My father recently bought 4 olive trees.
Now we are pickling the olive with the traditional recipe, just adding salt in a jar.
If the tree is large, place cloth sheets on the ground and strip the fruit from the tree with your hands or with a rake with suitably spaced prongs. Collect the fruit from the sheet, remove odd stems and leaves and rinse olives in clean water in a bucket.
Place the olives on a clean stone surface or cutting board and bruise them with another stone or hammer. Alternatively prick several times with a fork, or make three slits in the skin of each olive with a small serrated knife while turning the fruit between the thumb and index finger. This bruising, pricking or cutting will allow the water and salt to penetrate the fruit thereby drawing out the bitterness and also preserving it.