What we know as substrate, essentially the soil that makes up the habitat of trees and plants, has different compositions. Soil is not only sandy grains but is a whole world of metals and elements necessary for life to arise. However, there are also considerable concentrations of heavy metals in its components, such as nickel and zinc, that almost no tree wants nearby.
Arboreal resilience
However, if there is one lesson that nature has taught us, it is resilience. Thus, a specialized group of trees called hyperaccumulators has evolved to incorporate toxic metals into their stems, leaves, and even their seeds. One such tree is the species known as Pycnandra acuminata, which grows on the island of New Caledonia in the South Pacific.
Pycnandra acuminata is a rainforest tree with a large size reaching up to 20 meters in height. It grows very slowly and takes decades to produce flowers and seeds. But as the saying goes, “what doesn’t kill you makes you stronger,” so they have learned to incorporate toxic metals into their stems to defend themselves against insects. This unusual behavior is also reflected in their appearance, which could not be more incredible. Their sap is a peculiar blue-green color because it contains up to 25% nickel.
Contrary to other types of vegetation that do not flourish in hard soils, hyperaccumulators are responsible for purifying the soil. They have been considered as an alternative to clean up the excess of heavy metals in soils in former mining sites exploited by human activities. Still, more research is still needed on the blue-blooded tree to purify human-polluted soil.
Text and images courtesy of Ecoosfera
Translated by María Isabel Carrasco Cara Chards