Understory

As part of the Lake Tahoe West Restoration Partnership, a science team worked with resource managers to evaluate effects of forest dynamics and management strategies on social and ecological values within a 59,000-acre landscape in the western part of the Lake Tahoe basin in California. Forest growth and fire dynamics were modeled across the landscape using the LANDIS-II platform over 100 years; interconnected models were used to evaluate changes in wildlife habitat, water quality, and economics. Additional modeling and some field monitoring were conducted to evaluate how treatments would affe...

This report presents an evaluation of forest road effects following the Phase III forest harvest (2017-2019) within the South Fork of Caspar Creek, Jackson Demonstration State Forest, California. A two-step approach was utilized: (1) road field measurements; and (2) use of the Distributed Hydrology Soil Vegetation Model (DHSVM) to examine road scenarios at the watershed scale. Storm runoff, turbidity, and suspended sediment measurements were collected for select forest roads in South Fork Caspar Creek during the winter of 2018-2019. Statistical relationships between road runoff, turbidity, and...

In forests where the overstory canopy has been disturbed, evapotranspiration (ET) by the understory may be the main flux of water back to the atmosphere. The ability to take field measurements of water use by understory plants, therefore, is vital for a complete ecosystem water budget. However, little research has been apportioned to directly measuring understory water use, and the technology to do so is thus limited. Portable ET chambers have been used to measure ET rates in agricultural fields, grasslands, and deserts, but not in a forest understory. Thus, a portable rapid chamber which can ...

Reopening abandoned forest roads altars the runoff and soil loss processes in a watershed. In this study, a forest watershed was chosen and abandoned roads were manually identified, aided by a high-resolution LiDAR topographic image and historic photographic images. GIS technologies were the used to describe topographic details and estimate runoff and erosion from a 10-m cell size non-road digital elevation model (DEM) for hillslopes. A 1-m cell size DEM was used to evaluate current effects of the road network, and a modified 1-m DEM to evaluate reopening closed roads with either an insloping ...

The Lake Tahoe West Collaborative Restoration Project study area contains 181 km or roads, 33.5 km of which are paved. Many of the unpaved roads are closed and covered with vegetation. An analysis of road surface erosion and sediment delivery using GIS topographic tools and the Water Erosion Prediction Project WEPP:Road Batch interface estimated that the current road network was delivering 55 Mg of sediment per year. Closing unpaved roads that are currently trafficked will reduce erosion by 20 percent. Traffic supporting thinning operations will on the average, increase sediment delivery by 19...