| 1. |
- Göransson, Hans, et al.
(författare)
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Nutrient acquisition from different soil depths by pedunculate oak
- 2006
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Ingår i: Trees. - : Springer Science and Business Media LLC. - 1432-2285 .- 0931-1890. ; 20:3, s. 292-298
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Tidskriftsartikel (refereegranskat)abstract
- Eight oak trees (Quercus robur L.) received P-32 at a soil depth of 50 cm and P-33 at a soil depth of 15 cm at the end of June 2002 through plastic tubes inserted into the mineral soil. The phosphorus uptake from different soil depths was estimated by analysing the concentration of P-32 and P-33 in the foliage of oak growing in a mixed stand in southern Sweden. P-32 and P-33 were recovered in the leaves/needles after 21 and 39 days. The recovery of labelled P in oak was higher from 15 cm soil depth than from 50 cm, however, more than 4% of the total amount of labelled P was taken up from 50 cm. This indicates that oak can utilize deep soil layers for nutrient uptake. A study on the uptake of Cs (as an analogue to K) and N-15 into the leaves was performed on the same trees and detectable amounts of N-15 and Cs were recovered in leaves and buds. This indicates that N-15 and Cs can be used to study nutrient uptake of mature trees from the mineral soil.
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| 2. |
- Hagen-Thorn, Anna, et al.
(författare)
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Micronutrient levels in some temperate European tree species: a comparative field study
- 2005
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Ingår i: Trees. - : Springer Science and Business Media LLC. - 1432-2285 .- 0931-1890. ; 19:5, s. 572-579
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Tidskriftsartikel (refereegranskat)abstract
- Micronutrient concentrations in foliage and stemwood (including bark) of six European tree species (Betula pendula Roth., Quercus robur L., Fraxinus excelsior L., Fagus sylvatica L., Tilia cordata Mill. and Picea abies (L.) Karst.) planted on the same type of soil at six sites in three different countries were studied. Micronutrient concentrations in foliage were considerably higher than in stemwood for all elements and species studied, except for Fe in spruce. Interspecies comparisons revealed significant differences in concentrations both in foliar and stemwood biomass, as well as in stemwood:foliage nutrient ratios. Lime foliage showed a considerably higher concentration of B than all other species, while the stemwood concentration of this element was highest in ash. Mn concentration in both foliar and stemwood biomass of ash was extremely low compared with concentrations in other species. Birch stemwood showed nearly double the level of Zn in other species at all sites. Zn concentrations in the birch foliage were also higher than in other species, with the exception of the Lithuanian sites, which showed lower EDTA-extractable Zn concentrations in the soils. The concentration of Cu was lowest in spruce foliage, while Cu concentrations in stemwood were similar in all species. It was concluded that species-related differences in microelement nutrition must be taken into account when evaluating the nutrient status of common European forest tree species, and when using them as bio-indicators of the effects of environmental pollution.
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| 3. |
- Reinap, Ausra, et al.
(författare)
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Oak leaves as aerosol collectors: relationships with wind velocity and particle size distribution. Experimental results and their implications
- 2009
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Ingår i: Trees. - : Springer Science and Business Media LLC. - 0931-1890 .- 1432-2285. ; 23:6, s. 1263-1274
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Tidskriftsartikel (refereegranskat)abstract
- Advancing the understanding of the aerosol-capture efficiencies of forest components such as leaves and needles, and of the mechanisms that underpin these efficiencies, is essential to the many related issues of forest turnover of nutrients and pollutants. For idealized collectors (such as artificial plates or cylinders) aerosol-mechanics offers a means for calculating capture efficiencies. For living collectors, in particular deciduous leaves, experimental investigations become necessary to assist in formulating the sub-models of capture efficiency that are fundamental to the modelling of fluxes of aerosol-borne substances to forests. We here present wind-tunnel based methods and results for leaves of Quercus robur L. exposed to an aerosol whose mass versus aerodynamic particle size distribution is characterised by a geometric mean aerodynamic particle diameter around 1.2 mu m and a geometric standard deviation around 1.8. With respect to that distribution, and founded on a specially designed leaf wash-off method, we obtained average oak-leaf capture efficiencies ranging from 0.006% of the approaching aerosol mass flux at wind-speed 2 ms(-1) to 0.012% of the flux at wind-speeds 10 ms(-1), respectively. These values can be translated into deposition velocities (V (d) ) for a leaf ensemble with a given leaf area index (LAI). With LAI in the range 2-5 (commonly found in the field) and for wind-speeds 2, 5 and 10 ms(-1), resulting V (d) -values would be 0.02-0.05, 0.05-0.13, and 0.2-0.6 cm/s, respectively. To the extent comparisons are possible, our capture efficiency values are at the low end of the range of values reported by other researchers. The strong wind-speed sensitivity of V (d) has implications for the deposition of aerosol-borne substances to forests for which wind regimes may shift as a result of climatic and land-use changes.
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| 4. |
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