<tans love to talk weather, and the native and adopted Minnesotan population at Carleton is no exception! This last week has been one of changing seasons as we’ve moved from late-summer into what is surely autumn, complete with sunset foliage, the final flowerings of the asters in the prairies and migrating waterfowl. Some notes as we move into the fall season:
– Green husked walnuts are dripping off the native black walnuts (Juglans nigra). The dark brown dye that leaks from the husks, turning local roadside puddles black, has been used as a natural coloring, and sometimes gives away a squirrel’s nibbling habits! The gray squirrels (Sciurus carolinensis) in the Arb and around campus are busy caching their winter stock of nuts. Each squirrel will bury thousands of nuts, using spatial landmarks to relocate many during the infertile winter months. This caching activity is equally important to the walnuts, who benefit in recruitment of those nuts forgotten by the squirrels.
– The fall equinox has come and gone (September 22), but characteristic fall weather only arrived in Northfield this last week. While this has been a cool year overall, we have not set any chilling records despite a few cold nights. The median date of the first fall frost (nighttime temperature below the freezing point of water, 32F) over the last 50 years in the Northfield area is September 29. Our first frost this fall was early in the morning of Saturday, October 4th. In fact, thus far, it has been a balmy fall compared to the historic mean fall temp (Sept through Nov) of 44-48 degrees. Local weather data can be found at the Minnesota DNR website.
– Upcoming activities in the Arb include a Volunteer work day on Saturday, October 18 to clean up Buckthorn Menace, an Arb Tour led by Professor Mark McKone during Parents’ Weekend (Saturday October 18), and a fall Mushroom Field Trip on Saturday October 25.
If you are interested in these activities or others, please contact Director Nancy Braker or check out the Arb website.
