2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/215947We introduce two operads which own the set of planar forests as a basis. With its usual product and two other products defined by different types of graftings, the algebra of planar rooted trees H becomes an algebra over these operads. The compatibility with the infinitesimal coproduct of H and these structures is studied. As an application, an inductive way of computing the dual basis of H for its infinitesimal pairing is given. Moreover, three Cartier-Quillen-Milnor-Moore theorems are given for the operads of planar forests and a rigidity theorem for one of them.30 pagesRings and Algebras16W30, 05C05, 18D50.The infinitesimal Hopf algebra and the operads of planar foreststext