One million species of plants and animals are now threatened with extinction, according to a 2019 United Nations report. Already, scientists have documented precipitous declines in the populations of birds (29% in North America) and insects (45% worldwide) since the 1970s. (See Decline of the North American Avifauna, Science, September 2019 and As Insect Populations Decline, Scientists Are Trying to Understand Why, Scientific American, November 2018.) As these populations decline, species loss accelerates, ecosystems become less robust and less resilient, and the ecosystem services they provide, such as clean air, clean water, and protection from flooding and weather extremes, degrade. 

We are learning more every day about the importance of plants, trees, and healthy soil for storing carbon. Much of the carbon-rich humus in our nation’s soils had been depleted by unsustainable land use patterns. The Cornell University professor and researcher, David Wolfe, suggests a new approach called “carbon farming” (also an important feature of organic regenerative agriculture). As reported by Janet Marinelli in Audubon, Wolfe asserts that “implementing this method on cultivated lands could slow the pace of global climate change by offsetting as much as one-quarter to one-third of annual increases in atmospheric CO2 for 20 to 50 years, until soil carbon stocks are once again fully restored. Others have argued that a 5 to 10 percent offset benefit is more realistic, ‘but even those lower numbers are significant.’” The article goes on to outline how carbon farming can be adapted for back yards. 

Composting is a part of the carbon picture, too. Please see the “Composting Action / Steps to Take” section for more information on the relationship between composting and the carbon cycle, and how households can participate.  

Trees are an important source of carbon storage. Over the course of a year, a young tree can remove approximately 13 pounds of atmospheric CO2. By the time that tree is 10 years old, that amount jumps to 48 pounds. Within 50 years, a mature tree has removed almost one ton of carbon dioxide (see Arbor Day Foundation Tree Facts).

Planting a tree or two may seem like a small step toward decreasing your carbon footprint, compared to some other actions, such as driving an electric vehicle or transitioning to heat pump technology for your home. And indeed, those are high-impact Actions! However, trees affect CO2 and heat exchange in other important ways. Trees cool the atmosphere and the ground around them through transpiration, (absorbing water through their roots and releasing water vapor through the pores of their leaves). On a sunny day, a mature tree can transpire up to 100 liters of water — thereby converting 70 kilowatt-hours of solar energy into latent heat held in water vapor. Without tree cover, the soil absorbs heat instead, contributing to a rise in temperature not only of the ground, but also, the surrounding atmosphere. (See the PBS special, H2O: The Molecule That Made Us, Part 1 for a fascinating investigation of the link between forests and weather patterns.) 

The good news is we can all make a difference! By changing what we plant and how we care for our outdoor spaces, each of us can help create a mosaic of habitats that support threatened birds and insects — and keep us healthy. 

You can give a big boost to native insects — and to the birds that eat them–by planting native species. Over millennia, insects have adapted to digest the plants native to their regions, but many of the imported cultivars we find at nurseries and big box stores, and then grow in our yards, are inedible to them. Avoid planting — and if you’ve already got them, remove — invasive plant species. Some popular garden plants are invasive and actively displace native plants, even in our local conservation areas. Invasive species having the worst impacts on New England landscapes include bittersweet vine, multiflora rose, Japanese knotweed, burning bush, and buckthorn.

Tending your garden with wildlife in mind can make a big difference for local fauna. Cutting back on fall clean up, for example, is beneficial for birds and insects. (See the “Get Dirty in the Garden” Action, Key Principles section, for how and why to “Leave the Leaves.”) Leaving spent flowers standing provides food for birds and shelter for insects. If you need a more manicured look, chop up your leaves with a lawnmower to enrich your lawn, or add to your compost.

About the lawn: nature abhors monocultures because they deplete soil and reduce biodiversity (including organisms that help store carbon in the soil). Consider alternative forms of lawn (e.g. ground covers or a wildflower meadow), perhaps a smaller lawn, and/or conversion of some lawn to attractive hardscape. Maintaining a traditional lawn uses huge amounts of water, and often involves treatment with chemical fertilizers that seep into waterways and water bodies (causing toxic algae blooms). 

Eliminate (or at least reduce significantly) the use of chemical fertilizers (which are made from petrochemicals), herbicides, pesticides, fungicides, and other toxins. Switching to organic lawn care is great, and not hard! Avoid buying plants that have been treated with neonicotinoids — a category of herbicide that harms imperiled bee populations, including native bee species. 

Protect and grow Acton’s tree canopy. We need our trees: they filter our air and water, cool buildings (and us) in warm weather, and host a wide variety of wildlife. Trees dying from disease may need to be removed, but otherwise, consider leaving them in place. Too much shade? “Limb up” your trees; trimming branches of mature trees can improve their health and allow more light through, while preserving the cooling, wildlife, and carbon storing benefits!

Resources

• For a fun activity about Acton trees, try the Acton Tree Scavenger Hunt created by Mothers Out Front Acton.
• As part of its CanaryTrees campaign, Mothers Out Front Acton also produced a web page — Resources about Trees & Climate — with lots of “tree book” suggestions for both children and adults.