The commission for planning and designing a real estate development of approximately 240 hectares in the district of Puchuncaví, Valparaíso region, meant an opportunity to initiate an ecological rehabilitation of the land as a design strategy not only for the landscape, but for the entire urbanization. At the time of planning, a significant fraction of the site (80 hectares) housed a radiata pine forest that grew unsupervised for more than 20 years, resulting in poor phytosanitary conditions and affecting the biodiversity. The rest of the site presented typical characteristics of sclerophyllous scrub of coastal Mediterranean climate, which were taken as the reference ecosystem for the strategy of rehabilitation of the soon-to-be deforested area and degraded sites (Figura 1) (Figura 4).

Figure 1 Aerial view of previous condition. 

Figure 2 Master plan and ecological rehabilitation 

Figure 3 Pilot plantation plan 

Source: © Francisco Croxatto

Figura 4 Existing conditions. (a) Reference ecosystem; (b) Radiata pine forest; (c) Deforestation. 

Faced with the requirements of a low-density housing development on the central coast, where water is very scarce and the original ecosystems have lost ground, the almost compulsory response was to restore the landscape that evolutionarily adapted to this bioclimatic region. This required not only selecting the adapted vegetal material, but also creating the conditions so it could be regenerative, developing into an autonomous functional ecosystem and allowing the promotion and development of biodiversity (Figure 7). To that end, this new landscape was designed to form a network of natural areas mainly located in the lower and deep sectors where the climate has shaped for years the areas of rainwater retention and drainage (Figure 2) (Figure 3).

Source: © Francisco Croxatto

Figure 5 Stablishing process 

Source: © Francisco Croxatto

Figure 6 Stablishing process 

Source: © Francisco Croxatto

Figura 7 Incentives for biodiversity and vegetal associations. 

Given the above, the process consisted of designing a colonization strategy for a large area - ensuring its establishment in time - and a planting methodology that, due to the scale, escaped the typical actions of a garden or a park. In this case, the dominant and structuring species location was the only one defined; for the rest, the plan used patterns, density, and association forms based on nature, shaping a natural and spontaneous landscape.

To define the partnerships that would make up this ecological rehabilitation initiative, the plan used the baseline developed for the environmental impact assessment of this project was used and the land was surveyed to evaluate the current conditions of existing native vegetation aiming to identify successful, vulnerable, and undescribed species, as well as the presence of invasive foreign ones. On site, it was also verified how these plant communities adapt to the different variables of the terrain: exposure, humidity, wind, soil conditions,and so on. Once this information was collected, a comprehensive list of species suitable to initiate a process of plant colonization of the soil was drawn up. These pioneer species had to respond to requirements such as low water demand, resistance to poor soils, rapid growth, self-sowing, and resistance to coastal wind, among others. Along with this, a plantation density of 4,050 individuals per hectare was defined.

Finally, to start the restoration process, a 1.6-hectare green area was prioritized as a pilot laboratory and as a representative sample of the project’s landscape. In October 2020, the plantation celebrated one year since its execution, a process that has been recorded through photographs and measurements, which has been key to continue planning the next planting stages (Figure 4) (Figure 5) (Figure 6) (Figure 7).