Pruning is not very expensive in terms of either cost or time. But only if done regularly: in this way, it is less invasive. There will be fewer shoots and less wood to remove.
A closer look: how to dispose of pruning waste
In our previous press releases, we already how to dispose of clippings in broad terms. The traditional practice is to burn the branches. These are accumulated at specific locations in the olive grove, far from the plants and especially woods, Mediterranean maquis and uncultivated areas. You must absolutely avoid causing a fire. Often small piles are burned alongside walls or rocks.
For many years, their practice of burning pruning waste was a cause of forest fires. Prevention and greater sense of responsibility on the part of growers have reduced this danger.
The basic rules to follow when burning pruning waste
always burn on days with no wind;
always burn just-pruned material (green leaves generate less heat);
burning sites must be far from areas at risk of ignition (abandoned shrubby areas or particularly dense undergrowth);
if less than 100 metres from houses or areas at risk of ignition, you must have a permit from the State Forestry Corps. At least in Liguria.
The State Forestry Corps monitors these practices and, when environmental conditions are particularly hazardous, it issues an order to mayors that prohibits this practice.
What did we do in our olive grove?
In the Riviera Ligure Olive Grove, we used a mechanical system. The branches were accumulated in the centre of the larger terraces where a small tractor could manoeuvre. This towed a machine with rotating hammers to the site that chopped up the branches. This produces an organic carpet that controls weeds and returns organic matter to the biological cycle.
Where this organic carpet is placed, you don’t need to mow the grass.
This machine is commonly called a “shredder”. However, given the steep terrain, it can’t be used everywhere in Liguria. Its cost is undoubtedly significant, but it saves time, has no environmental impact, and eliminates the danger of fire. As noted in the previous expense table, the work is done in a single day by two operators: one prepared the bundles along the terraces and the other passed over them with the tractor.
In the areas of terraces not affected by the elimination of pruning waste, it was necessary to mow the grass with a shoulder trimmer. This is an approved organic method. It is necessary in the spring, to prevent the weeds from growing too big and then drying out and becoming a fire hazard.
Late spring (May to June depending on the altitude) is one of the most delicate moments for our olive grove: flowering.
Flower buds appear on two-year-old shoots. Differentiation occurs in late winter, so a month earlier. At that stage, an outline of the flower buds can be seen at the base of the leaves.
The flowers are very small, white and gathered in clusters (called inflorescence) in a number from 15 to 40 depending on the variety (for Taggiasca, from 15 to 18).
The flowers of the olive tree (white with four petals attached to the base) are hermaphrodites, which is to say, they have both male and female organs. The simultaneous maturation of the female and male organs often results in self-fertilization. Taggiasca for example, is a self-fertilizing variety. Other Italian varieties are not and need “friend” varieties for wind pollination.
The flower has no nectar because pollination is mainly anemophilous, i.e., through wind action. After full flowering, the petals fall off and, if fertilization has taken place, the ovary begins to swell to become a fruitlet (fruit set).
The percentage of fruit sets (number of fruits as a ratio of the number of open flowers) is highly variable in the first weeks after full flowering because many fruitlets fall off.
For this reason, it is necessary to wait at least 60 days after full flowering to assess the quantity of fruit sets.
This year we had a rainy winter. The trees may not have suffered water stress. The lack of water is one of the main factors limiting production. In addition to this, you need to take into consideration the alternating production of olive trees: a year of large production, like last season, is followed by a year of lower production.
To have a constant production over the years, it is a good idea to: prune periodically; harvest the fruit as soon as possible, since leaving the fruit on the tree for a long time means it must be nourished for a longer period; keep the plants low (less wood means greater resources for production), provide proper balanced fertilizer; use products that promote fruit sets, especially products based on the micro-nutrient boron.
In our olive grove, the first buds began to differentiate starting in mid-May: production appears to be significantly lower than last year although it is still very early to make an estimate in this regard.
Costs (net of VAT)
|Mowing with a dethatcher, one day
And in the past?
Dear friends, in the past there was a lot to do in the olive grove in this period. In addition to burning the pruning waste, the weeds were removed by hand. A scythe was used and the blade constantly needed to be sharpened to cut effectively.
The soil was turned with a heavy rake, called a harrow, drawn by oxen: this was done to aerate the roots, allowing the organic fertilizer to penetrate and, at the end, have a cleared surface on which to manually harvest the olives during the winter. It should also be said that the ground had to be as clean “as the back of your hand”.
Finally, since, in the past, no one knew that the Taggiasca were self-fertilizing, we were careful to place trees of different olive cultivars for pollination. It still happens today that a careful observer will notice plants that are, by now, similar to the Taggiasca but with different, perhaps bigger, olives. These are the pollinators that, as they say, “the ancients” planted.
One last thing: if there are enough olives for a good year, you will see them at the time called “the descent from the meadows”. This is at the end September when the flocks of sheep and herds of cattle come down to their winter stalls after spending the summer on the heights of the Ligurian Alps.