Forest Decline and Air Pollution : A Study of Spruce (Picea abies) on Acid Soils

During the last decade, forest decline has become increasingly apparent. The decline in forest health was often reported to be associated with air pollution. The present study on Norway spruce stands in the Fichtelgebirge analyses various processes interacting within forest ecosystems. It covers transport and deposition of air pollutants, the direct effects of pollutants on above-ground plant parts, the responses of soil to acid rain, and the changing nutrient availability, and the accompanying effects on plant metabolism and growth. The role of fungi, microorganisms and soil animals in the decline of these stands is also assessed. The volume is concluded with a synthesis evaluation of the influence of different factors, and their interactions on forest decline.

1 Introduction: The Problem of Forest Decline and the Bavarian Forest Toxicology Research Group..- 2 The Vegetation of the Fichtelgebirge: Origin, Site Conditions, and Present Status..- 1 Introduction.- 2 Vegetation History.- 3 Natural Forest Vegetations.- 4 Present Forest Vegetation.- 5 Vegetation of Raised Bogs.- 6 Vegetation of Boulder Streams and Summit Rocks.- 7 Water Plants and Acidic Swamp Vegetation.- 8 Vegetation of Farmland.- 9 Conclusion.- References.- 3 Potentials and Limitations of Field Studies on Forest Decline Associated with Anthropogenic Pollution..- 1 Introduction.- 2 Defining Forest Decline.- 3 Inference of Causality.- 3.1 The Inductive Approach.- 3.2 The Deductive Approach.- 3.3 The Integrated Approach.- 4 The Study of a Decline in the Fichtelgebirge ― a First Step in an Integrated Approach.- 5 Conclusion.- References.- 1: Air Pollution: Transport and Deposition: Preface.- 1-A Long-Range Transport and Deposition of Pollutants in the Fichtelgebirge..- 1 Introduction.- 2 Basic Equations for the Time-Dependent Prediction of Pollutant Transport in the Atmosphere.- 2.1 The Meteorological Model.- 2.1.1 Equations of Motion.- 2.1.2 The Parameterization of Turbulence.- 2.2 The Transport Equation.- 3 Two-Dimensional Prediction of Pollutant Transport.- 3.1 General Outline of the Experiments.- 3.2 Discussion of Results.- 3.2.1 Idealized Topography.- 3.2.2 Structured Topography.- 4 Three-Dimensional Predictions of Pollutant Transport.- 5 Conclusions.- Appendix I.- Appendix II.- References.- 1-B Air Pollution and Deposition..- 1 Introduction.- 2 General Geographical and Climatological Description of the Observation Areas.- 3 Gaseous and Particulate Atmospheric Pollutants and Atmospheric Conditions.- 3.1 Basic Immission Data.- 3.2 Some Selected Gaseous and Particulate Pollutants.- 4 Chemical Composition of Precipitation and Fogwater.- 4.1 Properties of Selected Precipitation Samples.- 4.2 Results of Time-Resolved, On-Line Monitoring of the pH Value and the Electrical Conductivity of Precipitation.- 4.3 Collection and Properties of Fog.- 4.4 Deposition of Fogwater upon a Spruce.- 5 Concentration of Hydrogen Peroxide in Precipitation and Fogwater.- 6 Comparison of Bulk Precipitation Water and Fogwater Data from Surrounding and Remote Areas.- 6.1 Bulk Deposition Studies in the Catchment “Große Ohe”.- 6.2 Comparison of Representative Data of Different Regions.- 7 Comments and Conclusions.- References.- 2: The Role of Fungi, Microorganisms and Soil Animals: Preface.- 2-A Soil Fungi and Other Microorganisms..- 1 Introduction: Aluminum and the Possible Effects of Microorganisms.- 2 The Effect of Aluminum and Heavy Metals on the Mycorrhizal Fungus Suillus variegates.- 2.1 Influence of Aluminum and Heavy Metals on Growth.- 2.2 Element Contents in the Presence of Lead and Aluminum.- 3 Mycorrhizal Flora of Two Forest Locations.- 4 Conclusion.- References.- 2-B Endophytic Needle Fungi: Culture, Ultrastructural and Immunocytochemical Studies..- 1 Introduction.- 2 Electron Microscopy of Needle Fungi.- 2.1 Isolation of Internal Fungi.- 2.2 Lophodermium piceae-Antiserum and Antibody Conjugates.- 2.3 Electron Microscopy.- 2.3.1 Scanning Electron Microscopy (SEM).- 2.3.2 Transmission Electron Microscopy (TEM).- 3 Needle Colonization by Fungi.- 3.1 The Isolation of Fungi from Green, Symptomless Needles.- 3.2 The Isolation of Fungi from Needles Showing Disease Symptoms.- 3.3 Observation of Needle Fungi at the Cellular Level.- 4 Needle Fungi and Forest Decline.- 5 Conclusions.- References.- 2-C Soil Fauna Comparisons in Healthy and Declining Norway Spruce Stands..- 1 Introduction.- 2 Sampling Procedure and Site Description.- 3 Species Composition and Density of Healthy and Declining Norway Spruce Stands.- 3.1 Macrosaprophagous Invertebrates.- 3.2 Microphytophagous ― Saprophagous Invertebrates.- 3.2.1 Enchytraeidae.- 3.2.2 Acari-Cryptostigmata.- 3.2.3 Collembola.- 3.2.4 Symphyla ― Protura.- 3.2.5 Diptera.- 3.3 Omnivorous Invertebrates.- 3.4 Predators.- 3.5 Comparison of Soil Fauna Biomass.- 3.6 Comparison of Decomposition Rates.- 4 Acid Rain and Soil Fauna.- 5 Conclusions.- References.- 3: Direct Effects of Pollutants on Above-Ground Plant Parts: Preface.- 3-A The Cuticles of Conifers: Structure, Composition and Transport Properties..- 1 Introduction.- 2 Fine Structure and Chemical Constitution of Cuticles.- 2.1 Fine Structure.- 2.2 The Composition of Cutin.- 2.3 Soluble Culticular Lipids.- 2.3.1 Chemical Composition.- 2.3.2 Fine Structure of Epicuticular Waxes.- 3 Transport Properties of Plant Cuticles.- 3.1 The Description of Cuticular Penetration.- 3.1.1 Nonelectrolytes.- 3.1.2 Electrolytes.- 3.2 Transport Parameters.- 3.3 Factors Affecting Cuticular Transport and Accumulation.- 3.4 The Role of Cuticles in Transport.- 3.5 Gas Diffusion in the Stomatal Antechamber of Pinaceae.- 4 Conclusions.- References.- 3-B Organic Micropollutants and Plants.- 1 Introduction.- 2 Occurrence and Distribution of Some Chlorinated Micropollutants in Norway Spruce Needles.- 3 Distribution Between the Cuticular Wax and the Needle.- 4 Phytotoxicity of Organic Atmospheric Micropollutants: A Summary.- 5 Conclusions.- 1 References.- 3-C Leaching and Uptake of Ions Through Above-Ground Norway Spruce Tree Parts..- 1 Introduction.- 2 Can Needle Surfaces Buffer Acid Rain?.- 2.1 Direct Measurement of pH Buffering on Spruce Needles.- 2.2 pH and Magnesium Concentrations on Wetted Spruce Needles.- 3 Short-Term Studies of Sulfate Uptake by Needles.- 3.1 Experimental.- 3.2 Time Kinetics of 35SO42- Uptake.- 3.3 Influence of pH on the Uptake of Sulfate by Norway Spruce Needles.- 3.4 Incorporation of 35S upon Drying of the Superficially Applied Solution.- 4 Uptake of Water and Solutes Through Bark and Needle Surfaces.- 5 Leaching of Cations by Acid Rain from Twigs and Single Needles.- 5.1 Materials and Methods.- 5.2 Leaching of Cations from Foliated Twigs.- 5.3 Leaching of Cations from Detached Needles.- 6 Leaching of Minerals from Seedlings under Laboratory Conditions.- 7 Leaching of Minerals with a Canopy Balance Model.- 8 Conclusions.- References.- 3-D Atmospheric Pollutants and Plant Metabolism.- 1 Introduction.- 2 Fluxes of Gaseous Air Pollutants into Leaves.- 2.1 Uptake of SO2.- 2.2 Fate of SO2 Inside the Leaf.- 2.3 Uptake of Nitrogen Oxide.- 2.4 Fate of NO2 Inside the Leaf.- 2.5 Uptake of Ozone.- 2.6 Fate of Ozone Inside the Leaf.- 2.7 Pollution Stress in the Fichtelgebirge.- 3 Direct Effects of Atmospheric Pollutants on Metabolic Features of Norway Spruce in the Fichtelgebirge?.- 3.1 Photosynthesis.- 3.2 Stomatal Responses.- 3.3 Chloroplast Pigments.- 3.4 Needle Sulfur Content.- 4 Discussion and Conclusions.- References.- 4: Soil Responses to Acid Rain and Associated Effects on Plants: Preface.- 4-A Mineral Nutrition of Forest Trees: A Regional Survey.- 1 Introduction.- 2 Sampling Procedure.- 3 Nutrient Status of Trees on Forest Sites in Bavaria.- 3.1 Nitrogen.- 3.2 Phosphorus.- 3.3 Sulfur.- 3.4 Potassium, Calcium and Magnesium.- 3.5 Trace Element Nutrition.- 4 Discussion.- 5 Conclusions.- References.- 4-B Effects of Acid Rain on Soil Chemistry and Nutrient Availability in the Soil..- 1 Introduction.- 2 Chemical and Physical Properties of the Study Soils.- 3 Mechanisms and Kinetics of Buffering in Acid Soils.- 3.1 Organic Horizons.- 3.1.1 Chemical Properties and Actual Acidification Status of the Organic Layers.- 3.1.2 Proton Consumption During pH 3 Stat Titration.- 3.1.3 Cation Exchange as a Buffering Reaction.- 3.1.4 Reduction of Fe and Mn as Buffering Reactions.- 3.1.5 Mineralization of Organic Matter as a Buffering Reaction.- 3.1.6 pH Changes and Cation Release in the Percolation Experiment.- 3.1.7 BNC and ANC of Humics.- 3.2 Mineral Horizons.- 3.2.1 pH 3 Stat Titrations: ANC, Kinetics and Cation Balance.- 3.2.2 Long-Term Batch Titration of pH 3.- 3.2.3 Sulfuric Acid Percolation.- 3.2.4 Nature of the Reactive Al Compound.- 3.2.5 Soil Acidification and Nutrient Availability.- 4 Effects of Soil Structure on Water Transport, Proton Buffering, and Nutrient Release.- 4.1 Soil Aggregate Formation and Its Possible Role in Water and Nutrient Transport.- 4.1.1 The Process of Soil Aggregate Formation.- 4.1.2 Soil Water Fluxes.- 4.1.3 Soil Aggregation, Ion Mass Flow and Diffusion.- 4.1.4 Soil Aggregation and Root Growth.- 4.2 Water Flux, Proton Buffering and Nutrient Release in Structured Forest Soils.- 4.2.1 Water Transport.- 4.2.2 Proton Buffering.- 4.2.3 Nutrient Release.- 5 Conclusions.- References.- 4-C Water Relations of Two Norway Spruce Stands at Different Stages of Decline..- 1 Introduction.- 2 Assessment of the Forest Water Balance.- 3 The Water Budget of the Healthy and the Declining Forest Sites.- 4 Water Uptake and Soil Water Status.- 5 Conclusions.- References.- 4-D CO2- Assimilation and the Carbon Balance of Healthy and Declining Norway Spruce Stands.- 1 Introduction.- 2 Photosynthesis and Stomatal Response.- 2.1 Gas Exchange Rates in Relation to Site and Needle Age.- 2.2 Stomatal Conductance in Relation to Changes in Climatic Factors.- 2.3 Diurnal Course of Assimilation.- 3 Seasonal Carbon Balance.- 4 Assimilation Rates in Relation to Needle Color.- 5 Annual CO2 Uptake in Relation to Canopy Leaf-Area.- 6 Conclusions.- References.- 4-E Root and Mycorrhizal Development in Healthy and Declining Norway Spruce Stands..- 1 Introduction.- 2 Distribution and Seasonal Development of Fine-Root Biomass, Number of Root Tips, and Ectomycorrhizas.- 2.1 Comparison Between Young Healthy and Declining Spruce Stands.- 2.2 Comparison of Young and Old Trees at the Declining Site.- 2.3 Root Tips and Ectomycorrhizas.- 3 Carbohydrate Concentration of Roots.- 4 Root Growth in Relation to Soil Chemical Properties.- 4.1 Comparison Between Young Healthy and Declining Spruce Stands.- 4.2 Comparison Between Old and Young Spruce Stands at the Declining Site.- 5 Influence of Acidifying Processes on the Soil-Root Interface.- 6 Conclusions.- References.- 4-F Nutrient Relations of Trees in Healthy and Declining Norway Spruce Stands..- 1 Introduction.- 2 Nutrient Status of Healthy and Declining Norway Spruce Trees and Stands.- 3 Interactions Between Root and Shoot.- 4 Nutrient Relations and Growth.- 4.1 Nutrient Pools and Nutrient Use for Growth.- 4.2 Relations Between Element Concentrations and Growth.- 4.3 Growth as Related to an Imbalance of Magnesium and Nitrogen.- 5 Conclusions.- References.- 4-G Effects of Fertilization..- 1 Introduction.- 2 Sprinkling Norway Spruce Trees with Nutrient Solutions.- 3 Soil Fertilization Experiments.- 4 Fertilization of Canopies.- 5 Conclusions.- References.- 4-H Nutritional Disharmony and Forest Decline: A Conceptual Model.- 1 Introduction.- 2 Canopy Growth Phase.- 3 Stem Growth Phase.- 4 Recharge Phase.- 5 Conclusion: Nutritional Disharmony and Decline.- References.- 4-I Nutrient Balance and Element Cycling in Healthy and Declining Norway Spruce Stands..- 1 Introduction.- 2 Assessment of the Ecosystem Balance.- 2.1 Quasi-Stationary Pools.- 2.2 Element Input to the Soil.- 2.2.1 Precipitation and Canopy Processes.- 2.2.2 Soil Processes.- 2.3 Output of Elements.- 3 Seasonal Variations of Precipitation, Throughfall, and Seepage of Elements.- 4 The Ecosystem Balance.- 5 Conclusions.- References.- 5.- Processes Leading to Forest Decline: A Synthesis.- 1 Introduction.- 2 Direct Effects of Pollutants on the Canopy.- 3 Effects of Pollutants Via the Soil.- 4 Conclusion.- 5 Historic Considerations.- 6 Future Perspectives.- References.