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* Metric Name: Giant Sequoia Stands  

* Tier: 2  

* Data Vintage: 2022  

* Unit Of Measure: Binary, 1 = existence, 0 = non-existence  

* Metric Definition and Relevance: The population of giant sequoia ( _Sequoiadendron giganteum_ [SEGI]) trees is an irreplaceable heritage to be studied, protected, and preserved as it faces increased threats from drought and fire. This species is only found in the Sierra Nevada Region and thus the data are only from that Region.  

* Creation Method: The Giant Sequoia grove locations are well described, and their approximate delineations have been used for analysis work for years with the Administrative Grove Boundary (AGB) dataset. These AGB polygons were exaggerated for a variety of reasons and led to erroneous analysis results. An explicit delineation of SEGI populations was needed, especially as the range of the tree is exposed to increased threats instigated by a mega-drought not seen in the region in over a millennia. This dataset addressed that need across the entire range of SEGI.

While some 70+ “Groves” are recognized with the AGB dataset; the historic
naming conventions of groves lost to generalization have been reapplied for
this work, referencing each distinct area as a “Map Unit.” Consider ‘Grove’ a
general term with ‘Map Unit’ a distinct population distribution for a unique
SEGI population. There are 94 Map Units as of 2022 covering 26,270 acres. To
create the Map Unit linework, individual SEGI pints were identified, both
remotely and in the field, to inform the boundary line work. In the case of
the National Park Map Units, the historic Sequoia Tree Inventory (STI) dataset
dictated the boundary shape. Elsewhere, the Observed Tree Inventory (OTI)
points guided the boundary formation.

For this effort, the giant sequoia stand polygons were subsequently converted
to a raster grid at 30m resolution based on existence/non-existence.

  

* Credits: USDA Forest Service, Region 5, MARS Team