I walked around my building around mid-day today, taking a few pictures. Most trees are starting to realize that it’s autumn, although this year it looks like there will be a lot more yellow and brown and less red and orange. Some trees haven’t gotten the memo yet, though, like this Ailanthus altissima (Tree of Heaven), whose leaves are still their summer green. It’s a weed tree around here, growing up anywhere there is unused space, often quickly outgrowing other trees. It gets quite large. According to the Missouri Botanical Garden’s web site, it was introduced from its native China into New York City in 1820 as a street tree and food source for silkworm caterpillars.