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Abstract Background Restoring erosion-prone land with indigenous species, whether by managed reforestation (planting) or by passive natural reversion, is reliant on knowing which species mix is likely to provide the quickest and most effective mitigation against shallow landslides. In turn, this requires knowledge of differences in growth metrics among plant species, particularly during their formative years. This study presents data on the root development and architecture of 12 of New Zealand’s commonest early colonising indigenous shrub and tree species. These data are crucial to the development of guidelines and policy for land use conversion and future land management options where unmitigated erosion is of increasing concern. Methods In a plot-based field trial, the growth performance of Coprosma robusta (karamū), Plagianthus regius (ribbonwood), Sophora tetraptera (kōwhai), Pittosporum eugenioides (lemonwood), Pittosporum tenuifolium (kōhūhū), Hoheria populnea (lacebark), Myrsine australis (māpou), Pseudopanax arboreus (fivefinger), Cordyline australis (cabbage tree), Knightia excelsa (rewarewa), Leptospermum scoparium (mānuka), and Coriaria arborea (tutu) was measured annually over five consecutive years. Results Eleven species developed a heart-shaped root system and Cordyline australis, a tap-rooted system. By year 5, the root/shoot ratio ranged between 0.24 and 0.44, > 99.5% of the total root mass and root length of all species was confined to within 0.5 m of the ground surface and > 73% within 1 radial metre of the root bole. Regressions between root collar diameter (RCD over bark) and root length were highly significant (P 1 mm in diameter. |
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