Density - All Trees Per Acre >1" Dbh

Trees per acre (TPA) is a common forest structure measurement that provides a useful index of forest and habitat condition. Many other metrics can be derived from having accurate estimates of trees 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 of trees per acre as estimates of tree density on the landscape. This raster surface represents all live trees greater than 1" dbh (TPA). Reference conditions can be generated from contemporary reference sites for mature forest conditions outside of the WUI. 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 TPA loss, using the formula: _2021 TPA = 2019 TPA '€“ (2019 TPA * MMI/100)_ Although the assumption of direct correlation between canopy cover and TPA 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 Live trees/acre
data_vintage 2022
date_updated August 2024
element Structure
encoding utf8
file_name SNV_TreesPerAcre_gt1in_202111_202209_T2_v5
format GeoTiff
harvest_object_id 64031ead-8e3c-4f59-ad01-bacbd858ce30
harvest_source_id a2637971-af12-457f-ae4a-831d2202a539
harvest_source_title WIFIRE Commons
maximum_value 13741.6
metric_definition_and_relevance Trees per acre (TPA) is a common forest structure measurement that provides a useful index of forest and habitat condition. Many other metrics can be derived from having accurate estimates of trees 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