Trees have been dying all over Western North America. British Columbia lost 80% of its mature lodgepole pine in 2006 and 2007 and changed from being a carbon sink to a carbon source. A few years ago 129 million trees died in California. Future megadroughts could devastate the southwestern forests. Hotter droughts are pulling water out of forests at an accelerating pace, and forest die-off is accelerating globally. The 1% largest trees hold 50% of the carbon held in forests. Big old trees are especially at risk because they need more water, and more energy to pump this water to their crown. They can be done in by drought, or weakened so much they fall prey to insects, disease or fire. Wildfires can incinerate large giant sequoias in large numbers.
www.bbc.com/future/article/20220623-the-genetic-power-of-ancient-trees