For a graph G, let t(G) denote the maximum number of vertices in an induced subgraph of G that is a tree. Further, for a vertex v ∈ V(G), let t(G, v) denote the maximum number of vertices in an induced subgraph of G that is a tree, with the extra condition that the tree must contain v. The minimum of t(G) (t(G, v), respectively) over all connected triangle-free graphs G (and vertices v ∈ V(G)) on n vertices is denoted by t 3 (n) (t * 3 (n)). Clearly, t(G, v) ≤ t(G) for all v ∈ V(G). In this note, we solve the extremal problem of maximizing |G| for given t(G, v), given that G is connected and triangle-free. We show thatand determine the unique extremal graphs. Thus, we get as corollary that t 3 (n) ≥ t * 3 (n) = 1 2 (1+ √ 8n−7) , improving a recent result by Fox, Loh and Sudakov. ᭧