Given the thermopluviometric and soil characteristics as well as its altitude and latitude, the study area was was included in the mesomediterranean bioclimatic level, represented by the series of alkaline Castilian-Aragonese mesomediterranean vegetation consisting of oak forests, with Quercus ilex, ballota subspecies being the maximum representative of the climatic community. As a result, Quercus was selected for afforestation.
This series occupies the largest area and its mature stage consists of an oak grove overlying alkaline-rich soils, with rainfall ranging between 350 and 550 mm per year. However, the agricultural transformations that have occurred in the area have been progressively reducing this type of plant formations, with only a few very degraded stands and very open pastureland patches remaining today that prove the existence of the dominance of this series throughout the territory in times past.
For the reforestation tasks in this case, the seedlings came from the cultivation of seeds collected in the National Park itself, in the area known as Quinto de la Torre.
Said seeds were collected in the fall of 2016, over an area of 125 ha in the National Park itself with a large number of parent trees, in an attempt to achieve the greatest possible genetic diversity and the future adaptability of the seedlings to the terrain.
The seeds were subsequently grown at TRAGSA’s greenhouse. Plants had the MANCHA certificate of origin.
Since the objective of afforestation was to achieve the restoration of the original pastureland (dehesa) overlying the limestone substrate that existed in many of the places in the surroundings of the Park, including the area selected before its transformation into irrigation land, an attempt was made to reproduce the arrangement of the trees in the pastures currently existing in the area (Zacatena and Casablanca). Finally, a random distribution of the plants was chosen, with a plantation density of about 50 ft/ha and with distances between plants of at least 15 m. Since 104 ha were replanted, the total number of plants used in the project amounted to 5,200.
The lands were cultivated until the moment of their acquisition after 11 years of inactivity. This was of utmost important for the new seedlings, which, as a result, would gain access to a soil with substantial improvements in terms of nutrients and the ability to provide them with greater vitality and quality.
Planting was done by hand by a team of professionals specialized in this type of work. The seedlings were supplied in rigid black trays (50 units), with 250 cm3 cells filled with organic substrate, mainly peat-based.
The appearance of the seedlings was consistently good, with no lesions, malformations, puncturing of the leaves or other apparent damage. All had a good consistency, turgidity, liveliness and leaf size.
Ground preparation was limited to 90x90x90-cm holes dug mechanically with a backhoe, with no other areas of the plot being cleared. Next, the removed ground had to be leveled, avoiding leaving heaps that could prevent the correct planting and installation of the subsequent protective fencing.
Next, a sufficient amount of soil was opened and removed to accommodate the plant comfortably so that the root ball could be properly buried. This job included the installation of a 60 cm high biodegradable protective tube.
The size of the hole (somewhat larger than normal) facilitated the nailing of three posts driven into the ground to anchor the individual protective mesh placed around each plant, in order to avoid damage by wildlife or livestock.
In addition, the increase in the depth also increased the water availability of the plant, much needed in climates as scarce in rainfall as the one existing in this location.
Subsequently, the surrounding land was trodden so that the removed soil came into contact with the root ball of the seedlings, avoiding any possible air pockets that could generate rooting problems.
Lastly, a pit was dug out and built around the tree to increase the rainwater collection and conservation capacity, which is of utmost importance, especially in areas where it is usually very scarce, as in the case of La Mancha.