Disease or rot?

[StudlyHogly]

I have several Alders with a horseshoe shaped trunk at the base and the heartwood is exposed. The ones I have felled typically have a void in the trunk also. Is there a name for this?
Alder stump is not typical shape but you see what I mean.

Alder I dropped the other day, showing the same symptoms:

Standing Cedar:

 

[CincyBurner]

Old basal wounds. Wounding highlights the importance of avoiding wounds, such as from logging roads construction and injuries sustained during harvesting, that degrade log & lumber quality. Trees don't heal - they compartmentalize wounds.