Why Fire is Necessary in the Prairie

It is the herbaceous perennial habit that necessitates the use of fire in prairies. Well, to be correct it is the herbaceous perennial habit mixed with the elimination of grazing bison from the prairies that once ate most of the old vegetation.

Being herbaceous perennials means that no woody tissue is produced and that new vegetation must be produced every year while the roots continue to grow and live for decades, if not centuries.

Every fall the old vegetation dies, and every spring new vegetation is produced in a relatively short manner of time. A massive explosion of life happens in the Chicago area prairies around late May/early June.

Within three months, what was once a flat, open area suddenly becomes dense and thick with an incredibily large amount of green biomass - but again, none of it woody. By "woody", we are referring to secondary growth as opposed to primary growth ( ie lateral meristems as opposed to apical meristems, where a "meristem" is a point of active cell division). This is an essential term concerning the issue of plant physiology, and even beginner horticulturalists should try to understand this concept. If you're simultaneously confused and interested, I suggest reading up on this stuff here :

https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Book%3A_General_Biology_(Boundless)/30%3A_Plant_Form_and_Physiology/30.04%3A_Stems_-_Primary_and_Secondary_Growth_in_Stems

So the prairies, being composed almost entirely of herbaceous perennials, produce a massive amount of vegetation every year that only lives for a few months while the roots stay alive for decades. This vegetation collects light, builds up carbohydrates which it sends down to storage in the roots, and - if energy resources allow - it flowers. But when the season is over, this massive build-up of vegetation then dies and begins to rot throughout the winter. It is such a large amount of vegetation that it is too much for fungi and bacteria to eat in one year before the next round of vegetative material is produced. This is where fire comes in.

Fire consumes and clears out this massive amount of biomass, enabling the nutrients in the resulting ash to be washed into the root zone to super charge the roots. While burning does release a decent amount of carbon dioxide, it is negligible to the amount being stored in the roots and which slowly builds soil. Further, the above-ground vegetation would simply.ne decomposed by bacteria and fungi and released as CO2 during their metabolis

m, anyway.