The branch spread is the length from the trunk of the tree to the tip of the longest branch. So a young tree with the lowest branch reaching out 3 feet from the trunk would have a 3 foot branch spread. Also the fertilizer for trees in the ground is best placed near the drip line. This is the area at the tip of the branches where the rain would drip onto the soil. The feeding roots of the tree are in this area. For trees the area close to the trunk is usually dry soil and the roots in this area are thick stabilizing roots. The important feeder roots are in the moist soil at the tips of the branches. This does not apply to potted young trees. Just add the Osmocote to the top of the soil in the pot and work into the top inch of soil gently. The rate of use measuring the branch spread still applies to potted trees. So a tree with a three foot branch spread would need one and one half capful of Osmocote using the guideline of one capful for each two feet of branch spread. One more thing to consider. Osmocote is a slow release plant food and you do not need to worry about using a bit too much or too little. The plant takes in only what it needs when it needs it. Keep growing, Marianne Binetti