The first line in his scientific paper reads: "The fine roots of trees are a royal pain to study."
In contrast to the large woody roots that serve as tree anchors, fine roots absorb and transport nutrients and water from the soil. They’re much like the tiny but critical capillaries in the human circulatory system.
Because they’re imbedded entirely below ground, early research techniques of coring and trenching destroyed the very systems being studied.
So, researchers created rhizotrons, underground wooden booths with large plexiglass windows. Each month, they descended into them and painstakingly marked the new growth of each fine root that was growing against the windows. They could then calculate the rate of growth of individual roots and the whole root system.
Recent technical advances provide less laborious measurements. Transparent tubes called minirhizotron are sunk vertically into the soil. A miniature video camera or fiber optic probe is lowered down the tube to monitor root growth without disturbing the soil environment.
But even with new technology, many questions remain. What’s their life span? Do roots of the same size class function in the same way? What’s the nature of their associations with soil fungi?
Fine roots may indeed be a royal pain to study, but this work is critical to better understand the hidden world of trees.
