MFR tree farm ---> charcoal ---> max sized high pressure boiler ---> either industrial steam engines or TE steam dynamos.
Too start, you'll need plenty of power to run the planter, harvester, and furnace until the boiler is up too temperature. As well as enough saplings to get the farm going. As for the setup:
1: The planter and harvester should be set to farm a 7x7 area, but not all of the area needs to have saplings. You will not need fertilizer at all for this farm. You'll only need a min of 11 spots for saplings to grow because....(see: #2)
2: Look for and gather a good half or full stack of either Pink or White Cherry Blossom saplings, from biomes o plenty. I know, they are a bit flowery and all, but one tree can net you over half a stack of wood, and nearly half a stack of saplings. And they grow quite quickly, much faster then vanilla trees. There are other trees in the mod pack that grow as quickly, but few, if any, produce as much wood per minute as these silly trees do. If you can't get past the flowery nature of these trees, there are many others that will work, but you'll need a bigger tree farm. Do note though, these trees grow pretty big, matching the size of large oak trees.
3: You'll need some type of powered furnace to turn the wood into charcoal. Preferably one that uses either MJ or RF power since that is the type of power the farm will most easily produce. Two TE Redstone Furnaces should be able to keep up with the boilers demand once it is up too temperature, but a third might be needed initially. As for your MJ powered option, not sure how they compare in terms of speed to the redstone furnace.
4: You'll need something to store the extra saplings, which there will be a bunch of. You'll also want another storage to act as a buffer for both the wood and charcoal.
5: Max sized high pressure boiler from Railcraft. Takes a while to get up to temp, and reach full efficiency. But once it does, you'll have a large supply of steam available. You can also choose to hold off on the high pressure boiler and go for two low pressure boilers instead. Takes more resources to make, but takes less time to heat up and burns less fuel initially. Your choice, both ways you'll have about the same amount of steam and burn through about the same amount of charcoal.
6: Pipe this steam to either industrial steam engines if you favor MJ power, or pipe it into steam dynamos to get yourself some RF. Either way, you'll be able to run about 16 engines off the steam produced by the 1 boiler(HP), or 2 boilers(LP). But note here, until the boiler is at full temp, the number of engines it will run will be dramatically reduced. Your power from this setup will be around 128MJ/tick or 1,280RF/tick when at full temp.
And there you go. Self sustained, once up to temperature, power from a tree farm. Whether this is more effective then just burning the charcoal in steam dynamos is debatable. But the setup is a bit more interesting at least.
Thanks for this, I appreciate you writing a little more detailed guide, it really helps, especially since I haven't used pressure boilers before. I might try this just cause I've never done it before.