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

1999 ◽  
Vol 29 (12) ◽  
pp. 1944-1957 ◽  
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.

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

1994 ◽  
Vol 24 (6) ◽  
pp. 1089-1100 ◽  
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.

Base cation leaching from the canopy of a subtropical rainforest in northeastern Taiwan

2001 ◽  
Vol 31 (7) ◽  
pp. 1156-1163 ◽  
Author(s):  
Teng-Chiu Lin ◽  
Steven P Hamburg ◽  
Yue-Joe Hsia ◽  
Hen-Biau King ◽  
Lih-Jih Wang ◽  
...  
Keyword(s):  
Forest Canopy ◽  
Base Cations ◽  
Acid Precipitation ◽  
Base Cation ◽  
Subtropical Forest ◽  
Continuous Exposure ◽  
Negative Effects ◽  
Subtropical Forests ◽  
Cation Leaching ◽  
Temperate Deciduous Forests

We examined base cation leaching from the canopy of a subtropical rainforest in northeastern Taiwan. The forest is characterized by extremely low levels of base cations in both canopy vegetation and in the soils. The rates of canopy leaching of K+, Ca2+, and Mg2+ were very high, representing up to 30, 35, and 190%, respectively, of the amount stored in leaves. The rate of H+ retention in the canopy was close to the rate of base cation leaching, suggesting that cation leaching is neutralizing acid precipitation. The subtropical forest studied leached cations from the canopy throughout the year, unlike temperate deciduous forests, which are physiologically inert in the winter. The forest canopy of the subtropical forest we studied is impacted by acid deposition and fog throughout the winter because of frequent rainfall and high relative humidity. This continuous exposure to acid precipitation could cause more intense negative effects on the canopy of subtropical forests as compared with temperate forests exposed to similar pollution loads. We suggest that the low base status of subtropical forests growing on low base status soils may make them very vulnerable to the negative effects of air pollution.

Acidic atmospheric deposition and canopy interactions of adjacent deciduous and coniferous forests in the Georgia Piedmont

1993 ◽  
Vol 23 (6) ◽  
pp. 1114-1124 ◽  
Author(s):  
Rosanna Cappellato ◽  
Norman E. Peters ◽  
Harvey L. Ragsdale
Keyword(s):  
Atmospheric Deposition ◽  
Deciduous Forest ◽  
Major Ions ◽  
Coniferous Forest ◽  
Base Cations ◽  
Base Cation ◽  
Coniferous Forests ◽  
Cation Leaching ◽  
Major Mechanism ◽  
Georgia Piedmont

The effects of acidic atmospheric deposition on leaching of base cations from the canopy and the origin of the major ions in throughfall and stemflow were evaluated in a 2-year study of adjacent deciduous and coniferous forests at Panola Mountain Research Watershed in the Georgia Piedmont. In each forest, the NO3− and SO42− in throughfall and stemflow were derived primarily from atmospheric deposition, whereas the base cations Ca2+, Mg2+, and K+ were derived primarily from canopy leaching. Acidic atmospheric deposition was partially neutralized in each forest. Exchange of H+ with base cations appeared to be the major mechanism for the neutralization of atmospheric acidity by the deciduous canopy. Major neutralization mechanisms could not be differentiated in the coniferous canopy. Base-cation leaching accounted for 86% of the base cations in throughfall and stemflow in the deciduous forest and 69% in the coniferous forest. Exchange with H+ accounted for about 30% of base cations in throughfall in the deciduous forest, whereas it could not be clearly estimated in coniferous throughfall. The current level of acidic atmospheric deposition is hypothesized to have caused an increased leaching of base cations of the deciduous canopy, but methods were insufficient to determine its effect on the coniferous canopy.

scholarly journals Cycling of nutrient base cations in a twelve year old Sitka spruce plantation in upland mid-Wales

2000 ◽  
Vol 4 (2) ◽  
pp. 311-321 ◽  
Author(s):  
B. Reynolds ◽  
M. J. Wood ◽  
A. M. Truscott ◽  
S. A. Brittain ◽  
D. L. Williams
Keyword(s):  
Forest Canopy ◽  
Base Cations ◽  
Base Cation ◽  
Sitka Spruce ◽  
Rate Of Change ◽  
Element Cycling ◽  
Calcium Leaching ◽  
Calcium Magnesium ◽  
Nutrient Base ◽  
Podzol Soils

Abstract. The effects of the early growth of plantation forestry on the biogeochemical cycling of potassium, calcium and magnesium have been investigated in a stand of 12 year old Sitka spruce and adjacent moorland growing on acid peaty podzol soils in mid Wales. Element budgets have been calculated for both systems using measurements of soil and vegetation base cation pools and fluxes. In the moorland, the magnesium budget is approximately at steady-state with no net change to the soil store whilst the soil is accumulating potassium. The calcium budget is approximately balanced but contains significant uncertainties due to between plot variability in calcium leaching losses. Afforestation has greatly increased the above-ground living biomass which holds 7 to 15 times more nutrients compared to the living aerial biomass in the moorland. With the exception of magnesium, the base cation stores within the forest soil are being depleted as the increase in atmospheric deposition due to the forest canopy provides only a small offset to the much larger accumulation of base cations within the trees. The current net rate of change in the soil store of calcium is sustainable for only 65 years. However, as the trees mature, their demand for calcium will be reduced and they should be able to ‘tap' deeper sources of calcium in the soil profile as well as in the drift and regolith material. Keywords: Forestry, base cations, element cycling, calcium, magnesium, potassium

scholarly journals Bulk deposition of base cations in a subalpine natural forest landscape estimated by canopy budget model: A focus on the forest edge canopy

2021 ◽  
Author(s):  
Siyi Tan ◽  
Dong Qing ◽  
Xiangyin Ni ◽  
kai Yue ◽  
Shu Liao ◽  
...  
Keyword(s):  
Base Cations ◽  
Base Cation ◽  
Forest Edge ◽  
Natural Forest ◽  
Subalpine Forest ◽  
Budget Model ◽  
Canopy Exchange ◽  
Closed Canopy ◽  
Canopy Budget Model ◽  
Throughfall Deposition

Calculations of base cation inputs of loads in forest edge canopies are rare, although forest edge canopies play a paradoxical role in the effective capture of atmospheric deposition. Throughfall deposition and canopy exchange of base cations were studied with a continuous throughfall investigation under a natural forest edge and a closed canopy in a subalpine forest over a period of 2 years. Compared with precipitation, the concentration of base cations in the throughfall of both canopies was enriched as expected, but the enrichment level in the forest edge was less than that in the closed canopy. Moreover, the throughfall deposition of base cation fluxes in the closed canopy (35.19 kg ha-1 y-1) was slightly higher than that in the forest edge canopy (33.50 kg ha-1 y-1). Seasonally, the base cation input in the rainy season was 2.32–2.70 times higher than that in the snowy season in throughfall in forest edge canopy and the closed canopy. Furthermore, the canopy budget model suggested that the direction and magnitude of canopy exchange and dry deposition controlled the net throughfall fluxes (NTF) of base cations, and obvious differences could be observed between the canopy and seasonal scales. Compared with other elements, K and Mg leached from the main canopy exchange process, while Ca was absorbed by both canopy types in the annual NTF. These results highlight the spatial variability of base cation chemical characteristics, enhance cognitive the deposition of nutrients and regulatory factors in different forest landscapes, preferably guide the formulation forest ecological management strategies.

scholarly journals Current, steady-state and historical weathering rates of base cations at two forest sites in northern and southern Sweden: a comparison of three methods

2020 ◽  
Vol 17 (2) ◽  
pp. 281-304 ◽  
Author(s):  
Sophie Casetou-Gustafson ◽  
Harald Grip ◽  
Stephen Hillier ◽  
Sune Linder ◽  
Bengt A. Olsson ◽  
...  
Keyword(s):  
Steady State ◽  
Soil Depth ◽  
Base Cations ◽  
Base Cation ◽  
Mineral Weathering ◽  
Soil Horizon ◽  
Soil Horizons ◽  
Weathering Rate ◽  
Weathering Rates ◽  
Forest Sites

Abstract. Reliable and accurate methods for estimating soil mineral weathering rates are required tools in evaluating the sustainability of increased harvesting of forest biomass and assessments of critical loads of acidity. A variety of methods that differ in concept, temporal and spatial scale, and data requirements are available for measuring weathering rates. In this study, causes of discrepancies in weathering rates between methods were analysed and were classified as being either conceptual (inevitable) or random. The release rates of base cations (BCs; Ca, Mg, K, Na) by weathering were estimated in podzolised glacial tills at two experimental forest sites, Asa and Flakaliden, in southern and northern Sweden, respectively. Three different methods were used: (i) historical weathering since deglaciation estimated by the depletion method, using Zr as the assumed inert reference; (ii) steady-state weathering rate estimated with the PROFILE model, based on quantitative analysis of soil mineralogy; and (iii) BC budget at stand scale, using measured deposition, leaching and changes in base cation stocks in biomass and soil over a period of 12 years. In the 0–50 cm soil horizon historical weathering of BCs was 10.6 and 34.1 mmolc m−2 yr−1, at Asa and Flakaliden, respectively. Corresponding values of PROFILE weathering rates were 37.1 and 42.7 mmolc m−2 yr−1. The PROFILE results indicated that steady-state weathering rate increased with soil depth as a function of exposed mineral surface area, reaching a maximum rate at 80 cm (Asa) and 60 cm (Flakaliden). In contrast, the depletion method indicated that the largest postglacial losses were in upper soil horizons, particularly at Flakaliden. With the exception of Mg and Ca in shallow soil horizons, PROFILE produced higher weathering rates than the depletion method, particularly of K and Na in deeper soil horizons. The lower weathering rates of the depletion method were partly explained by natural and anthropogenic variability in Zr gradients. The base cation budget approach produced significantly higher weathering rates of BCs, 134.6 mmolc m−2 yr−1 at Asa and 73.2 mmolc m−2 yr−1 at Flakaliden, due to high rates estimated for the nutrient elements Ca, Mg and K, whereas weathering rates were lower and similar to those for the depletion method (6.6 and 2.2 mmolc m−2 yr−1 at Asa and Flakaliden). The large discrepancy in weathering rates for Ca, Mg and K between the base cation budget approach and the other methods suggests additional sources for tree uptake in the soil not captured by measurements.

scholarly journals Riparian zone control on base cation concentration in boreal streams

2013 ◽  
Vol 10 (6) ◽  
pp. 3849-3868 ◽  
Author(s):  
J. L. J. Ledesma ◽  
T. Grabs ◽  
M. N. Futter ◽  
K. H. Bishop ◽  
H. Laudon ◽  
...  
Keyword(s):  
Stream Water ◽  
Temporal Stability ◽  
Base Cations ◽  
Base Cation ◽  
Forest Harvesting ◽  
Negative Consequences ◽  
Integration Model ◽  
Groundwater Levels ◽  
Zone Control ◽  
Precipitation Regimes

Abstract. Riparian zones (RZ) are a major factor controlling water chemistry in forest streams. Base cations' (BC) concentrations, fluxes, and cycling in the RZ merit attention because a changing climate and increased forest harvesting could have negative consequences, including re-acidification, for boreal surface waters. We present a two-year study of BC and silica (Si) flow-weighted concentrations from 13 RZ and 14 streams in different landscape elements of a boreal catchment in northern Sweden. The spatial variation in BC and Si dynamics in both RZ and streams was explained by differences in landscape element type, with highest concentrations in silty sediments and lowest concentrations in peat-dominated wetland areas. Temporal stability in BC and Si concentrations in riparian soil water, remarkably stable Mg/Ca ratios, and homogeneous mineralogy suggest that patterns found in the RZ are a result of a distinct mineralogical upslope signal in groundwater. Stream water Mg/Ca ratios indicate that the signal is subsequently maintained in the streams. Flow-weighted concentrations of Ca, Mg, and Na in headwater streams were represented by the corresponding concentrations in the RZ, which were estimated using the Riparian Flow-Concentration Integration Model (RIM) approach. Stream and RZ flow-weighted concentrations differed for K and Si, suggesting a stronger biogeochemical influence on these elements, including K recirculation by vegetation and retention of Si within the RZ. Potential increases in groundwater levels linked to forest harvesting or changes in precipitation regimes would tend to reduce BC concentrations from RZ to streams, potentially leading to episodic acidification.

scholarly journals Modelling bi-directional fluxes of methanol and acetaldehyde with the FORCAsT canopy exchange model

2016 ◽  
Author(s):  
Kirsti Ashworth ◽  
Serena H. Chung ◽  
Karena A. McKinney ◽  
Ying Liu ◽  
Bill J. Munger ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Atmospheric Chemistry ◽  
Forest Canopy ◽  
Global Scale ◽  
Exchange Model ◽  
Forest Site ◽  
Canopy Exchange ◽  
Harvard Forest ◽  
Leaf Level ◽  
Underlying Mechanisms

Abstract. The FORCAsT canopy exchange model was used to investigate the underlying mechanisms governing foliage emissions of methanol and acetaldehyde, two short chain oxygenated volatile organic compounds ubiquitous in the troposphere and known to have strong biogenic sources, at a northern mid-latitude forest site. The explicit representation of the vegetation canopy within the model allowed us to test the hypothesis that stomatal conductance regulates emissions of these compounds to an extent that its influence is observable at the ecosystem-scale, a process not currently considered in regional or global scale atmospheric chemistry models. We found that FORCAsT could only reproduce the magnitude and diurnal profiles of methanol and acetaldehyde fluxes measured at the top of the forest canopy at Harvard Forest if light-dependent emissions were introduced to the model. With the inclusion of such emissions FORCAsT was able to successfully simulate the observed bi-directional exchange of methanol and acetaldehyde. Although we found evidence that stomatal conductance influences methanol fluxes and concentrations at scales beyond the leaf-level, particularly at dawn and dusk, we were able to adequately capture ecosystem exchange without the addition of stomatal control to the standard parameterisations of foliage emissions, suggesting that ecosystem fluxes can be well enough represented by the emissions models currently used.

scholarly journals Soil properties determine the elevational patterns of base cations and micronutrients in plant-soil system up to the upper limits of trees and shrubs

2017 ◽  
Author(s):  
Ruzhen Wang ◽  
Xue Wang ◽  
Yong Jiang ◽  
Artemi Cerdà ◽  
Jinfei Yin ◽  
...  
Keyword(s):  
Soil Ph ◽  
Inorganic Nitrogen ◽  
Base Cations ◽  
Base Cation ◽  
Plant Tissues ◽  
Soil System ◽  
Plant Soil ◽  
Total Soil ◽  
Upper Limits ◽  
Trees And Shrubs

Abstract. To understand whether base cations and micronutrients in the plant-soil system change with elevation, we investigated the patterns of base cations and micronutrients in both soils and plant tissues along three elevational gradients and three different climate zones in China. Base cations of Ca, Mg and K and micronutrients of Fe, Mn and Zn were determined in soils, trees and shrubs growing at lower and middle elevations as well as at their upper limits on Balang (subtropical, SW China), Qilian (dry-temperate, NW China) and Changbai (wet-temperate, NE China) mountains. No consistent elevational patterns were found for base cation and micronutrient concentrations in both soils and plant tissues (leaves, roots, shoots and stem sapwood). Rather, soil pH, total soil nitrogen (TN), the soil organic carbon (SOC) to TN ratio (C:N), and total soil inorganic nitrogen (TIN) determined the elevational patterns of soil exchangeable Ca and Mg. Furthermore, multiple regression models showed that soil pH and C:N were pivotal factors affecting soil Fe, Mn and Zn availabilities. In return, soil base cation and micronutrient availabilities played fundamental roles in determining the base cation and micronutrient concentrations in plant tissues. Our results highlight the importance of soil physicochemical properties (mainly SOC, C:N and pH) rather than elevation (i.e., canopy cover and environmental factors, especially temperature), in determining base cation and micronutrient availabilities in soils and subsequently their concentrations in plant tissues.

Sign in / Sign up

Export Citation Format

Share Document