When autumn leafturn starts near equinox in the Midwest, the deciduous trees are bare in northern Canada. In Oregon and Maine, foliage colors are approaching their best. In the Rocky Mountains, bull elks are mustering their harems, and snow is falling. Along the 40th parallel, the smoky tint of last week’s canopy quickly becomes clear and bright. Now the soybean fields are yellow. Touch-me-nots are popping. Wood nettle seeds are black. Wingstem, clearweed and ironweed complete their cycle.