Greening the human environment: the untold benefits.

A myriad of benefits of plants that have been documented by research are presented in this paper, along with a discussion of possible mechanisms. Plants, which are essential for our survival, provide food, fiber, building material, fuel, and pharmaceuticals. Plants also produce intangible benefits for people, such as improving our health. These benefits occur with scenes of nature, individual plants indoors, gardens outdoors, parks, and forests. The understanding of the role of trees, in particular, in promoting both human and ecological health is increasing. Plants make our surroundings more pleasant, and they help us feel calmer. They contribute to cleaner, healthier air, thus improving our well-being and comfort. Plants have been associated with reduced stress, increased pain tolerance, and improved mental functioning in people. Human responses to plants appear to be both learned and innate. Some studies suggest genetic components to the responses. Some primates are known to detect subtle differences in leaf color, selecting to eat those leaves with the highest nutritive value; people also respond more positively to plants of some colors than to others. Most people in the world now live in urban areas. These areas are typically devoid of plants, resulting in concerns over children being raised in such unnatural areas. These impacts will also be examined. INTRODUCTION Plants are essential for the survival of life on earth as we know it. Plants provide us with food, fiber, fuel, shelter, and pharmaceuticals. We use plants to decorate our homes and workplaces and to mark special occasions, such as holidays. For thousands of years, in cultures across the globe, plants and gardening have been considered physically, mentally, and socially good for people, yet until recently, there has been no research to verify such claims. In the past thirty years, numerous scientific studies have begun to document the relationships between people and plants, showing that people exhibit aesthetic, emotional, and physiological responses to plants and nature (Relf and Lohr, 2003; Lohr, in press). The benefits from trees, gardens, and nature include: better air quality (Wood et al., 2002; Oyabu et al., 2003), lower stress (Ulrich et al., 1991; Park et al., 2010), lessened pain (Ulrich, 1984; Lohr and Pearson-Mims, 2000), reduced mental fatigue (Cimprich, 1993; Herzog, et al., 1997), improved children’s cognitive capacities (Wells, 2000; Faber Taylor and Kuo, 2009), and reduced violence (Taylor et al., 1998; Kuo and Sullivan, 2001). Such research is contributing to an increased use of plants to solve health, environmental, and community problems (see, for example, Tyrvainen et al., 2005; Nowak, 2010). Improved understanding of the theoretical basis behind these beneficial effects would lead to more effective use of plants to deal with these issues. This