This week, my colleagues from UC Berkeley braved the fall heatwave to check on how a few old redwood forests are handling the drought in the Santa Cruz Mountains. I joined them among the redwood giants at Henry Cowell State Park on Wednesday as they measured drought stress levels in both large and small coast redwood, douglas fir, and California bay trees.

Swinging from ropes in the canopy, researchers including Anthony Ambrose and Wendy Baxter from the League’s Redwoods and Climate Change Initiative, dropped small sections of leaves and stems to forest floor for analysis. I got to dust off my field techniques and help them analyze how drought stressed the foliage was using an instrument called a pressure chamber.

Early results show that the smallest trees were more drought stressed than the larger trees, likely because they have smaller roots and less access to water belowground. Fortunately, the trees have seen droughts like this one before and prevailed.

I’m confident that the redwoods will pull through these dry days, but we will keep studying how intense weather impacts the redwood forest so that we can do everything we can to protect them as climate changes.