Publications

Slope Stability Models (SSMs) are valuable tools used as decision support in land management to mitigate catastrophic effects caused by rainfall-induced shallow landslides. In particular, SSMs incorporating the presence and influence of vegetation allow for the evaluation of how trees influence relative slope stability and how forest management could ensure the root reinforcement effect in space and time. By implementing empirical knowledge about complex mechanical and hydrological processes, SSMs have been realized by employing different modeling approaches and methods, becoming suitable for different contexts and scales of analysis. Recent SSMs increasingly consider vegetation both as a mechanism to counteract the triggering process of shallow landslides and as a manageable and modifiable tool for mitigating hazards. This review aims to analyze the state-of-the-art of SSMs applicable to vegetated slope areas, investigating those that consider root reinforcement and some of the most cited SSMs in the literature that neglect this effect instead. After classification and exposition on the spatial and temporal dimension of the analysis, modeling approaches, and complexity, we discuss the identification of the most suitable Slope Stability Model (SSM) for individual applications considering four fundamental aspects: modeling approaches, the analysis scale, and purpose, and the output data. Although all SSMs allow for risk analysis by quantifying the factor of safety, only a few allow for an accurate assessment of how changes in vegetation structure, due to the occurrence of natural and human disturbances, also affect the stability of a studied area. Such information is critical to identifying land management criteria to preserve and enhance the protection effect. The improvement of data collection and measurement techniques to obtain parameters for stability analysis required the development of new SSMs able to exploit the improved detail of information, thus allowing for increasingly accurate analyses. © 2021

Suspended sediment and nutrients following forest management activities or wildfires are transported to streams and lakes via surface runoff and are a major threat to water quality. Land and water managers resort to hydrologic models to test hypotheses that can help them make informed decisions to minimize disturbances and protect water resources. We present applications of an online interface, WEPPcloud, for the Water Erosion Prediction Project (WEPP) model as a pre- and post-disturbance management tool to model various gauged and ungauged forested watersheds throughout the western U.S. We compare simulated streamflow, sediment, and phosphorus to observations at USGS gauging stations and assess the accuracy of the online interface with minimal or no calibration. Specifically, we present modeling results from 28 relatively undisturbed forested watersheds in the states of California, Nevada, Oregon, Washington, and Idaho. Across all watersheds, the NSEs based on the daily streamflow values, were in the range of 0.43 to 0.64 indicating satisfactory agreement between modeled and observed values. Similarly, annual average NSE for sediment yield was 0.61, while for phosphorus it was 0.75, 0.71, and 0.66, for total, particulate, and soluble reactive phosphorus, respectively. Additionally, we demonstrate the utility of the WEPPcloud interface as a tool to compare model results for ungauged watersheds from various disturbed conditions including prescribed fire, thinning, and wildfire to undisturbed model results to better understand the effects of forest management and wildfires on water quality and quantity. © 2022 Elsevier B.V.

The WEPPcloud interface is a new online decision-support tool for the Water Erosion Prediction Project (WEPP) model that facilitates data preparation and model runs, and summarizes model outputs into tables and maps that are easily interpretable by users. The interface can be used by land and water managers in United States, Europe, and Australia interested in simulating streamflow, sediment and pollutant loads from both undisturbed and disturbed (e.g. post-wildfire or post-treatment such as thinning or prescribed fires) forested watersheds. This article contains full hydrologic model runs for 28 forested watersheds in the U.S. Pacific Northwest with the WEPPcloud online interface. It also includes links to repositories with the individual model runs, a table containing default model parameters for disturbed conditions, and figures with model outputs as compared to observed data. The data in the repositories include all the raw data input and output from the model as well as the processed data, which can be accessed through tables and shapefiles to provide additional insights into the model outputs. Lastly, the article describes how the data are organized and the content of each folder containing the data. These model runs are useful for anyone interested in modeling forested watersheds with the WEPPcloud interface. © 2022 The Authors

Tree-level planning is gaining relevance supported by continuous advances in forest remote sensing methods. Spatial connectivity under spatial optimization methods applied to individual tree mapping data remains unexplored. This article presents a spatially explicit mathematical formulation that ensures the tree cuttings conforming a corridor can connect two points across a forest landscape. The created paths facilitate operational harvesting linking forest planning solutions to forest machinery operations. The model integrates production, economic and connectivity constraints using mixed integer programming as optimization method, while tree positions and attributes were mapped using airborne laser scanning. Model performance was tested towards different harvesting targets and for the assessment of trade-offs involving the connectivity of the solutions and the economic performance. The showcase area to test the model is pine forest located in Central Spain comprising more than 9000 detected trees. The results showed the mathematical formulation in the model is effective at creating paths connect proposed areas using optimized tree harvests. Global optimality was reached fast using mathematical programming for a complex and large combinatorial problem. The presented model is another step forward in the design of multi-objective tree-level planning models, enhancing the assimilation of planning solutions towards forest operations capable to maximize the use of individual tree mapping data. © 2022 Elsevier B.V.