Comprehensive Study Notes on Tree and Forest Definitions
Definitions and Fundamental Characteristics of the Tree
An árbol (tree) is defined as a plant with a leñoso (woody) stem, characterized by having a single principal trunk or eje principal and a well-defined crown (copa) formed by secondary stems or branches. Structurally, a tree is composed of three main parts: the roots, the trunk, and the crown. As a perennial vegetable, it lives for several years and possesses the inherent capacity to grow in height throughout its lifespan. From an environmental perspective, trees serve as large reservorios (reservoirs) for (carbon dioxide) and are essential for the atmosphere as they provide (oxygen).
Concepts and Ecological Role of Forests
Bosques (forests) are described as a set of trees that grow more or less together. Beyond being a simple collection of trees, a forest is a complex ecosystem where the trees function as the determinante (determining factor) in the management and distribution of available environmental resources. These resources include light, water, soil, and the overall landscape. The presence of trees shapes the specific conditions under which other organisms within the ecosystem exist.
Forest Classification by Structure
Forests can be categorized based on their physical structure and the distribution of their vegetation layers or strata. There are three primary structural types identified:
Selvas: These are characterized by having various strata of superimposed trees. In this structure, the main or primary stratum covers the entire ground, which results in very little light penetration reaching the sotobosque (understory). A specific example of this structure is the selva montana.
Cobertura/Bosque (Cover/Forest): In this structural type, the crowns (copas) of the individual specimens touch each other. Unlike the multi-layered selva, this type generally consists of only a single main stratum. Forest plantations (plantaciones forestal) are common examples of this structure.
Parques (Parks): In park-like structures, the crowns of the trees do not touch. This spatial arrangement allows for a significant amount of light to reach the sotobosque (understory), providing a different environmental dynamic compared to dense cover or multi-layered jungles.
Forest Classification by Origin
Forests are also classified according to how they originated and the nature of their growth. This classification distinguishes between natural and man-made systems:
Bosques Nativos (Native Forests): Also known as spontaneous forests, these grow alone or spontaneously without human intervention. They are characterized by being heterogéneos (heterogeneous), meaning they contain more than one species of tree. Furthermore, they are disetáneos, meaning the individual specimens have different ages. Their spatial disposition or distribution across the terrain is random (al azar).
Bosques Implantados (Implanted Forests): These are also referred to as plantaciones (plantations) and are man-made. They are established for various purposes, including production, protection, or conservation. These forests can be composed of exotic plants (species from areas other than where they are being planted) or native plants. They are distinguished by their order and uniform growth rates; they are generally homogéneos (homogeneous), meaning they consist of the same species and similar ages.
Intermediate and Semi-Natural Situations
There are situations that fall between purely native and purely implanted forests, often referred to as situaciones intermedias or seminaturales. This occurs when human elements are incorporated into a natural or spontaneous forest matrix. A primary example is enrichment (enriquecimiento), where fajas (strips) of trees are planted in a regular pattern within an existing spontaneous forest to improve its composition or value. Additionally, native forestations—where native species are planted by humans—can be considered a semi-natural situation rather than a standard commercial plantation.