A review of modeling the effects of vegetation on large wood recruitment processes in mountain catchments

Gasser, Eric; Schwarz, Massimiliano; Simon, Andrew; Perona, Paolo; Phillips, Chris; Hübl, Johannes; Dorren, Luuk

doi:10.1016/j.earscirev.2019.04.013

Cited by 41 publications

(42 citation statements)

References 201 publications

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“…Models fed with remotely sensed data, such as aerial imagery and forest cover information, enable the simulation and identification of recruitment processes and sources and the estimation of wood supplied volumes (Gregory and Meleason, 2003;Mazzorana et al, 2009;Ruiz-Villanueva et al, 2014a;Cislaghi et al, 2018). High-resolution canopy models obtained from LiDAR or photogrammetry may provide more accurate estimation of wood volumes (Steeb et al, 2017;Gasser et al, 2019). Scenarios based on forecasted climate change alterations of vegetation cover, flow regimes and human activities can be also designed to explore and quantify the range of variability of instream wood supply, and to make predictions about how differences in river and forest management may alter instream wood supply (e.g.…”

Section: Catchment-scale Modelsmentioning

confidence: 99%

Remotely sensed rivers in the Anthropocene: state of the art and prospects

Piégay

Arnaud

Belletti

et al. 2020

Earth Surf Processes Landf

168

103

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The rivers of the world are undergoing accelerated change in the Anthropocene, and need to be managed at much broader spatial and temporal scales than before. Fluvial remote sensing now offers a technical and methodological framework that can be deployed to monitor the processes at work and to assess the trajectories of rivers in the Anthropocene. In this paper, we review research investigating past, present and future fluvial corridor conditions and processes using remote sensing and we consider emerging challenges facing fluvial and riparian research. We introduce a suite of remote sensing methods designed to diagnose river changes at reach to regional scales. We then focus on identification of channel patterns and acting processes from satellite, airborne or ground acquisitions. These techniques range from grain scales to landform scales, and from real time scales to inter-annual scales. We discuss how remote sensing data can now be coupled to catchment scale models that simulate sediment transfer within connected river networks. We also consider future opportunities in terms of datasets and other resources which are likely to impact river management and monitoring at the global scale. We conclude with a summary of challenges and prospects for remotely sensed rivers in the Anthropocene.

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Section: Catchment-scale Modelsmentioning

confidence: 99%

Remotely sensed rivers in the Anthropocene: state of the art and prospects

Piégay

Arnaud

Belletti

et al. 2020

Earth Surf Processes Landf

168

103

View full text Add to dashboard Cite

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“…The motion of wood logs in rivers involves three steps: recruitment, transport, and deposition (Gasser et al, 2019). Recruitment is a combination of selection and delivery mechanisms of wood logs from river bedforms and banks into streams and is triggered by stochastic geophysical events such as hillslope failure (Cadol et al, 2009;Comiti et al, 2016;Iroumé et al, 2015;Keller & Swanson, 1979;Nakamura & Swanson, 1993;Rigon et al, 2012), bank erosion (Downs & Simon, 2001;A.…”

Section: Introductionmentioning

confidence: 99%

Biomechanical Properties and Resistance to Uprooting of Laboratory‐Scale Wood Logs

Bau

Perona

2020

JGR Biogeosciences

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Wood dynamics affects riparian ecosystem functioning and river morphology. The spatial and temporal dynamics of wood pieces in river corridors, in particular of deposited rejuvenated wood logs, depend on their biomechanical properties and resistance to uprooting. The ability of stranded wood logs to withstand drag forces depends on how efficiently their roots have sprouted and on the interarrival time, magnitude, and duration of the moderate floods to which they are subjected. We performed static pullout tests on small-scale wood logs (Salix species) of four different sizes, growth stages, and sediment moisture content. Statistics of root biomass growth rate and related spatial distribution along the trunk reveal important insights for upscaling dynamics. Similarly, force-displacement curves indicate the maximum resistance and related energy for uprooting. Autocorrelation analysis of the sequence of force drops in the force-displacement signal reveals the statistical nature of the mechanism of load redistribution among roots. These results are then used to advance a physically based mathematical model of the resistance of wood log roots to flow-induced drag forces. Given that the magnitude, duration, and return period of hydrologic events are typically correlated, our model implies the existence of windows of opportunity for wood logs to either survive or remobilize.

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“…The distance of the tree stem to the streambank/water interface was placed at 1.00 m. Relative cumulative erosion reduction of 100% was reached by four different cross sections: At the four cross sections, total modeled absolute erosion reduction was at most 1.04 m and the median sediment diameter was exclusively ≥ 112 mm. Based on the modeled results of the 37 study reaches in this study, we propose a modified version of the susceptibility matrix presented in Gasser et al [84] (Figure 12). While the matrix presented in Gasser et al [84] was based on values found in the literature, the matrix presented in this article was adapted based on the original matrix considering the modeled results.…”

Section: Susceptibility To Hydraulic Bank Erosion Considering the Effmentioning

confidence: 99%

“…The matrix is however only valid for streambanks where rooting depth is greater or equal to streambank height. Green areas represent channel conditions (channel width and slope) Based on the modeled results of the 37 study reaches in this study, we propose a modified version of the susceptibility matrix presented in Gasser et al [84] (Figure 12). While the matrix presented in Gasser et al [84] was based on values found in the literature, the matrix presented in this article was adapted based on the original matrix considering the modeled results.…”

Section: Susceptibility To Hydraulic Bank Erosion Considering the Effmentioning

confidence: 99%

A New Framework to Model Hydraulic Bank Erosion Considering the Effects of Roots

Gasser

Perona

Dorren

et al. 2020

Water

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Floods and subsequent bank erosion are recurring hazards that pose threats to people and can cause damage to buildings and infrastructure. While numerous approaches exist on modeling bank erosion, very few consider the stabilizing effects of vegetation (i.e., roots) for hydraulic bank erosion at catchment scale. Taking root reinforcement into account enables the assessment of the efficiency of vegetation to decrease hydraulic bank erosion rates and thus improve risk management strategies along forested channels. A new framework (BankforNET) was developed to model hydraulic bank erosion that considers the mechanical effects of roots and randomness in the Shields entrainment parameter to calculate probabilistic scenario-based erosion events. The one-dimensional, probabilistic model uses the empirical excess shear stress equation where bank erodibility parameters are randomly updated from an empirical distribution based on data found in the literature. The mechanical effects of roots are implemented by considering the root area ratio (RAR) affecting the material dependent critical shear stress. The framework was validated for the Selwyn/Waikirikiri River catchment in New Zealand, the Thur River catchment and the Sulzigraben catchment, both in Switzerland. Modeled bank erosion deviates from the observed bank erosion between 7% and 19%. A sensitivity analysis based on data of vertically stable river reaches also suggests that the mechanical effects of roots can reduce hydraulic bank erosion up to 100% for channels with widths < 15.00 m, longitudinal slopes < 0.05 m m −1 and a RAR of 1% to 2%. The results show that hydraulic bank erosion can be significantly decreased by the presence of roots under certain conditions and its contribution can be quantified considering different conditions of channel geometry, forest structure and discharge scenarios.

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A review of modeling the effects of vegetation on large wood recruitment processes in mountain catchments

Cited by 41 publications

References 201 publications

Remotely sensed rivers in the Anthropocene: state of the art and prospects

Remotely sensed rivers in the Anthropocene: state of the art and prospects

Biomechanical Properties and Resistance to Uprooting of Laboratory‐Scale Wood Logs

A New Framework to Model Hydraulic Bank Erosion Considering the Effects of Roots

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