Data for urban hot spots delay autumn leaf senescence in a subset of temperate deciduous tree species

<p>ABSTRACT</p>

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<li aria-level="1" style="list-style-type:disc"><span style="font-size:12pt; font-variant:normal; white-space:pre-wrap">Tree phenology is a key regulator of ecosystem function and a sensitive indicator of global change. Although warming temperatures have been linked to longer growing seasons, species-specific responses of autumn phenology to temperature remain poorly understood relative to the effects on spring phenology.</span></li>
<li aria-level="1" style="list-style-type:disc"><span style="font-size:12pt; font-variant:normal; white-space:pre-wrap">To assess whether warming delays autumn phenology, we used a heterogenous urban environment to quantify the timing of leaf off and the rate of leaf senescence for 10 deciduous species growing in hot spots and cold spots which differed by approximately 2 °C. We sampled leaves weekly for 12 weeks leading up to complete leaf off and measured photosynthetic pigment content to capture species-specific senescence rates across thermal microclimates.</span></li>
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<li aria-level="1" style="list-style-type:disc"><span style="font-size:12pt; font-variant:normal; white-space:pre-wrap">Across species, the timing of complete leaf off did not differ between microclimates. Additionally, we found that the rate of leaf senescence did not differ between microclimates for most species. However, red maple and ginkgo were sensitive to warmer temperatures, exhibiting a significantly slower photosynthetic pigment degradation in hot spots compared to cold spots.</span></li>
<li aria-level="1" style="list-style-type:disc"><span style="font-size:12pt; font-variant:normal; white-space:pre-wrap">Overall, our work suggests that the impacts of temperature on autumn phenology will vary by species, suggesting that species like ginkgo and red maple may be better able to adjust phenology in response to changing temperatures. Given that mid-century temperature projections align with the 2 °C difference examined here, our urban results could inform predictions of forest tree responses to future warming.</span></li>
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