Priority Conifer Forests

The following criteria were used to develop the priority conifer forests layer: 

•   Presence of old growth or mature conifer forests
•    Vegetation rarity

OLD GROWTH 

Old growth and mature conifer forests priorities are based on canopy structure information in the Sonoma County Fine-Scale Vegetation Map, for which canopy metrics were derived from the 2013 Sonoma County LiDAR point clouds. For each conifer vegetation class in the Sonoma County Fine-Scale Vegetation Map, mean canopy height values and maximum canopy height values were scaled from 0 to 1 using max-min normalization. Scaled values for mean canopy height and maximum canopy height were summed and the output was rescaled from 0 to 1 using max-min normalization. Additionally, canopy variance values were scaled from 0 to 1. The canopy height and canopy variance values were summed and rescaled from 0 to 1 using max-min normalization. Conifer vegetation polygons with values of 0.6 or greater were mapped as priority old growth/ mature conifer forests. 

VEGETATION RARITY

Vegetation rarity was evaluated using global and state conservation status rankings from the Survey of California Vegetation/NatureServe’s Heritage Program methodology, as well as local rarity. For a more detailed description of conservation status ranks, please see the Sonoma County Vegetation Descriptions prepared by CDFW VegCAMP and CNPS for the Sonoma Veg Map Program: https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=115808&inline=1 

A breakdown of vegetation classes by rarity priority class is described below:

Highest Priority: Critically imperiled (state rarity rank of 1) or locally very rare (<0.1% cover)

• Foothill pine – leather oak woodland (Pinus sabiniana/Quercus durata Provisional Alliance)
• Grand fir forest (Abies grandis Alliance)
• McNab cypress woodland (Hesperocyparis macnabiana Alliance)
• Ponderosa pine – Douglas-fir forest (Pinus ponderosa – Pseudotsuga menziesii Alliance)

Medium Priority: Vulnerable (state rarity rank of 3) or locally unique (state rarity rank of 4 or 5 with <1% cover)

• Bishop/bull pine stand (Pinus muricata Alliance)
• Black oak woodland (Quercus kellogii Alliance); conifer-dominated stands
• Coast redwood forest (Sequoia sempervirens Alliance)
• Douglas-fir - tanoak forest (Pseudotsuga menziesii – Notholithocarpus densiflorus Alliance)
• Knobcone pine stand (Pinus attenuata Alliance)
• Oregon white oak woodland (Quercus garryana Alliance); conifer dominated stands
• Sargent cypress stand (Hesperocyparis sargentii Alliance)
• Sugar pine (Pinus lambertiana Alliance)

• Douglas-fir forest (Pseudotsuga menziesii Alliance)

Priority Conifer Forests

The following criteria were used to develop the priority conifer forests layer: 

•   Presence of old growth or mature conifer forests
•    Vegetation rarity

OLD GROWTH 

Old growth and mature conifer forests priorities are based on canopy structure information in the Sonoma County Fine-Scale Vegetation Map, for which canopy metrics were derived from the 2013 Sonoma County LiDAR point clouds. For each conifer vegetation class in the Sonoma County Fine-Scale Vegetation Map, mean canopy height values and maximum canopy height values were scaled from 0 to 1 using max-min normalization. Scaled values for mean canopy height and maximum canopy height were summed and the output was rescaled from 0 to 1 using max-min normalization. Additionally, canopy variance values were scaled from 0 to 1. The canopy height and canopy variance values were summed and rescaled from 0 to 1 using max-min normalization. Conifer vegetation polygons with values of 0.6 or greater were mapped as priority old growth/ mature conifer forests. 

VEGETATION RARITY

Vegetation rarity was evaluated using global and state conservation status rankings from the Survey of California Vegetation/NatureServe’s Heritage Program methodology, as well as local rarity. For a more detailed description of conservation status ranks, please see the Sonoma County Vegetation Descriptions prepared by CDFW VegCAMP and CNPS for the Sonoma Veg Map Program: https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=115808&inline=1 

A breakdown of vegetation classes by rarity priority class is described below:

Highest Priority: Critically imperiled (state rarity rank of 1) or locally very rare (<0.1% cover)

• Foothill pine – leather oak woodland (Pinus sabiniana/Quercus durata Provisional Alliance)
• Grand fir forest (Abies grandis Alliance)
• McNab cypress woodland (Hesperocyparis macnabiana Alliance)
• Ponderosa pine – Douglas-fir forest (Pinus ponderosa – Pseudotsuga menziesii Alliance)

Medium Priority: Vulnerable (state rarity rank of 3) or locally unique (state rarity rank of 4 or 5 with <1% cover)

• Bishop/bull pine stand (Pinus muricata Alliance)
• Black oak woodland (Quercus kellogii Alliance); conifer-dominated stands
• Coast redwood forest (Sequoia sempervirens Alliance)
• Douglas-fir - tanoak forest (Pseudotsuga menziesii – Notholithocarpus densiflorus Alliance)
• Knobcone pine stand (Pinus attenuata Alliance)
• Oregon white oak woodland (Quercus garryana Alliance); conifer dominated stands
• Sargent cypress stand (Hesperocyparis sargentii Alliance)
• Sugar pine (Pinus lambertiana Alliance)

• Douglas-fir forest (Pseudotsuga menziesii Alliance)