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Air borne particulate distributions and their accumulation in tree canopies,Nottingham, UK

Summary The deposition of particulates emanating from the south of Nottingham, UK, where the coal-fired power station of Ratcliffe- on-Soar is an important industry was assessed using snow samples, dry deposition gauges, and precipitation gauges.Effects of leaf characteristics in terms of shape, surface area, presentation, and cuticular texture on particulate accumulation were examined. Leaves possessing a large surface area, rough cuticular surface and with a horizontal presentation, were particularly effective in the accumulation of particulates. The penetration of particulates through the foliar canopy is discussed.The senior author is Section Leader and Principal Lecturer in Ecology in the Department of Life Sciences at Trent Polytechnic.     

The development of private sheltered housing in Scotland: a changing market

The provision of sheltered housing for sale in Scotland has experienced rapid growth since the opening of the first scheme in 1982. Development has been geographically concentrated in a small number of inner city and rural (coastal) areas. The expectation of continued rapid expansion is unlikely if recent trends of slower growth continue. This paper uses evidence from interviews with developers and owners of sheltered and mainstream housing, to examine the possible future contribution of the private market. On the basis of such evidence it raises questions about the relevance of some existing planning policies.     

DROUGHT INDICATED IN CARBON-13/CARBON-12 RATIOS OF SOUTHWESTERN TREE RINGS1

ABSTRACT: Stomatal closure during periods of moisture deficiency should theoretically lead to elevated ¹³C/¹²C ratios as reduction of available CO₂ leads to diminished photosynthetic discrimination against ¹³C in favor of ¹²C. Stable-carbon isotope ratio chronologies developed from 5-yr tree-ring groups at 17 sites in six southwestern states were tested for a drought relationship by first fitting a spline curve to each chronology to remove the long-term trend and calculating indices as the ratio of actual to spline curve value. The time series of “Del Indices” so developed are significantly correlated with 5-yr mean Palmer Hydrological Drought Indices (post-1930 period) and reconstructed July Palmer Drought Severity Indices from respective areas. Overall, in the period since 1790, the driest pentads were 1900–04 and 1960–64, whereas the wettest were 1980–84 and 1915–19. Maps of drought represented for two pentads seem to be reasonable representations, although spatial correlations of Del Indices with PHDI were generally not significant. These Del Index drought reconstructions may provide a useful measure of past physiological response to drought (stomatal closure), although the present cost of analysis would prevent this from being a routine method.     

SOIL WATER CHARACTERISTICS OF TWO SOIL CATENAS IN ILLINOIS: IMPLICATIONS FOR IRRIGATION1

ABSTRACT: Soil water was monitored by neutron scattering in six soils, three each within two drainage catenas in east-central Illinois, over a 15-month time span. The prairie soils have formed in: (1) 76–152 cm of silt loam, eolian sediments (bess) over glacial till (Catlin-Flanagan-Drummer catena), and (2) bess greater than 152 cm in thickness (Tama-Ipava-Sable catena). We characterized the water content of these soils over the total time span and for wet and dry climatic subsets, as an aid to potential irrigation decisions. Soils of the thin bess, C-F-D catena dried out to lower water contents and had greater soil water variability than did the thick bess soils. Under wet conditions, soil water contents in the two catenas were quite similar. Alleviation of surface and subsurface drying via irrigation would thus be more advantageous to yields on the C-F-D soils than on the T-I-S soils.     

THE RHIZOSPHERE ECOLOGY OF SUBMERSED MACROPHYTES1

ABSTRACT: This article, based on a review of the literature, examines several aspects of the rhizosphere ecology of submersed macrophytes. These include the role of the rhizosphere microflora in affecting plant growth through influences on nutrient availability and production of plant growth regulating compounds. Interactions between components of the sediment microflora and plant roots are considered in relation to plant nitrition and growth. Possible applications of this information to the management of submersed macrophytes are considered.     

Social organization in deer: Implications for localized management

Populations of white-tailed deer (Odocoileus virginianus) inhabiting many state and national parks and suburban areas have grown to the point that they conflict with human activities. Conflicts range from destruction of vegetation through browsing to public perception that diseases carried by deer pose threats to human health. Traditional modes of hunting to control populations are inappropriate in many of these areas because of intense human development and activity. This article explores an alternative approach for population reduction based on deer social organization. Female white-tailed deer are highly philopatric and female offspring remain near their dams for life. This suggests that a population expands slowly as a series of overlapping home ranges in a form analogous to the petals on a rose. Incorporating the rose petal concept into a model of population growth shows that removal of deer by family unit can potentially alleviate conflicts in localized areas for as many as 10–15 yr.     

Wastewood as a source of woodfuel

Land clearing and forest sector residues, notably the wastewood generated on large timber plantations, can provide a sizeable and hitherto neglected source of woodfuel. This article highlights experience in Malawi where wastewood from pine plantations is converted into charcoal that is sold to residential, industrial and agro-industrial users. Similar initiatives proposed in other countries of sub-Saharan Africa indicate that comprehensive utilization of wastewood resources could help to reduce regional and local imbalances.