Woods, forests, and scrub are terms we often use with ease, though not always with a clear understanding of their exact meanings. Let’s explore the differences between these concepts.
The forest is a natural formation of trees with tall, multi-layered trunks, comprising trees arranged at various levels, along with shrubs and herbaceous plants. It is defined by a rich diversity of species that coexist in a delicate balance. A forest typically spans a large area and consists of original vegetation, unaltered by human activity. In the past, Italy was almost entirely covered by forests. However, even in pre-Roman times, the inhabitants began deforestation to harvest wood, a valuable resource, and to clear land for pastures and agriculture. Sadly, only a small number of forests have survived to the present day.
In everyday language, a wood is often thought of as a small forest. However, in scientific contexts, the term typically refers to tall tree formations dominated by a single species. Such formations are rare in nature, as forests usually contain a mix of species, with one occasionally being more dominant. When a single species completely dominates an area, it is usually a sign of human intervention.
Classic examples are coppice woods: these are woods formed by trees whose main trunks are cut at the base or at a certain height, leaving the stumps to produce new shoots. The harvested trunks are utilized for firewood production, charcoal making, tannin extraction from bark, paper manufacturing, furniture crafting, and more. Notably, in areas where human-planted forests have been abandoned, the natural forest environment gradually begins to re-establish itself.
The maquis is a plant community consisting of trees with a shrubby growth habit and predominantly evergreen shrubs with thick, leathery, and relatively small leaves adapted to minimize water loss through transpiration. This type of vegetation is common in regions surrounding the Mediterranean, where it is known as the Mediterranean Maquis, as well as in areas with hot, dry summers and mild, moderately rainy winters.
Depending on the height and density of the vegetation, the scrub is categorized by different names. It is referred to as scrub-forest when the trees grow taller than three to four meters, exhibit an arboreal habit, and are interspersed with shrubs, lianas, and bushes so densely packed that they become impenetrable. When the vegetation reaches a height of two to three meters and the intertwined branches create spaces utilized by seasonal species, it is termed high maquis. If the vegetation remains under two meters in height, it is classified as low maquis.
In degraded areas or rocky substrates, we transition to another plant formation known as the garrigue. This ecosystem is defined by perennial species with woody stems growing close to the ground. These plants are often thorny, aromatic, and well-adapted to survive in dry climates with limited water availability.
Each of the formations described does not remain unchanged over time. What we observe upon entering a territory is merely a snapshot of its current “life” stage, which, depending on climate and soil changes, will gradually transform into a different ecosystem. Every ecosystem has its own lifecycle, comparable to that of a living organism: it consists of various components, each fulfilling a specific role, and it evolves over time, progressing through distinct stages of development.
The transformation of one ecosystem into another is called ecological succession: it is an evolution that has shorter times than the evolution of species; indeed, it is generally the evolution of the ecosystem that induces the evolution of the plant and animal species that compose it.
Let’s return to our forest and attempt to piece together its history. To illustrate, let’s consider a well-known example: a beach. To truly observe nature’s course, we must avoid a beach spoiled by cabins or bordered by a road. Instead, we need a pristine, expansive beach with a forested area just beyond it.
Starting from the stretch of sand shaped by the waves, we first encounter an area completely devoid of vegetation. Moving further, we begin to see plants adapted to survive in an arid environment with loose, sandy soil. These plants often have long roots, twisting stems, and thick or hairy leaves. This marks the dune ecosystem, where pioneer plants play a crucial role in stabilizing the sand to form dunes and begin compacting the soil. This process sets the stage for the floral species that will later give rise to the garrigue. Continuing our journey through these ecosystems, we find the garrigue just beyond the dunes. The plants in this ecosystem are low-growing, with narrow, often aromatic leaves, adapted to endure intense sunlight. The soil here remains largely sandy but begins to develop a humus layer. In the oldest areas, furthest from the sea, this organic matter supports the growth of the first shrubs.
At this point, we must pause to note that we are not only experiencing successive ecosystems but also witnessing the development of each one. In the garrigue, the area near the dunes represents the “young” section, while the part adjacent to the shrubland is the “older” section. In the dune environment, the strip close to the garrigue is the oldest, while the area near the beach is the youngest. As the sea gradually deposits sand, the dune, garrigue, and the ecosystems that follow continue to advance.
The shrubbery, which establishes itself through the contributions of plants and animals within the garrigue, also creates the conditions for the first trees to grow. This dense and intricate layer acts as a protective barrier against the sea wind, enabling young trees to strengthen and develop. Often, this initial band of trees serves as a transitional stage toward the formation of a true forest. In many coastal areas, with assistance from the Forestry Corps, the first tree band often consists of maritime pines. These trees are particularly effective at forming windbreaks, allowing species like holm oaks or other broadleaf trees to thrive. Over time, the latter, being taller and longer-lived, gradually replace the pine forest. As the years go by, the forest evolves in this manner. Provided there are no significant changes in the terrain or climate, this ecosystem remains stable, reaching a state known as climax.
Another simple example to observe and study, for those without access to a beach, is an abandoned field. Unlike the beach, the field starts with an advantage as it already has a layer of humus and a more stable ground. The journey toward becoming a forest is long but steady, provided no catastrophic events like fires or landslides take place.
A year after being abandoned, the field becomes quickly overtaken by plants often referred to as “weeds,” which we will call pioneers. These plants were spread by birds seeking insects and worms, by animals passing through, or carried by the wind. After roughly three years, the first shrubs start to emerge—species that thrive in minimal shade. Initially small and scattered, they gradually grow denser and more robust. During this process, many of the original sun-loving herbs vanish, replaced by species better suited to the increasingly shaded environment.
The first bushes have encouraged the growth of tall shrubs, which, with their shade, provide a protective environment for young broad-leaved trees to sprout and grow. Similar to the previous stage, the forest, with all its richness and grandeur, will serve as the final chapter of this remarkable ecological journey, where each stage reflects the life of an evolving ecosystem. In the case of the field, it is important to note that each successive ecosystem occupies an increasingly longer period: the meadow lasts only two to three years, the bush five to seven years, the shrub fifteen to twenty years, and from the young forest to the climax stage, no less than thirty years pass. At this point, as mentioned earlier, the forest can remain in this state for millennia.
It is fascinating to compare the initial stage of ecological succession with the climax stage or, if unavailable, the most advanced stage currently present. Take, for instance, a meadow of “weeds” compared to a forest. The forest exhibits a far more intricate structure due to the presence of diverse “sub-environments” such as treetops, undergrowth with moss and lichens, decaying logs, shrubs, small puddles, and more. In the forest, the variety of plant and animal species is significantly greater, resulting in complex food webs. In contrast, the meadow typically features only short, often entirely independent, food chains.
Finally, we will say that a forest in its climax stage possesses a remarkable ability for self-regulation. The ecosystem tends to maintain stability in the population of each species, even in the face of external disturbances, as long as they are not catastrophic. In contrast, less complex communities lack this capability; the population of each species can fluctuate significantly due to the underdeveloped self-regulation mechanisms.
From this, we can conclude that an ecosystem becomes more stable as it increases in diversity and complexity. Consequently, the older and more “mature” a forest is, the greater its ecological value.
Author: Anna Lacci is a scientific popularizer and expert in environmental education and sustainability and in territory teaching. She is the author of documentaries and naturalistic books, notebooks and interdisciplinary teaching aids, and multimedia information materials.
Translated by Maria Antonietta Sessa
