Or, Are The Trees Just Over It?

Chief of Operations writes:

I really shouldn’t be trying to instruct this course, as after forty years of trying to predict the strength of sap runs, I am still only vaguely successful.

April 12/16 This week the weather seems so perfect for sap runs. Why, then, is their vigor so diminished? This same weather earlier in the season would have meant being inundated with sap. Trying to nail down what makes trees run well or not is somewhat futile, but here is my best attempt at listing some of the main ingredients.

1) Oscillating temperatures above and below freezing.
2) Other environmental factors including wind direction and amount of sunshine. North and West winds are regarded as the best, and early morning sunshine, especially after a hard freeze, is good.

A few trees were tapped low this year; this technique is controversial.
A few trees were tapped low this year; this technique is controversial.

3) Hard rain usually tends to slow a run, and, surprisingly, snow with the temperature above freezing often tends to invigorate it.
4) Age of taps (i.e. how long ago tap holes were drilled in the trees). Fresh taps always run the best.
5) A long period of very cold temperatures will usually cause a delay in the time it takes for the run to get going when the freeze finally ends.
6) Multiple days of warm weather with no freezing nights will gradually lower sap volume and quality. Each extended warm spell will have an accumulative negative impact on future runs.

Ear to the ground.
Ear to the ground.

7) Temperatures into the upper sixties and higher will severely curtail a run and extended days of this warmth will end the season regardless of what happens after.
8) Solar cycle. As April progresses, the longer days and warmer temperatures promote bud development, which ends the possibility of collecting quality sap.


Early in the season with fresh taps, oscillating temperatures are really all that’s needed for a good run. As tap holes age and are exposed to warm weather, contamination builds and the trees start compartmentalizing the wound, which closes off the sap loss. Check valve taps have been developed to counteract this problem, though I believe their effectiveness is limited.

Late in the season all the problems associated with old taps come into play, which diminishes sap run vitality regardless of how ideal the immediate weather may be. Aging taps, like people, become susceptible to decline in vigor.


bit by buie

Iced witch hobble blossom, biding its time,

2 thoughts on “Sap Run 101

  1. Hey CHOPS- what about the trees being sympathetic towards Audrey’s wrist? Anyway, hope the yield was good and we can’t wait to get a taste of the 2016 batch.

    Liked by 1 person

  2. Hi Audrey and Lew, Kay just read your blog to me and I’m very impressed with what you’ve been doing. We just learned more about your operations. love Mom


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