Phoenix's record heat is killing off cacti [View all]

[EarthFirst]

(CNN) -At a botanical garden in Phoenix some cactuses can’t take the heat.

Record-high temperatures in Arizona, combined with a lack of seasonal monsoons, have caused saguaro cactuses at the Desert Botanical Garden to become “highly stressed,” according to Chief Science Officer Kimberlie McCue. She said a saguaro can appear “fairly normal” or feel somewhat squishy before it suddenly collapses and reveals it has been rotting from the inside out due to heat-related stress.

Every February, the Desert Botanical Garden takes inventory of its saguaro cactuses and assesses each one’s condition. McCue said since 2020, when record temperatures caused stress in many of the saguaros, she and her team have seen more of the garden’s cactuses die. Present-day heat records are sending some of those previously affected cactuses over the edge, causing them to lose limbs and even collapse.

Wednesday night ended a record streak of 16 days above 90 degrees in Phoenix. The city is forecast to see temperatures over 110 degrees again on Thursday, which would make for the 28th consecutive day.

Cactuses carry out essential functions at night. That’s when they open their stomata, or pores, and carry out a gas exchange in which they take in the carbon dioxide they use to photosynthesize during the day. But because nights in Phoenix have experienced record-high heat, McCue said this suffocates and stresses out the saguaros, which dehydrates them and makes them more susceptible to infections and insects.

cnn.com/cnn/2023/07/27/us/phoenix-arizona-heat-saguaro-cactuses/index.html