Can I just point out that taking almonds and olives from other peoples land is basically stealing, even if the land appears to be unused. I spoke to a farmer recently who was hopping mad  because to quote 'an English man had been stealing almonds from his land without his permission' He said he had told the man in question that he should seek his permission first and pay him something if he wants to take them.
I'm just mentioning this incase anyone out there has had a problem with people taking their almonds or olives. The farmer told me that the agents rural are keeping an eye out for this practice and will ask people they suspect to provide evidence of ownership of land or permission from the landowner before they take any produce, including firewood, from land. They will prosecute if permission has not been sought as it is becoming such a problem.
If you have experienced thefts of this nature you can report it to the agents rurales.

Another reason to put fences round your land, to stop people and dogs coming onto it!

what about mushroom pickers and hunters...?