How bad is this damage?

[brylande]

I bought my run down farm four years ago and it has some nice mature trees. One particular maple had lost a limb some time ago and has some rotting taking place where the limb once was. Is there any way I can prevent this from continuing so that the limb doesn't fall or end up killing the whole tree? I've attached a pic. Thanks for any help you can provide!

 

[treeseer]

Is there any way I can prevent this from continuing so that the limb doesn't fall or end up killing the whole tree? !

1. Check the link below for info on Mulching, Mature Tree Care, etc.

2. this won't make a lot of difference, but you could get up there on a ladder with a trowel and a hose. Scoop out, then flush out the loose decay. At the very least, this will tell you how much rot it has, and you can monitor its spread over time.
You can take a stiff brush and scrub that black stain below the wound too, so it doesn't look so ugly.

It looks like at the bottom the cut was made too close, or "flush" to the trunk. Focus on invigorating the tree so it can fight off the rot and grow scar tissue.

 

[helpmytrees]

After looking much closer at this picture, it looks like this limb or lead of the tree broke or split within the last five years or so and the tear went down well below where the cut was made to clean everything up.

Perhaps a picture of the entire canopy would help to analyse the overall health of the tree.

Also, is this tree cabled or braced in any way? Although the bark looks excluded, it looks like some structural issues could be hidden inside the stem between the rotted wound and the major fork or even lower.

You may seriously consider hiring a reputable arborist in your town.