Metabolic Forest

Silvia Cox | Prentiss Darden 

Sensing, Capturing, and Metabolizing Air Pollution

Exceptional conditions of contaminated urban sites require highly efficient and novel methods that function to enhance urban ecologies and infrastructural performance while also contributing to the creation of new cultural spaces. Metabolic Forest is a synthetic ecology designed to address West Oakland’s poor air quality, lack of open space and poor ecological functioning through a network of urban forest sites that sense, capture and metabolize air pollutants. 

The design includes two forest typologies—a pollution absorption forest and a biofuel production forest. Within both typologies, planted areas are anchored with misting devices strategically placed at areas of high emissions. As the devices sense high emissions they emit mist, increasing the humidity of the air,  allowing greater facility for particulate matter to fall out of the air and onto the foliage of forested vegetation where it eventually falls to the ground and is metabolized by mycelia and microorganisms in the soil. The absorption forest becomes a humid, wild place that strongly juxtaposes the industrial and infrastructural landscapes of West Oakland. By contrast, the production forest, located in open spaces within the Port of Oakland, reads as a methodical organization of regularly spaced trees, a form useful for production operations.

The agency of computation plays an integral, supporting role to vegetation; computationally controlled devices amplify biological systems to create this synthetic ecology. As a solution for West Oakland’s poor air quality, Metabolic Forest generates emergent forested sites, accentuated vertically with misting devices. The system honors the innate qualities and functions of nature while weaving in the power of computation to support and augment living systems.

West Oakland

West Oakland is bounded by heavily used interstates and bordered by the port to the west. As a result, the community experiences particulate matter concentration nearly three times that of the rest of the Bay Area.1 Consisting mainly of a middle to low income African-American population, West Oakland residents have a much lower life expectancy than the surrounding areas. These health issues are only exacerbated by diesel trucks emitting massive amounts of particulate matter—a known trigger of heart and lung disease.


In order to highlight areas of high vulnerability, we used particulate matter dispersion models to select points at 500-foot intervals along lines perpendicular to the centerline of I-880, the heaviest used interstate. To understand this data spatially, the location of each point was assigned x and y coordinates and the particulate matter concentrations were assigned to the z axis for each point. From these coordinates, a series of contour lines were extruded to express the highest and lowest emission levels during the seasons. 

Recent research into the capacity of fog to lower pollution levels steered us towards Stoke’s Law, a parameter that guided our development and design of a computationally controlled device that senses pollution levels of the immediate environment and adjusts humidity with misters. In addition to creating new humid microclimates in response to emissions, the devices are also designed to sense and collect vital weather information to build an open data repository that will provide public access to air quality data.

A Multifunctional Sensor

The misting device is multifunctional, sensing air quality and atmospheric conditions including wind, temperature, humidity, barometric pressure, ozone, nitrous oxides, oxygen oxides and particulate matter. The device also generates energy from a wind turbine and serves as a connection for drip irrigation pipes circulating nutrients and water. A camera is mounted at the top of the device to monitor forest growth and offer new views of the landscape. At the base of the device, sensors in the soil read nutrient needs including basic nitrogen, phosphorus, potassium and humidity levels. Air quality sensing is computationally translated as a colored code via embedded bands of lights. Residents and visitors to West Oakland would be able to visualize air quality from a delicate scattering of lights throughout the forest when moving through the city, either at grade or on the elevated highways. 

Gradual Integration

Phased implementation of the design begins with establishing growth at the source of emissions and moving into the fabric of the city over time. As each device is installed, vegetation is fitted along with it. The initial planting pattern is laid out in concentric circles and planted with regular spacing so that the work can be carried out according to plan, ensuring successful establishment. The trees are inoculated with mycelia to boost and catalyze growth of the rhizosphere, an important factor in the metabolism of elements, such as the heavy metals often found in particulate matter. As the first phase of the project grows and performs, the system is evaluated to adjust future expansion and contraction.

Feedback Loops

The feedback loops programmed into the operational logic of the Metabolic Forest allow the synthetic ecology to be a dynamic system that contracts and expands over time as air pollution levels change and the production of poplars increases. Sending and receiving data on several timescales, the system detects multiple aspects of the changing environment. At the smallest scale, nutrient and water needs are read in milliseconds. Air quality is sensed on a timescale of minutes, sending a signal to indicate the amount of mist to expel. The longest timescale is the seasonal consideration of expansion and contraction of the system. The system uses data to suggest new device placement or vegetation and mycelia amplification to increase particulate matter remediation. If levels are sensed below average for several months, the system indicates that this device can be removed and installed in a new area. 

The operational protocol for the production forest operates similarly, the difference being that the types of data measured on a seasonal basis and stored within the system are about the quantity of biomass produced and market information about poplar as a resource, which would aid in calculating the value of an annual crop. Rather than following potentially outdated prescriptions of a master plan, Metabolic Forest uses computation to read and write finer adjustments on a more continuous basis.

Versatile, Multifaceted, Flexible, Fluctuating

The Metabolic Forest is a proposal to address air quality issues with a hybrid configuration of technology and vegetation. Sensing and computation work in concert to drive the performance of vegetative systems, enabling this synthetic ecology to function with feedback loops. This allows it to self-regulate and adapt to the changing environment, tuning itself to perform as an intelligent expression of the surrounding environment. Growing over time, the forest becomes a register of pollution absorbed, creating a visible analog of invisible byproducts from a fossil fuel-based economy. It becomes a register of a progressive, technological-biological hybrid design approach to improve quality of life in West Oakland. Metabolic Forest address the symptoms of the current system, but it also addresses the cause of the overall problem through the production of an alternative fuel.


. Di, Pingkuan. Diesel Particulate Matter Health Risk Assessment for the West Oakland Community. Sacramento: California Air Resources Board, 2008. Print.

Silvia Cox is a native designer of Guatemala, where she obtained a bachelor’s degree in Architecture. She graduated with an MLA from the Robert Reich School of Landscape Architecture at Louisiana State University. Her current work at Pharis Design in Austin, Texas focuses in urban and residential planning.

Prentiss Darden works as an Innovation Generalist at Sherwood Design Engineers to create resilient, regenerative and district scale infrastructure. She has a Masters in Landscape Architecture from LSU and a bachelor’s in International Relations from Lewis and Clark College.