We give a short proof that for every apex-forest X on at least two vertices, graphs excluding X as a minor have layered pathwidth at most $2|V(X)|-3$. This improves upon a result by Dujmovi\'c, Eppstein, Joret, Morin, and Wood (SIDMA, 2020). Our main tool is a structural result about graphs excluding a forest as a rooted minor, which is of independent interest. We develop similar tools for treedepth and treewidth. We discuss implications for Erd{o}s-P\'osa properties of rooted models of minors in graphs.
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Hodor et al. (2024) studied this question.
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