The following series of columns entitled ‘Soil to Sky’ are an examination of five different facets of environment, structure, and life that are instrumental to trees in our forests and landscapes. Trees are instrumental to our wellbeing, both individually and collectively as a society. Healthy urban forests and natural areas are the responsibility of professional arborists, policy-makers, volunteers and individuals, among others. We will be sharing our enthusiasm with you in weekly installments and encourage you to become tree stewards, heralding forth the future of healthy trees. See the first column here: Soil.
Roots by Alyssa Vinson
The foundation, sending forth tendrils searching for sustenance, interwoven highways of communication, forming delicate friendships and vast strategic alliances. Roots are not only the stability anchoring the organism living above-ground, rather they exist for a multitude of purposes including seeking out and transporting water, minerals, irreplaceable nutrients and forming life-long bonds with microbes, fungi, and other micro-organisms. In the daily dance from root to air, water is transported upwards, through osmotic pressure, and the magic of transpiration defies gravity, channels brimming, carrying vital nutrition and chemical messages throughout the structure of the tree. We rest on the outstretched and uplifted topmost roots, gazing upward or inward. Contemplative, a sense of groundedness, we seek out the stability of deeply rooted things, finding comfort in the reminder of this connection.
Gifts given without expectation of return; roots offer services to us through their function to the entire tree. Filamentous and ample, feathery, and aggressive, roots create an interwoven web of fine lignin and cellulose which hold the voluminous soil. This netted basket of soil and root provides a plush sponge for the absorption of rainwater. Our drastically altered human landscapes come with a hardening of the earth’s surface. Our streets, sidewalks, roofs, and other infrastructure shed water, flooding pluvial vast rivulets of rain sheeting rather than being absorbed within our soil. Interspersed within this hardened landscape, vast monuments to verdancy, tree roots guide this sheeting rainfall downward, inward. Held within the dark rivers underground, some minute in scope while others beg for exploration. This holding, slowing down of the rainfall allows chemical reactions to occur, filtering or breaking down pollutants, and making dissolved nutrients available.
Not only anchoring the upright structure of the tree, roots also act as an anchor for the nutrient cycle. Roots take what they need and return in abundance chemicals that alter the rhizosphere. Changing the availability or usefulness of nutrients, holding some for later use and creating an abundance of cyclical nutrition that extends beyond the dripline of the canopy above. Symbiotic dances of root, fungi, and bacteria within and on the surface of roots can add nitrogen, exchange sugars, and facilitate the spread of information.
Tree to tree, to plant and mushroom, scavengers, and benefactors alike, share the vast resources of sun and land through the interconnected infrastructure of roots and fungi. A tree in stress will produce chemicals that can transfer to those trees around it ‘warning’ of pests, diseases, drought, or environmental disturbance, and provide sustenance and support to damaged neighbors. Vast expanses of root reach out from the oldest of the trees sharing resources with the future generations or preventing competition from other tree species.
Even in death, roots provide sustenance, slowly returning their nutrients, consumed by the fungi and microbes that teem within the darkness of the soil. The richness of organic matter so essential to tree health is supported first and finally by the foundation. Protect tree roots by careful consideration of hard infrastructure, provide adequate space for maturity when trees are planted. Be aware of tree roots when driving, or otherwise compacting the surface of the soil. When planting trees look carefully at the roots, they should be light tan to white or light brown, with no wrapping, spiraling, or girdling and give the roots room to breathe and space to grow. Situated in the softness of the soil, and supported by tender care, healthy roots are the foundation upon which healthy forests, urban or otherwise are built and maintained.
From soil to sky, trees add value to our communities, healthy roots support the overall health of the urban forest. These urban forests in turn contribute to improved air quality, reduced stress, lower crime, longevity of critical infrastructure and increased resilience in the face of global climate change. A healthy urban forest minimizes the impact of urban heat island effect, buffers storm damage and can create microclimates. A healthy community starts at the foundation and the roots of our urban trees form the basis for tree health.