Boost growth

[tonka]

I have been doing some thinning of competition in my sugar bush, have a lot of beautiful 6-8 inch sugars with a good full canopy. How much fast can a sugar maple grow when properly managed vs left growing naturally? I know all the benefits of managing the sugar bush, just wonder on how much it can speed the trees up to be tappable trees.

[DrTimPerkins]

Growth rates of trees are dependent upon a number of factors (genetics, soil, climate, water availability, stress, competition, etc.), however one of the dominant factors affecting (reducing) growth is competition for light. By thinning you are removing that bottleneck to growth and allowing the tree to reach its maximum site potential. If the site was fairly heavily stocked (crowded) before thinning, then you should see an appreciable increase in growth over the next five years.

[Big_Eddy]

I had several clumps of regrowth where 4-5 stems were starting within a foot of each other. All were about 2" in diameter. 4 years ago as an experiment, I cut all but 1 or 2 stems per clump, leaving one clump alone. The surviving stems are now greater than 6" in diameter, except on my "reference sample" where the 5 stems are still 2" in diameter. Eliminating the competition made a huge difference over 4 years.

[unc23win]

I was reading on PMRC about fertilizing and that's what it said was no matter what leave some alone as a sample to see if what you are doing makes a difference. That's pretty cool Big Eddy. I am doing some thinning and I am looking forward to seeing some results.

[DrTimPerkins]

... I cut all but 1 or 2 stems per clump, leaving one clump alone. The surviving stems are now greater than 6" in diameter, except on my "reference sample" where the 5 stems are still 2" in diameter.

You did two things simultaneously in this example.

1. You removed the competition from the remaining stem.
2. You altered the root:shoot ratio to favor top growth. Trees typically have a narrow range of the amount of shoots (top) that are supported by roots. When you cut most of the tops off the tree, there was way too much root. Therefore the tree put most of its energy into regrowing the top and didn't need to grow any new roots. Thus it could grow the top much faster.

[tonka]

This spring I am going to be testing sugar content where there are maples growing too close together to help promote branching out on the higher sugar content trees and was thinking the other day, each year the sugar content can vary, what is an extreme difference of sugars in sap from lowest to highest?, can it very 1-2% on the extreme end or can it even be more or less?

[maple flats]

While I haven't tested many individual trees, I do test every load that arrives at the sugar house. During the main part of the season, I have had sugar % range anywhere from 2% up to 3.75% and when I get a good spike it rarely lasts more than a day or 2. I think the main point is that local daily conditions can play a major role. I don't recall at this time, but maybe the few times I got the highest readings there may have been a double or maybe even triple freeze thaw cycle overnight (cold-warm enough, then cold anf then daily warm up for instance). While I have little ability to thin my leases because the landowners retain firewood rights, as such I don't test trees. I do however point out some over crowding the the landowners from time to time, of 2 leases 1 listens the other is of the opinion that he should only cut dead, leaning or dying trees and will not cut healthy ones to thin.
I think those who can do TSI cutting in their bush are at a big advantage. On my own property I thinned about 8-10 yrs. ago, but only took the canopees into account, keeping the canopies that were better to start and are now even better from opening up 1-2 sides.

[DrTimPerkins]

...what is an extreme difference of sugars in sap from lowest to highest?, can it very 1-2% on the extreme end or can it even be more or less?

Sugar content varies annually, seasonally, and even daily. Between individual trees the sugar content can vary by 2% or more, although typically it is less than that. In general, the actual sugar content value will change, however the ranking of the sweetness in relation to trees in an area remains about the same. Therefore, it is important that when you compare tree sap sugar content, you measure it on your candidate trees within a fairly short time period (several hours) in order to get a good sense of which are sweeter.

Maybe an example would help. Take two trees, A and B, on two different days, 1 and 2.

____Day 1_ Day 2__
Tree A 2.2 2.8
Tree B 2.0 2.5

If you measured the two trees on the same day (either day), it is pretty clear that Tree A has the higher sap sugar content. However if you measure Tree A on Day 1 and Tree B on Day 2, you would incorrectly conclude that Tree B was the sweeter of the two. By measuring them at about the same time, you get a better sense of which is sweeter.

You only need to do a fairly small area and know the relationships of the trees to those around each other in order to make a decision. A tree a hundred yards away in your sugarbush won't impact your decision on which of the two trees that distance away to cut and which to leave....only the trees right next to each other matter.

[tonka]

Thanks Dr. Tim for clarifying that. Here's another question for you Dr. Tim, I have this situation in my woods as did Big Eddy, with multiple trees growing from one root system, is the sugar content ruffly the same in each trunk since it is off the same root system or is the sugar content different in each trunk?

[DrTimPerkins]

Thanks Dr. Tim for clarifying that. Here's another question for you Dr. Tim, I have this situation in my woods as did Big Eddy, with multiple trees growing from one root system, is the sugar content ruffly the same in each trunk since it is off the same root system or is the sugar content different in each trunk?

Should be pretty much the same.

[NhShaun]

I sadly don't have many maples on my 10 acres, i would say somewhere around 45 large enough to tap. There is a lot of competition out there from mostly large oaks and birches. There are quite a few(50 or so) younger maples around 10-15 years old.. I have thought about clearing out a bunch of the competition in the area but don't like killing innocent healthy trees. But i am sure if i do it now, i will be happy i did in another 20 years.

[StayinLowTech]

I tested many trees with the same goal (to cull the less sweet) in mind. Again, did them all within hours on the same day. From this small unscientific sample I found that the higher sugar content corresponded with larger size. Most trees were in the 5 - 8" diameter range and were in the range of 2.0% to 2.8%, with the higher sugar content in the slightly larger trees. For fun I tested a 30" fencerow tree a few feet away and it was 4.4%! Notice if size is the factor when you test.

[maple flats]

If you thin now, you will be happy in less than 20 yrs. if the trees have decent soil, moisture and are healthy. A tree in the 10-15 yr. age group will do well if given the sun. Don't however open them too fast. You are best off opening 2 faces (sides) at a time. Then after the tree adds the new growth to fill in the openings, at least 50%, then open another side or 2. If done too quickly the tree will generally not do as well. They need time to adapt to their new growing space.

[NhShaun]

If you thin now, you will be happy in less than 20 yrs. if the trees have decent soil, moisture and are healthy. A tree in the 10-15 yr. age group will do well if given the sun. Don't however open them too fast. You are best off opening 2 faces (sides) at a time. Then after the tree adds the new growth to fill in the openings, at least 50%, then open another side or 2. If done too quickly the tree will generally not do as well. They need time to adapt to their new growing space. Hey thanks! I will start with 1 or 2 sides in a couple areas and see how things go. I am only 25, so i have some time to wait for these babies to grow and thrive!