Vegetation as a major conductor of geomorphic changes on the Earth surface: toward evolutionary geomorphology, Corenblit & Steiger 2009

Compendium Volume 3 Number 1 July 2019

Geomorphology is the study of landforms and processes and how they developed. This conceptual commentary proposes that the emergence and evolution of life, especially vegetation, has played a major role in physically shaping the Earth. For example, plant roots trap and hold sediment (preventing erosion), resulting in the formation of hillsides, sand dunes, fluvial islands, river banks, floodplains, and river channels, for example. Without vegetation to hold sediment in place, it would be blown or washed away, creating different land patterns. Roots also contribute to rock weathering, resulting in soil formation and even the formation of marine black shale, while aboveground, plants create a rough surface which affects flows of matter and energy. Indirectly, in being the primary source of energy for animals and microorganisms, plants “also control geomorphic processes through their engineering activities in soils and at the surface of the Earth.”

Trees play a central geomorphological role:

In particular the development of the lignin-containing plants (shrubs and trees) in the middle Devonian (380 Ma[9]) have produced the most significant geomorphic changes. Their complex and resistant root and stem systems combined with their slower decomposition has contributed to increase global sediment stability and storage in time and in space on the Earth’s surface [Corenblit & Steiger 2009: 894].

The authors contextualize the role of life in geomorphology in terms of energy sources available to do geomorphic work. Vegetation dynamics, driven by photosynthesis, which converts solar energy into stored chemical energy, is one of four such energy sources. The other three are: gravity, solar energy, and geothermal activity. This article helps us to visualize Earth’s systems (in particular lithosphere and biosphere) as interwoven, where biology drives not only life processes, but land formation process as well.

Corenblit, Dov & Johannes Steiger, 2009, Vegetation as a major conductor of geomorphic changes on the Earth surface: toward evolutionary geomorphology, Earth Surface Processes and Landforms 34, https://onlinelibrary.wiley.com/doi/abs/10.1002/esp.1788.

[9] “Ma” means millions of years ago.

For the full PDF version of the compendium issue where this article appears, visit Compendium Volume 3 Number 1 July 2019