Table 1. Skill of discriminant models in predicting the modern distributions of blue and valley oak.

	Satellite data		Range maps
Model	Percent correct	κ	Percent correct	κ
Blue oak
(50%)	82	0.41	84	0.50
(80%)	87	0.48	87	0.53
Valley oak
(50%)	71	0.10	81	0.52
(80%)	79	0.12	83	0.51

Numbers in parentheses indicate the likelihood threshold for assigning individual cells to the oak-present group in the discriminant model. Increasing the threshold from 50% to 80% likely improves the models' match to the satellite data and range maps, reducing the modern area predicted as suitable for blue oak (–24%) and valley oak (–27%). Percent correct reflects the percentage of all cells correctly assigned to oak-present and oak-absent groups. κ values account for the cells that would be assigned correctly by chance, where κ < 0.4 is poor agreement, 0.4 < κ < 0.55 is fair agreement, 0.55 < κ < 0.70 is good agreement, and κ > 0.7 is very good to excellent agreement (24).