As a consequence of global warming we are all going to have to face increasing temperatures and a growing shortage of water, so it is useful now to look at how others cope with these problems. For example, Syrian farmers have faced heat and semi-arid conditions for many, many years and have developed a practical response that may be worth adapting for use elsewhere.
During a visit to Syria several years ago before the recent troubles I visited one of the prime olive-growing areas around the town of Idlib some 70 km southwest of Aleppo.
Along the way there I noticed that the olive trees were an unusual shape, almost globe-like on their trunks, and later I learned that they are pruned this way deliberately. There is no attempt to keep the centre of the tree open with three or four main branch systems sticking up like fingers as we do in Tuscany; on the contrary, the top of the tree is allowed to close and the vegetation is kept thick to protect the branches and trunk from the sun. Pruning is thus kept to the minimum.
Another technique practised in that part of Syria concerns mulching. In that semi-arid climate there is not much ground vegetation in the olive groves that can be used as mulch, so the farmers have come up with a simple, if laborious, solution: spreading limestone dust. Two sources of this dust are readily available: stone houses that but have collapsed, and the landscape itself (this is limestone country). The limestone dust is then taken out to the fields, where it is distributed around the base of the olive trees as if it were grass and weeds.
This practice retains whatever moisture there is in the ground by protecting the soil from the sun, reflects sunlight up into the heart of the tree (which is almost closed on top because of the pruning method mentioned above), and discourages unwelcome insects which are deterred by the reflected light.
While we don’t have limestone dust (ours is sandstone country), we can still do something to protect the heart of our olive trees from sun damage. For some years we have been clearing out the interiors of the trees but leaving some horizontal branches at the tops. This helps to break up the intensity of the sun’s rays and thus to protect the trunks and major branches. Sun damage to our trees has never been on the scale of that in the photo above, but I am convinced that our efforts are worthwhile.