ECOLOGICAL BENEFITS
Dry stone walls offer a wide range of ecological benefits including ‘green’ construction, sustainability, and the provision of a secure, biodiverse habitat for a varied range of flora and fauna. The walls present a low-carbon footprint, and are completely and infinitely recyclable. Dry stone structures are always made with local stone in harmony with the environment, and time-tested building techniques exemplify and reinforce a harmonious relationship between human endeavor and nature.
Dry stone walls are the greenest way to build, in that they do not employ mortar or concrete, the manufacture of which is the third largest producer of CO2 in the world. Nor do they require concrete foundations or block back-up walls as do ‘wet’ walls. Stone is the only material employed and is harvested from the site or as near to the site as possible. Standard tools are simple, require no power, and fit comfortably in a small bag or bucket. The only water required for construction is to keep the Waller hydrated!
Stone walls change everything from the soil level to the top of the wall. Wall orientation influences shade, sunlight, and wind, thereby creating implications for moisture, temperature, and shelter. Rain quickly drains off dry stone walls and, in general, south and west facing walls are hot and dry while east and north facing walls are cooler and wetter. The base of the wall is generally cool and moist while the top is hot and dry. South facing walls absorb heat through solar-gain during the day and radiate stored heat through the night. A south-facing wall provides dry, warm, sunny positions for warmth-loving insects and basking and hibernating reptiles. All of these factors influence where flora and fauna will choose to locate.
A well constructed dry stone wall is, depending on the skill of the Waller (and the variety of stone) between 5% to 20% air between stones. Yet the gaps and crevices, left in stone walls by omitting mortar or synthetic sealants, create natural interstices for plants to grow and animals to shelter in. The wall becomes a linear ecological nature preserve contributing greatly to local ecosystems, microclimates and biodiversity.
To insure the longevity of a wall, it is not a good practice for plants (and their ever insistent root systems) to be allowed to grow on or in the wall. However, on a smaller scale, a recent study revealed that stone walls support up to 75 different vascular plants, more than 50 bryophites, and over 20 lichens, mosses, and liverworts.
Animals of all types utilize stone walls; from foxes to chipmunks to salamanders to mice, ants, spiders, snakes, beetles and rodents. Larger creatures, such as toads, frogs, lizards and adders use walls as winter homes as well as hunting grounds. Cats and foxes use the tops of the walls as traveling lanes and useful vantage points, where the extra elevation helps them spot prey or predators. So, while it is a wall, it is also a corridor.
Dry stone walls can also benefit solitary and social bees. The walls provide cavities for bees to nest in, but they also create permanent, undisturbed habitat for perennial herbs to grow alongside them, indirectly providing diverse floral resources for bees to forage on.
A dry stone wall can make your landscape come to life as the wall becomes an edge, a refuge, and a habitat, with impeccable, eco-friendly credentials.