Silver maples not running

I live east of St. Paul and have three silver maples that I decided to tap this year for the first time in addition to my black walnuts trees. I tapped 16 walnut trees two days ago and they all started running right away, but the maples were dry when I tapped them and they still are. The maples are located in a lower ravine area on my property, which was noticeably cooler when I put in the taps on Sunday. I checked the buckets on the maples today but they are dry and there is still no sap running (the walnut trees are running very nicely). I identified the maple trees by their leaves last summer and there are also silver maple leaves at the base of the trees now under the snow so I'm pretty confident that they are maples. Two of the trees are about 14" across and the third is 24"+ across. Any insights on what may be going on with these trees would be very much appreciated. Thank you!

Ground still frozen around them?

If you're on buckets, these trees might not do much. I've given up on some silver maples after repeatedly getting nothing on buckets. Some are just that way. Get them on vacuum and they may wake up. It's probably just a bit early for them though; give them some time.

Yes, the ground is frozen in the ravine. I use buckets so will give them some more time. My black walnuts are running very nicely but as they produce much less sap than maple I wanted to give these silver maples a try. Thank you for your reply!

YEs they just haven't woken up yet. I have 50 Silvers tapped and so far have 5 gallons out of pretty much one tree. Why that one is kicking it out and most others haven't shown signs is a mystery to me. You will be fine and happy in a few days!

Great to hear @keitha333!

They are awake... finally!

Excellent! A little over half of 50 are showing life for me. Today hopefully more turn on!

Great to hear!