Maple Disease? Pictures

[Dictionary]

I cut a few maple saplings growing amongst some pine behind a nearby school. Most maple i cut, the bark is very easily scraped off with a machete at right angles to the wood in winter. But with a couple of these saplings, the bark clings much tighter to the wood. After i scrape off this section, underneath there are often dark markings on the sapwood and the smell is a little foul as well when it is freshly green, smells something like ink. I have encountered this before and usually just don't use the wood but some of these saplings are good peices of wood.  I am wondering if i should not worry about it and just give it a shot. Sorry i don't know the species of maple and the pictures aren't too good but you can see the dark markings and spots running across the belly and on the back. I am guessing these are portions of dead wood, making these saplings unserviceable.

[Prarie Bowyer]

There is a beetle that can cause that or a fungal infection.  I think it's just stained and not dead. 

[Mangeur de lard]

When wood discolours like that, usually it means decay. Could be from a wound the tree had a while back that has been grown over. I don't know how much it could weaken the wood, I guess it depends on the extent of the decay. Like you say, you could always try ot and see what comes out of it.

[Dictionary]

Yea i think i'll give it a shot. Some of it i noticed is just wood discoloration and others it looks slightly like decay(i'll take a wildlife biologist's word on that), but it is mostly on the belly side of the bow and when i rough it down some, it often disappears leaving only parts of it. Hopefully it'll be alright

[randman]

If you hadn't told me it was maple, I woulda thought it was Scotch Broom. The heart wood on Scotch Broom has a kind Vanilla-Chocolate swirl look like that. Sometimes more sometimes less. If that is on the belly it might be alright. On the back.... I dunno. What kind of maple is that?