Relative importance of factors controlling the leaching and uptake of inorganic ions in the canopy of a spruce forest

Abstract

Abstract. Sequential sampling of precipitation under mature spruce trees and time-series analysis of the data were performed in order to assess, in natural conditions, the relative importance of different factors that could influence the leaching and uptake of inorganic ions in the canopy. Eleven rain events were analyzed in order to estimate how external factors, rain intensity, H + , and ionic concentration of the incident rain influence the ionic throughfall concentrations and the net throughfall fluxes.The results led to the conclusion that leaching or uptake mostly occur by diffusion. The influence of the open rain acidity was not conclusive; however, it was shown that the tested external factors only controlled a few percent of the variation of the data. By contrast, the autocorrelation of the data always explained a large portion of the variance. It could result from the gradual changes in the course time of internal factors related to the exchange system including waxes, cuticles, apoplast and xylem sap. These constituents were known to control the exchange at the canopy surface and to be sensitive to the plant physiology and environmental conditions.

Seasonal and within-event dynamics of rainfall and throughfall chemistry in an open tropical rainforest in Rondônia, Brazil

“…In temperate regions, throughfall solute concentrations at the initiation of events are often high, but constant concentrations late in natural events are not typically reported (Crockford et al 1996;Hambuckers and Remacle 1993;Hansen et al 1994). We assume that constant concentration levels are reached after the complete removal of dry deposition, which requires a critical amount of water (Neary and Gizyn 1994).…”

“…Leaching, which is controlled by nutrient mobility within plants (Hambuckers and Remacle 1993), differed between solutes. In our study, better WS correlation for Mg 2+ than for Ca 2+ with Cl -and K + in throughfall might be explained by faster uptake by roots and transportation within plants for Mg 2+ than for Ca 2+ (Kozlowski and Pallardy 1997).…”

Canopy interactions of rainfall in an off-shore mangrove ecosystem dominated by Rhizophora mangle (Belize)

“…Leaching of internal plant pools and ion-exchange processes occurring in the tree canopies contribute to solute enrichment in throughfall (Scherbatskoy and Tyree, 1990;Hambuckers and Remacle, 1993), however, the controls of foliar leaching are still not fully understood. Parker (1983) suggested that fertilisation affects throughfall concentrations by raising the foliar pools of leachable nutrients which has been demonstrated for temperate forest ecosystems (e.g.…”

Spatial and temporal patterns of throughfall quantity and quality in a tropical montane forest in Ecuador

“…Parker, 1983;Lovett and Schaefer, 1992;Hambuckers and Remacle, 1993;Hansen et al, 1994;Crockford et al, 1996) only a few studies deal with tropical environments (Stallard and Edmond, 1981;Germer et al, submitted for publication).Within-event throughfall solute concentration dynamics can be highly variable, both between sampling sites and individual events (Parker, 1983). Several authors reported decreasing concentrations that did not reach a constant level during the observation period (Parker, 1983;Hansen et al, 1994), others observed more variable patterns (Hambuckers and Remacle, 1993;Hansen et al, 1994;Crockford et al, 1996). Rainfall intensity is an important control of leaching and wash-off processes (Lovett and Schaefer, 1992;Hansen et al, 1994;Neary and Gizyn, 1994).…”