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G. P. J. Draaijers W. P. M. F. Ivens W. Bleuten 《Water, air, and soil pollution》1988,42(1-2):129-136
Atmospheric dry deposition in two forest edges was studied by means of monitoring canopy throughfall in Douglas Fir stands. Throughfall fluxes in the first 50 to 100 m of forest edges were found to be substantially higher than fluxes in the interior of forest stands. Sodium and chloride showed the steepest throughfall flux gradients. Ions important for soil acidification and eutrophication showed relatively less steep but still significant gradients. The mean increase of the throughfall flux at 10 m, with respect to the flux at 200 m from the forest edge amounted to 150% for Na+, 119% for Cl?, 54% for S04 2?, 38% for NO3 ? , and 39% for NH4 + The enhancement of dry deposition in forest edges strongly depends on wind velocity and wind direction during dry deposition. Particularly trees in forest edges exposed to prevailing wind directions receive relatively large amounts of dry deposition. 相似文献
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E. P. Van Leeuwen G. P. J. Draaijers C. J. M. Potma W. A. J. Van Pul J. W. Erisman 《Water, air, and soil pollution》1995,85(4):2173-2178
Precipitation concentrations in 1989 on a European scale were obtained from national organisations responsible for wet deposition monitoring in their countries and from the EMEP database. In total, results from about 750 monitoring locations scattered over Europe were gathered. Spatial analysis based on Regionalised Variable Theory revealed auto-correlation in all ion concentrations and reasonable bounded models were fitted to the experimental variograms. Maps of concentrations of acidifying components and base cations were compiled on a 50×50 km scale using the block-kriging interpolation technique. To obtain fluxes, concentrations were multiplied by long-term mean precipitation amounts from the EPA database. An extensive uncertainty analysis was performed to assess the quality of the maps. 相似文献
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Erisman J. W. Draaijers G. P. J. Steingröver E. van Dijk H. Boxman A. de Vries W. 《Water, air, and soil pollution》1998,105(3-4):539-571
Within the framework of the Dutch Priority Program on Acidification, 10 yr of research was conducted in a Douglas fir stand at Speulder forest. Research was conducted to establish the loads and levels of acidifying and eutrophying pollutants and ozone, to determine forest vitality characteristics and follow growth parameters and nutrient status in time and to determine the effects of reduction of loads and levels by manipulation experiments. Results indicate that during the last 20 yr critical levels for air pollutants have hardly been exceeded except for ozone, which slightly affected assimilation. Elevated nitrogen deposition has caused several adverse effects including (i) inhibited mycorrhizal development, leading to a decreased base cation and phosphorus uptake; (ii) elevated foliage/root (fine and coarse) ratios, making the forest more sensitive to drought and windthrow; (iii) elevated nitrogen and arginine concentrations in the foliage, associated with relative base cation and phosphorus deficiency, and (iv) elevated nitrate leaching polluting the groundwater. High inputs of acidity have caused elevated ratios of Al to base cations, affecting fine root (uptake) and depletion of the readily available Al pool, thus affecting the long-term sustainability. Despite these effects, forest vitality, in terms of defoliation/discoloration, is reasonable and forest growth even increased in response to nitrogen. The exceedances of critical loads for nitrogen and acidity, however, implies a (large) risk for the long-term sustainability of the Speulder forest. 相似文献
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G. P. J. Draaijers E. P. Van Leeuwen C. Potma W. A. J. Van Pul J. W. Erisman 《Water, air, and soil pollution》1995,85(4):2389-2394
Atmospheric deposition of base cations in Europe is mapped on a 10×20 km grid using the inferential modeling technique. Deposition fields are found to resemble the geographic variability of sources, climate and land use. In large parts of southern Europe, more than 50% of the potential acid deposition is found counteracted by deposition of base cations. In central and northwestern Europe, however, base cation deposition usually amounts less than 25% of the acid input. An uncertainty analysis to assess the quality of the base cation deposition maps revealed that for an average grid cell the deviation from the estimated value can be as large as 140%. 相似文献
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A canopy exchange model is presented which allows atmospheric deposition to be estimated from longterm throughfall and precipitation measurements. For a forest in the Netherlands, the combination of throughfall measurements and this model resulted in deposition estimates which were similar to deposition estimates derived from micrometeorological measurements and inferential modeling, deposition of NOy being the only exception. Unfortunately, several basic assumptions in the canopy exchange model are not properly evaluated, which up to now limits its application. Suggestions are made on how the model can be improved. 相似文献
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During one year, dry and wet deposition onto thirty forest stands is studied by sampling throughfall and bulk precipitation. Nine measurement sites are situated in Douglas fir (Pseudotsuga menziesii Mirb. Franco) stands, ten in Scotch pine (Pinus sylvestris L.) and eleven in Oak (Quercus robur L.) stands. Because the stands are situated in each other's proximity (i.e. within a radius of approximately 1.4 km) it is assumed that they experience an approximately equal air pollution load. For the acidifying compounds SO4 2?, NO3 ? and NH4 + spatial variability in wet deposition was small within the area studied. Dry deposition, as estimated by net throughfall, displayed a much higher spatial variability. Significant differences existed between tree species and growing seasons. Douglas fir mostly displayed the highest, Oak the lowest and Scotch pine intermediate values for net throughfall fluxes of acidifying compounds. The annual net throughfall fluxes for nitrogen compounds were significantly higher for the coniferous tree species than the broadleaved tree species. For SO4 2?, however, Oak showed a relatively high throughfall flux during the summer. By comparing the temporal pattern of net throughfall fluxes between the three tree species it was concluded that considerable canopy leaching occurred for SO4 2?, Mg+, PO4 3?, HCO3 ? and K+ in Oak stands during the sprouting of leaves in spring. From surface wash experiments in the laboratory it is concluded that canopy leaching of these ions may also be enhanced when Oak leaves are infected by Oak mildew, a fungal disease caused by the fungus Microshaera aliphilitoides. 相似文献
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