When you plant olive trees or use olive oil, you are expressing two things: 1) You Like Healthy Food. 2) You Care for Our Earth. Healthy, fresh and strong olive oil is the healthiest fat of all. Olive trees are the least water requiring trees out of all crops. Being evergreen and with a fast metabolism makes them the biggest absorber of carbon monoxide, and the highest producer of oxygen. They also can be easily and successfully farmed organically.