I bought a house three months ago with a medium size maple tree. There was a branch cut before me that was not according to the three point cut. I see the color of this branch's collar to be different than the tree body. Is the tree infected? How can I improve its condition?

It suffered an injury and a messy trim, but I don't see signs of "infection". Keep an eye on it and trim off any branches or stumps that are clearly dead.

See Alex Shigo's abpit his CODIT (compartmentalization of decay in trees) model, to visualize how that cut stob will decay further over time, and how the live stem it's attached to will heal around it.

Thank you for your responses.
The tree looked healthy in the late fall when I moved in. It didn't have any dead branches. For the messy prune that was done on this tree, does one of the following help the tree to seal the damage faster?

1) Cut the already pruned branch down to the collar?
2) Use pruning sealer spray on the tree ? Or another product?

I'd just do #1 and not #2. The tree is young, if the stobb is cut flush with the root collar, the collar tissue will grow around the cut surface and cover it over time. The cut will start to decay, but because the tree is young and healthy (looking) the decay won't move very far into the healthy wood (see CODIT to visualize this.)

As for sealing the cut surface, don't bother. It would make no difference.

I didn't mean "root collar". I meant the collar at the live tissue on the lower branch!

At this point, there is no branch collar to worry about. The branch collar Shigo talks about is dead on your tree. That's OK. If you want to know about what a branch collar is, look on a live branch to learn.

I think what greenriverfs is saying (and I concur) is cut the dead part flush with the encircling rolls of growth. (That is where the tree is attempting to grow over and enclose the dead area.) Don't leave any jagged surfaces where water will collect and encourage rot. Your goal is to keep the area naturally as dry as possible. Painting is only advantageous for a few certain trees for specific purposes (not healing), and is not advantageous for maples.

Leftwood said: At this point, there is no branch collar to worry about. The branch collar Shigo talks about is dead on your tree. That's OK. If you want to know about what a branch collar is, look on a live branch to learn.

I think what greenriverfs is saying (and I concur) is cut the dead part flush with the encircling rolls of growth. (That is where the tree is attempting to grow over and enclose the dead area.) Don't leave any jagged surfaces where water will collect and encourage rot. Your goal is to keep the area naturally as dry as possible. Painting is only advantageous for a few certain trees for specific purposes (not healing), and is not advantageous for maples.

Thank you very much for your help. Just to be clear, which one of these cuts should I perform? I think red and blue will make the cut surface exposed to rain water. I am in California where it still rains here. Should I do the almost vertical cut shown by yellow?

The most vertical cut would drain best, yes, but it would also expose a larger cut surface area, probably requiring a longer time for the wound to heal over. The middle (red line) would drain well enough and the cut surface area would be less - and that's the cut line I would favor.

But as Leftwood says, it is important not to leave a jagged surface. The new healing tissue should have a path of least resistance when growing over the cut surface.

Go ahead and do it. The tree will be fine. Maples heal easily, especially when young.

greenriverfs said:
it is important not to leave a jagged surface.

Thank you very much! One more question: How can I make a smooth cut? I use a Corona, 10inch folding saw for tree pruning. Is there a better tool? Does an electric mini chain saw be better for this cut?

I agree with greenriverfs.

I would just stick with the handsaw. Although you could use either, handsaws naturally make smother surfaces. Some large grit sand paper might be useful to smooth out a rough surface. Or a file if something large is jutting out.