Resprout survival and vigour in urban woody plantings are related to water availability, climate of origin, and root morphology

Abstract

Woody plants can be used for resilient urban greening in cities with drying climates. Coppicing – regular cutting of plants to 10–20 cm aboveground – can be used to maintain plants in cities by stimulating resprouting and regeneration. Species selection could consider climate adjusted provenancing and the habitat template approach, yet little is known about how these methods translate to coppiced urban plantings. Therefore, we investigated resprouting survival and vigour of species from two bioregions with one representing the future climate of the other, and with a range of root traits. We also compared coppiced and non-coppiced plant survival and vigour under two watering regimes. Twenty-four woody species were grown in a common garden experiment for two years in southwestern Australia. There were four treatments based on water availability (summer watering and not watered) and coppicing (coppiced after one year and non-coppiced) with five replicates. Survival, vigour, and plant traits were measured on all plants after two years, including basal area, height, stem number, specific leaf area, total leaf area ratio, and root:shoot ratio. Coppiced (81 %) and non-coppiced (90 %) plants had similar survival, however survival of individual species was highly variable (range 0–100 %). Coppicing increased stem number and total leaf area. Summer watering increased survival of non-coppiced plants but did not change coppiced plant survival or traits. Species from the warmer and drier bioregion had the greatest survival in all treatments. Species with greater root:shoot ratio and/or with deeper roots had greater survival but lower vigour after coppicing. We found local plant communities were suitable for naturalistic woody plantings in an urban environment, and these could be maintained through coppicing. We suggest using climate adjusted provenancing and the habitat template approach, by using species from warmer and drier regions and with a range of root traits for short-term vigour and long-term survival.