Sap production 7/16 vs 5/16

[Papa]

Just had some questions about 5/16 taps. I started tapping 10 years ago as a hobby with 20 trees tapped with 7/16 metal taps, buckets and lids.
A few years back I decided to expand and bought 5/16 eco taps with a piece of tubing to a bucket on the ground. Last year I was up to 50 trees and had a poor year. Low sap flow. Put it up to bad weather for sap.
This year I decided to tap 100 trees and went and bought 50 sap bags, holders and 5/16" taps. I also bought 20 plastic 5/16" taps that would hold my existing cans and lids. So I have a mixture of 50 bags, 20 cans and 30 eco taps with tubing to buckets.
That said, this year is worse than last year. My best day so far has been 40 gal of sap from 100 trees. Often only getting 15 gal or less per day.
My questions are

Should I expect significant less flow from 5/16 tap than from 7/16
Does the smaller tap hole seal sooner resulting in a shorter season once weather warms up
Is this just climate change and this is to become the new norm

Any info, suggestions or ideas would be appreciated. Thanks.

[Obidiah]

I started out with 5/16 tree saver spikes with 2 taps per 5 gallon bucket with 5/16 lines and generally collect about 20-30 gallons per tap over the season. Reds and silvers will produce less and close earlier without vacuum but sugars should do well with the smaller tap especially if you're using new taps

[Russell Lampron]

I don't know where Huntsville is but here in NH the weather hasn't been right for good flows on gravity. It's either been too cold or when it did warm up too warm. When I first started tapping I used 7/16" metal taps and buckets and then went to 5/16" metal taps and buckets. The difference in flow, if any was minimal and the season lasted just as long with the 5/16" taps. With proper sanitation I could get 6 weeks out of most of my taps.

[hogisland42]

I am not on gravity, I have vacuum, but I used to always use 5/16 taps. I switched to 1/4 a few years ago and have not seen any reduction in sap. same amount of sap with the smaller hole

[Sugarmaker]

Have been on 5/16 spiles for many years now and the weather has the biggest effect. Also the trees. As mentioned sugar maples generally produce the best.
And these are much easier on the trees, with faster healing.
Regards,
Chris

[DrTimPerkins]

See attached figure. Under vacuum there is little difference between 5/16" and 7/16" spouts. Under gravity there is a small amount of sap yield reduction. Either way there is about a 50% reduction in the size of the internal wound (compartment) created with a 5/16" spout compared to a 7/16" spout. Some of this is due to the size of the wound and the number of vessel elements in the wood that are cut, but the other effect is on the rate of sap flow out. For long flow periods, the amount of sap coming out of a 5/16" vs 7/16" spout is roughly the same. For short flow periods, less sap is able to get out of the 5/16" hole before the subsequent freeze, so a little less sap is collected. I hope that makes sense.

1/4" spouts yield about 10-11% less than 5/16" spouts at the same vacuum level. Although we hear frequently that people don't think they get less sap. Any research that has been done shows the same thing...about 10-11% less. Given that amount is within the range of year-to-year variability, most people wouldn't notice a difference...but it is there, just buried in the noise.

This assumes good sanitation practices are used.

20002

[Trapper2]

See attached figure. Under vacuum there is little difference between 5/16" and 7/16" spouts. Under gravity there is a small amount of sap yield reduction. Either way there is about a 50% reduction in the size of the internal wound (compartment) created with a 5/16" spout compared to a 7/16" spout. Some of this is due to the size of the wound and the number of vessel elements in the wood that are cut, but the other effect is on the rate of sap flow out. For long flow periods, the amount of sap coming out of a 5/16" vs 7/16" spout is roughly the same. For short flow periods, less sap is able to get out of the 5/16" hole before the subsequent freeze, so a little less sap is collected. I hope that makes sense.

1/4" spouts yield about 10-11% less than 5/16" spouts at the same vacuum level. Although we hear frequently that people don't think they get less sap. Any research that has been done shows the same thing...about 10-11% less. Given that amount is within the range of year-to-year variability, most people wouldn't notice a difference...but it is there, just buried in the noise.

This assumes good sanitation practices are used.

20002

Tim, Am I reading this chart correctly? 5/16 on gravity only produces approx. 38% of what 5/16 vacuum does? Wow!

[littleTapper]

Trapper, I believe that! I went from buckets to vac on many of my silvers and it's easily that much of an increase. I have some monster yard silvers I have to keep on buckets that nearly outperform my vac silvers - I couldn't imagine what I'd get out of them with vacuum. Wish I could do that with those. When I pulled my 3/16 line taps a few days ago, the lines were still running amazingly well despite no freeze for at least 5 days. But, after pulling the spiles, not a single tree dripped sap.