Book Review: Edible Estates: Attack on the Front Lawn

In light of Americans’ increasing awareness of environmental issues, many have started to take a critical look at the way in which natural resources are used. One staple of American life which has recently come under attack is the front lawn. In Edible Estates, architect and designer Fritz Haeg proclaims the front lawn to be a harmful element of the American landscape. In his view, lawns are unproductive consumers of water and other resources, requiring harmful practices such as the spreading of chemical fertilizers and the use of fuel-powered lawnmowers and weed-eaters. As an alternative, Haeg suggests ripping out lawns and planting productive vegetable gardens in their place

Sowing the seeds of a vibrant community

Throughout many cities and states across the United States, an increasing number of community gardens are being developed, planted, and enjoyed. Community gardens are defined as "any piece of land that is gardened by a group of people" (Baldwin, et al, 2009, p. 2). While community gardens vary by type, size, and organization, the common link between all community gardens is that they are developed and maintained by community members (Kirby, et al, 2008, p. 5). Community gardens are distinguished from private gardens in that community gardens are "in some sense a public garden in terms of ownership, access, and degree of democratic control" (Ferris, et al, 2001, p. 560). Community gardens can be created in any neighborhood, be it urban or rural, and can serve a variety of participants, be they schoolchildren or the elderly. Many varieties and types of gardens exist. Each garden is structured in a different way or offers different services depending upon the needs of the local community (Ferris, et al, 2001, p. 560). For example, they can be located in urban, suburban, or rural settings on municipal land, land trusts, or private land (Kirby, et al, 2008, p. 5). They can be established at schools, parks, places of worship, public housing, or vacant lots (Baldwin, et al, 2009, p. 2). Some gardens are large, encompassing many acres, while other are located in pocket parks or on small half-acre lots. Some community gardens are official and sanctioned by the municipalities where they are located while others are "guerilla acts of cultivation" (Kirby, et al, 2008, p. 5). At some community gardens, hundreds of volunteers participate while at others just a few gardeners work collectively or individually. The flexibility of community gardens make them ideal for wide use. Community gardens have no set criteria or structure; they can be suited to the needs of their participants and neighborhoods. This adaptability has encouraged and allowed the implementation of community garden programs throughout the United States. In order to answer these questions, four community gardens which are each located in low-income neighborhoods in the United States were interviewed about their programs and outreach activities. Also, an in-depth look into the current literature discussing community gardens and their benefits was undertaken. Some difficulties exist with creating community gardens, and these problems are addressed to provide a planners and neighborhoods with a better understanding of the process of implementing community garden programs. The lessons learned from this literature review and the case studies were synthesized into policy suggestions for cities and communities. Encouraging the development of individuals and communities is an important goal for many urban planners, and community gardens may provide a unique tool for community development.Master of City and Regional Plannin

Book Reviews

Book reviews of the following: Urban Design and the Bottom Line: Optimizing the Return on Perception by Dennis Jerke, Douglas R. Porter, and Terry J. Lassar; A Paradise Built in Hell by Rebecca Solnit; Edible Estates: Attack on the Front Lawn by Fritz Hae

Thiol–Ene Elastomers Derived from Biobased Phenolic Acids with Varying Functionality

The synthesis and physical properties of thiol–ene elastomers derived from plant-based phenolic acids were explored. Phenolic acids of varying functionality (ranging from 2 to 4 hydroxyl and carboxyl groups per molecule) and relative placement of functional groups (<i>ortho</i>, <i>meta</i>, <i>para</i>) were allylated and subsequently reacted with a multifunctional thiol using a photoinitiator. The thermal and mechanical behaviors of the resulting elastomers were characterized. The networks derived from difunctional allylated phenolic acids exhibited narrow glass transitions (indicating a high degree of network homogeneity) and glass transition temperatures (<i>T</i>_g) which correlated with their cross-link density. The <i>para</i> placement of allyl groups on the allylated phenolic acid produced a network with the highest cross-link density, <i>T</i>_g, modulus, tensile strength, and elongation at break (followed by <i>ortho</i> and then <i>meta</i>). As the functionality of the allylated monomer increased (to 3–4 allyl groups per molecule), the cross-link density remained high yet the <i>T</i>_g decreased, attributed to a lower concentration of benzene rings throughout the network structure (as all networks were prepared at the stoichiometric ratio of allyl and thiol functional groups). The networks derived from the higher functionality allylated phenolic acids also exhibited lower elongation at break and associated tensile strength and tensile toughness, likely due to increased heterogeneity of the networks (indicated by higher glass transition widths compared to the networks derived from difunctional allylated phenolic acids). All networks exhibited behavior consistent with an ideal elastomer (affine network) at low to moderate strains, albeit with lower moduli than predicted from the monomer chemical structure. At the high end of the strain ranges achieved, some of the networks exhibited strain hardening behavior. This work develops fundamental relationships between the molecular structure of the phenolic acids, including number and placement of functional groups, and the physical properties of the resulting networks

Synthesis and Physical Properties of Thiol–Ene Networks Utilizing Plant-Derived Phenolic Acids

Elastomeric polymer films synthesized through thiol–ene chemistry, suitable in applications as coatings and adhesives due to their ease of preparation and superior physical properties, are traditionally derived from petroleum sources. Of recent interest is the exploration of sustainable alternatives for the precursors to these materials. Here, we report the synthesis of thiol–ene networks through the photoinitiated reaction between allylated plant-based phenolic acids (salicylic acid and 4-hydroxybenzoic acid) and a multifunctional thiol, followed by isothermal annealing. Plant-sourced phenolic acids offer many advantages as biorenewable monomers: their rigid aromatic rings are expected to provide mechanical strength to the resulting polymers and the presence of multiple hydroxyl and carboxyl groups leads to ease of functionalization. Both phenolic acids produced networks with high degrees of homogeneity and few defects, as evidenced by narrow glass transitions and consistency of their tensile behavior with the ideal elastomer model at low-to-moderate strains. The 4-hydroxybenzoic acid based network, which had a higher cross-link density, exhibited a higher glass transition temperature, modulus, tensile strength, and elongation at break as compared to the salicylic acid based network. This work develops fundamental relationships between the molecular structure of the phenolic acids and the physical properties of the resulting networks