Spatial variability of throughfall under single birch and pine tree canopies

Abstract

The influence of tree characteristics and meteorological variables on spatial variability of throughfall under a single silver birch and black pine tree was evaluated. During the year 2016 throughfall was measured at 11 points under each tree canopy. For 30 analysed events total throughfall under the birch tree accounted for 73% and under the pine tree 56% of the rainfall in the open. The coefficient of variation of point throughfall was 30% and 40% for the birch and pine tree, respectively. In case of the birch tree both the distance from the stem and canopy coverage influenced throughfall spatial variability, which also showed different patterns during leafed and leafless periods. Additionally, the amount of rainfall and its microstructure influenced the spatial variability of throughfall under the birch tree. However, among the considered tree characteristics only canopy coverage was recognized as a parameter influencing spatial variability of throughfall under the pine. Furthermore, its spatial patterns were specified by meteorological variables, namely the amount of rainfall and its intensity.

Application of Copula Functions for Rainfall Interception Modelling

“…Rainfall in the open, throughfall and stemflow were measured in a park in the city of Ljubljana, Slovenia (46.04 • N, 14.49 • E) [13,14,65]. The typical climate for the area is temperate continental with well-defined seasons.…”

“…One was connected to a tipping bucket flow gauge (Unidata 6506G; 50 mL/tip) and an automatic data logger (Onset HOBO Event), while the other was connected to a manually-read polyethylene barrel (60 L capacity), collected after each event. Under each group of trees, ten manually-read funnel-type gauges (catch area of 78.5 cm 2 ) were also randomly placed and moved around during the three and half years of measurements [65].…”

“…Furthermore, for three events, throughfall under birch trees exceeded the amount of rainfall in the open, which resulted in negative values of rainfall interception (Table 2). This phenomenon is usually attributed to so called "drip points", where rain drops concentrate at the edge of the canopy e.g., [4,65]. Pine trees intercepted on average 68% (±25%) of rainfall per event ( Table 2).…”

Evaluating the Influence of Rain Event Characteristics on Rainfall Interception by Urban Trees Using Multiple Correspondence Analysis

“…Comparing the threshold values for MCA, the chosen 6 mm better describes the initial value of interception expressed by the regression trees for birch and pine trees at the same time. The distinct influence of the rainfall amount on rainfall interception was often observed in various studies, connecting the decrease of the interception ratio (I/P) with the increase in rainfall amount [12,14,[22][23][24]30,36].…”

“…However, in the case of the birch tree, the decrease in rainfall interception ratio (IB36:0) can be observed also during smaller (Pa6:0) and lighter (Pi1.8:0) events, with a duration of more than 4 h (Pd4:1). The distinct influence of the rainfall amount on rainfall interception was often observed in various studies, connecting the decrease of the interception ratio (I/P) with the increase in rainfall amount [12,14,[22][23][24]30,36]. As intercepted rainfall is assumed to evaporate from the canopies, this prominent influence of rainfall amount, considering the negligible influence of air humidity [14], can be explained by the splash droplet evaporation [53][54][55].…”