Impact of interacting bark structure and rainfall conditions on stemflow variability in a temperate beech-oak forest, central Germany

Abstract

Trees concentrate rainfall to near-stem soils via stemflow. When canopy structures are organized appropriately, stemflow can even induce preferential flow through soils, transporting nutrients to biogeochemically active areas. Bark structure significantly affects stemflow, yet bark-stemflow studies are primarily qualitative. We used a LaserBark to compute bark microrelief (MR), ridge-to-furrow amplitude (R) and slope (S) metrics per American Society of Mechanical Engineering standards (ASME-B46.1-2009) for two morphologically contrasting species (Fagus sylvatica L. (European beech), Quercus robur L. (pendunculate oak)) under storm conditions with strong bark water storage capacity (BWSC) influence in central Germany. Smaller R and S for F. sylvatica significantly lowered BWSC, which strongly and inversely correlated to maximum funneling ratios and permitted stemflow generation at lower rain magnitudes. Larger R and S values in Q. robur reduced funneling, diminishing stemflow drainage for larger storms. Quercus robur funneling and stemflow was more reliant on intermediate rain intensities and intermittency to maintain bark channel-dependent drainage pathways. Shelter provided by Q. robur's ridged bark also appears to protect entrained water, lengthening mean intrastorm dry periods necessary to affect stemflow. Storm conditions where Downloaded by [University of Nebraska, Lincoln] at 17:55 24 August 2015A c c e p t e d M a n u s c r i p t 1 BWSC plays a major role in stemflow accounted for much of 2013's rainfall at the nearest meteorological station (Wulferstedt).

Effects of phenology and meteorological disturbance on litter rainfall interception for a Pinus elliottii stand in the Southeastern United States

“…Average S L,max for P. elliottii bark flakes was low (0.27 mm; Table ) compared to bark water storage capacities measured in the lab using intact bark sampled from the stems of rough, thick‐barked tree species, being 1–2.7 mm (Levia & Herwitz, ; Van Stan, Lewis, Hildebrandt, Rebmann, & Friesen, ). Water storage experiments performed on the bark of in situ P. elliottii trunks by others in nearby North‐Central Florida (USA) were closer to our estimate (0.5 mm), but still nearly double the magnitude of bark flakes sampled from the litter at our study site (Liu, ).…”

How Deep Can Surface Signals Be Traced in the Critical Zone? Merging Biodiversity with Biogeochemistry Research in a Central German Muschelkalk Landscape

“…Tracer experiments show that stemflow routed along biopores contributes disproportionately to groundwater recharge and is therefore a shortcut from the surface to depth (Taniguchi et al, 1996). Even the structure of a forest canopy can provide preferred pathways for water by focusing dripping, and therefore enhance water input in spatially heterogeneous ways (Stan et al, 2015). The inputs of chemical constituents also depend on preferred pathways.…”

Hydrological properties of bark of selected forest tree species. Part 2: Interspecific variability of bark water storage capacity

“…The water capacity of stems and branches depends on bark tissue properties, such as its thickness, texture and surface roughness, which change along with tree age (Liu 1998;Pypker et al 2011). Van Stan et al (2016) studied the bark structure of beech and oak trees showing that, while a difference between species could be found, intraspecies differences in bark structure were statistically not detectable. Differences in water capacity and roughness of the bark of different species of forest trees affect the amount of stemflow production (Návar 1993;Aboal et al 1999;Levia et al 2010;Van Stan and Levia 2010).…”