Crack Gardens

I've always admired the tenacity of trees, shrubs, grasses and vines to be able to thrive in the harshest of urban conditions; including rooftops, building sides, gutters, culverts and roadway cracks. These 'crack gardens' are most often colonized by early pioneer plants which do an important job of paving the way for other plants to become established, and mimic how plants colonize old lava flows or exposed rock faces. How these plants survive a lack of soil or rooting space, little nutrients or access to water during droughts, and extremes of heat or cold is a complete mystery to me, and gives me great hope in the reclamation of our most damaged landscapes. They can also be hauntingly beautiful in their own linear or spotty way. Here are a few crack gardens that caught my eye:

Old Royal Drive-in Theater, Meridian, MS

San Antonio Botanic Garden, TX

Felder Rushing's designed 'Crack Garden' Driveway, Jackson, MS

Managing for Urban Biodiversity

 

Filbert steps, San Francisco, CA

How does one increase the plant and animal biodiversity in a city? Alexis Alvey gives us four places to start in her 2006 article in Urban Forestry & Urban Greening, entitled "Promoting and preserving biodiversity in the urban forest" (5, 2006). Alvey suggests that landscape management should increase the biodiversity in all available parts of the urban forest; including street trees, parks, woodlots, abandoned sites, and residential areas. There are four steps that she recommends to concentrate on: 1) developing a tree inventory, 2) planting for biodiversity, 3) urban parks and woodlots, and 4) residential areas and people. Establishing a tree inventory is a great place to start and creates baseline data from which to make decisions. Software programs such as i-Tree and CITYgreen are available to use for data collection and organizing. Planting for biodiversity simply expands the city tree palette to include more diverse species. Municipal landscape regulations are increasingly recommending or mandating that street tree monocultures are no longer to be used. Adding a diversity of species by planting in existing parks and woodlots is a simple way to increase biodiversity through arbor day plantings or annual planting efforts. Finally, Alvey concludes that public education about diversifying yards and gardens is crucial to create an informed public.

Cities and biodiversity

Biodiversity occurs at multiple scales, from site to citywide to regional to global. At the urban level, how a city is designed, planned, and managed can have significant impacts upon its region and other parts of the world. Just as the collective outputs of farmers, industries, and municipalities from 40% of the North American continent have created an aquatic dead zone in the Gulf of Mexico about the size of the state of Connecticut. The Gulf of Mexico is one of the most productive commercial fishing regions in the world, and this hypoxic zone displaces the shrimp, oysters, and fish that feed a global market. Similarly, the collective actions of a city’s property owners impact its levels of urban biodiversity. We all know the drivers of loss of biota in urban systems, but how can we think about it at a municipal scale? Authors de Oliveira, Balaban, et al discuss this in their article entitled "Cities and biodiversity: Perspectives and governance challenges for implementing the convention on biological diversity at the city level" (Biological Conservation  144, 2011). In it, they outline six avenues of improving biodiversity at the municipal scale: 1) development and implementation of proper housing and infrastructure policies; 2) provision of a good network of urban green spaces and functional aquatic habitats, 3) support of sustainable productive uses of biodiversity in urban areas; 4) improvements in public transportation and more compact cities; 5) increase the awareness among urban residents and decision-makers, and 6) stronger links with national and international networks. They make the case that cities can make significant strides in biodiversity levels for the following reasons:

• Cities can be an efficient form to protect biodiversity. Municipalities that reduce sprawl and their development footprint maximize more space for forests, agricultural lands, and biodiversity.
•  Cities are involved in policies to tackle global problems. The development of a City Biodiversity Index by the Conference of Parties to the Convention on Biological Diversity (CBD) created a ranking system for biological health in urban areas.
• Urban residents tend to be more educated and environmentally sensitive.
• Policies can be more effective at the city level scale.
• There are opportunities for a win-win situation between biodiversity conservation and other benefits. Areas for biodiversity conservation are similar zones for other ecosystem services.
• Convergence of movements on biological diversity and urban planning. Urban planning is more accepting of including biological components, just as biologists are more accepting of the biological relevance of urban areas.

There are definitely some challenges to enacting policies and gaining community acceptance of increasing biological services in urban areas. But as this report concludes, “cities are fundamental players to achieve the objectives of the CBD, as most of the world population lives in cities today and many of the important decisions that affect biodiversity are made in cities.”

The Proximity Principle

Vacant lands are often viewed as the waste products of a city. As they have outgrown their prior use, current land owners speculate that the land value will increase through time and become more valuable. Vacant urban lands typically have a low annual tax burden so there is incentive for the landowner to hold onto the lot (Albert Hartheimer, Affordable Housing and the Land Value Tax Perspective, 2014). But there is another advantage to keeping open green space within communities: property values increase when they are located close to a green space. In the past few decades there have been numerous research articles that support this claim, and John Crompton of Texas A&M University calls this the Proximity Principle. In Crompton’s 2007 article in Leisure Studies (Volume 63, No. 1), he writes that “communities are often confronted with the difficult decision of land use development. Often the assumption is that developing the land for residential homes offers more revenue to the community than developing parks and open spaces. Several factors show that this assumption is in error. The evidence shows that preserving open space can be a less expensive alternative to development.” He concludes that maintaining open space does not take away from a community but is instead an integral part of its economic health.

Schools Need Nature Too

It's been well established that being exposed to nature based places in everyday life is a major determinant of sensitivity to environmental issues (Sebba 1991; Rohde and Kendle 1994). Richard Louv took this one step further and called it a disorder if humans are separated from natural processes (Last Child in the Woods, 2005). In his 2012 interview with Camping Magazine (Jan/Feb), Louv argues to do something about this by "building natural play spaces at schools and in neighborhoods, promoting the use of biophilic design for schoools (thus making them much more conducive to learning and creativity), working for the return of recess and field trips, and creating nature-focused schools, especially preschools" (p. 27). A growing body of research supports the many benefits of children being active in nature-based play, including stronger immune systems, being more physically active and less overweight, more resistance to stress and behavior disorders, being more creative, reduction in bullying behavior, and reducing the symptoms of ADD and ADHD (http://www.kidsafewa.com.au/naturalplay.html 2014). The benefits are clear, so why do our schoolyards continue to resemble prison yards? For 30+ years I have designed and built school gardens for a number of settings--from small school vegetable gardens to entire native plant school campuses. It isn't difficult to find a well-intentioned teacher (usually science) who wants to take classes out in the schoolyard for nature-based lessons. However, it is difficult to get a majority of teachers, maintenance personnel, neighbors, or administrators to buy into the idea. And when that inspired teacher leaves so usually does the garden. It's even more difficult to find funding for garden construction or for upkeep and maintenance. But it's not impossible either. Louv is correct in his assessment that schools are a perfect place to work in a bit of natural play space. We need more examples of inexpensive yet creative schoolyard designs that the parents and school administrators can buy into. For a few inspired case studies check out http://www.natureplaywa.org.au/case-studies

The Flora of the Future?

Intriguing essay by Peter Del Tredici that was posted this month entitled The Flora of the Future: Celebrating the Botanical Diversity of Cities. Peter is an associate professor at Harvard GSD and author of Wild Urban Plants of the Northeast. In it he makes a case for novel ecosystems, which are “a system of abiotic, biotic and social components that, by virtue of human influence, differ from those that prevailed historically, having a tendency to self-organize and manifest novel qualities without intensive human management” (Hobbs, Higgs, and Hall; Novel Ecosystems). In other words, these are plant and animal systems that differ from natural systems and have formed because of humans. These have been occurring wherever humans have lived for millennia and have followed our dump heaps. Del Tredici maintains that we have to recognize that these not only exist, but are spreading due to urbanization, globalization, and climate change. These are our new urban ecosystems. Interestingly, he defines a few new ‘infrastructural taxonomies’ that are urban places where survivor plants co-exist—chain link fences, vacant lots, median strips, stone walls, pavement cracks, specialized microclimates, and river corridors. He acknowledges that some of these plants are problematic, such as the invasive exotics or plants that cause problems for people. Del Tredici’s thesis is that landscape architects should embrace these common urban systems and enhance their potential in design. And he’s right, designers should be looking at the potential aesthetics of our most common and biologically significant landscapes. A goldenrod growing on a railroad bank and a goldenrod growing in a perennial garden bed are the same species. The only difference is intent, and it will take very creative solutions to get public acceptance. You can view the full article at http://places.designobserver.com/feature/flora-of-the-future-urban-wild-plants/38417/