Basal Area

Basal area (BA) is a common forest structure measurement that provides a useful index of forest and habitat condition. Basal area is the cross-sectional area of the bole of a tree at diameter breast height (dbh). It is measured at the stand level as the cumulative sum of basal area of all trees and expressed as square feet per acre.

Data and Resources

Additional Info

Field Value
Version Version 5.0
Last Updated March 28, 2025, 08:36 (UTC)
Created March 7, 2025, 07:52 (UTC)
category /Forest and Shrubland Resilience/Structure
collection_name California Landscape Metrics
creation_method This data layer currently exists only for the Sierra Nevada region. Efforts are underway to explore development of F3 data for the rest of California. The F3 model generated several raster surfaces as estimates of basal area. This raster surface represents all live trees greater than 1" dbh (BASATOT). 2019 to 2021 Update: Values for 2021 were adjusted using the Ecosystem Disturbance and Recovery Tracker (eDaRT), described in the Introduction. All eDaRT events beginning August 1, 2019 through November 30, 2021 were identified, and the corresponding Mortality Magnitude Index (MMI) values for these events was summed, giving the estimated fractional canopy cover loss per 30m pixel over that time period. The MMI value for canopy cover loss was used as a direct proxy to estimate basal area loss, using the formula: _2021 Basal Area = 2019 Basal Area '€“ (2019 Basal Area * MMI/100)_ Although the assumption of direct correlation between canopy cover and basal area should be viewed with caution, it serves as a reasonable approximation for representative mixed conifer forests in the Sierra Nevada affected by the recent drought (Slaton et al. 2022).
data_resolution 30m Raster
data_units Sq ft/acre
data_vintage 2021
date_updated August 2024
element Structure
encoding utf8
file_name SNV_BasalArea_202111_202209_T2_v5
format GeoTiff
harvest_object_id 5f525ceb-6b5e-4033-9bb4-b33068742589
harvest_source_id a2637971-af12-457f-ae4a-831d2202a539
harvest_source_title WIFIRE Commons
maximum_value 467.1
metric_definition_and_relevance Basal area (BA) is a common forest structure measurement that provides a useful index of forest and habitat condition. Basal area is the cross-sectional area of the bole of a tree at diameter breast height (dbh). It is measured at the stand level as the cumulative sum of basal area of all trees and expressed as square feet per acre.
minimum_value 0.0
pillar Forest and Shrubland Resilience
spatial {"type": "Polygon", "coordinates": [[[-122.2883616476824, 35.05769372687348], [-117.5563290826801, 35.05769372687348], [-117.5563290826801, 42.00332292672577], [-122.2883616476824, 42.00332292672577], [-122.2883616476824, 35.05769372687348]]]}
tier 2