Hello Nate,
The good news is that KSL ought to be doable for your location via digital translator K36FS-D. Your description of trees in your immediate vicinity does though highlight some problems that could result in non-reception.
First, KSL via K36FS-D is at 16.9 dB strength with a broadcast power of 284 watts and a distance of 51.1 miles. Normally, signals this weak require a more robust antenna and clear pathway for reception success. When you introduce obstructions (read - trees)to signals of this strength level, the signal may be reduced sufficiently to drop it below reception threshold.
There is a good chance this is the situation for K36FS-D.
I would also call KSL's engineering department and confirm K36FS-D is broadcasting. If K36FS-D is indeed operating normally this leaves you with some choices which we can cover later.
It may be helpful to post a picture of your antenna you are using. The forum's collective wisdom could likely identify whether it is a proper application or not especially in light of the transition to digital broadcasting.
If your antenna is a reasonable fit for your application, there are two options really - the first being play with your antenna location and try to find a spot where you get somewhat of an opening towards the NNW. The other option is to get above the trees and eliminate obstructions to the weak signal you are trying to receive. In the old days, analog broadcasts were more tolerant of obstructions. Today, in the digital television world the signal is there or it isn't. There is no "slow fade" to snow.
Thus, the best thing you can do to help us help you better is be able to provide additional information on your antenna and details of your setup such as # of TVs, splits etc.
This could mean you might need a new antenna tailored precisely for UHF signals (which is what you need) or a more involved installation requiring you to mount on a tree to clear obstructions such as this type of mount:
Cheers,
SS