Microforests in Los Angeles: Tiny Urban Forests Yield Big Biodiversity and Climate Benefits

Microforests are small, human-designed forests placed in urban spaces to boost biodiversity, carbon sequestration, and resilience to climate change. This NPR Shortwave episode follows researchers in Los Angeles as they plant, monitor, and compare a microforest to a weed-dominated control plot, using GPS mapping, drones, and spider-web DNA to track plant health, wildlife, and overall ecosystem performance. Early results show high plant survivorship, significant weed suppression, and measurable climate benefits, with neighbors and park visitors increasingly engaging with nature in the city.

Overview: Urban microforests redefine city green space

Microforests are compact, human-designed forests created to mimic natural forest ecosystems in urban settings. The Los Angeles example at Ascot Hills Park shows a quarter-acre ecosystem using dense layers of native plants such as Southern California black walnut and blue elderberry. The Miyawaki-inspired technique accelerates forest formation by planting canopy, understory, and ground cover all at once rather than waiting for natural succession. This approach yields rapid biodiversity gains and climate benefits in a heat-prone city. "it's the largest microforest in California." - Damian Wollett, associate professor of biology at Loyola Marymount University.

Field deployment and research design

Damian Wollett and Catherine Pockradoi lead a two-year field project beside a control plot filled with invasive weeds. They map every plant with GPS coordinates, use drones to measure growth, and track insects, birds, lizards, and even small mammals. Spider webs serve as environmental DNA samplers, revealing nocturnal and elusive wildlife moving through the space. "We're crowding out the space with the plants that we do want." - Catherine Pockradoi, horticulturist.

Biodiversity, plant health, and early results

Initial survivorship averages around 89 percent as plants mature, while weed pressure drops by about 80 percent compared with the weed-dominated plot. The microforest hosts roughly 100 animal species, a notable increase from prior park counts. The dense plant layering supports soil health and a faster move toward forest-like structure, enabling ecosystem services to emerge sooner than in traditional forests. "Spider webs are nature's DNA swabs." - Damian Wollett, associate professor of biology at Loyola Marymount University.

Climate benefits and community impact

Beyond biodiversity, the project contributes to carbon sequestration and neighborhood cooling, with ongoing estimates of about 1 metric ton of CO2 per year now, projected to rise to more than 50 metric tons per year in the next two decades. The microforest also invites public curiosity, with park visitors asking questions and a park-wide data app engaging over 150 community scientists who scan plant QR codes to help track growth. It all demonstrates how small urban forests can become living classrooms and community assets while supporting climate action in cities. "It also helps bring people into nature." - Rachel Carlson.