"Science has not shown that Pa can overwinter 25 dpsm statewide without impacting the regeneration."
Several areas have shown it possible to have far more than that. Here in Pa and in surrounding states.
Also "impacting" is very open to interpretation. Some like to refer to any nipped leaf that can be noticed as "impact" (see habitat tour).
One mans "impacting" is another mans "no significant unacceptable effect".