Hawthorn (Crataegus monogyna) Populations in Mid-Canterbury

Hawthorn (Crataegus monogyna) is a naturalised tree that is classified as a noxious plant in several counties in the eastern South Island. It is locally abundant in lowland forest remnants, and with the indigenous spiny shrub matagouri (Discaria toumatou), on grazing land in Canterbury. Two scrub sites near Porters Pass, where the original hawthorn trees still existed, and a forest site near Kowai Bush were sampled by measuring stem diameters and counting growth rings, to determine the age structure and dynamics of hawthorn.