[6][7] The eastern slopes of Tutamoe were home to the largest kauri tree, Kairaru, having a circumference of 20 m and being 30.5 m to the first branches, double the size of Tāne Mahuta.

[7][8][10] The mountain's soils, primarily composed of soft sedimentary material, provide ideal conditions for kauri trees to establish deep root systems and access moisture during the summer months.

[7] Additionally, basalt rocks, originating from the ancient Waipoua volcano, are abundant on the slopes.

[8][11] These mineral-rich rocks contribute to the fertility of the soil over time, creating favourable growing conditions.

Many of the large kauri trees that remain today are found in areas with deep, fertile soils.