It would be interesting to learn whether the rabbits you're observing are native brush rabbits (Sylvilagus bachmani) or introduced/released eastern cottontails (Syl. floridanus), or possibly the product of released pet (European species) rabbits.
Rabbits are obligate herbivores, so our best management strategies to immediately control damage is to block them from accessing the plants that you most want to save. A rabbit-proof fence doesn't have to be tall (2-ft is probably enough) but should be of small enough mesh (such as hardware cloth or 1" mesh) to avoid letting young rabbits to squeeze through. You also should bury the bottom of the fence at least 6", and in the best case scenario, create an outward-facing "apron" of metal fencing 6"-1' to avoid under-digging by rabbits or other small animals. Individual tree trunks & shrub stems subject to girdling (bark-gnawing) can be wrapped in hardware cloth. There are some taste-based repellents on the market, but those require reapplication due to sun & rain degradation of the product, and few have been rigorously tested for effectiveness. Finally, modifying the habitat in and around your yard to remove hiding spots provided by brushy, grass-clumpy features is a good idea.
Finally, you are allowed to hunt rabbits, so population reduction is another management route to consider. There is no closed season, but you must have a license - Lots of valuable information is available here https://myodfw.com/articles/how-hunt-rabbit You might also consider contracting with a trained and licensed Wildlife Control Operator (WCO) https://www.dfw.state.or.us/wildlife/license_permits_apps/wildlife_control_operator_contacts.asp#WCO..