Multi-scale analyses of wildland fire combustion processes: Small-scale field experiments – terrestrial laser scans

The United States Department of Defense (DoD) Strategic Environmental Research and Development Program (SERDP) funded project: "Multi-scale Analyses of Wildland Fire Combustion Processes in Open-canopied Forests using Coupled and Iteratively Informed Laboratory-, Field-, and Model-based Approaches (RC-2641)" small-scale field experiments were designed to investigate how contrasting fuel conditions (e.g., fuel load, particle type, bulk density), fire spread type (e.g., heading vs. backing), and ambient conditions (e.g., seasonality, moisture, flow, temperature) influenced physical processes associated with combustion (e.g., heat transfer, flame propagation, flow) and the scale-dependent coupling of these processes. Additionally, these experiments provide 1) a linkage between small-scale laboratory combustion experiments and large-scale operational prescribed fires, and 2) archived datasets for further model development and evaluation. Our experimental design incorporates complementary approaches, methods, and instrumentation employed at these other scales, to quantify critical properties of the experimental fires’ physics domains (e.g., fuels and ambient conditions) and processes associated with combustion (e.g., heat transfer, flame propagation, flow). The small-scale field experiments include a series of highly instrumented, intermediate-scale experiments conducted on 100 square meter plots at the Silas Little Experimental Forest, New Lisbon, New Jersey. This dataset contains terrestrial laser scans (TLS) of 31 burn plots collected in 2018 and 2019 using a FARO Focus 3D X 330 TLS. For each burn a scan was taken at each corner of the burn block before ignition (pre-burn), and after the completion (post-burn). The corner scans for the pre- and post-scans were merged to create a single pre- and post-scan. Additional mineral soil scans were taken for the 2019 burns where all burned and unburned material was removed before the first burn of the day. TLS data were used to map instrument locations, evaluate fuel characteristics and evaluate changes in fuel loading.
Many DoD facilities utilize low intensity prescribed fire to manage hazardous fuels, restore ecological function and historic fire regimes, and encourage the recovery of threatened and endangered species in the forests they manage. Current predictive models used to simulate fire behavior during low-intensity prescribed fires (and wildfires) are empirically based, simplistic, and fail to adequately predict fire outcomes because they do not account for variability in fuel characteristics and interactions with important meteorological variables. This study used a suite of measurements at the fuel particle, fuel bed, field plot, and stand scales to quantify how variability in fuel characteristics and key meteorological factors interact to drive fire behavior during low intensity prescribed burns. These experiments were designed to inform the development and evaluation of physics-based models that explicitly account for combustion, turbulent transfer, and energy exchange by coupling and scaling individual component processes. These datasets provide measurements to improve the understanding of, and ability to accurately predict, fire behavior under a wide range of management scenarios.
A summary of the SERDP Project RC-2641 can be found at the RC-2641 Project Overview (serdp-estcp.org): https://www.serdp-estcp.org/Program-Areas/Resource-Conservation-and-Resiliency/Air-Quality/Fire-Emissions/RC-2641. Please reference the plot layout and documentation data publication (Gallagher et al. 2022) as these data provide the sensor locations of each burn, a detailed description of data collected and a burn summary.