This uses IC2, BC, and Power Crystal's IC/BC power converter mod. I'm also using redpower2 redwire, but it isn't required.
It's "semi-automatic" because you have to re-plant manually, and then start it once the trees are grown. However, after that, you do nothing until it's done. Don't have to feed it anything - it's even solar powered.
There are 12 solar panels on top of the quarry frame, which is enough to run it pretty quickly (roughly equal to one combustion engine). The converter block has a redstone torch next to it, and deactivates the converter when the power is shut off to the torch (more on that below). You can't see in the screenshot, but there's just tin cable directly to the converter. Buildcraft sends all available power to a machine, even if it can't use it, so any storage you put in here is wasted.
There is a diamond pipe that sends wood to storage, and saplings and dirt to storage adjacent to the farm. If I built it again, it would be a 1 x N or 4 x N quarry, to minimize time spent mining leaves (but you still need enough to get saplings).
OK, so now the trees are all quarried, but quarries have a habit of going straight on to bedrock if you're not around to shut it down...
Fortunately, once the trees are all gone, there's a perfectly flat dirt area left. A quarry will always go for one of the corner blocks first in such a case.
The whole quarry has redwire around the edge, with the following arrangement in the corners. When the quarry mines the corner dirt block, it breaks the circuit, and shuts off the converter sending power to the quarry. It stores some power, so it will still tear up a row or two of dirt, but that ends up in a chest nearby and is easy to replace. The lever is what powers the detection circuit and starts/stops the farm.