Kari Mikkola - Academia.edu (original) (raw)
Papers by Kari Mikkola
Biological Conservation, 2016
Http Dx Doi Org 10 1080 01431169608949177, Apr 27, 2007
Acidification in Finland, 1990
Scandinavian Journal of Forest Research, 1994
ABSTRACT From 359 study plots on coniferous forest soil in southern Finland, 232 humus and 359 mi... more ABSTRACT From 359 study plots on coniferous forest soil in southern Finland, 232 humus and 359 mineral soil (top 5 cm) samples were taken in 1991 and analyzed for their cation exchange capacity, base saturation, pH, total S content (humus samples only), and extractable Al, Fe, and Mn concentrations in order to assess the impact of acidic air pollution on soil acidity. The main sources of local air pollutants (SO2 and NO(x)) were from the capital region and an oil refinery. Although concentrations of S in the humus layer were 8% higher near the emission sources, it was concluded that air pollution has not resulted in a detectable increase in soil acidity. Mean values for humus layer pH (BaCl2), cation exchange capacity (CEC), base saturation, and extractable Al concentration for the overall study area were 2.9 (0.2), 310 (50) meq kg-1, 48 (12)% of CEC, and 530 (340) mg kg-1. The respective values for the mineral soil layer were 3.3 (0.3), 56 (19) meq kg-1, 13 (8)% of CEC, and 320 (130) mg kg-1. Standard deviations are given in parentheses.
Journal of Vegetation Science, 1990
ABSTRACT Compositional gradients of forest vegetation in Finland were determined using detrended ... more ABSTRACT Compositional gradients of forest vegetation in Finland were determined using detrended correspondence analysis, and ecologically interpreted with regression analysis. The data were collected in association with the 8th National Forest Inventory, and they comprised 1514 samples and 472 species, covering the whole forested land area of Finland.In the ordination space the first, very stable axis (DCA1) was much stronger than the following three, more unstable axes (DCA2 - 4). Site fertility (reflected by the forest site type series) and latitude had strongest covariation with the ordination space, followed by a number of variables primarily related to forest age or tree stand volume. Fertility variables were most closely parallel with DCA1, latitudinal ones with DCA1 and DCA2, and successional variables with DCA3.The results indicate that compositional overlap of sites classified into different Caj ander site types is considerable.
International Journal of Remote Sensing, 1996
The huge sulphur dioxide and heavy metal emissions from the nickel and copper smelters in the Kol... more The huge sulphur dioxide and heavy metal emissions from the nickel and copper smelters in the Kola Peninsula, Russia, have caused severe vegetation damage and destruction in the surrounding areas during the past few decades. An attempt was made to detect changes in the state of the vegetation in the environs of the Monchegorsk smelters using Landsat MSS images from
Geoderma, 2013
ABSTRACT Long-term effects of mechanical site preparation on soil chemical properties of Norway s... more ABSTRACT Long-term effects of mechanical site preparation on soil chemical properties of Norway spruce (Picea abies) clearcut areas have remained unclear. In 1960 a forest fire burned a Norway spruce forest in Finnish Lapland and the remaining trees were harvested. Subsequent mechanical preparation with disk trenching created continuous cross-contour disturbance tracks. We measured soil dielectric permittivity as dependent on water content, electrical conductivity, temperature, pH, as well as ammonium acetate extractable concentrations of mineral soil elements in a clearcut area. After forty-six years the loss of soil nutrients was considerably high, particularly with exchangeable Ca (− 40%) and Mg (− 51%), Ca:Al ratio (− 57%), and soil electrical conductivity (− 53%). The disk trenching had no considerable long-term effect on soil water content. The results indicate that intensive mechanical site preparation is a risk for long-term soil fertility and forest productivity in boreal conifer stands.
Ecography, 1996
... Especially such forests strongly grazed by semidomestic reindeer (Helle and Aspi 1982, Vare e... more ... Especially such forests strongly grazed by semidomestic reindeer (Helle and Aspi 1982, Vare et al. 1995). ... On the vegetation the main consequence of grazing is reduction of lichens and increase of bryophytes and bare patches of soil (Helle and Aspi 1982, Vare et al. 1995). ...
Biological Conservation, 2016
Http Dx Doi Org 10 1080 01431169608949177, Apr 27, 2007
Acidification in Finland, 1990
Scandinavian Journal of Forest Research, 1994
ABSTRACT From 359 study plots on coniferous forest soil in southern Finland, 232 humus and 359 mi... more ABSTRACT From 359 study plots on coniferous forest soil in southern Finland, 232 humus and 359 mineral soil (top 5 cm) samples were taken in 1991 and analyzed for their cation exchange capacity, base saturation, pH, total S content (humus samples only), and extractable Al, Fe, and Mn concentrations in order to assess the impact of acidic air pollution on soil acidity. The main sources of local air pollutants (SO2 and NO(x)) were from the capital region and an oil refinery. Although concentrations of S in the humus layer were 8% higher near the emission sources, it was concluded that air pollution has not resulted in a detectable increase in soil acidity. Mean values for humus layer pH (BaCl2), cation exchange capacity (CEC), base saturation, and extractable Al concentration for the overall study area were 2.9 (0.2), 310 (50) meq kg-1, 48 (12)% of CEC, and 530 (340) mg kg-1. The respective values for the mineral soil layer were 3.3 (0.3), 56 (19) meq kg-1, 13 (8)% of CEC, and 320 (130) mg kg-1. Standard deviations are given in parentheses.
Journal of Vegetation Science, 1990
ABSTRACT Compositional gradients of forest vegetation in Finland were determined using detrended ... more ABSTRACT Compositional gradients of forest vegetation in Finland were determined using detrended correspondence analysis, and ecologically interpreted with regression analysis. The data were collected in association with the 8th National Forest Inventory, and they comprised 1514 samples and 472 species, covering the whole forested land area of Finland.In the ordination space the first, very stable axis (DCA1) was much stronger than the following three, more unstable axes (DCA2 - 4). Site fertility (reflected by the forest site type series) and latitude had strongest covariation with the ordination space, followed by a number of variables primarily related to forest age or tree stand volume. Fertility variables were most closely parallel with DCA1, latitudinal ones with DCA1 and DCA2, and successional variables with DCA3.The results indicate that compositional overlap of sites classified into different Caj ander site types is considerable.
International Journal of Remote Sensing, 1996
The huge sulphur dioxide and heavy metal emissions from the nickel and copper smelters in the Kol... more The huge sulphur dioxide and heavy metal emissions from the nickel and copper smelters in the Kola Peninsula, Russia, have caused severe vegetation damage and destruction in the surrounding areas during the past few decades. An attempt was made to detect changes in the state of the vegetation in the environs of the Monchegorsk smelters using Landsat MSS images from
Geoderma, 2013
ABSTRACT Long-term effects of mechanical site preparation on soil chemical properties of Norway s... more ABSTRACT Long-term effects of mechanical site preparation on soil chemical properties of Norway spruce (Picea abies) clearcut areas have remained unclear. In 1960 a forest fire burned a Norway spruce forest in Finnish Lapland and the remaining trees were harvested. Subsequent mechanical preparation with disk trenching created continuous cross-contour disturbance tracks. We measured soil dielectric permittivity as dependent on water content, electrical conductivity, temperature, pH, as well as ammonium acetate extractable concentrations of mineral soil elements in a clearcut area. After forty-six years the loss of soil nutrients was considerably high, particularly with exchangeable Ca (− 40%) and Mg (− 51%), Ca:Al ratio (− 57%), and soil electrical conductivity (− 53%). The disk trenching had no considerable long-term effect on soil water content. The results indicate that intensive mechanical site preparation is a risk for long-term soil fertility and forest productivity in boreal conifer stands.
Ecography, 1996
... Especially such forests strongly grazed by semidomestic reindeer (Helle and Aspi 1982, Vare e... more ... Especially such forests strongly grazed by semidomestic reindeer (Helle and Aspi 1982, Vare et al. 1995). ... On the vegetation the main consequence of grazing is reduction of lichens and increase of bryophytes and bare patches of soil (Helle and Aspi 1982, Vare et al. 1995). ...