Radek Novotný

Changes in the air pollution load in the Jizera Mts.: effects on the health status and mineral nutrition of the young Norway spruce stands

The article evaluates changes in the forest health status and nutrition, caused by the historical development of the air pollution load, in the Norway spruce (Picea abies L. Karst) stands in the Jizera Mts. The Jizera Mts. are located in northern Bohemia, on the border between the Czech Republic and Poland close to western Saxony (Zittau). The 19 research plots selected on the plateau within the forest sites of the young Norway spruce stands were installed in 1991. Since 1993 the defoliation of the tree crown has been assessed every year; sampling of needles for nutrient analyses has also been undertaken annually. Soil samples were taken in 1995, 1999, 2003 and 2009. Long-term investigation confirmed that the health condition of the trees, evidenced by crown defoliation, is influenced by a combination of various stress factors. To define the relationship between the crown defoliation, nutrients and stress element contents, a linear regression model was proposed. The model for the current year needles demonstrates that the defoliation of the spruce crowns in the Jizera Mts. is a function of the nitrogen, phosphorus, potassium, magnesium sulphur and fluorine concentration. The crown defoliation of the spruce stands is increasing with the decrease in the nitrogen and magnesium concentrations and the increase in the sulphur and fluorine concentrations in the needles. The unbalanced nutrition in the Jizera Mts. is affected by the ongoing nitrogen deposition to the forest ecosystem. This is manifested as a disturbed N:P and N:Mg ratios in the needles. Acidification of the soil environment and the phosphorus and magnesium deficiency may be limiting factors to the forest’s nutrition in the future. The optimal range of N:Mg ratio (8–30) is relatively wide for the Jizera Mts. The upper optimal limit for the young spruce stands in the Jizera Mts. should be decreased to 25. The comparison of the element concentration in the needles and mineral soil confirmed the nutritional threat and the deterioration in the condition of the spruce stands in the Jizera Mts.

The impact of ambient ozone on mountain spruce forests in the Czech Republic as indicated by malondialdehyde.

Malondialdehyde (MDA), a product of lipid peroxidation and biomarker of oxidative stress, is measured over the long term in spruce Picea abies needles under real conditions in three Czech mountain border areas. The trends presented collate the MDA content in spruce needles with ambient ozone, temperature and precipitation as casual, and defoliation as a subsequent factor for the period 1994-2006. We have found the overall decreasing trends in MDA and defoliation. The highest MDA and defoliation are recorded in the Jizerske, the lowest in the Krusne hory Mts. Out of the examined variables the MDA is predicted best by mean temperature in vegetation season, median of O(3) concentrations and AOT40; these three variables account for 34% of MDA1 and 36% of MDA2 variability. Our hypothesis that higher ambient O(3) exposure results in higher MDA contents in P. abies needles under real conditions has not been approved.

Monitoring of Ozone Risk for Forests in the Czech Republic: Preliminary Results

Ozone (O3) is supposed to represent a significant risk for the health of forest ecosystems in Central Europe. So far, however, its impact on stands growing under natural conditions has not been clearly proved. A new project of the National Agency for the Research in Agriculture is focused on the O3 effect on selected parameters of forest health. This paper presents the results of the first year of monitoring, 2005. In 2005, high O3 concentrations were measured, mainly in the spring. In the summer, due to wet and cold weather, the O3 load was comparatively low. In the plots investigated, the concentrations of O3 were higher with the altitude. The amount of epicuticular waxes on 1-year-old Norway spruce needles was the only factor showing significant correlation to O3 concentration. Defoliation of the stands depended only on the stand age. The amount of malondialdehyde (MDA), an oxidative stress marker, was related to the altitude, and only for European beech. The results are preliminary, as the summer O3 development was not typical in 2005, and the results may change over the next monitoring periods.

Monitoring of ozone effects on the vitality and increment of Norway spruce and European beech in the Central European forests

The ozone effect on Norway spruce (Picea abies (L) Karst.) and European beech (Fagus sylvatica L.) was studied on 48 monitoring plots in 2005-2008. These plots represent two major forest tree species stands of different ages in eight regions of the Czech Republic. The forest conditions were represented by defoliation and the annual radial increment of individual trees. The ozone exposure was assessed by using modeled values of mean annual O(3) concentration and the AOT40 index. The malondialdehyde (MDA) content of the foliage was analysed and used as an indicator of oxidative stress. The correlation analysis showed a significant relation of Norway spruce defoliation to the AOT40 exposure index, and European beech defoliation to the MDA level. The radial increment response to ozone was significant only for the European beech: (a) the correlation analysis showed its decrease with increasing AOT40; (b) the regression model showed its decrease with increasing mean annual ozone concentration only at lower altitudes (<700 m a.s.l.).

Quantifying Carbon and Nutrient Input From Litterfall in European Forests Using Field Observations and Modeling

Litterfall is a major, yet poorly studied, process within forest ecosystems globally. It is important for carbon dynamics, edaphic communities, and maintaining site fertility. Reliable information on the carbon and nutrient input from litterfall, provided by litter traps, is relevant to a wide audience including policymakers and soil scientists. We used litterfall observations of 320 plots from the pan-European forest monitoring network of the “International Co-operative Programme on Assessment and Monitoring of AirPollution Effects on Forests” to quantify litterfallfluxes. Eight litterfall models were evaluated (four using climate information and four using biomass abundance). We scaled up our results to the total European forestarea and quantified the contribution of litterfall to the forest carbon cycle using net primary production aggregated by bioregions (north, central, and south) and by forest types (conifers and broadleaves). The 1,604 analyzed annual litterfall observations indicated an average carbon input of 224 g C · m2· year 1 (annual nutrient inputs 4.49 g N, 0.32 g P, and 1.05 g K · m2), representing a substantial percentage of net primary production from 36% in north Europe to 32% in central Europe. The annual turnover of carbon and nutrient in broadleaf canopies was larger than for conifers. The evaluated models provide large-scale litterfall predictions with a bias less than 10%. Each year litterfall in European forests transfers 351 Tg C, 8.2 Tg N,0.6 Tg P, and 1.9 Tg K to the forestfloor. The performance of litterfall models may be improved by including foliage biomass and proxies for forest management.