Management of Nutrition in Forests under Stress : Proceedings of the International Symposium, sponsored by the International Union of Forest Research Organization (IUFRO, Division I) and hosted by the Institute of Soil Science and Forest Nutrition at the Albert-Ludwigs-University in Freibu

During the 1970s and 1980s, Sitka spruce (Picea sitchensis, Bong. Carr. ) was planted extensively on northern Vancouver Island (B. C. , Canada) to regenerate slashburned clearcuts previously occupied by old-growth Thuja p1icata, Donn, Tsuga heterophy11a, Raf. Sarg. , and an ericaceous unders tory shrub salal (Gaul ther ia sha11on, Pursh [CH sites 1 ) . The planted Sitka spruce grew well initially on these sites, but experienced nutritional stress and reduced growth 8 to 14 yr after planting (Germain, 1985; Weetman et a1. , 1990a,b). Accompanying the onset of the nutritional stress was the reestablishment of a complete ground cover of salal, and it has been suggested that there is a causal connection between these two temporally synchronous events (Weetman et al. , 1990a,b). Other ericaceous species have been implicated in nutritional stress in conifer plantations (Mallik, 1987; Robinson, 1972; Handley, 1963; Rose et a1. , 1983). Three hypotheses to explain this nutritional stress were tested in the study reported in this paper: (1) that salal competition for N can provide an adequate explanation for the observed nutritional stress; (2) that salal inhibits the availability of nutrients to seedlings by interfering with their mycorrhizae; and (3) that the fertility of these CH sites declines after 8 yr following clearcutting and slashburning due to the termination of the flush of nutrients (or "assart effect") associated with this disturbance. A series of pot and field experiments was carried out to test these hypotheses. 1 2.

I Environmental Pollution and Forest Nutrition.- Environmental Pollution and Impacts on Soils and Forests Nutrition in North America.- Dynamics of “Acute Yellowing” in Spruce Connected with Mg Deficiency.- Effects of Ammonia, Ammonium Sulphate and Sulphur Dioxide on the Frost Sensitivity of Scots Pine (Pinus sylvestris L.).- Survival Rate of Tree and Shrub Seedlings under Extreme Environmental Nitrogen Pollution.- Nutrient Disturbances in Forest Trees and the Nature of the Forest Decline in Quebec and Germany.- Foliar Symptoms on Norway Spruce and Relationships to Magnesium Deficiencies.- Nutritional Disturbances and Declining Armand Pine in Southwestern China.- Element Composition of Leaves and Wood of Beech (Fagus sylvatica L.) on SO2-Polluted Sites of the NE-Bavarian Mountain.- Element Contents of Spruce Needles (P. abies [L] Karst.) Along an Altitudinal Gradient in the Bavarian Alps.- Nutrient Response to Diagnostic Fertilization of Norway Spruce Picea abies (L.) Karst Plantations in Western Quebec, Canada.- Watershed-Scale Responses to Ozone Events in a Pinus strobus L. Plantation.- The Influence of Acid Precipitation and Ozone on Nitrogen Nutrition of Young Loblolly Pine.- Fall Exposure of Beech Saplings (Fagus sylvatica L.) to Ozone and Simulated Acidic Mist: Effects on Gas Exchange and Leachability.- Solute Concentrations and Fluxes of Major Nutrients in Potted Red Spruce Saplings Exposed to Simulated Acid Rain Treatments.- Scattered CaSO4-Crystallites on Needle Surfaces After Simulated Acid Rain as an Indicator of Nutrient Leaching.- Mineral Nutrition, Carbohydrate Content and Cold Tolerance of Foliage of Potted Red Spruce Exposed to Ozone and Simulated Acidic Precipitation Treatments.- The Spatial Heterogeneity of Chemical Properties in Acid Forest Soils and its Importance for Tree Nutrition.- II Natural Stresses and Forest Nutrition.- Forest Decline and Soil Nutritional Problems in Pacific Areas.- Management of Forests under Nutrient and Water Stress.- Changes in Soil Properties and Site Productivity Caused by Red Alder.- Growth Variation and Environmental Stresses: Long-Term Observations on Permanent Research Plots in Southwestern Germany.- Nutritional Stress in Picea sitchensis Plantations in Coastal British Columbia: The Effects of Gaultheria shallon and Declining Site Fertility.- Mineral Supply of Healthy and Declining Trees of a Young Spruce Stand.- Nutrient Stress in Young Scots Pines Suffering from Needle Loss in a Dry Heath Forest.- The Influence of Weather Variation on Regional Growth of Douglas Fir Stands in the U.S. Pacific Northwest.- The Effect of Nitrogen and Potassium Availability on Scleroderris Canker of Scots Pine Seedlings.- Stress Related Changes in the Architecture of Seedlings of Three Provenances of Eucalyptus camaldulensis Dehnh.- Simulation of Nutrition of Forests under Stress Using Forcyte-11.- III Effects of Liming and Fertilization in the Forest Ecosystem.- Effects of Forest Liming on the Nutrient Status of Podzolic Soils in Finland.- Effects of Liming on Carbon and Nitrogen Mineralization in Coniferous Forests.- The Effects of Forest Liming and Fertilization on Fine-Root Growth.- Effects of Liming and Fertilization on Soil Solution Chemistry in North German Forest Ecosystems.- Liming and Fertilization of Acid Forest Soil: Short-Term Effects on Runoff from Small Catchments.- Liming and Wet Acid Deposition Effects on Tree Growth and Nutrition: Experimental Results.- Bioelement Content and Biomass in Scots Pine: Effect of Acidification and Liming.- Initial Compensation of Acidic Deposition in Forest Ecosystems by Different Rock Meals.- Effects of Calcined Magnesite, Magnesium Hydroxide and “Geosan” on Soil Properties in Declining Spruce Stands (NE Bavaria).- Effects of Fertilization with MgSO4 and (NH4)2SO4 on Soil Solution Chemistry, Mycorrhiza and Nutrient Content of Fine Roots in a Norway Spruce Stand.- The Influence of Mg Fertilization on Growth and Mineral Contents of Fine Roots in (Picea abies [Karst.] L.) Stands at Different Stages of Decline in NE-Bavaria.- Foliar Potassium Status Explains Douglas Fir Response to Nitrogen Fertilization in the Inland Northwest, USA.- IV Strategies for Increasing Health and Productivity of Forests.- A New Fertilization Strategy in Declining Forests.- Terrestrial Liming as a Tool to Mitigate Acidification of Woods Lake, NY.- Liming Effects on Some Chemical and Biological Parameters of Soil (Spodosols and Histosols) in a Hardwood Forest Watershed.- An Integrated Watershed/Plot-Scale Study of Element Cycling in Spruce Ecosystems of the Black Forest.- Effects of Magnesium Fertilizer on the Vitality and Nutrition of a European Beech (Fagus sylvatica L.) Stand in the Southern Black Forest of West Germany.- The Use of Organic and Mineral Fertilizers in Reforestation and in Revitalization of Declining Protective Forests in the Alps.- Fertilization of Declining Conifer Stands in the Vosges and in the French Ardennes.- Correction of Magnesium Deficiency in a Young Stand of Norway Spruce.- Second Rotation Decline in P. radiata Plantations in South Australia has been Corrected.- Productivity, Nutrient Immobilization and Soil Chemical Properties in an Eucalyptus globulus plantation under Different Irrigation and Fertilization Regimes.- Effect of Water and Nutrient Supply on Root Distribution in an Eucalyptus globulus Plantation.- Fertilizer Application in Aid of Plantation Establishment in the Savanna Areas of Nigeria.- Relationships between Growth, Mineral Nutrition, and Soils in Young Teak Plantations in Benin and Liberia.- Inherent Differences in Response of Douglas Fir Families to Nitrogen and Phosphorus Supply Levels.- Author Index.