With the exception exception of SST (R.I.P.), no damage was done to any of the trails.
Anyone knowing better can feel free to correct me on this...
Most of the work being conducted is on the dirt road (2-track) coming and going from the parking lot. So, the park is closed because the only public access is being utilized for the logging. Safety/liability is always an issue, so with all the logging trucks and machinery out there, they don't want to deal with that issue (bike vs. tractor trailer = no contest).
I did go out last weekend, and the road out to the trails was in far better shape than expected.