I may have had nothing to do with putting them there, as my olive trees were already mature, and some of them are probably a good deal older than me, but from a self-sufficiency perspective they really are an A1, top notch ecological-asset in that they produce A LOT of calories (tasty calories with some essential vitamins too) for hardly any maintenance, albeit if harvesting and processing them is a bit of effort!
The calorific maths of my olives - olive oil...
Last year only around 25 of my 45 trees were productive (due I think, to prior years of neglect), and that yielded me around 30 litres of oil, I think.
I say I think, I didn't keep track of how many olives came off my trees, having done a pool for oil with four other quintas - my share came out at 50 litres, but I think some of the other farms were much more productive than mine, so I'm being conservative, and it was apparently a very good year too, so a typical year might produce less.
Still, with only around 60% of my trees productive last year I think it's safe to say that, following a good (but not harsh) pruning this year, I should be on for 40 litres of oil per year going forwards.
Anyway, onto the math....
- 1 litre of olive oil has approximately 8000 calories in.
- With my trees producing 40 Litres a year, that's 320 000 calories
- 320 000/ 365 (days of the year) = 876 Calories a day.
- 876 calories = around 2628 calories, which is sufficient for me to lead a reasonably active life.
I wouldn't want to consume more than a third of my calories in olive oil ordinarily, although apparently there are no health disadvantages to doing so (according to the famous Crete study which followed fishermen who got one third of their daily calories from drinking olive oil and they lived longer than people who didn't on average!).
Normally I like to eat a wider range of food, but if the shit hits the fan and global food supplies go tits up, I could do a lot worse than drinking a small glass of olive oil a day, that's for sure!
Maintenance, Harvesting, Processing...
Olive Trees take very little maintenance, at least once you're done clearing up after years of neglect, an hour a tree in winter will be sufficient easily, AND you get some kindling into the bargain.
They don't need watering, they don't need feeding, although this year I've opted to give them some manure, but it's not necessary.
Harvesting is a bit of a pain - you really need a team of people to make it fun, on your own it would be PAINFUL, but you don't need too much capital outlay on equipment, but it has to be factored in!
And processing... here one is dependent on the local presses, so that makes one not 100% self-sufficient, but outsourcing this particular process is more cost efficient than buying your own press, they are EXPENSIVE!
Final thoughts....
I've been thinking a lot recently about what trees I can plant and what food I can store to buffer myself against future price-shocks, and it's nice to know that I've already got one of the best food producing plants up and running, and the oil is delicious too!