For 20 years, I have been using threaded 3/8" white or light gray HDPE supply line for spiles: drill the hole, remove bit from drill, put spile in drill and spin it into the tree. NE Tennessee is frozen up. We are getting very little sap. While bemoaning this, it occurred to me that black "tappies" might take in enough solar energy to promote thawing the hole area. Anybody else think this might be significant? Are the metal spile and bucket guys counting on conductivity from the air to warm the tree and start a run earlier?

Lynwood Wagner
20 years putting on a maple syrup festival
15 taps, RO system
stainless pans doubling from sorghum