Hours of daylight

[Dale Sparrow]

Just wondering what people's thoughts are on the correlation of hours of daylight and a tree's sap production. Seems to me that since trees go through their foliage stage according to hours of daylight that sap production/quality would also depend on amount of daylight.

[ennismaple]

Daylight tends to have very little to do with sap production. Some of the best runs are overcast nights (low pressure) where it's about 10 F above freezing.

A warm sun can get the sap started earlier on a cold morning but isn't necessary.

[DrTimPerkins]

Just wondering what people's thoughts are on the correlation of hours of daylight and a tree's sap production.

There is no good physiological mechanism which might account for there being any relationship between daylight and sap production. The only effect that could come into play would be temperature due to solar insolation being higher with longer days, but that would be quite minor and quite indirect.

The environmental and biological factors which affect sap sugar content and yield are mostly driven by the conditions which occur DURING the sap flow season and are very specific to the freeze/thaw of the tree. Outside of that time period there are some relationships between things like weather (rain, snow, temperature) and biology (stress, seed production, insects), but they tend to be fairly small in comparison and, as you might expect, there are a lot of interactions in factors so that teasing out those that are truly important can be difficult.

[Dale Sparrow]

Was more thinking about whether or not sap flows and sugar content are affected by the change of season brought on by days getting longer, as trees begin to "wake up" from being dormant in the winter months. I put out most of my taps in the second week of Feb. last year and then put out 30 more around the 10th of March. At the end of march many of the trees tapped in Feb. had weak sap flows while the taps I had put out around the 10th were running like crazy and saw strong sap flows run well into April while many of the earlier taps had dried up completely. Was thinking if I had waited till the last few days of Feb to put out all the taps I likely would have made more syrup. The runs in the last half of March were not only stronger but lasted longer as well. Stronger sun angle later in the season?

[tcross]

i'd say your taps you put out earlier had started to "dry up" due to bacteria growth in the tap hole... especially if you were using buckets! once you put a hole in the tree, bacteria starts growing and the tree will slowly start to heal that part! I don't think it had much to do with sun angle. obviously the sun is stronger later in the spring, so when a good freeze/thaw cycle happens, the sun can warm up the tree earlier and keep it thawed out longer.

[MapleTeacher]

i'd say your taps you put out earlier had started to "dry up" due to bacteria growth in the tap hole... especially if you were using buckets! once you put a hole in the tree, bacteria starts growing and the tree will slowly start to heal that part! I don't think it had much to do with sun angle. obviously the sun is stronger later in the spring, so when a good freeze/thaw cycle happens, the sun can warm up the tree earlier and keep it thawed out longer.

Question about this: If the tree was starting to heal a particular hole, would it be worth revisiting with a drill, say in early March? Not going deeper, but sort of freshening up the hole? I use buckets, too, and have found the same thing happening. Early trees had poor production during the best runs, and this makes sense as to why. Would re-drilling hurt the tree?

[madmapler]

Question about this: If the tree was starting to heal a particular hole, would it be worth revisiting with a drill, say in early March? Not going deeper, but sort of freshening up the hole? I use buckets, too, and have found the same thing happening. Early trees had poor production during the best runs, and this makes sense as to why. Would re-drilling hurt the tree? There's been some who have tried that but apparently it doesn't last long. I might try it for kicks if I only had a few taps. Some have gone with a smaller tap at first then bored to a larger one. I've heard the results were somewhat disappointing.