San Francisco is one of the most densely populated urban environments in the country. And yet, in the midst of it, natural ecosystems struggle to survive. On Saturday, volunteers in one of those areas – the Presidio – helped remove the hand of man and return the land to a more natural environment.
The annual Presidio Planting Day began with the removal of a stand of towering trees that used to stand on the hill overlooking Baker Beach.
When the military established the Presidio more than 200 years ago, they deliberately began altering the natural environment by planting Monterey Pines. With the trees already at the end of their lifespan, the park decided to change the area back to the enormous rolling sand dune it once was.
“If you have a bunch of trees here, the dune sand is kind of held in one place because of the really intense root structures,” says Kristen Jones, ecological horticulture project manager at Presidio. And so it doesn’t allow the native species that would normally grow here to grow here because they need the sand to have more exercise and more light than they would in the shade of those trees.”
With the trees removed, about 100 volunteers spread out across the 10-acre site, removing unwanted ground cover species such as oxalis and ice plants and replacing them with native plants that prefer the shifting sands of a dune.
Nine-year-old volunteer Oliver Murray said it was quite fun once you took the plant out of the container.
“Sometimes it can be difficult because the plant is stuck in there,” he said, hitting the seedling tray with his trowel. “It’s important to restore the dune because some of these plants are endangered. And the animals too… some animals may come back.”
Many animals disappeared as the land changed, but at least one failed to return.
The Xerxes Blue butterfly went extinct right there in the Presidio in the 1940s, becoming an international symbol of the sometimes irreversible damage caused by habitat loss.
But Dr. Durrell Kapan, a senior researcher at the California Academy of Sciences, has led an effort to introduce into the ecosystem a replacement for the Xerxes, a close genetic cousin called the Silvery Blue butterfly.
“The main reason for biodiversity loss is the transformation of habitats so that we can bring those habitats back,” says Dr. Kapan. “And in some cases the butterflies are gone, so we have to look for an alternative. But in many cases the animals come back on their own.”
That’s what they hope will happen once the dune is restored. And volunteer planter Alberto Rodriquez was more than happy to lend a hand.
“It’s a personal area for me,” he said. “I walk here a lot and I wanted to help bring it closer to what it could have looked like hundreds of years ago. We came here and kind of imposed ourselves on the land, and I think it’s important to to respect the country as much as possible. And that also means letting it be as it is meant to be and of course it should be. And so it is important for me to help achieve it as much as possible.
From a distance, the hill looks barren, as if all life has been removed. But if you look closer, you will see the little new plants, waiting for the winter rains that will begin a whole new life cycle for the Presidio, with the realization that there is a place in nature for all creatures, great and small.
Saturday was the big annual Presidio Planting Day, but they also host volunteer events in the park every Saturday and every other Wednesday. Anyone interested in helping can find more information at www.presidio.gov.
