 This classification system is common in modern root research, as many studies have shown that significant differences in fine-root traits can be detected when distinguishing roots by order.Traits that have been shown to increase with root order include root diameter, life span, and secondary growth, while root nitrogen content, mycorrhizal colonization, and turnover have shown decreases with increasing root order.By this system, fine roots are classified as either absorptive fine roots or transport fine roots.