Editing Devonian (section)

====The greening of land====
{{main|Devonian explosion}}
[[File:Devonianscene-green.jpg|thumb|The Devonian Period marks the beginning of extensive land colonization by [[plant]]s. With large land-dwelling [[herbivore]]s not yet present, large forests grew and shaped the landscape.]]
Many [[List of Early Devonian land plants|Early Devonian plants]] did not have true roots or leaves like extant plants, although vascular tissue is observed in many of those plants. Some of the early land plants such as ''[[Drepanophycus]]'' likely spread by vegetative growth and spores.<ref>{{cite journal |last1=Zhang |first1=Ying-ying |last2=Xue |first2=Jin-Zhuang |last3=Liu |first3=Le |last4=Wang |first4=De-ming |title=Periodicity of reproductive growth in lycopsids: An example from the Upper Devonian of Zhejiang Province, China |journal=Paleoworld |year=2016 |volume=25 |issue=1 |pages=12–20 |doi=10.1016/j.palwor.2015.07.002}}</ref> The earliest land plants such as ''[[Cooksonia]]'' consisted of leafless, [[Dichotomous branching|dichotomous]] axes with terminal sporangia and were generally very short-statured, and grew hardly more than a few centimetres tall.<ref>{{cite journal |last1=Gonez |first1=Paul |last2=Gerrienne |first2=Philippe |title=A new definition and a lectotypification of the genus ''Cooksonia'' Lang 1937 |journal=International Journal of Plant Sciences |year=2010 |volume=171 |issue=2 |pages=199–215 |doi=10.1086/648988|s2cid=84956576 }}</ref> Fossils of ''[[Armoricaphyton|Armoricaphyton chateaupannense]]'', about 400 million years old, represent the oldest known plants with [[wood]]y tissue.<ref name="Chateau">{{cite web | url=https://www.lightsource.ca/news/details/analyzing_the_worlds_oldest_woody_plant_fossil.html | title=Analyzing the World's Oldest Woody Plant Fossil | publisher=[[Canadian Light Source]] | date=28 August 2019 | access-date=19 May 2021 | last=MacPherson | first=C. | archive-date=14 April 2021 | archive-url=https://web.archive.org/web/20210414132810/https://www.lightsource.ca/news/details/analyzing_the_worlds_oldest_woody_plant_fossil.html | url-status=dead }}</ref> By the Middle Devonian, shrub-like forests of primitive plants existed: [[Lycopodiophyta|lycophytes]], [[Equisetales|horsetails]], [[fern]]s, and [[progymnosperm]]s evolved. Most of these plants had true roots and leaves, and many were quite tall. The earliest-known trees appeared in the Middle Devonian.<ref>{{cite news |url=http://www.timesonline.co.uk/tol/news/uk/science/article1674051.ece |archive-url=https://web.archive.org/web/20080704130342/http://timesonline.co.uk/tol/news/uk/science/article1674051.ece |url-status=dead |archive-date=4 July 2008 |newspaper=The Times |location=London |title=Fossil from a forest that gave Earth its breath of fresh air |first=Lewis |last=Smith |date=April 19, 2007 |access-date=May 1, 2010 |df=dmy-all}}</ref> These included a lineage of lycopods and another arborescent, woody vascular plant, the [[Cladoxylopsida|cladoxylopsids]] and progymnosperm ''[[Archaeopteris]]''.<ref>{{cite encyclopedia |first1=C. Michael |last1=Hogan |date=2010 |url=http://www.eoearth.org/article/Fern?topic=49480 |title=Fern |encyclopedia=Encyclopedia of Earth |editor-first1=Saikat |editor-last1=Basu |editor-first2=C. |editor-last2=Cleveland |publisher=National Council for Science and the Environment |location=Washington DC}}</ref> These [[tracheophyte]]s were able to grow to large size on dry land because they had evolved the ability to biosynthesize [[lignin]], which gave them physical rigidity and improved the effectiveness of their vascular system while giving them resistance to pathogens and herbivores.<ref>{{cite journal |last1=Weng |first1=Jing-Ke |last2=Chapple |first2=Clint |title=The origin and evolution of lignin biosynthesis: Tansley review |journal=New Phytologist |date=July 2010 |volume=187 |issue=2 |pages=273–285 |doi=10.1111/j.1469-8137.2010.03327.x|pmid=20642725 |doi-access=free }}</ref> In [[Eifelian]] age, cladoxylopsid trees formed the first forests in Earth history.<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|volume=181 |issue=4 |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> By the end of the Devonian, the first seed-forming plants had appeared. This rapid appearance of many plant groups and growth forms has been referred to as the Devonian Explosion or the Silurian-Devonian Terrestrial Revolution.<ref name="SilurianDevonianTerrestrialRevolution">{{cite journal |last1=Capel |first1=Elliot |last2=Cleal |first2=Christopher J. |last3=Xue |first3=Jinzhuang |last4=Monnet |first4=Claude |last5=Servais |first5=Thomas |last6=Cascales-Miñana |first6=Borja |date=August 2022 |title=The Silurian–Devonian terrestrial revolution: Diversity patterns and sampling bias of the vascular plant macrofossil record |journal=[[Earth-Science Reviews]] |volume=231 |page=104085 |doi=10.1016/j.earscirev.2022.104085 |bibcode=2022ESRv..23104085C |s2cid=249616013 |doi-access=free |hdl=20.500.12210/76731 |hdl-access=free }}</ref>

The 'greening' of the continents acted as a [[carbon sink]], and [[Atmosphere of Earth|atmospheric concentrations]] of [[carbon dioxide]] may have dropped. This may have cooled the climate and led to a massive [[extinction event]]. (''See'' [[Late Devonian extinction]]).

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|File: Lycopod axis.jpg|Lycopod axis (branch) from the Middle Devonian of Wisconsin
|File: Cladoxylopsid bark.jpg|Bark (possibly from a cladoxylopsid) from the Middle Devonian of Wisconsin
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