Study finds trees in cities more vulnerable to heat waves and drought

The discovery has major implications for urban forestry, say American scientists.

The findings show how trees in New York City and Boston were more negatively impacted by heat waves and drought than trees of the same species in nearby rural forests.

Researchers at City University of New York (CUNY) say their study highlights the challenges urban trees face in the context of climate change.

The team said it also underscores the importance of tailored urban forestry management as a tool for protecting tree species and reducing urban heat islands.

The findings, published in the journal Ecological Applications, detailed how urban trees' growth rates and carbon storage capabilities are "significantly" reduced during extreme weather conditions.

The researchers suspect that the harsh urban environment, characterized by hotter, drier conditions and higher pollution levels, exacerbates the vulnerability of urban trees to climate stress.

They used tree cores from urban and rural forests to reconstruct historical growth rates and then compared them with climate data.

The aim was to determine if urban trees are more adversely affected by climate stress than their rural counterparts.

The study found that urban trees suffer more during periods of heat waves and drought, raising concerns about their long-term health.

Principal investigator Professor Andrew Reinmann said: “Trees are integral to urban sustainability and climate resiliency strategies, offering benefits such as temperature reduction, stormwater management, recreational spaces, biodiversity support, and improved human health."

He added: “Understanding why urban trees are more sensitive to climate stress is the next step so that urban planners, forest managers, community groups, and policymakers can develop effective urban forestry plans.”

Reinmann says such plans might include designing new management protocols that maximize the size of tree planting pits and selecting tree species better suited to urban conditions.