Climate Crisis Threatens Half of Kew Species.

A recent study conducted by Kew Gardens reveals that over half of the tree species at the Royal Botanical Gardens are at risk due to climate change. Founded in 1840, Kew boasts the world’s largest botanical collection. In 2022, a severe drought in south-west London led to the loss of 400 trees, prompting scientists to assess how many more could succumb to evolving weather patterns over the next several decades.

_{A Hungarian oak tree at Kew Gardens. Oak trees sourced from hotter European climates may be more resilient than English oaks. Photograph: Yui Mok/PA}

This assessment showed that about half of Kew’s 11,000 trees could potentially die from climate-related changes, pushing the organization to develop a plan for replacing the most vulnerable species. Many trees at Kew were planted over a century ago without consideration of future climate scenarios, assuming a stable environment that favors moisture-loving trees.

Record-breaking heat has become more common in the UK, with the hottest years since 1884 occurring this century. Predictions for 2050 suggest London’s climate could resemble today’s Barcelona. This climate shift is critical as urban trees play a vital role in cooling cities and providing shade during heatwaves.

Researchers at Kew combined local weather data, global tree information, and empirical testing to predict which trees are at risk. They found that by 2090, more than 50% of the species might be vulnerable, with 45% living on the edge of their climatic tolerance and another 9% entirely outside it. Native species like the English oak, common beech, silver birch, and holly could face significant risks across the UK.

In response, Kew is focusing on replacing endangered trees with species that can withstand drier conditions, such as the Iberian alder from Portugal and Spain, Farges’ fir from central China, and other drought-resistant varieties from regions like Central America and Mexico.

Additionally, the report highlights that tree species from warmer European climates might fare better than local varieties. Richard Barley, the director of gardens at Kew, emphasized the importance of this succession plan not only for Kew but as a broader initiative to enhance the resilience and diversity of urban and garden landscapes against climate change.

Echoing these sentiments, Ross Cameron, a professor of environmental horticulture at the University of Sheffield, supported the report’s conclusions. He noted that species preferring moist conditions might struggle to survive in England’s drier future, making the case for adapting our planting choices to the new climate reality.

Re-reported from the article published originally in The Guardian.