OK. That makes sense. I haven't done any drilling to check depth and I haven't measured soil temps. I did go to that same tree this morning, about 8 feet away in undisturbed snow. The soil surface is frozen there. The maul bounced off like before. In some areas there is surface water from snow melt, which around here is the indicator that thesis is still frozen. One day, all the collected water we have been slogging through is just gone, and we have entered the next season in the woods: Mudtember
So how deep is the root mass that we are concerned with?
"IF the soil is truly frozen, where is the water for sap recharge coming from?"
I am thinking that when the surface is still frozen as I see here, that the soil is thawing out from the bottom up, especially in snow covered areas, and that as the lower roots are thawed they contribute sap. Around here that is just now happening.....Finally!. Yesterday many trees started running well, including the one I was pounding next to. Others are still quiet. In suburbs closer to Minneapolis, the backyard trees are reported to be running very well. Heat island effect to some extent, good snow cover in the back yards, no kids packing down the snow in the woods with snowmobiles....
In this area, really cold winters and sometimes not a lot of snow, I guess the maples root near the surface suffer and most are further down in the more moderate temperatures.
John
2x8 Smokylake drop flue with AOF/ AUF
180 taps on sacks
75 on 3/16 tubing with shurflo
Eden Prairie, Minnesota