The “Urban Mini Forest” project aims to transform underutilized urban microspaces in Gibraltar into dense, biodiverse, and functional green areas through the implementation of the Miyawaki afforestation technique. This methodology, originally developed in Japan by botanist Akira Miyawaki, consists of recreating native forests at high density using exclusively native species, selected for their ecological compatibility and resilience to the local climate. Through intensive soil preparation and layered planting (herbaceous, shrub, and tree strata), accelerated ecological regeneration is achieved, allowing a mature ecosystem to develop in just 2 to 3 years, instead of the decades a traditional forest would require.
This type of intervention generates environmental benefits such as improved air quality, carbon capture, thermal regulation, and rainwater infiltration. On a social level, it provides spaces for contact with nature, improves the mental and physical health of the population, and strengthens the community fabric through citizen participation in its design, planting, and monitoring. In the case of Gibraltar, the project is part of the “Green Gibraltar” strategy and aims to serve as a replicable model of urban green infrastructure, aligned with sustainability policies, climate adaptation, and collective well-being.
Gibraltar faces constant pressure on its limited natural resources due to a historical process of intensive urbanization, driven by rugged topography and a high population density in an extremely small territory. This situation has led to the near-total occupation of available land, severely limiting the presence of functional green areas, which have been relegated to ornamental strips or marginal spaces without ecological planning.
The lack of adequate vegetation not only affects urban aesthetics but also has direct consequences on local natural systems. With the reduction of vegetation cover, the urban microclimate regulation capacity is lost, intensifying the heat island effect, especially during periods of high temperatures. The lack of roots and soil structure prevents the infiltration of rainwater, generating rapid runoff that overloads drainage systems and increases the risk of localized flooding. Moreover, exposed soil suffers from erosion, compaction, and nutrient loss, hindering natural regeneration.
Ecologically, this situation leads to a progressive decline in biodiversity, both in flora and urban fauna, affecting the ecosystem services provided by natural environments such as pollination, biological control, and air quality. From a social and health perspective, the lack of daily contact with natural spaces affects mental health, increases stress levels, and limits opportunities for active recreation and emotional well-being. This problem is further exacerbated in post-pandemic contexts, where the connection with nature has proven to be a key factor for community resilience.
The Miyawaki strategy makes it possible to transform residual urban spaces—normally degraded or underutilized—into high ecological value nodes in a short period, achieving in just 2 to 3 years what a natural forest ecosystem would take decades to accomplish. This methodology begins with intensive soil preparation, including decompaction, incorporation of organic matter, and the application of mycorrhizae that promote symbiosis between roots and subsurface nutrients, improving soil structure and its water retention capacity.
The technique is based on the dense planting of a minimum of 25 to 30 native species adapted to the local climate, distributed in different strata: herbaceous, shrub, and tree. This functional diversity favors synergy between species, accelerates growth, and maximizes urban ecosystem services such as carbon capture, pollutant particle fixation, shade provision, and humidity stabilization.
The rapid ground cover reduces erosion and favors rainwater infiltration, decreasing surface runoff. At the same time, the density and heterogeneity of the vegetation create cooler and more humid microclimates, mitigating the heat island effect in densely built urban areas.
From a social perspective, these mini forests become spaces of high symbolic and educational value: places of environmental learning, community interaction, and restoration of the bond between people and nature in urban contexts. The involvement of schools, families, and volunteers in planting and monitoring activates a sense of belonging and co-responsibility over the urban environment.
The project will begin in September with site characterization, soil analysis, mechanical aeration, and organic substrate enrichment. Planting design will follow principles of functional biodiversity and ecological niche density. Community planting days will take place in November, involving schools, local businesses, and citizen volunteers. An intensive maintenance protocol will be established during the first two years, including assisted irrigation, weed control, and growth monitoring.
Technologies applied: Miyawaki technique adapted to the Mediterranean-subtropical climate context, in situ composting, mycorrhizae incorporation, use of soil moisture sensors, satellite data capture systems for canopy and ecological indicator monitoring.
Monitoring plan: Soil moisture sensors, satellite imagery to assess canopy cover and surface temperature, and community biodiversity monitoring protocols (birds, pollinators, vegetation regeneration). Annual reports will include indicators of forest structural evolution and ecosystem benefits.
Alliances or implementing actors: General coordination by the Gibraltar Horticultural Society. The project is also supported by the City Council and will be promoted as a reference model for replication in other areas of the city.
The “Urban Mini Forest” project is an environmental and social intervention that seeks to restore key ecosystem services in densely built urban environments through the creation of small-scale native forests in Gibraltar. Using the Japanese Miyawaki technique, it proposes the planting of a diverse mix of native species in reduced, currently degraded or underutilized spaces to generate high-density and high-biodiversity green areas in the heart of the city.
The project responds to multiple environmental and social challenges: the scarcity of functional urban vegetation, increasing thermal stress, the reduction of local biodiversity, the disconnection between citizens and nature, and the limited capacity of urban soil to regulate the hydrological cycle. Through accelerated ecological restoration, it seeks to mitigate these effects and contribute to the community and climate well-being of Gibraltar.
The Miyawaki technique makes it possible to establish urban forests in record time (2 to 3 years) thanks to dense and multi-strata planting that replicates the structure of a mature ecosystem but in spaces ranging from 100 to 300 m². These forests not only beautify the surroundings, but also provide tangible benefits: improved air quality, reduced urban temperature, enhanced rainwater infiltration, creation of habitats for local wildlife, and development of spaces for environmental education and social cohesion.
Driven by the Gibraltar Horticultural Society and framed within the “Green Gibraltar” strategy, the project includes active participation from schools, citizens, local authorities, and companies. Its implementation includes a scientific and community monitoring plan as well as a replicability and scalability strategy for other parts of the urban area. The model proposes synergy between nature-based solutions, citizen participation, resilient urban planning, and verifiable sustainability metrics under frameworks such as VWBA 2.0, SDGs, and CDP Water Disclosure.
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