Responses of forest trees to defoliation by insects such as gypsy moth vary greatly from site to site and from individual to individual. To determine whether some of this variation could be explained by variation in other stress factors, red oak (Quercus rubra L.) seedlings were exposed to low and high light, water, mineral nutrient, and defoliation treatments, in a complete factorial design in a greenhouse. Significant interactions were observed among factors for photosynthesis, growth, and mortality, indicating that the response to defoliation was influenced by other stresses. Defoliation increased the photosynthetic capacity per unit leaf area of seedlings grown in the low-water, but not in the high-water, regime. In response to defoliation, growth of seedlings in a low-mineral-nutrient, or low-light, regime was depressed less than that of seedlings grown in a high-mineral-nutrient, or high-light, regime. However, defoliation resulted in a similar percent reduction in biomass in all seedlings in both the high and the low light, water, and mineral nutrient treatments. Defoliation-induced mortality of shaded plants was twice that of plants grown in full sun.

The prevalence of obesity and diabetes has been studied in adolescent and adult populations in poor, medically underserved rural Appalachia of West Virginia. A web-based questionnaire about obesity and diabetes was obtained in 989 family members of 210 Community Based Clinical Research (CBPR) trained adolescent members of a network of 18 science clubs, incorporating 142 families. After age-correction in <20 years old, 50% of both adolescents and adults were obese. The frequency distribution of obesity was trimodal. In the overall population 10.4% had type 2 diabetes, while 24% of adult, obese subjects had type 2 diabetes. A new metric, the family diabetes risk potential, identified a trimodal distribution of risk potential. In the lowest most common distribution 43% of families had a diabetic family member. In the intermediate distribution, 69% had a diabetic family member, and in the distribution with highest scores all the families had a diabetic member. In conclusion, the poorest counties of rural Appalachia are at crisis level with the prevalence of obesity and diabetes. The distribution of age-corrected obesity and family diabetes risk potential are not normally distributed. We suggest that targeting individual family units at greatest risk offers the most efficient strategy for ameliorating this epidemic.

Community-Based Participatory Research (CBPR) has been advocated to translate advances in health care sciences to the community. We describe a novel approach applied to obesity management and diabetes prevention. This takes advantage of a network of science clubs organized by the Health Sciences and Technology Academy (HSTA) for extracurricular activity of disadvantaged high school students in rural Appalachia. Physician scientists and educators provided an intensive summer course on CBPR, ethics, and study design on obesity management and diabetes prevention. Ethical certification for CBPR investigation was obtained for 210 students and 18 mentors for a study on the prevalence of obesity and Type II diabetes within their community. Over a 6-month period, 989 had a collection of complete analyzable data, of which 103 had diabetes. The proportion with obesity (BMI ≥ 30) was over 50%. The frequency of diabetes was related to increasing BMI. When BMI ≥ 40, the frequency approached 50%, and exhibited a clear familial distribution. We conclude that trained adolescents can effectively conduct CBPR, and obesity and diabetes are more prevalent than previously reported in this community. This experience provides encouragement to conduct future studies to influence weight management from high-risk populations in this medically disadvantaged community.

1983. Effects of nitrogen addition on the growth of Vaccinium ulginosurn and Vaccinium vitis-idaea. Can. J . Bot. 61: 23 16-2322. Nitrogen fertilization may affect plant growth by changing ( i ) shoot size and hence shoot weight,(ii) shoot mortality, and (iii) shoot branching dynamics. This study assessed the effects of nitrogen addition on all three aspects of aboveground growth in cooccurring evergreen (Vaccirzium vitis-idaea) and deciduous (Vacciniurn uliginosurn) species. Growth responses were used to estimate parameters for a model of overall shoot population growth. Shoot population size increased at similar rates in both species with nitrogen fertilization. However, the addition of nitrogen elicited a different type of response in each species. Vacciniurn uliginosurn showed an increase in the size of the shoots produced. This result, combined with the fact that larger shoots produced a greater number of daughter shoots, was responsible for the shoot population increase. In contrast, the addition of nitrogen increased the rate of lateral meristem release for shoots of all sizes in V . vitis-idaea. The ecological implications of the results are discussed with respect to evergreen and deciduous habits. CHESTER, A. L., et J. B. MCGRAW. 1983. Effects of nitrogen addition on the growth of Vacciniurn ulgir~osurn and Vaccinium vitis-idaea. Can. J . Bot. 61: 23 16-2322.La fertilisation azotCe peut affecter la croissance des plantes en modifiant ( i ) la dimension et donc le poids des pousses, (ii) la mortalit6 des pousses et (iii) la dynamique de la ramification des pousses. Cette Ctude Cvalue les effets d'un apportd'azote sur ces trois aspects de la croissance CpigCe chez deux espkces de Vaccinium partageant les mCmes sites, une espkce a feuilles persistantes ( V . vitis-idaea) et une espkce a feuilles dkcidues ( V . uliginosum). Les reactions de croissance ont CtC utilisCes pour estimer les paramktres d'un modkle gCnCral de croissance de la population de pousses. La taille de la population de pousses augmente avec la fertilisation azotCe, selon le mCme taux chez les deux espkces. Cependant, l'apport d'azote provoque une rCaction diffkrente chez les deux espkces. Vacciniurn uliginosurn rCagit par une augmentation de la dimension de pousses. Cet effet, combink au fait que les plus grosses pousses produisent un plus grand nombre de pousses-filles, explique l'augmentation de la population de pousses. Au contraire, chez V . vitis-idaea, l'apport d'azote augmente le taux de dCveloppement des mCristemes latCraux sur les pousses de toutes dimensions. La signification Ccologique de ces rCsultats est discutCe en relation avec les Ctats dCcidu et persistant du feuillage.[Traduit par le journal]

The dynamics of seedling establishment, and growth of native cotton grass‐tussock tundra species were studied during the natural revegetation of small bare areas excavated in tussock tundra. The seedlings of Eriophorum vaginatum spp. spissum and Carex bigelowii, two sedge species, established most successfully. Few seedlings of nonsedge species emerged with the small disturbances. Most seedling emergence occurred early in the first growing season following the excavation of the bare areas. The density of emerged seedlings was higher in bare areas excavated in the autumn preceding the observations, rather than in bare areas excavated at the start of the first season of observation. After two growing seasons, survival of seedlings was not affected by the time the seedling emerged within the growing season. Eriophorum vaginatum was the most abundant species because it: (1) had the highest seedling emergence rates, particularly early in the growing season: (2) produced more tillers per seedlings; and (3) had a higher growth rate per seedling than C. bigelowii.