My time in the Southwest supports the notion that ponderosa pines have remarkable decay resistance in part due to their extractives and in part due to the remarkably dry climate of the Southwest. I know there are papers out there on how long, but I can't recall them off the top of my head.
I can however provide some anecdotal information. My first year as a GS-3 Forestry Aide with the BLM in eastern Oregon, I served on a survey crew doing Original Corner Restoration. Using K & E Mountain Transits like the original surveyors used in the 1880's, with declinations corrected to match them, we used the original survey notes to as close as possible duplicate their survey line...many times we found their original Bearing Trees, and with the notes were able to identify original corners, (scribed rocks, preferably tall, four-sided rocks, scribed on each of the edges to assign location). We occasionally found their intermediate chaining points (a branch lopped off at an angle at one end, stubbed off at the other, then hammered into the ground for distance measurement points) still intact. Most remarkable, we occasionally would find planks the surveyors had fashioned to practice scribing the numbers and letters on Bearing Trees (such as SEC 1, T3N, R8E).
That was 1967, some 80 years after the passage of the original surveyor. When they actually did survey the sections they were assigned. But that's another story...; > }
It was a wonderful job for a guy starting out his career in Forestry, first time away from home, staying in remote government cabins for a week at a time, all in John Day River country.
Don Bertolette - President/Moderator, WNTS BBS
Restoration Forester (Retired)
Grand Canyon National ParkBJCP Apprentice Beer Judge
View my Alaska Big Tree List Webpage at:http://www.akbigtreelist.org