A concern about the Arborist Splice

[Brion Toss]

Hello,
Excellent question. On some ropes, like Sta-Set-X, all of the strength is in the core. An overlap splice in that rope would have some strength, but not enough; that's why the X splice is the way it is. But in arborist and similar ropes, most or all of the strength is in the cover, and the core is there to keep the rope round. The overlap is meant to maintain constant diameter, not to contribute to strength.
Note that some arborist rope, like Fly, has all the strength in the core, even though the construction looks the same as cover-strength ropes. So as with any splice, make absolutely sure you are doing the right splice, before you pick up your tools.
Fair leads,
Brion Toss