Sequestering Carbon the Natural Way–in the Soil

Could plants help to trap carbon in the soil?

What do you think is the main reservoir of carbon in the biosphere?  The atmosphere, right?  Well, no.  The main reservoir is the soil, holding approximately five times as much carbon as the atmophere!  Too bad there’s not a way to sink carbon into the soil and trap it there, decreasing the carbon in the atmosphere.  But guess what!  There is!

When plants grow and produce sugars in photosynthesis, the sugars remaining after the plant uses what it needs are transported down the stem to the roots to be stored there.  But some of the sugary liquid oozes out into the soil immediately surrounding the roots.  There it feeds the microbial partners of the plant, such as mycorrhizal fungi that help provide water and nutrients for the plant.  (Talk about a nice symbiotic relationship!)

But some of those sugars stick to clumps of mineral particles in the soil, forming soil aggregates.  Here’s the amazing thing:  those aggregates can last for hundreds of years if undisturbed, and all the while they are trapping carbon because sugars are built on a backbone of carbon.  Carbon trapped for hundreds of years in the soil –out of the atmosphere!

So plant some plants, especially native perennial grasses, because they have extremely long and extensive root systems to exude that oozing syrupy sugar.  And support restorations that are planting in your area because it’s the “carbon smart” thing to do!

Beautiful Foliage, But the Rash Isn’t So Pretty!

Here’s a picture of beautiful fall foliage in the oak woodland in Annadel Trione State Park in Northern California, and the striking plant is— poison oak! Lots of people suffer itchy rashes when exposed to the oil it contains, urushiol. The Native Americans who live where poison oak is found have long made use of it in basket-making, dyes for tattoos, and medicines. Apparently they developed some immunity to it, though they also made medicines to treat its rash.

In spite of its name, it’s not actually an oak. It does play an ecological role, providing food for many birds and small mammals, as well as deer and insect larvae. It also helps to anchor slopes and prevent erosion. And it’s a pioneer species, meaning it is one of the first plants to return after a disturbance like a wildfire. Since climate change is leading to more and more wildfires, we can expect to see more poison oak in the future.

Photo courtesy of Neill Fogarty.

Salt Marsh Returns to San Francisco Bay! Why Does It Matter?

Looking north across San Pablo Bay (part of San Francisco Bay). In the foreground is ancient salt marsh.

This is ancient salt marsh, a remnant of wetlands that used to surround San Francisco Bay.  Only 5-10% remain.  All around the bay, environmental non-profits are working with citizens to restore wetlands.  Transition zones and marshes are being planted, and levees are being breached.  Eventually wetlands will once again surround the entire bay.

But why does it matter?  After all, sometimes the existing marshes and mudflats are pretty smelly, but that is a sign of the richness of living things being nurtured there!  Here are just a few of the ecosystem services provided by wetlands.  In the wetlands, marshes and estuaries, the soils sponge up water and release it slowly, helping to mitigate flooding.  The marsh plants’ roots form a mesh that traps sediments and pollutants flowing into the bay from creeks and rivers.  Wetlands act as nurseries for the immature larvae of many different species–some of which, like crabs and fish, are commercially valuable, and all of which play roles in the ecosystem.  There is much more (Google!) but here’s one that’s of huge importance:  wetlands, mudflats, and marshes act as a buffer zone, protecting areas further inland from storm surges and sea level rise.  And here’s another service they provide that is vitally important:  salt marshes and mudflats are especially powerful in carbon sequestration!

Place-Based Learning: Restore a Watershed!

STRAW Student Restoring a Wetland
A smiling student hauls mulch for newly planted trees in a wetland restoration.   Photo courtesy of STRAW

When you’re looking for project-based learning that is rich and rewarding, having your class restore a creek or wetland can’t be beat!  Kids are out of doors, learning by doing, and benefiting their community and the environment.  Fresh air, physical exercise and teamwork make a powerful combination.  Plus at-risk students sometimes come alive at a restoration, experiencing the benefits of teamwork and performing real work that helps the environment.  Sometimes the unexpected happens:  the kids find a snake or lizard, tracks of a raccoon or even mountain lion scat!  One team dug up the champion of all root balls from an invasive Himalayan blackberry.  And once, working on a creek at a ranch,  the class was super excited as a calf was born in front of their eyes!

Elementary school students working together to restore a wetland
Students restoring a wetland–teams spread out to get the job done. Photo courtesy of STRAW

Many topics related to watersheds, creeks, and wetlands can be explored in the classroom, either before or after the restoration takes place.  You’ll find some suggestions at the end of this article.

But how do you get your class involved with a restoration of a creek or wetland?  Read on.

Of course, you can plan and carry out a restoration all on your own, though it’s a lot of work, and the expense for plants, tools, watering arrangements, etc. will certainly add up.  But here’s the valuable bit of information you should know:  there are many watershed groups around the country doing this kind of work.  Friends of the ___ River, Friends of the ___Bay, as well as other environmental NGO’s, local water agencies, and local departments of public works, may have restoration projects in the works or may be able to connect you with other groups that are involved.  And that could save you an enormous amount of work (and money), but still have your students restore a creek or wetland.

For the ten years since I retired from teaching biology,  I’ve worked with a watershed group north of San Francisco Bay called STRAW, Students and Teachers Restoring a Watershed, a project of Point Blue Conservation Science.  My classes— biology, physical science, and environmental studies— worked with this group before I left  the classroom, so I knew what they were all about and went to work for them eagerly.  STRAW began 23 years ago and performed its 500th restoration in 2015, having coordinated restorations involving many thousands of students, K-12, and having restored over 30 miles of creek banks and acres and acres of wetlands.  STRAW also has our team of dedicated retired educators who take related lessons into the classrooms.  Having repeatedly seen students restore creeks and wetlands and the impact on students and teachers, I can’t think of a more powerful project to benefit everyone!

So what kinds of classroom lessons make a smooth fit with restoration and have rich educational value?  Here are just a few:  water quality and testing, native plants and animals, food webs and energy flow, rain gardens, water-borne disease, population studies and estimating numbers, identification and classification, carbon sequestration, and sustainable water policy.  Plus another big one: positive ways of dealing with climate change!  Read about climate smart restoration here.

And here you can read one teacher’s comments after she had her students restore a creek with STRAW.  

Creek Restoration: Tony Plants a Tree!

deskWe know that place-based learning can make a positive difference in kids’ lives.  For example, restoring creeks can restore kids.  At-risk kids, kids with gang affiliations, kids with low self-esteem:  all of these can benefit from accomplishing the restoration of a creek.  But sometimes it doesn’t lead to a complete turnaround…

There he was—the kid who was placed in my sheltered biology class to wait out the two weeks till he could be transferred to the continuation high school. Well-groomed and fastidious, doused with aftershave, he walked in and put his head down on the desk as soon as he was assigned a seat. And there his head remained day after day. He was absolutely determined not to do a thing. The day arrived when the class went to the creek bordering the school to work on a restoration, removing some invasive plants and planting native trees, shrubs and forbs. “Tony” asked to stay in the classroom, but I refused— after all, no one else would stay behind. So he came along as we walked down to the creek. Proper planting techniques were demonstrated and tools were distributed. The work began. I brought Tony a shovel and led him to a spot that needed a tree. He balked, I insisted. His clothes would get dirty, but “Not to worry—it’s not muddy.” His hands would blister and get dirty; “You’re in luck, Pal—here’s some work gloves.” And finally Tony went to work. The class was there for an hour and a half, and Tony planted three trees, with a little help from a couple of classmates. As we walked back to class he had a little swagger in his step and was more animated than I had ever seen him.

I wish I could report that Tony turned the corner that day, but no. He kept his head on the desk the few remaining days till he transferred out. Still, he planted three trees, trees that are growing there even now. And I don’t know what that might have meant to Tony. Maybe the experience had some positive value for him. It certainly had positive value for the creek!

And it had a lot of value for the rest of the class. The students were proud of their work and supportive of their team members. They made a positive difference for the environment, their school, and their community. More to come about restoration in our next posting.