14 or 15 cents for 2 year old olive or orange is right, and I'm interested in a couple of tonnes at that rate.  To the original post : light it when you need it, the great (er grate) thing about woodburners is their almost immediate output of heat.  Use plenty of dry kindling and small loglets to start off with.  The biggest problem you might come across is cheap Spanish woodstoves are made of thin steel and the doors usually aren't air tight and so the draft isn't totally controlable.  Damp cheap wood is your worst enemy so do not think about using olive you've hacked off in the same year.  Not only the flue will coke up but you'll not get the same calorific value from fresh wood that you wood wood if you used old would.   Geddit?