Short Wave

Micro Forests: An Emerging Climate Hero?

January 7, 2026

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  • Microforests are small, human-designed urban ecosystems using native plants to mimic natural forests, aiming to cool cities and increase climate resilience. 
  • The concept of microforests originated in Japan over 50 years ago with Dr. Akira Miyawaki, focusing on restoring degraded land by planting dense, multi-layered ecosystems simultaneously. 
  • Researchers are using scientific methods, including DNA analysis of spider webs and community science apps, to track the rapid biodiversity increase (documented over 100 species) and carbon sequestration (one metric ton per year currently) in these two-year-old microforests compared to control plots. 

Segments

Introduction to Microforests
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(00:00:35)
  • Key Takeaway: Microforests are small, lush, human-designed forests using native plants specifically engineered for urban environments.
  • Summary: Microforests are small, lush, and entirely designed by humans for urban settings. They are intended to cool cities and increase resilience to climate change. Producer Rachel Carlson visited the largest microforest in California, located in Los Angeles.
Defining Forest Characteristics
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(00:01:43)
  • Key Takeaway: A forest is defined by touching canopies and multiple vertical layers of vegetation, which microforests simulate.
  • Summary: A forest requires tree canopies to touch, creating a blockage of sunlight and establishing distinct vertical layers of plants. Microforests simulate this structure, despite their smaller scale. The term ‘micro’ refers to the small footprint, ranging from 200 square feet up to an acre.
LA Microforest Location and Scale
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(00:01:07)
  • Key Takeaway: The largest California microforest, located in Ascot Hills Park, Los Angeles, covers 10,000 square feet near major freeways.
  • Summary: The visited microforest is situated in Ascot Hills Park in northeast Los Angeles, an area typically lacking green space, surrounded by freeways. This specific site is 10,000 square feet, or about a quarter acre, making it the largest in California. It features drought-tolerant native plants like Southern California black walnut and blue elderberry due to LA’s climate.
Origin and Planting Strategy
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(00:04:44)
  • Key Takeaway: The microforest approach was pioneered in Japan over 50 years ago by Dr. Akira Miyawaki to rapidly restore degraded land.
  • Summary: The original idea for this tiny forest approach dates back over 50 years to Japanese ecologist Dr. Akira Miyawaki. Planting involves densely layering different species—from roots and soil enhancers to shrubs and canopy trees—simultaneously, rather than waiting for natural ecological succession. This dense, layered planting helps the ecosystem mature faster, potentially in a couple of decades versus a century for a large forest.
Field Trip and Scientists
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(00:06:00)
  • Key Takeaway: The two-year-old LA microforest is maintained by biologist Damian Willette and horticulturist Catherine Pockraduni.
  • Summary: Producer Rachel Carlson met with scientists Damian Willette and Catherine Pockraduni during a warm November weekday. The scientists have been maintaining this specific microforest since 2024, celebrating its second birthday. The small size allows researchers to use the plot as a direct science experiment.
Biodiversity Comparison Study
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(00:07:07)
  • Key Takeaway: The microforest is scientifically compared against an adjacent, identical plot filled only with invasive weeds to measure ecological impact.
  • Summary: Researchers compare the thriving microforest against a control plot of the same size filled with invasive weeds. They conduct bi-weekly counts of insects, birds, and lizards, finding around 100 animal species in the microforest, significantly more than the 100 documented species in the entire surrounding park previously. This comparison directly studies the biodiversity benefits of using native plants.
Advanced Tracking Methods
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(00:08:12)
  • Key Takeaway: Biodiversity tracking utilizes GPS-mapped plants, drone measurements, and genetic analysis of DNA collected from spider webs.
  • Summary: Scientists map every plant with GPS coordinates and use drones to measure growth and volume. Spider webs act as natural air filters, collecting shed skin cells and metabolic waste from animals moving through the area in the last 24-48 hours. Genetic tools applied to the web washings reveal nocturnal and hard-to-spot species like barn owls and bats, providing a complete picture of forest activity.
Community Science and Growth
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(00:10:04)
  • Key Takeaway: Community scientists contribute data via an app, helping measure plant growth, which has resulted in rapid development, such as elderberries exceeding 10 feet in two years.
  • Summary: Damien’s lab developed an app allowing over 150 park visitors to scan QR codes on plants to measure height, look for flowers/seeds, and confirm vitality. This community input aids in tracking growth, which is notably fast; some elderberries are over 10 feet tall, surpassing the growth of a decade-old black walnut in the scientist’s own backyard.
Health Metrics and Climate Benefits
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(00:11:10)
  • Key Takeaway: The microforest shows high success (89% plant survivorship) and actively excludes weeds, while currently sequestering one metric ton of carbon annually, expected to rise significantly.
  • Summary: The forest health is measured by an average survivorship rate of over 89% for the planted species. The dense planting crowds out unwanted plants, resulting in an 80% reduction of weeds between year one and year two without human intervention. This specific microforest removes one metric ton of carbon dioxide per year, with projections to exceed 50 metric tons annually within two decades, equivalent to removing emissions from 10 SUVs.
Conclusion and Call to Action
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(00:12:46)
  • Key Takeaway: Beyond ecological benefits, microforests successfully draw people into nature and foster community engagement.
  • Summary: The microforest provides cooling, food for wildlife, and brings people into nature, evidenced by passersby stopping to ask questions and offer help. Listeners are encouraged to follow Short Wave and submit science questions to shortwave@npr.org for the Nature Quest series.