Extractability of elements in sugar maple xylem along a gradient of soil acidity

Dendrochemistry has been used for the historical dating of pollution. Its reliability is questionable due primarily to the radial mobility of elements in sapwood. In the present study, the extractability of seven elements was characterized to assess their suitability for the monitoring of environmental conditions. Nine mature sugar maple trees (Acer saccharum Marsh.), a wide-ranging species in eastern North America that has suffered decline in past decades, were sampled in three Quebec watersheds along a soil acidity gradient. Five-year groups of annual tree rings were treated by sequential chemical extractions using extractants of varying strength (deionized H2O, 0.05 M HCl, and concentrated HNO(3)) to selectively solubilize the elements into three fractions (water-soluble, acid-soluble, and residual). Monovalent K; divalent Ba, Ca, Cd, Mg, Mn; and trivalent Al cations were found mostly in the water-soluble, acid-soluble, and residual fractions, respectively. Forms more likely to be mobile within the tree (water-soluble and acid-soluble) do not seem to be suitable for temporal monitoring because of potential lateral redistribution in sapwood rings. However, certain elements (Cd, Mn) were responsive to current soil acidity and could be used in spatial variation monitoring. Extractability of Al varied according to soil acidity; at less acidic sites, up to 90% of Al was contained in the residual form, whereas on very acidic soils, as much as 45% was found in the water-soluble and acid-soluble fractions. Sequential extractions can be useful for determining specific forms of metals as key indicators of soil acidification.     

Soil and tree-ring chemistry response to liming in a sugar maple stand

An evaluation of the impact of dolomitic lime [CaMg(CO3)2] on soils (five years after treatment) and sapwood chemistry (after four growing seasons) was realized for a Ca-deficient sugar maple stand at the lake Clair watershed. The effect on humus chemistry was significant: exchangeable Mg and Ca, effective acidity (EA), base saturation (BSe), pH, and effective cation exchange capacity (CECe) significantly increased, while exchangeable Fe significantly decreased. In the B horizon, liming increased exchangeable Ca, Mg, and Mn concentrations while decreasing other acid cations. No significant temporal trends in element concentrations in tree rings could be detected, although the lime treatment significantly changed the average xylem Mg and Mn concentrations as well as the average Mg/Mn and Ca/Mn ratios of the sapwood. The absence of temporal trends in rings from the last 20 yr implied a significant re-equilibration of elements through the sapwood. Significant relationships were found between averaged xylem Ca/Mn and Mg/Mn ratios and exchangeable humus Ca, Mg, Mn, Al, Fe, and H+ concentration, EA, CECe, and BSe, suggesting that the average xylem Ca/Mn and Mg/Mn ratios are strong indicators of the soil acid-base status.     

Are EMS environmentally effective? The link between environmental management systems and environmental performance in European companies

Based on the analysis of a large dataset on the environmental performance of European companies in five industrial sectors, this paper examines the question of whether the presence of an environmental management system (EMS) has a positive impact on the eco-efficiency of companies. It begins with a review of evidence about the link between EMS and environmental performance in business organisations, finding that, despite much research, there is still little quantitative evidence. The second part of the paper uses three independent statistical methods (simple correlations, Jaggi-Freedman indices and a ‘trend differences’ approach) to assess whether companies and production sites with EMS perform better than those without and whether performance improves after an EMS has been introduced. The paper shows that there is currently no evidence that EMS have a consistent and significant positive impact on environmental performance. Policy action based on the simple assumption that companies with an EMS perform better than those without therefore seems inappropriate.     

Collective action and the traditional village

This article considers the dispute between moral economy and rational peasant theories of agrarian societies in application to problems of collective action. The moral-economy theory holds that traditional peasant society is organized cooperatively through shared moral values and communal institutions; while the rational-peasant theory maintains that peasant society shows the mark of rational individual calculation, leading to free-rider problems that undermine successful collective action. This article offers an abstract model of a traditional village and assesses the applicability of recent qualifications of the collective action argument to this model. It will emerge that the social characteristics of the traditional village embody features that facilitate collective action by rational peasants.     

Carbon and nitrogen mineralization rates after application of organic amendments to soil

The objective of this study was to quantify C and N mineralization rates from a range of organic amendments that differed in their total C and N contents and C quality, to gain a better understanding of their influence on the soil N cycle. A pelletized poultry manure (PP), two green waste-based composts (GWCa, GWCb), a straw-based compost (SBC), and a vermi-cast (VER) were incubated in a coarse-textured soil at 15 degrees C for 142 d. The C quality of each amendment was determined by chemical analysis and by 13C nuclear magnetic resonance (NMR). Carbon dioxide (CO2-C) evolution was determined using alkali traps. Gross N mineralization rates were calculated by 15N isotopic pool dilution. The CO2-C evolution rates and gross N mineralization rates were generally higher in amended soils than in the control soil. With the exception of GWCb all amendments released inorganic N at concentrations that would be high enough to warrant a reduction in inorganic N fertilizer application rates. The amount of N released from PP was high indicating that application rates should be reduced, or alternative amendments used, to minimize leaching losses in regions where ground water quality is of concern. There was a highly significant relationship between CO2-C evolution and gross N mineralization (R2= 0.95). Some of the chemically determined C quality parameters had significant relationships (p < 0.05) with both the cumulative amounts of C and N evolved. However, we found no significant relationships between 13C NMR spectral groupings, or their ratios, and either the CO2-C evolved or gross N mineralized from the amendments.     

Cultural Influence on Crowding Norms in Outdoor Recreation: A Comparative Analysis of Visitors to National Parks in Turkey and the United States

Formulation of standards of quality in parks and outdoor recreation can be guided by normative theory and related empirical methods. We apply this approach to measure the acceptability of a range of use levels in national parks in Turkey and the United States. Using statistical methods for comparing norm curves across contexts, we find significant differences among Americans, British, and Turkish respondents. In particular, American and British respondents were substantially less tolerant of seeing other visitors and demonstrated higher norm intensity than Turkish respondents. We discuss the role of culture in explaining these findings, paying particular attention to Turkey as a traditional “contact culture” and the conventional emphasis on solitude and escape in American environmental history and policy. We conclude with a number of recommendations to stimulate more research on the relationship between culture and outdoor recreation.     

Desertification: The time for action

Summary Following the severe droughts in the Sahel and Ethiopia in the late 1960s and early 1970s, which focused the world’s attention on drought and desertification, the United Nations system organized and held the UN Conference on Desertification (UNCOD) in Nairobi in 1977. The principal outcome of the Conference was a Plan of Action to Combat Desertification (PACD), containing 28 major recommendations. The follow-up and coordination of implementation of the PACD was entrusted to UNEP, which created a Desertification Branch in 1978 to undertake the task. Desertification Branch UNEP