Windborne is another poem in my sugar maple cycle; when I first began working on this poetry series and thinking about trees more deeply, I came to the conclusion that trees wouldn’t obey our seasons. So I created what I thought were important ‘seasons’ for trees: Sunleaves, Deepnight, Sapriver, Budbreak, and Windborne. Windborne occurs as the trees begin to let loose their seeds (known as samaras, or helicopters), allowing for them to be carried on the wind across the land (this is known as anemochory).
In Budbreak, adult sugar maples that are at least 22 years old begin to produce leaves and flowers; these flowers cover the entire crown of the tree and contain both male and female parts. However, within a particular flower, only one sex will be functional – even though each tree will contain both sexes of flowers. Sugar maple pollen is carried by the wind from male to female flowers, fertilizing the ovules within the female flowers that will ripen into seeds over the next sixteen or so weeks. Each double samara (two wings) generally contains one seed which is ripe and ready when it turns a nice green color. Over the next two weeks, the ripened samaras will fall – leaving a pit in their coat, called the hilum, where they were once attached to the tree. The shape of the double samara and the size of the ‘wings’ allow samaras to be carried at least 100m!
Seeds are packed with their own food source (the endosperm) to help fuel the plant embryo’s growth. The embryo has several important parts – the plumule (rudimentary shoot), a radicle root that will emerge first upon germination to reach water through the leaf litter, and the first leaves, or cotyledons. In sugar maples (dicotyledons) there are two of them, which I wrote more about here in the Biopoetics for my poem “Dicotyledons”. Seeds typically have only a year to germinate before losing viability so it’s critical they land in a welcoming, wet environment. Seeds that are carried by the wind to extremely dry areas, rocks, or other inhospitable places will likely never germinate – which is why adult trees produce so many samaras. One year in Michigan, 8.56 million samaras/acre were recorded!
Check out the link of the photo, where the photographer has provided a few more maple seed facts in the description!