>>2194857I recon you could just use regular climbing slings + carabiners on the branches. If there are no branches you could probably use friction knots around the trunk using static rope and attach a carabiner to that.
But I don't think (free) lead climbing trees is very common. Most trees won't be very challenging for a rock climber. And professional tree climbers just use aid equipment and top rope set by shooting/throwing up a rope to a solid branch.
