I have a maple 3-yr old, trunk 3 in. Organic Espoma Tree-Tone from Valley View Question - how much to use Package says 4 lb per in. That would be 12 lbs.! (My package is 4 lbs!) It says: Holes 2-3 ft apart, 12 - 18 in. deep Thank you
Yes, your understanding is correct. Based on 4lbs. per inch of trunk diameter, it would be 12lbs. of total product spread out at 2-3 foot intervals under the dripline of the tree. However, newly planted trees do not require fertilization for one to three years, and, healthy, mature trees do not require fertilizers. Woody plants receive nutrients from lawn fertilization if their roots are adjacent to or growing under a turf area. And they pick up nutrients from decaying mulches and leaves and from the minerals in soil. https://extension.umd.edu/hgic/topics/fertilizing-trees-and-shrubs
You could put down just the package of product you have. For a young tree like this, you can sprinkle the fertilizer under and just beyond the dripline of the tree.