Tree Roots

Stream walking the Rocky River last week led me down a rabbit hole. For reasons unexplained, I’m fascinated by natural phenomena that grace your everyday periphery. As a result, I scramble for more info until my brain feels denatured. This ambitious routine builds a jack-of-all-trades mental underpinning. 

The hanging tree roots exposed along undercut banks of Rocky River scream “Look at me, look at me!” Okay they don’t actually resonate at a frequency heard by our ears, but they do beg your attention. A story is waiting to be told, a page turned, a rock skipped. As water rushes downstream heading north to Lake Erie, its velocity can be so bold and intense that small molecules of water can scrape and move large chunks. As a result, the physical features of the stream shore are gradually cut away (bank erosion). As the dirt is washed away, the water channel grows deeper and wider (channel incision). The phenomenon exposes what would otherwise lie hidden beneath your hiking feet. What immediately caught my attention is the mass of dangling roots firmly suspended in void space above the water’s surface, but below ground level. Let’s take a closer look.
 

Roots exposed underneath a large oak tree unproductively reaching for soil long gone.

 

Two steps back reveal tree after tree unluckily rooted along the bank’s edge.

Roots serve as anchors and plant liaisons to a world of otherwise untapped nutrients in the soil. The procured goods are sent to the wood tissue called xylem, which transports the nutrients upwards through the tree. Specifically, roots have the unusual ability to harness mineral ions and water molecules via osmosis. Nutrients are also provided via mycorrhizae, fungal appendages that receive carbohydrates and other vitamins from the biological handshake. Roots efficiently accomplish this function with the help of microscopic hairs that increase surface area. These elongated tubular extensions line the lateral roots and primary root (taproot) that at first crowd, but then spread and matriculate the fossorial world beneath. In fact, a root system can spread two to three times as wide as the tree crown. As described, the lateral roots and primary root together form a taproot system, as opposed to a fibrous root system seen in grasses. 

In the case of my observed oaks poignantly fading to their demise, it all started with a single acorn. This nut has but one agenda: send a taproot out and down in search of a reliable source of water. Next grow the lateral roots to seal the deal and send a young seedling with lofty aspirations to one day be a sapling, or maybe even a stately oak.

-Marty Calabrese, Naturalist