heart rot, butt-rot of hardwoods, red heart of pine i.d.

[caveman]

I am looking for general rules of thumb for high school forestry students to follow when trying to tell the difference between  red heart of pine and heart rot on pines on an FFA forestry contest.  The google image pictures seem interchangable.

Also, butt-rot of hardwoods and heart rot found in hardwoods...how do you know which to call it?  Often conks are found around the base of a hardwood tree and the inner xylem is rotten.  Even in some of the books published by forest service groups show pictures and written descriptions that seem interchangable.  Thank you for your help.
Kyle

[mesquite buckeye]

Often the location of the conks will give a hint of the location of the rot within. Basal conks could only mean there is a cone of rot from the base or it could run all the way through. Scattered conks up the trunk indicate a heart rotted tree, probably with little or no recoverable wood. Best way to find out what is going on is to salami slice up an infected tree. Then you can see the whole pattern. If you do a lot of them for a given species and area you can come up with a pretty good idea of the rot patterns with different fungi and trees.

If you want to really let them learn, I think a trip to the woods with chainsaws is in order. A good reference is Diseases of Trees and Shrubs: 1987, Sinclair, Lyon and Johnson, Cornell University Press