Eastern Cottonwood (Populus deltoides)
General Information
The Eastern Cottonwood or Plains Cottonwood (Populus deltoides) is the state tree of Kansas and can be found in riparian areas or areas near water throughout the Midwest and Eastern US (1). At FLRM the cottonwood can be found almost exclusively in the floodplain forest, especially as you near the Missouri River.
The trees are particularly large and can grow to heights of up to 120 feet tall with trunk diameters of up to 6 feet (3). The cottonwood gets its name from the mature fruit of the female trees that usually drops in May or June (1). Identifying the cottonwood can prove to be relatively easy. The main characteristic are the leaves which are alternate, simple, generally triangular in shape, abruptly pointed at the tip, coarsely toothed along their edges, and have a shiny underside (3, 4). The bark of the cottonwood is gray to gray-brown in color with deep furrows and wide flat ridges (3). If the bark is peeled away or naturally sloughing long brown fibrous string may be present. Stems when broken at nodes will have a star-shaped pith.
Natural History
Although cottonwoods can grow to impressive heights, they are not a very long-lived tree only living on average 70 to 100 years old compared to some of the hardwood giants they share the forest with that can reach ages of up to 500+ years old (5, 7).
Cottonwoods are dioecious meaning the female and male reproductive structures are found on different trees (3). Trees with female reproductive structures are the ones that ultimately produce seeds attached to the “cotton” for which the tree is named. The light and fluffy cotton aids in the wind distribution of seeds. Once on suitable growing material in direct sun seeds germinate within the first 48 hours (7). Growth after germination is rapid with favorable conditions (7).
The Eastern Cottonwood grows in riparian areas and serves to help control erosion of banks and soils along waterways thanks to their elaborate root systems (7).
One of the unique interactions that the Eastern Cottonwood has is with the Cottonwood Boring Beetle (Plectrodera scalator). This species of beetle is a wood-boring species that has cottonwoods, willows, and poplars as their host plants (6). Female adult boring beetles dig small shallow holes near the roots of host trees and use their formidable jaws to gain access to the interior of the tree where they deposit one egg per site and partially fill in the holes (6). Once larvae develop, they bore further into the tree’s roots and around the base of the tree taking around 1 to two years to fully develop into a mature adult beetle which will only live around one month after emergence (6).
Historical and Indigenous Uses
Colonial uses of the Cottonwood center around woodworking. The wood has been used for veneer and ice cream sticks (2). In some areas along waterways, cottonwoods can be used to stabilize the banks of streams.
Indigenous uses of the Eastern Cottonwood are plentiful. Many different tribes used various-sized Cottonwoods as lodge poles (5). A subspecies, the Rio Grande Cottonwood (Populus d. wislizeni) was used by the Navajo for fence posts and firewood. A chewing gum-like treat was made from the sap, and catkins mixed with various animal fats (7). A tea was from the bark made by various tribes (2)
Citations
1) Cottonwood. Kansas Forest Service. (2023, September 19). https://www.kansasforests.org/conservation_trees/products/deciduous/cottonwood.html#:~:text=Populus%20deltoides%2C%20or%20Cottonwood%2C%20the,state%20tree%2C%20occurs%20throughout%20Kansas.&text=It%20grows%20to%2070%20to,spreads%2050%20to%2070%20feet.&text=Cottonwood%20is%20a%20fast%20growing,as%208%20feet%20per%20year
2) Cottonwood. Missouri Department of Conservation. (2009). https://mdc.mo.gov/discover-nature/field-guide/cottonwood
3) Haddock, M. J., & Freeman, C. C. (2019). Trees, shrubs, and Woody Vines in Kansas. University Press of Kansas.
4) Kurz, D. R., Nelson, P., Ritter, T., Chasteen, B., & Porter, M. (2009). Trees of Missouri: Field guide. Missouri Dept. of Conservation.
5) Populus deltoides (Eastern Cottonwood) salicaceae. Lake Forest College. (n.d.). https://www.lakeforest.edu/academics/majors-and-minors/environmental-studies/populus-deltoides-(eastern-cottonwood)-salicaceae#:~:text=Yet%2C%20they%20are%20also%20known,have%20a%20good%20growing%20environment
6) Solomon, J. D. (1995). Cottonwood Borer Striking black and white longhorned beetle. USDA. https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5349693.pdf
7) Taylor, J. L. (2001). SPECIES: Populus deltoides. Fire Effects Information System (FEIS). https://www.fs.usda.gov/database/feis/plants/tree/popdel/all.html#145