The point here is whether or not it is cost effective/worthwhile to grow your own fuel -
I think thats the key question but it should be split.
Whereas it may not be 'cost effective' it may definitely be worthwhile.
You will not be increasing carbon output by getting fuel delivered.
If you plant tress, immediately you are reducing your carbon footprint.
This might be very very important if carbon taxes are introduced.
You also have the added advantage of the self gratifying feeling of being more self sufficient.
The addition of the tress will create a biodiversity for flora and fauna. For this I would advise planting different species of trees rather than one.
Plus you can create a wonderful playing area for children.
Whether its cost effective definitely comes down to a few factors.
1. the area and amount to be planted
2. their growth rate and seasoning rate
3. their specific thermal capacity
4. your energy needs (obviously the less energy you need, the less lumber you need)
5. your willingness to attend to your harvest.
personally i would absolutely love to be in your situation.