Our coastal forest confirmed little impact from the first 10-hour publicity to salty water in June 2022 and grew usually for the remainder of the yr. We elevated the publicity to 20 hours in June 2023, and the forest nonetheless appeared largely unfazed, though the tulip poplar bushes have been drawing water from the soil extra slowly, which can be an early warning sign.
Things modified after a 30-hour publicity in June 2024. The leaves of tulip poplar in the forests began to brown in mid-August, a number of weeks sooner than regular. By mid-September the forest cover was naked, as if winter had set in. These adjustments didn’t happen in a close-by plot that we handled the identical manner, however with recent water moderately than seawater.
The preliminary resilience of our forest might be defined partially by the comparatively low quantity of salt in the water on this estuary, the place water from freshwater rivers and a salty ocean combine. Rain that fell after the experiments in 2022 and 2023 washed salts out of the soil.
But a significant drought adopted the 2024 experiment, so salts lingered in the soil then. The bushes’ longer publicity to salty soils after our 2024 experiment could have exceeded their potential to tolerate these situations.
Seawater being dumped on the Southern California fires is full-strength, salty ocean water. And situations there have been very dry, significantly in contrast with our East Coast forest plot.
Changes Evident in the Ground
Our analysis group remains to be attempting to perceive all the components that restrict the forest’s tolerance to salty water, and the way our outcomes apply to different ecosystems corresponding to these in the Los Angeles space.
Tree leaves turning from inexperienced to brown effectively earlier than fall was a shock, however there have been different surprises hidden in the soil under our toes.
Rainwater percolating by way of the soil is often clear, however a couple of month after the first and solely 10-hour publicity to salty water in 2022, the soil water turned brown and stayed that manner for 2 years. The brown coloration comes from carbon-based compounds leached from useless plant materials. It’s a course of comparable to making tea.