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The global positioning system (GPS) exhibits much potential for forestry applications, where traditional methods of position determination still dominate. Recent advances in GPS technology may offer improved performance of GPS in forested conditions, and at a considerable cost advantage compared with previous GPS alternatives. We examined the use of several mapping- to recreation-grade GPS receivers across a topographic gradient and the influence of using the Wide Area Augmentation System (WAAS) to their performance under leaf-on and leaf-off conditions. Generally, the mapping-grade receiver with postprocessed differential correction offered the highest position accuracies, which improved root mean squared error (RMSE⁹⁵) from 3.64 to 5.32 m across leaf conditions, compared with recreation-grade receiver performance, which ranged in RMSE⁹⁵ from 12.76 to 38.74 m under leaf-on conditions …