You're dealing with deadwood above you and shock-loading from rigging. Look over the whole tree to identify hazards.
Throwlines are your friend. Pull on loose hangers and break out weakly attached wood and watch/ listen/ feel the tree react from shaking before rigging on it.
Pretensioning, positive and negative rigging reduces shockloading, such as with a Rigging Wrench for light weights and GRCS/ HOBBS/ Stein bollard with winch/ etc lowering devices. Stretchy ropes reduce shockload (polydyne, for one example)
When rigging, make a plan between the cutter and roper of what is supposed to happen when everything goes to plan.
Make a plan between the cutter and roper of what to do if something goes wrong, such as the piece breaks off earlier than expected when rigging to swing sideways and downward. If the plan is to keep lowering the piece steadily to the ground, and it prematurely breaks in a different location where continuing to lower will put the rigged piece directly into a fork, the roper have to know to steadily decelerate the rigged piece to a stop much earlier.
What should the roper do if the rope gets fouled, snagged or redirected by a limb? What if the cutter get caught in the "bite" (sp?)?
In the spring of this year, a heavily-loaded rigging rope snagged my carabiner saw hook (a paddle biner with the gate taped open, a la a Caritool and Shembiner combo, can be used with and without the gate, but pre-dating them) when the rope took an unexpected path past me, due to premature breakage from decayed heartwood, and was running through ithe saw hook, pulling on me a bit. It was the first day of warm, sunny weather and I was in short sleeves. I got some rope burn on my arm. Not much, but it was a lesson learned...clothing definitely can be protective.