# 12 Make a whistle in wood Whistles by willow and rowan are fun to make. But you have to take the opportunity now, in the spring when the trees sap is running. Shaping the nozzle in one end of a 10 cm long stick of willow or ash (Fig. 1) Cut a slanted slit about 2 cm into the pin. Make an incision through the bark, around, about 5 cm into the pin. Gently tap the handle of the knife on the bark and turn it loose.