Climate change is real. For a long time now the "window" for maple production all across the northeast (where we have the best records) was shrinking as the production season started earlier and ended earlier and the season duration was getting reduced. Seasonal total yields were decreasing very slowly as a result.
Research into how to boost sap yields and on timing of tapping showed that as long as we tapped early, used good vacuum, and practiced very good spout and drop sanitation, we could actually maintain good sap flows for 3-4 months. Yields are about double or more than they were 20 yrs ago and we have reversed the loss in season duration in a big way.
What people generally don't think about is that there are actually both fall (Oct-Nov) and spring (Feb-Apr) sap flow seasons, with a period mostly without good flows (winter) in the middle. Most producers don't tap in the fall for a variety of reasons (getting colder, lower sap sugar content). With climate change however, those two distinctly separate sap flow seasons are getting closer and closer together. Depending on how much climate warms and how fast, these will likely merge at some point....or at least be close enough so that you might be able to tap in the fall and still collect from the same taphole in the spring.
We are currently engaged (2020 will be our third year) in doing research to determine just how long we can keep a taphole viable or whether there are other strategies to rejuvenate early tapholes WITHOUT creating a second wound or making the original wound substantially wound. I will also note here that tapping above or below a recent taphole with the idea of not making a larger wound by falling within the same staining column as created by the original wound (as you might have seen or heard about) is extraordinarily difficult. We find that tapping just a few inches above or below a previous taphole can entirely miss the original stain a good percentage of the time, and that most of the time the best is that it only results in a somewhat larger wound volume. It is not a recommended practice at this time.
It's on the long side (48 min), but we have a video presentation on this on our YouTube page at:
https://www.youtube.com/watch?v=FAm5...v&index=2&t=2s
The "sapling" project is another climate change adaptation strategy. Small stems both freeze and thaw considerably faster than large stems, so production will likely be somewhat better in a warming climate.
I often think our motto at UVM PMRC should be...
Trying the crazy stuff so maple producers don't have to.