PURPOSE: A roadside tree guard board is provided of which longevity can be lengthened since it is rarely cut by an impact caused by the load of a pedestrian because of its light-weight and superior endurance. CONSTITUTION: The roadside tree guard board comprises: a 10 to 30 weight portion(a) of urethane prepolymer generated by reaction between a polyisocyanate compound and a first polyol compound; a 30 to 50 weight portion(b) of a second polyol compound; a 0.05 to 0.5 weight portion(c) of a catalytic compound; a 20 to 50 weight portion(d) of filler; a 1 to 5 weight portion(e) of a plasticizer; and a 0.05 to 0.2 weight portion(f) of a stabilizer. The roadside tree guard board is made by hardening a composition having a 0.65 to 1.3 molar ratio of isocyanate group of the polycyanate compound to total hydroxyl group of the first and second polyol compounds.
