"Rangituhi/Colonial Knob is one of several remnants of a peneplain – an eroded landmass that existed 30 million to 40 million years ago, before it was raised by earthquakes and erosion began to form hills.
"The trek to Rangituhi/Colonial Knob takes you through some of the last remaining native forest in the Tawa-Porirua basin. Most of its original cladding of rimu and rata was logged, although some mature trees survive in the Porirua Scenic Reserve.
"The forest today comprises mainly kohekohe, tawa and some rewarewa. On the higher slopes it is dominated by mahoe with broadleaf, stinkwood and mapou. These species are often associated with higher altitudes, reflecting the influence of the weather on this environment".