The Die-Off Dynamics of Siberian Larch Under the Impact of Pollutants Emitted by the Norilsk Enterprises
A. V. KIRDYANOV1, V. S. MYGLAN2, A. V. PIMENOV1, A. A. KNORRE1,3, A. K. EKART1, E. A. VAGANOV1,2
1V. N. Sukachev Institute of Forest SB RAS, 660036, Krasnoyarsk, Akademgorodok, 50/28
2Siberiаn Federal University, 660041, Krasnoyarsk, Svobodny ave., 79
3Stolby State Nature Reserve, 660006, Krasnoyarsk, Kar’yernаja str., 26-A
Keywords: Larix sibirica L, dendrochronology, pollutant emissions, die-off of tree stands, forest-tundra
Abstract
The radial growth of Siberian larch under the impact of pollutants emitted by the enterprises of Norilsk was analyzed to reconstruct die-off dynamics of larch stands located along Rybnaya River, along the main direction of pollutant air transport. Dendrochronological cross-dating was used to detect the year of die-off of 268 trees growing at 4 sites located at 22, 45, 68 and 85 km from Norilsk. Death of individual trees at the sites nearest to Norilsk was recorded immediately after the first enterprises had started to operate in early 1940s. Mass mortality of the trees had started in 1960s due to operation of new smelters and consequent increase in pollutant emissions. Complete degradation of the stands (100 % die-off of larch trees) had occurred in 1970s. At the most distant site (85 km), the highest rate of larch had been observed between 1975 and 1980 and in 2004 only 23 % of larch trees were alive. Comparative analysis of tree-ring width of the studied trees testified on decrease of tree radial growth at the period before the complete degradation of stands. Unfavorable climatic conditions became an additional factor that enhanced the rate of tree die-off due to the impact of pollutants. Although the increase of tree radial growth had been found in late 1990s - early 2000s at the site located 85 km from Norilsk, the status of studied trees indicated that the area of completely degraded forest ecosystems might become larger under the present conditions.
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