Drought in the Redwoods

Last week I traveled northwards up the coast redwood range to check on weather conditions in the forest at Humboldt Redwoods, Prairie Creek, and Jedediah Smith Redwoods State Parks. Through our Redwoods and Climate Change Initiative, we are studying how climate varies within the large range of the coast redwoods from the typically drier southern forests in Big Sur to the wetter northern forests near the California border with Oregon. A series of our weather stations are recording how temperature, humidity, and soil moisture change over the year and we even are measuring how often the leaves are wet in the forest, a good indication if rain or fog have brought water to the forest.

In the midst of this hard-to-ignore drought, I went on this field trip expecting to find extremely dry conditions in the forests as I had a few months ago and was actually surprised by what I found. The forest in Humboldt Redwoods was crunchy dry to the touch as I had feared, but when I arrived in the more northern parks, I found patches of damp forest that is so typical of the rainforests in this area. Both in Prairie Creek and Jedediah Smith, I walked across soggy duff-covered ground under the redwoods and found many ferns and shrubs that were dripping water off of their leaves.

These moist places were near creeks, in valley bottoms and on north-facing slopes shaded this time of year by the low sun angle during the day. I was so cheered to find areas of the forest that were not bone dry, but I also found that these places were islands surrounded by more exposed and significantly drier areas of the forest. Drought intensity seems incredibly location specific and how the plants and animals respond to current drought and longer-term climate change will likely vary throughout the coast redwood forest.

Learn more about how the redwood forest is responding to climate here and we will update you with more insight on drought in the redwoods as our study continues.