There is no stated max per tree, unless something changed in my year hiatus.
There has always appeared to be more to the resource code than the last decade's worth of Devs thought.
Essentially, there are 2 variables range for each resource square for mining, and separate ones (of similar type) for lumberjacking.
These variables are base chance for colored material, and number of digs/chops.
The number of chops (wood) and number of digs (mining) variable ranges differ for EVERY resource square, but are apparently permanent and were set at some point in the past (shard creation, most likely), though might have been modified with the launch of Mondain's Legacy. There's stories in the old days of "magic trees" seem to have indicated either trees whose # of chops took longer to reach than the reset time for the resource square, or were bugged - either of which might have been fixed as part of the coding for colored wood in ML.
The base chance for colored material is supposed to be fixed, at least by statements given by devs, but anyone who has ever mined or chopped knows better. Each square is different (and has different numbers for wood and mining). Elves have a bonus, but instead of it being a 40% chance for non elves, +20% for elves, it's whatever the resource square chance is (I've seen spots that have been reliably as bad as <10% to as good as >80%, and have remained so for a decade) for non-elves, with the base chance apparently multiplied by 120% for elves (so a 10% spot would be 12% for an elf, and an 80% spot being 96%). And, the ratio stays the same for all the ores wood, as the sites randomly shift between types; even when a mining spot is iron only, and a tool used to allow colored ore, the normal colored ore chance for that spot will express itself once the elevation occurs.
When I was resource gathering regularly, a couple years ago, some places would do as little as 6 chops/digs, and some I could get 30 from - and that's without even going to Fel, just more out of the way parts of Trammel, Malas and Ilshenar with a human. The only rule of thumb was that the closer you were to civilization in Trammel, the lower the resource output for trees, and that caves/mines/dungeons produced better ore numbers - and even then, there was occasionally an outlier (one crappy spot surrounded by great stuff, or vice-versa) if you were REALLY methodical in your searching.
This make any sense?