Urban trees face significant challenges, from compacted soils to limited nutrient availability. At New Life Presbyterian Church in Escondido, California, decorative trees planted in the parking lot median struggled for years, showing symptoms of decay, insect infestations, and poor canopy development. In 2018, the Nutrient Enrichment Passive System (NEPS) was installed to address these issues. This case study examines the transformative impact of NEPS on tree vitality and growth over two years.
Identifying the problem: Struggling urban trees
The church’s parking lot median presented a difficult environment for tree growth, with narrow, curbed spaces and high foot traffic. Flowering plum trees previously planted in the area suffered from decay and failed to thrive. In January 2016, the church replaced them with 15 Brisbane Boxwood (Tristania conferta) and Pink Trumpet Trees (Tabebuia ipe), selected for their adaptability to urban conditions. Despite a drip irrigation system, these trees showed signs of stress and stagnation after two years, prompting the facilities manager, John Robertus, to seek a solution.
The NEPS installation: A low-impact, sustainable solution
In February 2018, NEPS units were installed around each of the 15 trees. Four units were placed per tree (three for one tree obstructed by a concrete block), forming a subsoil network to deliver essential nutrients. The ultra-light HAZL drilling rig ensured a quick and minimally invasive installation process. Within two days, the NEPS system was fully operational, with no visible impact on the parking lot or landscaping.
John Robertus praised the simplicity of the installation:
“The stigmas were almost invisible after installation, and we were able to resume normal activities immediately. This is a very positive point of your system.”
Results: Transforming tree health and appearance
Rapid improvement in tree growth
Within four months, the trees showed significant growth and vitality compared to previous plantings.
By 20 months post-installation, the Brisbane Box trees grew from 10 feet to nearly 15 feet, while Pink Trumpet Trees increased from 7 feet to 10 feet in height.
Foliage became dense and vibrant, with no need for fertilizers or pesticides.
Sustained vitality without additional inputs
The trees thrived with the existing irrigation system, demonstrating NEPS’s ability to optimize nutrient delivery and water use.
Robust health indicators, including enhanced foliage density and color, suggested a strong defense system against pests and environmental stressors.
John Robertus remarked on the visible transformation:
“The trees look amazing! In a location where trees have failed in the past, these trees are growing aggressively year-round without fertilizer, pesticides, or changing the water regimen. The difference is really night and day.”
Environmental and maintenance benefits
Reduced maintenance efforts: NEPS eliminated the need for chemical fertilizers and pesticides, reducing costs and environmental impact.
Improved aesthetics: The dense, healthy canopies enhanced the visual appeal of the parking lot.
Water efficiency: NEPS optimized nutrient absorption and allowed the trees to thrive under the existing drip irrigation system, conserving water resources.
NEPS is a model for sustainable urban forestry
The successful implementation of NEPS at New Life Presbyterian Church demonstrates the system’s potential to revolutionize urban tree care. Exlterra's NEPS technology addressed fundamental challenges in nutrient delivery and soil health, and provided a sustainable solution that improved tree vitality, reduced maintenance costs, and enhanced the urban landscape. This case study highlights the role of innovative technologies like NEPS in creating resilient, green cities for the future.
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