Black Hills National Forest Light Detection and Ranging (LiDAR) Project
Overview
The Black Hills National Forest has been investing in data gathering to better understand forest conditions. The data gathered will help inform the forest plan revision process, local project implementation, and forest inventory. In 2023, a Light Detection and Ranging (LiDAR) project was implemented to provide consistent and precise estimates for common forestry metrics, including volume, across the entire forest. Aerial LiDAR data was collected through the U.S. Geological Survey 3D Elevation Program across the entire forest. At the same time, 1,700 ground-level field plots were to be installed in areas defined as pine or mixed conifer throughout the Forest to use in conjunction with the LiDAR data. The ground-level field plots were installed by professionals from South Dakota State Forestry, the Wyoming State Forestry Division, Pennington County, and U.S. Forest Service staff. The data and information from this project will be delivered to the public, cooperators, industry and Tribal Governments in three separate phases as it becomes available. The three phases of the project are:
Phase I: Ground-Level Field Plots – this phase of the project was completed in 2024, and the data and all corresponding documents can be accessed in the Phase I section below. This phase includes the following data collected from field crews on the ground:
- Tree-level information such as species, status (live, dead, or dying), and diameter at breast height (DBH) for all measured trees; as well as total height, growth and age metrics for a subset of measured trees.
- Plot-level information such as plot location, trees per acre, basal area per acre, quadratic mean diameter (QMD), and stand density index (SDI) estimates.
Phase II: First group of LiDAR derived products – this phase of the project is expected to be completed in late spring 2025. This set of products will be derived directly from the LiDAR data and will include height, cover, strata, and topographic metrics.
Phase III: Second group of LiDAR modeled products - this phase of the project is expected to be completed in late summer 2025. This set of products will include modelled outputs describing vegetation characteristics that describe tree density, biomass, and volume. This set of products will be developed from the combination of the ground-level field plot data and the LiDAR data.
Questions and Answers
Forest officials have made a concerted effort to gather field data to better understand forest conditions on the Black Hills National Forest. Field data was collected from July 2023 through January 2024. The data gathered will help inform the Forest management plan revision process, local project implementation, and forest inventory. More than 1,600 fixed plots, each 1/10th of an acre in size, were installed in a grid across the forest. For more information see the Sampling Design Methodology Document and the Field Guide.
The data provides a wide sampling of forest conditions across the Black Hills and represents over eighty percent of the forested area. Information for the areas where plots were not installed is expected to be available by the end of the year.
We are very grateful to our partners, the Wyoming State Forestry Division and South Dakota State Forestry staff, who worked with Forest Service employees to collect the data. A project of this scale could not have been accomplished in such a short timeframe without their support.
The data collected includes basic forestry measurements such as tree species, diameter at breast height (DBH, measured at 4.5 feet from ground), total height, and some growth measurements. For a complete list of measurements and how they were taken, see the Field Guide.
Every crew was given training prior to collecting the data to ensure they understood and followed the field protocols. Check in meetings were also conducted on a regular basis with the crews. Once the data was finalized, quality control was done to identify any issues. All issues were resolved prior to releasing the final data. The Quality Control Process Document contains an explanation of this process and the code/outputs for that process.
Basic forestry metrics have been computed for each plot contained within the analysis. This includes metrics that describe the density and average size of trees such as trees per acre, basal area per acre, quadratic mean diameter, etc. The Data Summary Document contains information on how each metric was calculated and the data files (both the geodatabase file and Excel workbook) contain metadata to describe each metric. The Data Summary Document and data files can be found on the website. In addition, plot-level metrics can be viewed spatially on the website.
The Forest Inventory and Analysis (FIA) program is a national census conducted by the Forest Service. On the Forest, field plots installed through the FIA program are placed one plot every 6000 acres. In the past, the Forest has intensified the FIA program to ensure one plot every 3000 acres. The field plots for this effort were installed one plot every 562 acres (75 chain apart). The field data is not related to Forest Inventory Analysis (FIA) data in any way. FIA data is more comprehensive than the field data collected for this effort. In fact, this field data is similar to common stand exam (CSE) data which is collected by field foresters across the Forest Service every day to understand forested conditions to information management decisions. Unlike FIA data which contain repeated measures on trees which are valuable for assessing change through time, there are no plans to revisit these field plots in the future.
We will know more about forest conditions when this data is combined with ancillary data sources such as satellite imagery and other remote-sense data such as Light Detection and Ranging (LiDAR). This work will happen throughout the next year.
No efforts to link this field data to the Rocky Mountain Research Station GTR 422 have been attempted as the field data does not contain the same information as FIA data. At this point in time no analysis nor research has been conducted with the field data.