i sometimes ascend SRT with a foot cam and my blakes hitch. i get my line over a likely branch, then clip the biner/spliced end of the climbing line to the standing part, and pull the rope up to the branch, a running bowline will also work. This eliminates the step of having to secure the SRT line to the bottom of the tree. to ascend; stand on the cam, advance my knot, sit down, advance the cam, repeat. every 4rth or 5th cycle i have to loosen my blakes hitch a little. Its not an ideal entry technique, the blakes is hard to advance, but if i only have 30' to climb it works well enough, and once i get up to the tie in there is no switching of gear/knots. i tie in with my flipline and then disconnect the rope from the branch it is cinched to and i'm ready to climb. (Note: it helps to firmly grab the climbing line directly below the blakes hitch, so the hitch kind of rests on your hand. This seems to keep the blakes hitch from binding up so much.)
If i'm going further than 30' or have many trees that need to be entered using SRT i replace the blakes hitch with a second ascender, much easier this way. I'm thinking of buying a mar-bar, or a double handled ascender, but ive been thinking of doing so for 5 years now
If i'm going to be in the tree for a long time i footlock up, and use a separate line for climbing on. That way if someone needs to come up and rescue my ass they can use the footlocking rope which is already installed in the tree. I use a Kleimheist (?SP) for my footlock safety.
As for descending SRT i almost always use a muenter hitch. Although if i have to go up and down SRT i use a figure 8, as it is easier to pull slack through when up climbing.
The thing to remember about SRT is that 100% of your weight is on that knot, this will cause them to bind and tighten up much more so than doubled rope techneque (DdRT).
Except for having to loosen my blakes every so often SRT doesn't affect my knots all that much.