The first known forests on Earth arose in the [[LateMiddle Devonian]] (approximately 380390 [[Mya (unit)|million years ago]]), with the evolution of [[cladoxylopsid]] plants like ''[[Calamophyton]]''.<ref>{{cite journal|author=Davies, Neil S., McMahon, William J. and Berry, Christopher M.|year=2024|url=https://orca.cardiff.ac.uk/id/eprint/166971/1/davies-et-al-2024-earth-s-earliest-forest-fossilized-trees-and-vegetation-induced-sedimentary-structures-from-the.pdf|title=Earth's earliest forest: fossilized trees and vegetation-induced sedimentary structures from the Middle Devonian (Eifelian) Hangman Sandstone Formation, Somerset and Devon, SW England|journal=Journal of the Geological Society|doi=10.1144/jgs2023-204|archive-url=https://web.archive.org/web/20240309154116/https://orca.cardiff.ac.uk/id/eprint/166971/1/davies-et-al-2024-earth-s-earliest-forest-fossilized-trees-and-vegetation-induced-sedimentary-structures-from-the.pdf|archive-date=2024-03-09|url-status=live}}</ref> Appeared in the [[Late Devonian]], ''[[Archaeopteris]]'' was both tree-like and fern-like plant, growing to {{convert|20|m|ft}} in height or more.<ref name=firstDevonian>{{cite web|url=http://www.devoniantimes.org/opportunity/forests.html |title=The First Forests |website=Devonian Times |access-date=289 MayMarch 20162024 |url-status=livedead |archive-url=https://web.archive.org/web/20160510190820/http://www.devoniantimes.org/opportunity/forests.html |archive-date=10 May 2016}}</ref> which was a plant that was both tree-like and fern-like, growing to {{convert|10|m|ft}} in height. It quickly spread throughout the world, from the equator to subpolar latitudes;.<ref name=firstDevonian/> andIt it formed the first forest by beingis the first species known to cast shade due to its fronds and by forming soil from its roots. ''Archaeopteris'' was deciduous, dropping its fronds onto the forest floor, the shade, soil, and forest duff from the dropped fronds creating the firstearly forest.<ref name=firstDevonian/> The shed organic matter altered the freshwater environment, slowing its flow and providing food. This promoted freshwater fish.<ref name=firstDevonian/>