Are the leaves 2" to 5" wide, 3- to 5-lobed, with watery sap coming from the petiole (leaf stalk) when broken? Clue: these are native to Logan Canyon. It is a canyon maple or bigtooth maple (Acer grandidentatum).
Are the leaves 5" to 7" wide, 5- to 7-lobed, with milky sap coming from the petiole when broken? Clue: these are not native to Logan Canyon; a few are found in developed areas in the lower part of the canyon. It is a Norway maple (Acer platanoides).