Around olive tree, drought-resistant tree Olive cultivation is central to much of the Mediterranean agricultural economy, but it also embodies a long history of agricultural knowledge, conservation, and adaptation to climate change. From how a tree is pruned after the olive harvest on an Andalusian farm to plans for storing its seeds in an underground chamber in the Arctic, this crop today straddles tradition and advanced science.
While technicians remind farmers that Each pruning cut alters the tree's internal balance And since it will affect the harvest in the coming years, researchers and international organizations are finalizing the shipment of olive genetic material to the Svalbard Global Seed Vault in Norway, the so-called "doomsday vault" for seeds. Two sides of the same challenge: keeping the olive tree alive, productive in the present, and protected for the future.
Olive tree pruning after harvest: a decision that shapes the next harvest
Once the olive harvest is over, the olive grower enters one of the most delicate phases of the year: pruning the olive groveFar from being a simple mechanical job with saws and scissors, specialists from the Andalusian Plant Health Alert and Information Network (RAIF) insist that it is an intervention with direct effects on future production, the regularity of harvests and the profitability of the farm.
In each tree, Pruning alters the leaf/root and leaf/wood balanceThat is, how the olive tree distributes its energy between growing, maintaining its structure, and producing fruit. Excessive pruning or a poor choice of which branches to remove can force the tree to expend a significant portion of its reserves rebuilding its canopy instead of producing productive shoots, something particularly problematic in older plantations. Therefore, it's advisable to avoid excessive cutting that disrupt the tree's physiology.
The agronomic goal is to fine-tune this balance: ensuring the olive tree maintains enough active foliage to nourish the roots and wood, but without creating an old and inefficient structure. Pruning, explains RAIF, should orient the tree architecture towards greater productive efficiency, not leaving it "bare" without criteria.
In the background appears a concept very well known in the field: the marked alternationSince olives develop from the previous year's shoots, poorly planned or overly intensive pruning can trigger a marked alternation of very productive seasons followed by poor ones. Therefore, experts recommend avoiding drastic changes in management and opting for consistent and coherent practices from one season to the next.
This strategic vision is not new. Even in Antiquity, authors such as Lucius Junius Moderatus Columella They embraced the idea that whoever plows the olive grove asks for fruit, whoever fertilizes it asks for it politely, and whoever prunes it forces it to produce. The proverb, often cited in technical conferences, summarizes with a certain starkness the impact of pruning on the tree's response.
Balancing growth and production: how to avoid alternate bearing
One of the points most emphasized in the official recommendations is the need to to balance vegetative growth with productionThe olive tree cannot expend all its energy in a single growing season, because it needs to prepare young wood and fertile shoots for the next. Furthermore, proper nutrition and soil management, as explained in guides on [missing information - likely "plant guides" or similar text], are essential. fertilization of the olive trees, contributes to balancing that vegetative development.
When old wood predominates in a tree and well-lit leaves are scarce, the result is usually a drop in new growth and a progressive decrease in the harvest. In these situations, pruning must act as a corrective measure. lighten aged branches and make room for new shoots, but without leaving the tree without photosynthetic capacity.
In very old or poorly renewed olive groves, this problem is clearly visible: dense crownsThe interiors are shady, and the fruit is concentrated at the tips. In these cases, technicians recommend a gradual renewal of branches, staggered over several years, so that the tree does not suffer a sudden drop in production.
The key is to gradually increase the intensity of the intervention. A drastic pruning might seem tempting to quickly "rejuvenate" the olive tree, but drastically reduces the immediate harvest and can weaken the tree's overall vigor. Therefore, it is recommended to reserve heavy pruning for very specific situations and, in general, opt for gentler, more continuous pruning.
This approach also allows for a reduction in alternate bearing, since the olive tree reaches each season with a more stable structure, less subject to extreme fluctuations, and with more regular harvestsIn practical terms, this means more regular harvests and less risky economic planning for the farmer.
Young olive groves: prune little and often to enter production sooner
If the tree is young, the approach changes. In new plantations, the goal is for the olive tree to begin producing fruit as soon as possible without compromising its future structure. To achieve this, Heavy pruning in the early years is considered a common mistake which delays the start of the harvest. The so-called formation pruning It should be light, but regular.
Experts recommend that the call formation pruning The pruning should be light but regular. The aim is to guide the tree's structure—trunk height, number and arrangement of main branches—avoiding drastic cuts that disrupt the leaf/root balance. If too many young shoots are removed, the olive tree must invest much of its energy in replacing them, instead of consolidating a strong root system and a productive structure.
In this type of olive grove, intervene each year with small corrections It usually yields better results than pruning every few years with severe pruning. The tree grows more continuously, suffers less stress, and reaches a profitable canopy volume sooner.
In modern high-density, hedgerow farming, where the mechanization of harvesting This idea is key, and even more evident: canopy formation and maintenance are designed from the outset with machinery in mind, but always with the same underlying principle: not to excessively hinder vegetative development. Technological innovation facilitates this work, as has been demonstrated in projects of pruning equipment, it can reduce labor costs.
Extending the life of the olive grove and preventing premature aging
One of the olive tree's greatest virtues is its ability to live and produce for centuries. However, this potential longevity depends on how the tree and the soil are managed. The technical notes remind us that A well-maintained olive grove can maintain an almost unlimited productive life.even in dry conditions, provided that healthy trunks and an active root system are maintained.
Severe and repeated pruning significantly shortens that lifespanEach heavy pruning leaves wounds, reduces leaf area, and forces the tree to expend reserves rebuilding its structure. In the long run, a series of aggressive interventions results in a fatigued olive grove, less able to respond to droughts, frosts, or pests. Furthermore, sustainably utilizing pruning waste is a complementary measure, as explained by initiatives on sustainable use of pruning.
That's why the experts recommend evaluate each action not only for the next harvest, but for its cumulative effect in the physiology of the tree. When a branch shows clear signs of aging - a lot of wood, little budding, low production - the solution is to renew it, but progressively: replacing it with better-positioned buds, staggering the removal of old wood and avoiding making large clearings all at once.
This approach also helps maintain a more secure crown structure against wind and snow, with less risk of breakageand facilitates tasks such as harvesting or phytosanitary treatments. A balanced olive tree, with renewed and well-distributed wood, is also usually easier and faster to prune, which translates into lower labor costs.
Pruning and watering: adjusting the canopy to water availability
In Andalusia, and indeed in much of Spain, water is the number one limiting factor. That is why official recommendations emphasize that The canopy volume should be in line with the average water availability. of the farm. An oversized tree, with too many leaves, transpires more and can come into conflict with the actual water that the soil and climate can provide.
In dryland olive groves, the rule is especially clear: pruning must be prudent, but it must also maintain the tree at a size compatible with rainfall and soil depth. Leaving enormous canopies in orchards with scarce rainfall and shallow soils often leads to Small fruits, with little pulp and a reduced fat yieldbecause the plant suffers water stress at key moments of fattening.
In irrigated areas, the margin is greater. If adequate and well-managed irrigation is guaranteed, a larger canopy volume can be permitted, provided that a good interior lighting of the tree. A gloomy interior, full of leafless wood, is synonymous with poor productive efficiency, even if water is available.
In both systems, pruning thus becomes a tool for modulate the olive tree's water demandAdjusting the size and density of the canopy helps reduce the risk of intense water stress at critical times, something increasingly relevant in a scenario of climate change and prolonged drought episodes.
Pruning as an economic investment, not just as an annual task
Beyond the physiological aspects, agricultural organizations emphasize that pruning should also be considered from a financial perspective. Overly meticulous work, or the use of unsuitable equipment, can increase the cost of the operation without providing equivalent benefits. The idea is to conceive of pruning as an investment with a returnnot as a fixed ritual every winter.
In this sense, the importance of define clear objectives per plotRejuvenate, control height, correct imbalances, improve machinery access, combine skilled labor with well-maintained tools, and avoid unnecessarily pruning the same tree repeatedly. Solutions also include innovation and sustainability influence those objectives.
Field experiences show that Clear and logical pruning reduces time and costsEspecially when the teams understand the farm's criteria and don't work according to each worker's individual preferences. For many farms, the training of the pruners and the technical supervision during the first few seasons makes all the difference between a well-managed olive grove and one riddled with contradictory decisions.
This economic approach is intertwined with the other factors: a well-balanced tree, adapted to the available water and with a renewed structure, usually to reduce maintenance costs year after year and requires fewer drastic corrections, which stabilizes revenues.
From the Mediterranean fields to the Arctic: the olive tree travels to the Svalbard Global Vault
While these management details are being fine-tuned on the farms, the olive tree is preparing to take an unprecedented symbolic and scientific leap. For the first time, genetic material from this crop will be added to the Svalbard Global Seed Vault., in the Norwegian archipelago that holds backups of the world's agricultural biodiversity more than a thousand kilometers from the North Pole.
This underground chamber, excavated in rock and permafrost and maintained at temperatures around -18 degrees Celsius, It functions as a global insurance against catastropheswars or accidents that could destroy seed collections in their places of origin. With a capacity for millions of samples, it already houses material from key crops on all five continents.
Until now, the olive tree had been left out of that frozen archive. That will change between now and now. February 23 and 27, 2026, when the vault is scheduled to open one of its few annual windows to receive, among other shipments, a consignment of olive seeds coordinated from Spain.
The project is driven by the International Olive Oil Committee (IOC), in collaboration with the FAO and framed within the European Gen4Olive initiative of the Horizon 2020 program. In Spain, the Ministry of Agriculture, Fisheries and Food, the World Olive Germplasm Bank of the University of Cordoba, the University of Granada and the Center for Plant Genetic Resources and Sustainable Agriculture of the CSIC, among other entities, participate directly.
How is the genetic material that will travel from Spain prepared?
The shipment isn't simply about packing a few olives. Currently, teams in Córdoba and Granada are working on it. collecting olive pits from trees that have produced this harvestThe seeds are extracted from both plantations and wild olive trees. After purification and homogenization, they are frozen to ensure their germination viability.
The World Olive Germplasm Bank, located on the Rabanales Campus (University of Córdoba), contributes material corresponding to a large part of the more than 700 varieties cataloged in its international collection. For its part, the University of Granada focuses on collect material from wild olive trees, the wild relatives of the cultivated olive tree, essential for preserving traits of resistance and adaptation.
Once conditioned, these seeds will be organized into batches and boxes, which will be managed by the CSIC center in Alcalá de Henares before their journey to Norway. In total, it is expected that approximately 1.500 samples from several hundred genotypeswhich will be added to the approximately 1.200 already sent from Spain for other crops in previous years.
The International Olive Council emphasizes that, strictly speaking, what is being deposited are not “clonable varieties” as such, since the olive tree does not normally reproduce by seed but through vegetative propagation (cuttings or grafts). Given that it is a species with varying levels of self-pollination and frequent cross-pollination, the aim is to... preserve the olive tree's genetic poolThat is, the set of heritable diversity that characterizes the crop and its wild relatives in the Mediterranean basin.
In a hypothetical future scenario of massive loss of plant material, these seeds would not allow for the detailed reconstruction of the same current commercial varieties, but they would offer a valuable basis for genetic improvement programs and reconstruction of populations adapted to extreme conditions.
Why protecting olive diversity is so strategic
Recent experience has shown just how crucial having a physical backup of seeds can be. In 2015, the International Center for Agricultural Research in the Dry Areas requested material from the Svalbard Global Seed Vault for Reconstitute lost wheat collections in Aleppo due to the war in Syria. Thanks to the samples preserved in Norway, it has been possible to recreate a collection virtually identical to the one that disappeared in the conflict.
For the olive tree, the risk is not limited to war scenarios. Emerging pests, devastating diseases, and episodes of extreme drought and heat These are among the threats most frequently mentioned by researchers and farmers. Having a broad reserve of genetic diversity is a way to have biological tools available in the future to respond to these threats: genes for drought tolerance, resistance to pathogens, or the ability to adapt to new climatic conditions. Learn more about olive tree diseases It helps to understand those risks.
Spain, as the world's largest producer of olive oil and a country with a vast varietal heritage, plays a central role in this strategy. The World Olive Germplasm Bank in Córdoba It brings together more than a thousand accessions from almost thirty countriesa kind of living map of international olive growing. The portion of that material that travels to Svalbard will act as a second backup in an extremely stable climatic environment.
Those working on the project speak of a certain sense of historical responsibilityUnderstanding that what is done today can determine the crop's adaptation options for generations to come. In the words of the experts involved, it's about doing something "important for humanity," beyond the immediate interests of a country or a specific season.
Viewed as a whole, the olive tree appears today as a crop caught between two very different but intimately related scales: that of the farmer who decides each winter which branch to cut to ensure the following year's harvest, and that of the scientific team that packages seeds for a trip to the Arctic with an eye toward possible crises decades from now. Between the Proper pruning that extends the life of each tree And the global conservation of its genetic diversity reveals the same underlying idea: caring for the olive tree requires combining field work, long-term planning and a significant dose of collective foresight.
