COS 271-1 - What doesn’t kill you makes you stronger – using climate of origin and plant traits to predict resprouting success and vigour of Australian shrubs and trees after coppicing.

Abstract: Woody Meadows are a novel approach to urban greening using diverse plantings of Australian shrubs and small trees to create low maintenance plantings which are managed through coppicing (hard pruning 10-20 cm above the ground every 2-4 years). Coppicing may mimic woody plant response to fire but little is known about plant response to coppicing, making it difficult to select plants for Woody Meadows. We investigated whether resprouting success (ability to resprout) and vigour after coppicing could be predicted from plant traits prior to coppicing. We hypothesised that species with greater bud availability (i.e., greater basal area and greater number of stems) before coppicing would have greater resprouting success and vigour. We also anticipated a trade-off between resprouting success and vigour in some traits and hypothesised that species with less acquisitive traits (i.e., lower height, lower leaf area ratio, lower shoot-to-root ratio, lower specific leaf area) but greater biomass before coppicing would have greater resprouting success but lower resprouting vigour. We expected plants with greater stem and root starch concentration (i.e., greater starch storage) before coppicing to have greater resprouting success but lower resprouting vigour, reflecting the trade-off between resprouting success and vigour. We evaluated resprouting success and vigour in a common garden experiment with 77 species (10 plots; five pre-coppiced and coppiced treatments). Some selected species had known resprouting response to fire, which helped to create a gradient of weak to strong resprouters for the experiment. Pre-coppiced traits were measured destructively six-months after planting (five plots) and the remaining five plots were coppiced two weeks later. Coppiced plants grew for six-months before resprouting success (yes/no) and vigour (height and shoot biomass) were measured. As hypothesised, plants with greater bud availability before coppicing were more likely to resprout, but only those with greater basal area had greater resprouting vigour. Surprisingly, plants with greater pre-coppiced number of stems had lower height after coppicing. Plants that were taller and had greater biomass before coppicing were more likely to resprout and had greater resprouting vigour. As expected, plants with greater storage reserves before coppicing were more likely to resprout. Interestingly, plants with greater pre-coppiced stem starch concentration had greater resprouting vigour, which contradicted our expectation of a trade-off between resprouting success and vigour. We propose that pre-coppiced plant size and stem starch concentration are strong predictors for post-coppicing resprouting success and vigour and can be used to identify suitable plants for Woody Meadows.