool is that?! The male tree releases pollen to pollinate the female trees. After pollination occurs catkins form (see the illustration below) and the seeds are released creating a brand "new" Aspen tree!

I have included a link to the live version of the exploration as well as some links and diagrams below about where I found information on Aspens. Feel free to check them out and build your own knowledge treasure chest on this amazing tree species.