Holm Oak

What is the holm oak?

The holm oak, Quercus ilex, is the evergreen oak of the Mediterranean and, across much of the hard-leaved zone, the tree that stands at the end of succession. Its leaves are small, thick and leathery, and it keeps them all year, which means it works whenever there is water rather than only in a growing season.

Three things make it the anchor species of these landscapes. Its canopy is dense, so the ground beneath it stays cooler and holds moisture into the dry months. Its roots go deep, reaching water and minerals far below the layer grass can use, and holding a slope while doing so. And it carries acorns, which in a grazed landscape is not a detail but a food supply for domestic animals and wildlife alike.

Its longevity was underestimated for a long time. A study published in 2023 established that the holm oaks of Montecristo, in the Tuscan Archipelago, exceed 700 years, well beyond the roughly 500 years that reference works had assumed. What such a tree has seen is not comparable to anything a planting can produce quickly.

European nature law lists the habitat in Annex I of the Habitats Directive, as Quercus ilex and Quercus rotundifolia forests. The Sardinian expressions are distinctive enough to be classified separately in the regional forest typology, both the lowland holm oak woods and the supra-Mediterranean ones at altitude.

The awkward truth is how little of it remains. Across the Mediterranean, holm oak woodland was cleared for grazing, charcoal and cultivation over millennia, and what stands in its place is largely macchia. The shrubs are the same community in an earlier stage, held there by fire and grazing pressure.

How Terra Humana understands it

For Terra Humana the holm oak is the reference point, in the strict sense that ecological restoration uses that word.

The official landscape survey of the Ogliastra records that the district's original cover was cork oak on acid soils and holm oak on neutral to basic ones, and that fire, overgrazing and unsuitable tillage removed much of it. The district has both kinds of ground, acid granite and schist as well as the calcareous Tacchi. Which tree belongs where is therefore a question of soil, not of preference, and we answer it place by place.

That does not make the holm oak a target to be planted everywhere as fast as possible. A seedling on an open slope in a Sardinian summer has poor odds. It needs shade, and the shade that exists is the macchia. So the sequence matters more than the species list: the shrubs that are already there are the nursery for the oaks that are meant to follow.

We also read its longevity as an obligation. Planting a tree that can stand for seven centuries is a decision made on behalf of people we will never meet. It fits the way this foundation was set up, and it is the plainest answer to the question of what long-term work means.