The freeze-thaw swings finally showed up, which means one thing: the sap is running. Maple season in northern Illinois is short and it's started early this year.

What I'm reading

• How to tap a maple in your own parkway — the Morton Arboretum runs a sugaring program every winter, and their how-to is the clearest I've found. Silver and box elder maples count too, not just sugar maples.
• North Park Village Nature Center events — they host a maple syrup festival most Februaries. Worth it just to taste box elder syrup side by side with sugar maple.
• The chemistry of why sap runs — pressure, not gravity. I think about this every time I drill a spile.

Field note

Tapped two box elders behind my building. Forty parts sap to one part syrup means a lot of boiling on a hot plate and a very steamy apartment. My neighbor asked if I was running a humidifier. Sort of.

If you tap anything this month, reply and tell me what tree.

— Jenna