Node yields assume the base harvest HP from game data (e.g. 1000 for Redwood trees, 620 for Metal nodes). In-game, trees and rocks with bAllowHarvestHealthScalinghave per-instance HP that varies with the node's size, so actual yields per node will vary. The values shown represent the average.
The Doedicurus is the best Element Dust farmer with a 21x gather multiplier from game data. The Rock Elemental is the runner-up with 9x.