Pyrophytes are

plants Plants are the eukaryotes that form the kingdom Plantae; they are predominantly photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with cyanobacteria to produce sugars f ...

which have adapted to tolerate

fire Fire is the rapid oxidation of a fuel in the exothermic chemical process of combustion, releasing heat, light, and various reaction Product (chemistry), products. Flames, the most visible portion of the fire, are produced in the combustion re ...

. Fire acts favourably for some species. "Passive pyrophytes" resist the effects of fire, particularly when it passes over quickly, and hence can out-compete less resistant plants, which are damaged. "Active pyrophytes" have a similar competing advantage to passive pyrophytes, but they also contain volatile oils and hence encourage the incidence of fires which are beneficial to them. "Pyrophile" plants are plants which require fire in order to complete their cycle of reproduction. Pyrophytes while often considered being adapted to fire in general, they are actually just adapted to the specific fire regimes in which they are found. Problems can arise if the fire regime of a pyrophyte is disrupted or changed.

Passive pyrophytes

These resist fire with adaptations including thick bark, tissue with high moisture content, or underground storage structures. Examples include: *

Longleaf pine The longleaf pine (''Pinus palustris'') is a pine species native to the Southeastern United States, found along the coastal plain from East Texas to southern Virginia, extending into northern and central Florida. In this area it is also known as ...

(''Pinus palustris'') *

Giant sequoia ''Sequoiadendron giganteum'' (also known as the giant sequoia, giant redwood, Sierra redwood or Wellingtonia) is a species of coniferous tree, classified in the family Cupressaceae in the subfamily Sequoioideae. Giant sequoia specimens are the la ...

(''Sequoiadendron giganteum'') * Coast redwood (''Sequoia sempervirens'') *

Cork oak ''Quercus suber'', commonly called the cork oak, is a medium-sized, evergreen oak tree in the section Quercus sect. Cerris, ''Quercus'' sect. ''Cerris''. It is the primary source of cork (material), cork for wine bottle stoppers and other uses, ...

(''Quercus suber'') * Niaouli (''Melaleuca quinquenervia'') which is extending in areas where bush fires are a mode of clearing (e.g.

New Caledonia New Caledonia ( ; ) is a group of islands in the southwest Pacific Ocean, southwest of Vanuatu and east of Australia. Located from Metropolitan France, it forms a Overseas France#Sui generis collectivity, ''sui generis'' collectivity of t ...

). * Venus fly trap (''Dionaea muscipula'') – this grows low to the ground in acid marshes in North Carolina, and resists fires passing over due to being close to the moist soil; fire suppression threatens the species in its natural environment. * White asphodel (''Asphodelus albus'') For some species of pine, such as

Aleppo pine ''Pinus halepensis'', commonly known as the Aleppo pine, also known as the Jerusalem pine, is a pine native to the Mediterranean region. It was officially named by the botanist Philip Miller in his 1768 book ''The Gardener's Dictionary''; he pro ...

(''Pinus halepensis''),

European black pine ''Pinus nigra'', the Austrian pine or black pine, is a moderately variable species of pine, occurring across Southern Europe from the Iberian Peninsula and Lower Austria to the eastern Mediterranean, on the Anatolian peninsula of Turkey, Corsica ...

(''Pinus nigra'') and

lodgepole pine ''Pinus contorta'', with the common names lodgepole pine and shore pine, and also known as twisted pine, and contorta pine, is a common tree in western North America. It is common near the ocean shore and in dry montane forests to the subalpin ...

(''Pinus contorta''), the effects of fire can be antagonistic: if moderate, it helps

pine cone A conifer cone, or in formal botanical usage a strobilus, : strobili, is a seed-bearing organ on gymnosperm plants, especially in conifers and cycads. They are usually woody and variously conic, cylindrical, ovoid, to globular, and have scal ...

bursting, seed dispersion and the cleaning of the underwoods; if intense, it destroys these resinous trees.

Active pyrophytes

Some trees and shrubs such as the

Eucalyptus ''Eucalyptus'' () is a genus of more than 700 species of flowering plants in the family Myrtaceae. Most species of ''Eucalyptus'' are trees, often Mallee (habit), mallees, and a few are shrubs. Along with several other genera in the tribe Eucalyp ...

of Australia actually encourage the spread of fires by producing flammable oils, and are dependent on their resistance to the fire which keeps other species of tree from invading their habitat. Today, many non-pyrophyte invasive plant species are able to invade fire adapted ecosystems as humans disrupt local fire cycles. Raising questions about sustainable paths forward to preserve these ecosystems, their native biodiversity, and human based landscapes.

Pyrophile plants

Other plants which need fire for their reproduction are called ''pyrophilic''. Longleaf pine (''

Pinus palustris The longleaf pine (''Pinus palustris'') is a pine species native to the Southeastern United States, found along the coastal plain from East Texas to southern Virginia, extending into northern and central Florida. In this area it is also known as ...

'') is a pyrophile, depending on fire to clear the ground for seed germination. The passage of fire, by increasing temperature and releasing smoke, is necessary to raise seeds dormancy of pyrophile plants such as ''

Cistus ''Cistus'' (from the Greek ''kistos'') is a genus of flowering plants in the rockrose family Cistaceae, containing about 20 species (Ellul ''et al.'' 2002). They are perennial shrubs found on dry or rocky soils throughout the Mediterranean reg ...

'' and '' Byblis'' an Australian passive carnivorous plant. The importance of smoke in germination has been directly linked to its production of trace gases, mainly Nitrogen Oxide(NO) and Nitrogen dioxide(NO₂). These traces gases produced in wildfires share significant over lap with anthropogenic pollution. Leading some to believe premature germination of pyrophiles through accidental human interference is possible. ''

Imperata cylindrica ''Imperata cylindrica'' (commonly known as cogongrass or kunai grass ) is a species of Perennial plant, perennial rhizomatous grass native to tropical and subtropical Asia, Micronesia, Melanesia, Australia, Africa, and Southern Europe. It has al ...

'' is a plant of

Papua New Guinea Papua New Guinea, officially the Independent State of Papua New Guinea, is an island country in Oceania that comprises the eastern half of the island of New Guinea and offshore islands in Melanesia, a region of the southwestern Pacific Ocean n ...

. Even green, it ignites easily and causes fires on the hills.

Evolution

99 million-year-old

amber Amber is fossilized tree resin. Examples of it have been appreciated for its color and natural beauty since the Neolithic times, and worked as a gemstone since antiquity."Amber" (2004). In Maxine N. Lurie and Marc Mappen (eds.) ''Encyclopedia ...

-preserved fossils of '' Phylica piloburmensis'', belonging to the modern pyrophytic genus '' Phylica'', show clear adaptations to fire including pubescent, needle-like leaves, further affirmed by the presence of burned plant remains from other

Burmese amber Burmese amber, also known as Burmite or Kachin amber, is amber from the Hukawng Valley in northern Myanmar. The amber is dated to around 100 million years ago, during the latest Albian to earliest Cenomanian ages of the mid-Cretaceous period. Th ...

specimens. These indicate that frequent fires have exerted an evolutionary pressure on flowering plants ever since their origins in the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

, and that adaptation to fire has been present in the family

Rhamnaceae The Rhamnaceae are a large Family (biology), family of flowering plants, mostly trees, shrubs, and some vines, commonly called the buckthorn family. Rhamnaceae is included in the order Rosales. The family contains about 55 genera and 950 specie ...

for over 99 million years.

References

{{Commons category, Pyrophytes Plant physiology

Passive pyrophytes

Active pyrophytes

Pyrophile plants

Evolution

See also

References