Atmospheric Nitrogen Deposition To Global Forests

Atmospheric Nitrogen Deposition in Global Forests: Spatial Variation, Impacts, and Management Implications provides the most comprehensive knowledge on spatial variation and ecological impacts of reactive nitrogen deposition in global forests, as well as forest management options to mitigate the negative impacts. Written and edited by international experts in the field, this book synthesizes recent research developments and insights in monitoring and modeling nitrogen deposition in global forests. The book also assesses ecological impacts of enhanced nitrogen deposition on forest structure and function and responses of forest ecosystems to decreasing nitrogen deposition in regions such as the European Union and North America. Finally, the book reviews indicators and thresholds for nitrogen saturation in global forests and analyzes remediation options to reduce impacts of excess nitrogen deposition. This is an important resource for researchers in forestry and biodiversity conservation, as well as graduate students, policymakers and others who want to understand environmental issues of reactive nitrogen deposition in global forests. Offers a systematic view of the ecological impacts of enhanced nitrogen deposition Provides the most comprehensive knowledge on spatial variation and the ecological impacts of reactive nitrogen deposition in global forests Presents expert research and findings on forest management options to remediate negative impacts

Forests take up gaseous, liquid and particulate substances that are present in the air. Although considered nutrients on the one hand, nitrogen inputs exceeding the critical load that can be absorbed by an ecosystem act as pollutants. This chapter outlines the effects of N deposition to forest ecosystems and discusses recent progress that has been made to more accurately quantify dry deposition, which at many a forest location in Europe is larger than wet and occult deposition. To quantify the effects of N deposition on tree growth, a good measure for net ecosystem production (NEP) is needed. Eddy covariance (EC) flux measurements are one established way to quantify NEP. While EC flux measurements are costly and remain restricted in their application to a few suitable locations, dendrometer measurements with high temporal resolution show a similar seasonal and annual signal to NEP. Such measurements are becoming increasingly important to quantify ecosystem biomass accumulation, which can be related to N deposition rates. The policy relevance of such activities emerges from the UNECE's Gothenburg protocol to abate acidification, eutrophication and ground-level ozone, but also the quantification of natural sinks under the Kyoto protocol profits from such measurements.

Despite effective global-scale legislation to restrict the emissions of nitrogen (N) into the atmosphere, atmospheric deposition of N remains high in many forested regions. In addition, many N-impacted forests still retain the imprint of N saturation, such as altered species composition and leaching of essential base cations. Accordingly, we need a further understanding of the complexities of N cycling in forest ecosystems and the effects of excess N on forest biodiversity and biogeochemical cycling. This volume explores these complexities, including effects on plants, plant assemblages, and forest biogeochemistry, by synthesizing research from Asia, Europe, and North America. Because of the widespread nature of current declines in N deposition, this book ends with a look to the future as N-impacted forests experience a return to lower levels of atmospheric deposition of N.

In the past century, anthropogenic activities have increased N input drastically to terrestrial ecosystems and influenced the global N cycle. Especially temperate forest ecosystems are affected in their productivity, species composition, soil chemistry and water quality. N input to forest ecosystems is retained in trees and soil. Excessive N is leached out or released as gases. The retention of N input in soils is mainly influenced by the stability of soil organic matter (SOM). Many forests in central Europe and North America have been subjected to N saturation, i.e. excessive N appeared as nitrate in the leachate below the rooting zone. Reduction of atmospheric N emission and consequent atmospheric N deposition is proposed to be the only practical long-term solution to improve N-saturated forest ecosystems. However, responses of N-saturated forest ecosystems to reduced atmospheric N deposition have been seldom investigated. In the present study, atmospheric deposition was manipulated through roof constructions below the canopy of a mature Norway spruce forest on the Solling plateau in central Germany. A £^(5)N tracer field and a density fractionation laboratory experiment were conducted in the present study to investigate the influence of long-term reduced atmospheric N deposition on the partitioning of atmospheric N in different forest ecosystem compartments as well as on the partitioning of atmospheric N retained in the soil in different SOM pools.

This book provides an up-to-date synthesis of the understanding of the interaction between the emission of nitrogen, its deposition and impact on the most important components of natural and semi-natural ecosystems. The work consists of contributions from internationally renowned research scientists. Individual chapters deal with the factors and processes related to nitrogen deposition and soils, non-forest vegetation communities, forest ecosystems, and surface waters. The assessment of these impacts is discussed in terms of setting critical loads. The book is aimed at researchers, advanced course students and policy makers/advisors involved with aspects of the impact of air pollution.

Atmospheric reactive nitrogen (N) emissions, as an important component of global N cycle, have been significantly altered by anthropogenic activities, and consequently have had a global impact on air pollution and ecosystem services. Due to rapid agricultural, industrial, and urban development, China has been experiencing an increase in reactive N emissions and deposition since the late 1970s. Based on a literature review, this book summarizes recent research on: 1) atmospheric reactive N in China from a global perspective (Chapter 1); 2) atmospheric reactive N emissions, deposition and budget in China (Chapters 2-5); 3) the contribution of atmospheric reactive N to air pollution (e.g., haze, surface O3, and acid deposition) (Chapters 6-8); 4) the impacts of N deposition on sensitive ecosystems (e.g., forests, grasslands, deserts and lakes) (Chapters 9-12); and 5) the regulatory strategies for mitigation of atmospheric reactive N pollution from agricultural and non-agricultural sectors in China (Chapters 13-14). As such it offers graduate students, researchers, educators in agricultural, ecological and environmental sciences, and policy makers a glimpse of the environmental issues related to reactive N in China .

Over the past decade there has been considerable interest in the effects of atmospheric deposition on forest ecosystems. This volume summarizes the results of the Integrated Forest Study (IFS), one of the most comprehensive research programs conducted. It involved intensive measurements of deposition and nutrient cycling at seventeen diverse forested sites in the United States, Canada, and Norway. The IFS is unique as an applied research project in its complete, ecosystem-level evaluation of nutrient budgets, including significant inputs, outputs, and internal fluxes. It is also noteworthy as a more basic investigation of ecosystem nutrient cycling because of its incorporation of state-of-the-art methods, such as quantifying dry and cloud water deposition. Most significantly, the IFS data was used to test several general hypotheses regarding atmospheric deposition and its effects. The data sets also allow for far-reaching conclusions because all sites were monitored over the same period using comparable instruments and standardized protocols.