COMPARISON OF DRY DEPOSITION AND CANOPY EXCHANGE OF BASE CATIONS IN TEMPERATE HARDWOOD FORESTS IN FLANDERS AND CHILE

The field study in a mountain forest at Bílý Kříž provides a comparison of element fluxes for two adjacent forest spruce stands of the same age (29 years in 2005) but with different stem densities. During five years (2001–2005), bulk and throughfall precipitation was sampled and analysed. Total deposition, dry deposition and canopy exchange fluxes were evaluated on the basis of the Canopy Budget Model. Highly significant differences in base cations, dissolved organic carbon, SO42−, F−, and Cl− throughfall concentrations were found between the sparser and denser spruce stands.  Throughfall, dry deposition and canopy exchange fluxes were also influenced by stand density. Annual throughfall fluxes of inorganic nitrogen were within 11.9–17.8 kg N·ha–1·yr–1 on the sparser plot and within 15.4–20.6 kg N·ha–1·yr–1 on the denser plot; annual throughfall fluxes of sulphur were within 15.3–20.3 kg S·ha–1·yr–1 on the sparser plot and within 20.7–27.7 kg S·ha–1·yr–1on the denser plot. The critical load for nitrogen (11.2 kg N·ha–1·yr–1) was exceeded on both plots in all evaluated years 2002–2005.  Total annual inorganic nitrogen deposition was higher by up to 37.5% (in 2002) on the denser plot than on the sparser one.

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Dry Deposition and Canopy Exchange in a Mixed Oak Forest as Determined by Analysis of Throughfall

Journal of Applied Ecology ◽

10.2307/2405064 ◽

1984 ◽

Vol 21 (3) ◽

pp. 1013 ◽

Cited By ~ 236

Author(s):

G. M. Lovett ◽

S. E. Lindberg

Keyword(s):

Dry Deposition ◽

Oak Forest ◽

Canopy Exchange

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Throughfall and stemflow chemistry under deciduous and coniferous forest canopies in south-central Ontario

Canadian Journal of Forest Research ◽

10.1139/x94-145 ◽

1994 ◽

Vol 24 (6) ◽

pp. 1089-1100 ◽

Cited By ~ 92

Author(s):

A.J. Neary ◽

W.I. Gizyn

Keyword(s):

Dry Deposition ◽

Forest Canopy ◽

Coniferous Forest ◽

Base Cations ◽

Ion Sources ◽

Regression Technique ◽

Forest Canopies ◽

South Central ◽

Internal Sources ◽

Scavenging Efficiency

By measuring incident precipitation, throughfall, and stemflow chemistry, the roles of coniferous- and deciduous-dominated forest canopies as a source of and sink for ions in precipitation were examined. A regression technique for distinguishing between external (dry deposition) and internal (canopy leaching) sources of ions in the throughfall flux was evaluated. The effect of seasonal changes in the forest canopy on throughfall and stemflow chemistry was also examined. Throughfall comprised 74 and 84%, respectively, of the hydrologic flux at the coniferous and deciduous sites. Sulphate fluxes were highest at the coniferous site during both growing and dormant seasons, suggesting either a higher scavenging efficiency of the needles for atmospheric SO42−, or higher SO42− leaching from the foliage. The deciduous site neutralized acidic inputs, as demonstrated by its net negative H+ flux year round. The buffering capacity of the coniferous forest was exceeded by the higher amount of acid interception by the canopy. Nitrate behaved conservatively and base ions were exported from the canopy. Stemflow contributions of ions, although low, were generally higher than the contribution of stemflow to the hydrologic flux (2–3%). Independent dry deposition measurements for the growing season, when compared with net SO42− flux, overestimated dry deposition collected by the deciduous canopy, but were comparable to the flux at the coniferous site. These data suggest that dry SO2−SO42− deposition may be responsible for all SO42− enrichment seen in throughfall at these sites. A regression technique for separating internal and external ion sources in throughfall yielded inconsistent results, and attributed virtually all ion enrichment to internal sources. Problems with false assumptions and spurious correlations are discussed. We conclude that this method is not satisfactory for separating ion sources. Seasonal patterns in throughfall chemistry are present. During the growing seasons bases exchange for H+ and are exported similarly with SO42−. Hydrogen retention mirrors SO42− export. Base cations (particularly K+) are leached from the canopy primarily during senescence, but from the stem of the tree primarily during the dormant period. This was most evident at the deciduous site. Chloride behaved in a similar manner, while NH4+ and H+ were retained during the senescent period.

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Calculating Dry Deposition and Canopy Exchange with the Canopy Budget Model: Review of Assumptions and Application to Two Deciduous Forests

Water Air & Soil Pollution ◽

10.1007/s11270-008-9614-2 ◽

2008 ◽

Vol 191 (1-4) ◽

pp. 149-169 ◽

Cited By ~ 83

Author(s):

Jeroen Staelens ◽

Daniel Houle ◽

An De Schrijver ◽

Johan Neirynck ◽

Kris Verheyen

Keyword(s):

Dry Deposition ◽

Deciduous Forests ◽

Budget Model ◽

Canopy Exchange ◽

Model Review ◽

Canopy Budget Model

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Boreal forest BVOCs exchange: emissions versus in-canopy sinks

10.5194/acp-2017-493 ◽

2017 ◽

Cited By ~ 1

Author(s):

Putian Zhou ◽

Laurens Ganzeveld ◽

Ditte Taipale ◽

Üllar Rannik ◽

Pekka Rantala ◽

...

Keyword(s):

Boreal Forest ◽

Dry Deposition ◽

Large Scale ◽

Transport Model ◽

Oxidation Products ◽

Forest Site ◽

Chemical Production ◽

Chemical Transport Model ◽

Canopy Exchange ◽

Sources And Sinks

Abstract. A multi-layer gas dry deposition model has been developed and implemented into a 1-dimensional chemical transport model SOSAA (a model to Simulate the concentrations of Organic vapours, Sulphuric Acid and Aerosols) to calculate the dry deposition velocities for all the gas species included in the chemistry scheme. The new model was used to analyse in-canopy sources and sinks, including gas emissions, chemical production and loss, dry deposition and turbulent transport of 12 featured biogenic volatile organic compounds (BVOCs) or groups of BVOCs (e.g., monoterpenes, isoprene&plus;2-methyl-3-buten-2-ol (MBO), sesquiterpenes and oxidation products of mono- and sesquiterpenes) in July, 2010 at the boreal forest site SMEAR II (Station to Measure Ecosystem-Atmosphere Relations II). According to the significance of modeled monthly averaged individual source and sink terms inside the canopy, the selected BVOCs were classified into five categories: (1) most of emitted gases are transported out of the canopy (monoterpenes, isoprene&plus;MBO), (2) chemical reactions remove a significant portion of emitted gases (sesquiterpenes), (3) bidirectional fluxes occur since both emission and dry deposition are crucial for the in-canopy concentration tendency (acetaldehyde, methanol, acetone, formaldehyde), (4) gases removed by deposition inside the canopy are compensated by the gases transported from above the canopy (acetol, pinic acid, β-caryophyllene's oxidation product BCSOZOH), and finally (5) the chemical production is comparable to the sink by deposition (isoprene's oxidation products ISOP34OOH and ISOP34NO3). Most of the simulated sources and sinks were located above about 4 m for oxidation products and above about 8 m for emitted species except formaldehyde. In addition, soil deposition (including deposition onto understory vegetation) contributed 11–61 % to the overall in-canopy deposition. The emission sources peaked at about 14–16 m which was higher than 10 m where the maximum of dry deposition onto overstorey vegetation was located. This study provided a method to enable the quantification of the exchange between atmosphere and biosphere for numerous BVOCs, which could be applied in large-scale models in future. With this more explicit canopy exchange modeling system this study analysed both the temporal and spatial variations of individual in-caonpy sources and sinks, as well as their combined effects on driving BVOCs exchange. Twelve featured BVOCs or BVOC groups were analyzed in this study, more compounds could also be investigated similarly by being classified into the five categories.

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Observations of reactive nitrogen oxide fluxes by eddy covariance above two mid-latitude North American mixed hardwood forests

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-27891-2013 ◽

2013 ◽

Vol 13 (10) ◽

pp. 27891-27936

Author(s):

J. A. Geddes ◽

J. G. Murphy

Keyword(s):

Nitrogen Oxide ◽

Eddy Covariance ◽

Dry Deposition ◽

Land Surface ◽

Hardwood Forest ◽

Reactive Nitrogen ◽

Canopy Exchange ◽

Mixing Ratios ◽

Deposition Velocities ◽

Channel Analyzer

Abstract. Significant knowledge gaps persist in the understanding of forest–atmosphere exchange of reactive nitrogen oxides, partly due to a lack of direct observations. Chemical transport models require representations of dry deposition over a variety of land surface types, and the role of canopy exchange of NOx (= NO + NO2) is highly uncertain. Biosphere–atmosphere exchange of NOx and NOy (= NOx + HNO3 + PANs + RONO2 + pNO3− + ...) was measured by eddy covariance above a mixed hardwood forest in central Ontario (HFWR), and a mixed hardwood forest in northern lower Michigan (PROPHET) during the summers of 2011 and 2012 respectively. NOx and NOy mixing ratios were measured by a custom built two-channel analyzer based on chemiluminescence, with selective NO2 conversion via LED photolysis and NOy conversion via a hot molybdenum converter. Consideration of interferences from water and O3, and random uncertainty of the calculated fluxes are discussed. NOy flux observations were predominantly of deposition at both locations. The magnitude of deposition scaled with NOy mixing ratios, resulting in campaign-average deposition velocities close to 0.6 cm s−1 at both locations. A~period of highly polluted conditions (NOy concentrations up to 18 ppb) showed distinctly different flux characteristics than the rest of the campaign. Integrated daily average NOy flux was 0.14 mg (N) m−2 day−1 and 0.34 mg (N) m−2 day−1 at HFWR and PROPHET respectively. Concurrent wet deposition measurements were used to estimate the contributions of dry deposition to total reactive nitrogen oxide inputs, found to be 22% and 40% at HFWR and PROPHET, respectively.

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The effect of canopy exchange on input of base cations in a subalpine spruce plantation during the growth season

Scientific Reports ◽

10.1038/s41598-018-27675-9 ◽

2018 ◽

Vol 8 (1) ◽

Cited By ~ 2

Author(s):

Siyi Tan ◽

Hairong Zhao ◽

Wanqin Yang ◽

Bo Tan ◽

Xiangyin Ni ◽

...

Keyword(s):

Base Cations ◽

Growth Season ◽

Canopy Exchange

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Observations of reactive nitrogen oxide fluxes by eddy covariance above two midlatitude North American mixed hardwood forests

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-2939-2014 ◽

2014 ◽

Vol 14 (6) ◽

pp. 2939-2957 ◽

Cited By ~ 22

Author(s):

J. A. Geddes ◽

J. G. Murphy

Keyword(s):

Nitrogen Oxide ◽

Eddy Covariance ◽

Dry Deposition ◽

Land Surface ◽

Hardwood Forest ◽

Reactive Nitrogen ◽

Canopy Exchange ◽

Mixing Ratios ◽

Deposition Velocities ◽

Wildlife Reserve

Abstract. Significant knowledge gaps persist in the understanding of forest–atmosphere exchange of reactive nitrogen oxides, partly due to a lack of direct observations. Chemical transport models require representations of dry deposition over a variety of land surface types, and the role of canopy exchange of NOx (= NO + NO2) is highly uncertain. Biosphere–atmosphere exchange of NOx and NOy (= NOx + HNO3 + PANs + RONO2 + pNO3− + ...) was measured by eddy covariance above a mixed hardwood forest in central Ontario (Haliburton Forest and Wildlife Reserve, or HFWR), and a mixed hardwood forest in northern lower Michigan (Program for Research on Oxidants: Photochemistry, Emissions and Transport, or PROPHET) during the summers of 2011 and 2012 respectively. NOx and NOy mixing ratios were measured by a custom-built two-channel analyser based on chemiluminescence, with selective NO2 conversion via LED photolysis and NOy conversion via a hot molybdenum converter. Consideration of interferences from water vapour and O3, and random uncertainty of the calculated fluxes are discussed. NOy flux observations were predominantly of deposition at both locations. In general, the magnitude of deposition scaled with NOy mixing ratios. Average midday (12:00–16:00) deposition velocities at HFWR and PROPHET were 0.20 ± 0.25 and 0.67 ± 1.24 cm s−1 respectively. Average nighttime (00:00–04:00) deposition velocities were 0.09 ± 0.25 cm s−1 and 0.08 ± 0.16 cm s−1 respectively. At HFWR, a period of highly polluted conditions (NOy concentrations up to 18 ppb) showed distinctly different flux characteristics than the rest of the campaign. Integrated daily average NOy flux was −0.14 mg (N) m−2 day−1 and −0.34 mg (N) m−2 day−1 (net deposition) at HFWR and PROPHET respectively. Concurrent wet deposition measurements were used to estimate the contributions of dry deposition to total reactive nitrogen oxide inputs, found to be 22 and 40% at HFWR and PROPHET respectively.

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Interactions of atmospheric deposition with a mixed hardwood and a coniferous forest canopy at the Lake Clair Watershed (Duchesnay, Quebec)

Canadian Journal of Forest Research ◽

10.1139/x99-212 ◽

1999 ◽

Vol 29 (12) ◽

pp. 1944-1957 ◽

Cited By ~ 62

Author(s):

Daniel Houle ◽

Rock Ouimet ◽

Raynald Paquin ◽

Jean-Guy Laflamme

Keyword(s):

Forest Canopy ◽

Coniferous Forest ◽

Base Cations ◽

Growing Season ◽

Base Cation ◽

Ratio Method ◽

Water Volume ◽

Monthly Basis ◽

Canopy Exchange ◽

Wet Precipitation

From 1989 to 1996, ion deposition in precipitation, throughfall, and stemflow were measured under a deciduous and a coniferous stand, located in the Lake Clair Watershed, during the growing and the dormant seasons. During the growing season, throughfall deposition under both stands was significantly depleted in H+ and NH4+ compared with wet deposition, and a significant uptake of NO3- was observed under the coniferous canopy. Deposition of Ca2+, Mg2+, K+, Na+, Cl-, and SO42- was significantly higher in the throughfall than in the wet precipitation. During the growing season, the coniferous stand was more efficient in retaining nitrogen (NH4+ and NO3-), while H+ was more intensively retained in the deciduous stand. Significant interactions between precipitation and forest canopies were also observed during the dormant season: throughfall depositions of Ca2+, Mg2+, K+, Na+, and Cl- were significantly higher than wet precipitation under both canopies, while throughfall SO42- was significantly enriched only under the coniferous stand. Using a Na+ ratio method, foliar leaching was found mostly responsible for the throughfall enrichment on a full-year basis in both stands, with values averaging 61, 73, and 96% of the total throughfall fluxes for Ca2+, Mg2+, and K+, respectively. Under both stands, net canopy exchange (NCE) of base cations, expressed on a monthly basis, were correlated to water volume and to H+ and SO42- deposition. Multiple regression models including wet SO42- deposition and an estimate of dry S deposition, explained up to 88% (Ca2+ in the coniferous stand) of the variance in base cation NCE under both stands.

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