Forest death and soil degradation in the Jizera Mountains Katy Boon, Steven Cave, Madeleine Cobb, Chris Lewis & Jonathan Townrow

Introduction This presentation will cover: A brief geological overview of the area and history of coal burning Some facts about soil nutrients and plant growth Acid rain and its effects on local vegetation River water chemistry in the Jizera Mountains Our interpretations of how things could be improved

Geological history of the Jizera mountains Variscan age  340 Ma - Devonian Composed of 99% granite

History of coal burning for power generation billion tonnes of coal reserves 23% - black coal 77% - brown coal/lignite North Bohemian lignite basin - 160km 2 mined

Important reactions Formation of SO 2 and nitrogen oxides: N 2 + O 2  2NO NO + 0.5O 2  NO 2 2FeS O 2  Fe 2 O 3 + 4SO 2 Formation of acids: SO 2 + OH + O 2  H 2 SO 4 NO x + sunlight + OH  HNO 3

History of coal burning ’s - production started SO 2 emissions 2nd worst in the world productivity declined

History of forest decay in the Jizera mountains The original forest had a multi-species tree cover. 17th century exploitation of the forest for fuel and construction material led to replacement with a near monoculture of Spruce 1950’s : The new communist regimes emphasis on coal mining, ore smelting and power generation industries led to an ever-increasing level of atmospheric SO 2 emissions until the late 1980’s. 1970’s Tree damage and forest decay began to be noticed, 1980’s Forest decay now advanced with trees dying in large numbers and at elevations < 1000m and on South-East slopes.

Plant Nutrients Ca 2+ : Al 3+ has a much higher affinity for negatively charged surfaces than Ca 2+ leading to displacement and consequent loss of Ca 2+ when [Al 3+ ] is high, i.e. when pH is low. Mg 2+ : Important for photosynthesis as it is a vital component of chlorophyll. Mg 2+ is also stripped from soil by high [Al 3+ ] Mg 2+ deficiency leads to yellowing of needles, metabolic stress and ultimately plant death. Phosphate is also locked up by high [Al 3+ ] PO 4 2- is a major plant nutrient and lack of PO 4 2- is a control on vegetative growth.

Plant Nutrients 2 Lack of clay minerals due to low pH preventing their formation in the rock weathering horizons. Al(OH) 3 is formed in preference to sheet silicates (clays). Al(OH) 3 has no cation exchange capacity and little water retention, so Al(OH) 3 rich soils have very low fertility. Low pH leads to stressed, stunted trees susceptible to secondary damage by acid rain, frost, wind, and pests.

Composition of the parent rock Geology of Jizera Mountains is granitic in nature Geology directly affects soil formation and structure Weathering of bedrock provides plant nutrients KAl 3 Si 3 O 10 (OH) 2 + H H 2 O  K Al 2 Si 2 O 5 (OH) 4

Mineral composition of Jizera Mountain granites

Composition of alteration minerals in 2 soil profiles 2 main soil profiles in Jizera Mountains C horizon - Few alteration minerals B2 horizon - Chlorite and Kaolinite B1 horizon - Kaolinite and Al-Fe hydroxides A horizon - No primary minerals except quartz, lots of alteration minerals

Soil composition and acid rain Little dissolution of Quartz –Si H 2 O  H 4 SiO 4 Al H 2 O  Al(OH) 3 + 3H + 2Al(OH) 3 + H 4 SiO 4  Al 2 SiO 5 (OH) 2 + 3H 2 O + 2H + 2Al 2 SiO 5 (OH) Mg Na +  Na 0.5 Mg 0.5 Al 1.5 Si 4 O 10 (OH) 2 + 3H 2 O + 0.5Al 3+

Chemistry of the Jizera Mountain Rivers Seasonal changes in: pH - Ranges between 4 and 6. – minimum of 2 Al 3+ - Acid leaching – maximum of 10,000 ppm SO gradual decline since 90’s Others - major water-borne cations, anions and heavy metals

Drinking water in the Vodni nádrž souš dam Al 3+ was being leached from basin Lime added in the Spring of ’96 Problems Health and Aluminium

Jizera vs Ore Mountains Comparisons: Similar causes of forest decay Majority of pollution from Germany and Poland Similar chemical composition of bedrock

Jizera vs Ore Mountains 2 Contrasts: Ore Mountains composed of crystalline rock with mica schists and granitic intrusions. Ore Mountain’s forest decayed before the Jizera Mountain’s forest due to acidic air composition and relief.

Interpretations and Conclusion Further environmental legislation required Re-establishment of forest using acid resistant trees Lime addition and sludge removal in dam Potential addition of clay minerals to soil However some environmental recovery is already evident.