Distribution data for Joshua trees (Yucca brevifolia and Y. jaegeriana) throughout their range

We delineated the existing distribution of western and eastern Joshua trees (Yucca brevifolia and Y. jaegeriana, respectively) with high fidelity across the full range of both species in Arizona, California, Nevada, and Utah, USA. Presences and absences were identified by observers through an intensive visual grid search of online satellite imagery, including a uniform grid of 672,043 cells at a 0.25 square km resolution. Data from the initial satellite surveys was subsequently field validated at 29,050 cells along 15,000 km of driving routes. Where field validation was not possible, experienced observers re-evaluated grid cells using secondary satellite searches in the following three scenarios: 1) cells determined to be without Joshua trees but adjacent to cells having Joshua trees present; 2) cells having Joshua trees present but surrounded by cells without Joshua trees; and 3) cells in areas known to cause confusion because of other issues (e.g., plants, rocky outcrops, fire scars, the urban/wildland interface). The shapefiles provided in this release reproduce the distribution of Joshua trees at high resolution, incorporating all field and satellite validations. By reproducing the current range of the Joshua trees with high fidelity, our dataset can serve as a baseline for future research, monitoring, and management.

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  "010:12"
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  "geospatial"
]