One of the principles promoted by the Community Environmental Council’s (CEC) Ecological Framework for Revitalizing Santa Barbara’s City Core is creating a rich and abundant mix of nature — plants, trees, birds, and insects. The preference is for native plants because these require less water and less maintenance, and because they are hardier. The CEC document states, “This will lessen the effect of the urban heat island, provide visual attraction and enjoyment, and have beneficial effects on the physical and psychological health of citizens.” In addition to the beauty, pleasure, and improved air quality that nature provides us, strengthening our link with nature downtown offers one of the best strategies to offset the growing challenges of the unfolding climate crisis.
Unfortunately, our city is moving in the opposite direction. To conserve water and reduce maintenance budgets, it is creating plazas and public gathering places with large areas of hard paving. Take the soon-to-be-opened Towbes Library Plaza. The extent of unshaded concrete will exacerbate the heat island effect and deter citizens from gathering there in the ever-increasing and intensifying hot days we will be facing. The planning for a new De la Guerra Plaza seems to be heading in the same direction.
The principle in the CEC document is based on the mini-forest movement. Thousands of these forests have been created in cities around the world, some as small as five or six parking spaces. The approach, developed by the Japanese botanist Akira Miyawaki, follows nature’s forest succession steps but quick starts the process by densely planting selected native canopy trees and understory shrubs. Native groundcovers or flowing perennials are allowed, but no lawns.
Mini-forests require no maintenance after the first couple of years, are fast-growing, and hold major amounts of stormwater, thus lowering the risk of flooding. In addition, they reduce noise and air pollution while greatly enhancing biodiversity.
Pocket-forests now exist in Southern California and throughout the state. According to researchers engaged by the World Economic Forum, cities are warming 29 percent faster than surrounding rural areas. They also found that planting trees near buildings can reduce the need for air-conditioning (AC) by 30 percent. Moreover, the condensate water from AC or heat pumps (moisture in the air condensed on the coils to cool them) can provide all the water, if captured, we need for our downtown irrigation.
As recorded by satellite, land surface temperatures have been recorded as much as 15 degrees Fahrenheit lower in these small urban forests than in surrounding areas. Surface temperature is not the same as air temperature, but these latter are frequently 5-10 degrees lower.
Part of Santa Barbara’s reputation for beauty is its many trees and green spaces. Because of the increasing uncertainty of climate change, the planting of native trees needs to be multiplied many-fold. There are no drawbacks to urban pocket-forests.
