So, it's been a little over a year and a half since i joined this forum and posted the question above, and i thought that i'd post a quick update just in case anybody has any further thoughts before i move on to my next question (in another topic) ;-)
I ended up purchasing 50m of a Beal Industrie 11mm low-stretch rope, and that's what i've been using ever since. I've been climbing recreationally with relatively frequent use over 1--2-months-long periods of time with long breaks in between, inspecting it every once a week, or before the next use (whichever came later). It's worked fine so far, and it shows very little signs of wear besides some very minor fraying, and smudges from rubbing against the trees.
Last Summer i decided to cut those 50m in half during my cycle tour in order to reduce weight and volume, and that's what i've been climbing with since then. The main disadvantage so far is that i sometimes need to rappel in more than one stage, and accordingly plan my route down the tree very carefully. But it has otherwise worked fine for recreational tree-climbing --- i've actually enjoyed the puzzle (and often times extra workout) coming from working with a smaller piece of rope!
In the near future i plan to invest on a bonafide, 60m-long or so arborist rope following some of your recommendations to use with my "stationary" tree-climbing kit, leaving the 25m of the Beal Industrie 11mm to use with my "travel" kit.
@TimBr i'm a big fan of the climbingarborist.com videos as well --- thanks for sharing your story
@iclimbtreesbro When i cannot "free climb," my main ascension method is what i understand to be the DRT --- i tie myself in to a prusik loop, attached to the doubled rope with a prusik knot or klemheist, which i find easier to untie with only one hand, and a "footloop" sling clipped to a second prusik, to which i also tie myself in with another locking carabiner as a backup. I use 6mm accessory cords for the prusiks, but i'm thinking about switching to 7mm following the guidelines in Jeff Jepson's
Tree Climber's Companion. Once i'm "on the tree," i try to "free climb" as much as possible, advancing my tethers as i move along. I currently use a daisy chain and a multi-chain that i clip to girth-hitched slings, and whose lengths i adjust so it's always as stretched as possible. (I want to switch to lanyards, but i'll develop on that in a separate thread.)
Thank you all once again, and looking forward to talking more tree-climbing with you!
Cheers,
Mika