“What Do the Trees Know” imaginatively portrays swaying limbs and fluttering leaves. Trees are wise too: they patiently grow and endure wind. They stay rooted to the ground and lean into the wind, all the while silently producing buds for the next season. Hagen’s music flows and changes with the text, sometimes like swaying branches in the wind, or hard and accented like an oak. Singers will enjoy exploring the various interpretations.