Reduced run and "dead" trees after warm spell?

[BSD]

About 2 weeks ago we had some record high temps, 74 degrees and then nothing freezing for a week and a day. I pulled tanks to clean and then when we got a cold night i replaced tanks after it started running. that day i collected 1/10 what i normally would collect. Since then it has been trickling in, like 30 gallons in 48 hours from 125 taps. I went on a hike and found a few clogs, i replaced T's where necessary and put the system back together (3/16 natural vac, 2nd year for tubing with 5/16 drops, new 5/16 taps). 4 of my lines run at 27" of vac when running peak performance. the last one runs about 20" on this particular woods. after the first slow run i drilled a new tap-hole in a tree on a line that wasn't running to gauge if my tap-holes were dried up and that new hole didn't run either. I was able to get it run a little if i put some vacuum on it by sucking on a drop line though. Fast forward to today . we just had that huge Nor'easter come through and went through a big temperature swing, pressure changes, etc. I went to check the woods after plowing today and found that one line running pretty well, half of another line is barely running and the rest are just flat-lined.

my trees are 100% sugar maples on a big hill with filtered sunlight. I can't get my head around why the line right in the middle of woods is running very well and another line right next to it is totally dead. Does bacterial back-flow trigger a systemic shutdown on the tree and line?

I tapped a smaller woods after the big heat-wave on much less elevation drop 1/4 mile away and it's running slowly. Other producers in my area are still running on tree's that were tapped earlier than these, but definitely slowing down as well. most of mine on this woods are just seemingly dead though.

[maple flats]

When you are on vacuum tubing the taps will not dry up for 4-6 weeks on the short side and 10-14 weeks on the long side. If the taps were new, and sanitation was good, 74 degrees will not dry them up.
Have patience, the sap will flow when the trees are again ready.

[wnybassman]

I had something similar go on last week here. After a night with a slight freeze, two of my lines didn't have a drop in them, and the rest were all running halfway decent. Not a ton of sap, but I thought if most were running that good that day, even buckets, then why would two be dry like that? A couple days later, another slight freeze, and those two dry lines were running that day, but one other was not.

Not sure what to tell you about my findings other than we really need good freezes and good subsequent runs!

[Michael Greer]

A slight freeze isn't enough. 20 or 25 degrees is perfect.