Southern CA - Large Tree Density > 30" Dbh

Large trees are important to forest managers as they have a greater likelihood of survival from fire, provide sources of seed stock, wildlife habitat, and contribute to other critical processes like carbon storage and nutrient cycling. Large trees are often the focus of management in order to protect existing ones and to foster future ones. In consultation with National Forests, "large trees" have been designated as greater than 30" dbh.

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Field Value
Last Updated February 28, 2025, 07:38 (UTC)
Created February 28, 2025, 07:38 (UTC)
category /Forest and Shrubland Resilience/Structure
collection_name California Landscape Metrics
creation_method To determine the cutoff for the definition of large trees in the southern California area (> 30" dbh - need reference ), a statistical relationship between tree dbh and tree height was developed. We used Forest Inventory & Analysis (FIA) 2022 plot data from the region, testing three fits of DBH ~ HGT: Saturating (Michelis Menton), Power, or Linear. Saturating was the best according to Akaike information criterion (AIC). We then extracted heights that predicted DBH cut-offs: Block statistics were run on California Forest Observatory (CFO) canopy height pixels greater than or equal to 83.5' (25m) with 3x3 window to calculate the sum for input cells within a 30m rectangular neighborhood. This assigned number of pixels per 30m (900m2) cell. Resultant values of 1 through 9 were converted to percent. All background values were calculated to equal 0, meaning 0% large tree existence.
data_units Percent live trees per pixel
data_vintage 06/2020
element Structure
encoding utf8
file_name SoCal_LrgTreeDens_gt30in_202006_202312_T2_v5
format GeoTiff
harvest_object_id ce0a6d7a-308d-41f1-95cb-8ec929024758
harvest_source_id a2637971-af12-457f-ae4a-831d2202a539
harvest_source_title WIFIRE Commons
maximum_value 100.0
metric_definition_and_relevance Large trees are important to forest managers as they have a greater likelihood of survival from fire, provide sources of seed stock, wildlife habitat, and contribute to other critical processes like carbon storage and nutrient cycling. Large trees are often the focus of management in order to protect existing ones and to foster future ones. In consultation with National Forests, "large trees" have been designated as greater than 30" dbh.
minimum_value 0.0
pillar Forest and Shrubland Resilience
spatial {"type": "Polygon", "coordinates": [[[-120.67507971695304, 32.49712128212305], [-115.77464954452921, 32.49712128212305], [-115.77464954452921, 35.286938865864286], [-120.67507971695304, 35.286938865864286], [-120.67507971695304, 32.49712128212305]]]}
tier 2