Experts are Mindblown After Finding Trees Have a Second Layer of Roots

Similar to humans, plants have secrets that scientists value to unravel. Moreover, experts have left no stone unturned in examining plants in all their glory. Despite years of examination, something new continues to turn up. A new study reveals that experts in the past possibly missed out on the structure of roots, one of the most prominent parts of plants. The examinations showcase that many plants have two layers of roots, the second of which had remained hidden from experts before the study. The new findings introduce new implications, especially for the climate-mitigating impact of plants. Findings regarding this discovery have been published in Nature Communications.

Second Set of Roots

The study was centered around soil samples from all over the world. These samples arrived from a variety of habitats, from Alaskan tundra to rainforests in Puerto Rico. Different areas were considered, as experts wanted to incorporate as many climate zones and ecosystems as possible for the investigation. In total, they considered 44 sites for the assessment. The soil was reportedly from around 6 feet (1.8 m) below the surface. Investigation into the samples allowed researchers to learn specific root patterns exhibited by the plants and what the soils were essentially made of. 

Results from the analysis showed that 20% of the investigated sites exhibited "bimodality," according to Live Science. It means the mass in roots present in those particular sites peaked at two spots rather than one. Typically, root mass decreases with depth. However, in these cases, a peak was noted in the roots apart from the "top." It implied to the researchers that another deeper system of roots exists for certain plants. Mingzhen Lu, study lead author and an ecologist at New York University, said that he and his team were not only surprised to find this evidence of double-layered roots, but also by the frequency with which they detected it. 

The second layer of roots was mostly detected where the soil is rich in nitrogen, phosphorus, and moisture. Researchers believe that this layer pumps necessary resources to plants. If the assertion turns out to be true, then it challenges the long-held assumption that root activity reduces as they go deeper. This finding clearly indicates how few experts know about underground soil, a crucial factor in formulating climate policy and making decisions regarding climate management, per Lu. 

Implications for Carbon Storage

At present, one of the biggest issues Earth faces is the increased level of carbon dioxide. Roots can store carbon and, hence, play a huge role in keeping a large amount of carbon away from the atmosphere. To date, the carbon storage capacity of the roots has been determined based on the known length of the roots. The new finding indicates that the roots are deeper, which possibly increases their capacity.

Avni Malhotra, a co-author, does not deny the possibility but believes there are scenarios with carbon loss and not storage, according to Earth. She explains that in settings where subsoil is cool and compacted, microbial digestion slows down, and carbon gets locked away for centuries. However, there could also be situations where more roots energize buried microbes, and they increase the rate of decomposition. In this case, carbon will be freed from the roots. To understand which situation dominates, detailed stratified sampling needs to be conducted. "The good news is plants may already be naturally mitigating climate change more actively than we've realized – we just need to dig deeper to fully understand their potential," Lu added.

Change in the Ongoing Framework and Models

Experts believe the new finding impacts many management programs related to forests, agriculture, and conservation. More insights are needed about what kind of climate support bimodality would influence breeders when they choose which crop they want to plant in an area. For example, if the breeders are dealing with an arid region, and they know the site supports bimodality, they would incorporate a crop that can use the phenomenon to access nutrients deep in the soil, as the conditions around them are not providing it. 

Similarly, environmental enthusiasts would support crops exhibiting bimodality during reforestation to prevent more carbon from entering the atmosphere. Hence, a full profile analysis of the soil with roots must be conducted to find the real situation underground. "Scientists and policymakers need to look deeper beneath the Earth's surface as these overlooked deep soil layers may hold critical keys for understanding and managing ecosystems in a rapidly changing climate," Lu said. The team proposes using advanced imaging and sensors for this purpose.