How did ancient lycophyte forests contribute to the formation of coal beds?

Ancient lycophyte forests were instrumental in the formation of the world's major coal beds, particularly during the Carboniferous Period.21

During this era, massive tree-like lycophytes such as Lepidodendron and Sigillaria—which could reach heights of 30 meters (about 100 feet)—thrived in vast, warm, and humid swamp environments. As these plants died, their organic remains accumulated in low-lying, waterlogged areas. Because these environments were often stagnant and oxygen-poor, the plant material was protected from complete decomposition by microorganisms.23145

Over time, this accumulated organic matter was converted into peat through biochemical processes. As the land subsided and these peat deposits were buried under layers of sediment, they underwent geochemical coalification, eventually transforming into the extensive coal seams found today. The remains of these extinct lycophytes constitute the primary biological material in many of the world's most significant coal deposits.451