SD06: From twigs to trees: How irrigation frequency impacts tree seedling survival in municipal parks

In addition to rising temperatures, global climate change is altering rainfall patterns, resulting in longer and more intense periods of drought in some regions. Heat levels are frequently exacerbated in urban areas, which can intensify drought effects for urban trees. Urban trees are essential tools for mitigating the negative impacts of rising heat in cities, and they provide additional benefits via stormwater filtration and carbon sequestration. Due to the expected continuation of rising heat and drought in cities, it is important for urban tree planters to prepare for harsh planting conditions which may lead to tree mortality if proper aftercare measures are not taken. Thus, we have implemented tree plantings across 20 municipal parks located in Dayton, OH and administered the following irrigation treatments from May through September 2024: no additional irrigation after planting (control), five gallons of water per tree every other week with no more than one inch of rainfall between scheduled waterings, five gallons of water per tree once per month with no more than one inch of rainfall between scheduled waterings, and 20 gallons of water per tree administered by filling a 20-gallon gator bag once per month regardless of rainfall amounts. We tracked tree survival, growth, and health in response to these irrigation treatments to determine establishment success of native trees in urban areas. Our results will inform necessary tree aftercare practices for urban trees in the face of rising temperatures and drought.