Akiyama–Watanabe–Albertson–Haas conjecture on induced forests in bipartite planar graphs

Let $G$ be a finite simple bipartite planar graph of order $n$. An induced forest is a vertex-induced subgraph of $G$ that is a forest.

Akiyama–Watanabe–Albertson–Haas conjecture. Every bipartite planar graph of order $n$ admits an induced forest of order at least

$$\frac{5n}{8}.$$

This strengthens the general lower-bound problem for planar graphs by imposing bipartiteness and seeking a larger induced forest. The source states the conjecture but gives no resolution; partial lower bounds and related results are discussed.