By Boak Wiesner
Schedules have been on my mind of late as well as the proper “times” at which things are supposed to happen. To everything there is a season, it is said, and a time for every purpose, and the cycles in the natural world continually show this. For example, I, like many people, keep phenomological lists of “first’s” for the year. Today (April 22) I saw my first 13-lined ground squirrel. I remember the first time I saw one chow down on grasshoppers half again as big as he was; I gained a whole new respect for the multi-striped little beasts.
The record-setting and unseasonable warmth of March gave way to a much more normal April, with perhaps too few of the showers that are supposed to happen. Despite that, the normal progression of flowers in the forests and fields is in full swing. Get into the woods and look for anemone and rue anemone and dog-tooth violets of various colors. Lot of folks were out along the roads and trails today enjoying spring’s abundance of blossoms on apple, crabapple, redbud, and magnolia trees
What a fitting way to spend Earth Day. Some of the west prairie area had just been burned. (Interesting to be reflecting on the prairie at a place dedicated to trees.) Shortly after a burn, nearly 100% of the biomass is in actual living material as the nutrients that have been locked up in the dead plants are released to be absorbed freshly into new growth. It’s amazing how rapidly green shoots poke up above the black – a vivid contrast! It is such a short-lived phenomenon that I know the next time I’m back all traces of the fire will be gone.
Bur oaks, the “shock troops” of the eastern forest, have bark that can stand up to the fire. Along with the dry climate due to the rain shadow effect of the Rockies, the main abiotic factor creating the prairie is fire. Once the winter is gone, last year’s dead grasses provide ample fuel for lightning-caused fires. Once European immigrants began to suppress the prairie fires, the forest moved west and, where open oak savannah might have been found, denser copses of trees began to take hold. To reflect on the fact that all together the prairie area of North America was once that largest contiguous biome in the whole world and that it was so rapidly reduced to mere fragments of its former area makes me glad that Senator Nelson had the foresight to get Earth Day started.
Boak Wiesner is a Minnesota Naturalist volunteer.