We recently received a photo via text of what appeared to be a snow angel created by our grandson, Louie. But this was no ordinary snow angel. The cottonwood fluff was so thick in their yard that he got down and made a cottonwood fluff snow angel, with the angel being green and the white cottonwood seeds as the outline and background.
A single cottonwood tree can produce a staggering number of small seeds each year. Estimates range from around 25-48 million. But of course, the chances of a seed becoming established and living to maturity are extremely slim.
One might look at all those seeds as a waste of precious energy, but producing lots of small seeds as opposed to a few large seeds does have its advantages. Producing lots of small seeds can increases the probability that a seed will end up on a site suitable for the plant to become established.
Small wind dispersed seeds can travel considerable distances and as such have an increased chance of colonizing new areas. Cottonwood seeds, for example, may be carried by the wind for several hundred feet, and with a little luck perhaps several miles. Those distances also help reduce competition with the parent plant and overcrowding of the species in the area. And unlike larger and less widely dispersed seeds which can be eaten up by local seed eating animals, these seeds are so widely dispersed, the various seed eating animals cannot exploit them.
So, what does it take for a cottonwood seed to successfully germinate and become established? A high percentage of the seeds are viable when dispersed, and will remain viable for a week or two. Viability, however, drops quickly after that. Landing on a moist, exposed soil with lots of sunlight is essential. Growth will be slow for a couple weeks or so, followed by a growth spurt.
So, when you see all those cottonwood seeds blowing in the wind, keep in mind that producing lots of small seeds help cottonwood get around to new habitats. And with a little luck, a few will contribute to the next generation.
