could disappear in thick vegetation, maybe in overgrown orchards:-). Half life of root stocks...I used to think some 10+ years. Depends on hard or soft wood, size and how needy a mapper is for features. Old Quantico maps had "ancient" (15 yrs +) root stocks, weathered down to, say, 0.5m high. And virtually no rock piles, mostly reentrant and spur and, in places, wait-a-minute vegetation.
DVOA and Quantico A meets this fall, an historical "pass in review" (old Navy OCS term). Would love to make one of them but currently undecided.
I'll probably skip both. Am course consult for Quantico so time wouldn't count there. Will stick close to home and do Ontario Champs, Half-Raid (if I can find a partners) and maybe some ROC events.
I've gotten particular about rootstocks. For me to put them on the map, they've got to be taller than me; i.e. >= 2 m.
I'd guess a 2m root stock has a useful O life of 10 years, more or less, depending on exposure to weather. We have a fallen tree/RS out back from at least 10 years ago. The soil has washed away completely but it still has the same height. Now that the roots are soil-free, I've been meaning to make it disappear altogether with a chain saw.
You have excellent Canadian options close-by. In the day, we'd didn't really have second thoughts about driving to DVOA & Quantico or ROC or the Buffalo/Toronto area. I recall getting out of the car at Elk Neck SP in MD in March of 1998 after 10 hours driving. The welcoming spring peepers were the start of a memorable weekend. The temp climbed to 80F. We were on the Chesapeake. Life was good:-).