Conducting research with human subjects involves many of the same issues involved with conducting any type of research. As horticulturists, we are aware of the range of variability that can be introduced when working with living organisms. This variability can come from environmental influences as well as genetic variation. These can be major factors when conducting research with people as well. Research with people also introduces complicating interactions between the researchers and the subjects. When working with humans as subjects, federal regulations must be considered; these regulations are even stricter when the research involves youth. These additional factors, which should be considered when designing studies to understand the impacts of plants and plant programs on youth, will be discussed.
Evidence is growing that people exposed to environmental and mental stress benefit from having plants in their communities and from working with those plants in gardening and related activities. The benefits to the community range from improved social interactions to reduced littering. Feelings of self-confidence and self-worth are improved. Economic conditions can be improved: vegetable production reduces the need for individuals to spend money on food, and community improvement initiated by flower gardening increases property values. Some of these benefits are well-documented, while others are primarily supported by a long history of anecdotal evidence. More research is needed to fully document the importance of community gardening efforts and to justify expansions in these programs.
Several recent reports have been critical of the quality of general education in the United States (Assn, of American Colleges, 1985; Geiger, 1980; Schwerin, 1983). Baccalaureate education has not been spared from negative evaluation (Boyer, 1987). A report of the Assn, of American Colleges (1985) stated that the bachelor’s degree had lost its intrinsic value: undergraduate education was being dominated by a marketplace philosophy and universities were not promoting rigorous thinking.
Studies have shown that many people prefer landscapes with vegetation over those devoid of plants. Few studies have looked specifically at adolescents or people of different ethnic heritages. Understanding preferences of such groups could help in designing horticultural education programs for these populations. In this study, high school students were asked to rate their preferences for a series of plant-dominated and urban-dominated slides.
Students generally gave higher ratings to the plant scenes than the urban scenes, indicating that they preferred the plant scenes. Their preferences were similar to what would be predicted from studies with adults. Hispanic students rated urban scenes and formal plant scenes, such as a garden with sculptured shrubs, significantly higher than did Anglo students. Hispanics rated informal scenes, such as a deciduous forest with no ground cover, significantly lower than did Anglo students.
Seedlings of broccoli (Brassica oleracea L. Group italica), lettuce (Lactuca sativa L.), marigold (Tagetes patula L.), and tomato (Lycopersicon esculentum Mill.) were grown in 50% (by volume) vermiculite and 0%, 12.5%, 25%, 37.5%, or 50% fresh or aged spent mushroom compost, with Canadian peat comprising the remaining portion. Percent dry weight of the plants decreased linearly, whereas dry weight, height, and quality ratings showed quadratic responses as the rate of compost in the growing mix increased. Plants were smaller in fresh than in aged spent mushroom compost. Lettuce, marigold, and tomato (moderately salt-sensitive crops) grew best with 25% aged spent mushroom compost, and broccoli (moderately salt-tolerant) grew best with 37.5% aged compost.
Cut `Samantha' roses (Rosa hybrida L.) were placed in deionized water or a 20-mm Ca(NO3)2 pulsing solution for 72 hours. Flowers then were held in preservative solutions containing 0 or 4 mg fluoride/liter. Fresh weight gain, solution uptake, degree of flower opening, and flower longevity were reduced in the presence of fluoride in the holding solution. Visual symptoms of injury and reduced flower quality also were noted in treatments with fluoride. Pulsing improved fresh weight gain and degree of opening of flowers held in solutions containing fluoride. Pulsing also delayed the onset of visual symptoms of fluoride injury. Water uptake for flowers that were pulsed and exposed to fluoride was not different from uptake for flowers exposed to fluoride alone. Flower longevity for roses in all treatments was increased by using the calcium nitrate pulse, but pulsed flowers in fluoride did not survive as long as the control flowers.
Cut flowers of eight cultivars of Rosa hybrida L. were held in preservative solutions containing up to 4 mg F-/liter. Leaf diffusive resistance was increased by holding flowers in F-solutions. In most cultivars, fresh weight gain was decreased, the degree of flower opening was affected, and visual symptoms of injury were noted in the presence of. F- in the holding solution. Damage at 2 mg F-/liter was almost as severe as at 4 mg/liter. Number of days to petal abscission or bent-neck was shortened by F- for `Samantha' and `Bridal Pink'.
Community involvement is critical for the continued vitality of the urban forest. To encourage this involvement, an understanding is needed of what promotes shared stewardship as well as of different cultural perspectives regarding trees. A survey of the general public in 109 large metropolitan areas across the continental U.S., a culturally and ethnically diverse group, was conducted. Two thousand adults were surveyed to assess the extent of their childhood experiences with nature, their current attitudes toward urban forests, and their demographic backgrounds. Respondents were questioned particularly about their earliest experiences with nature and their current understanding and appreciation of the urban forest. Other researchers have examined the relationship between childhood contact with nature and attitudes toward nature among professionals in environmental fields, but this relationship has not been explored in the general public. Correlations between survey respondents' memories of childhood contact with nature, their current perceptions of the urban forest, and the influence of their cultural and ethnic backgrounds will be presented. For example, respondents who reported very easy access to nature as children were likely to agree strongly that trees should be planted in business districts to reduce smog. Results from this survey may be applied in programs to teach children about trees and gardening, thus better tailoring these programs to engender future appreciation for the urban forest. Raw data from this survey will be made available to other researchers.
Research has shown that people respond physiologically and psychologically to scenes of urban and natural landscapes. Viewing nature has been associated with improvements in health, and there is evidence that people have a preference for certain tree forms. Human responses to different tree forms (spreading, columnar, and rounded) and nonliving urban elements were examined. Blood pressure, skin temperature, and emotional states of participants were measured while viewing computer-enhanced slides of urban and residential settings. Respondents were calmer when viewing trees than when viewing nonliving urban elements, and they expressed strong preferences for some tree scenes