The number of trees half of whose vertices are leaves
and asymptotic enumeration of plane real algebraic curves
by V.M.~Kharlamov and S.Yu. Orevkov
Abstract. The number of topologically different plane real algebraic curves of a given degree d has the form exp(C d² + o(d²)). We determine the best available upper bound for the constant C. This bound follows from Arnold inequalities on the number of empty ovals. To evaluate its rate we show its equivalence with the rate of growth of the number of trees half of whose vertices are leaves and evaluate the latter rate.