A liana is a long-stemmed, herbaceous or woody vine that is rooted in the soil at ground level and uses trees, as well as other means of vertical support, to climb up to the canopy in search of direct sunlight. [1] The word liana does not refer to a taxonomic grouping, but rather a habit of plant growth – much like tree or shrub . It comes from standard French liane, itself from an Antilles French dialect word meaning to sheave.[ citation needed ]
Lianas are characteristic of tropical moist broadleaf forests (especially seasonal forests), but may be found in temperate rainforests and temperate deciduous forests. There are also temperate lianas, for example the members of the Clematis or Vitis (wild grape) genera. Lianas can form bridges amidst the forest canopy, providing arboreal animals, including ants and many other invertebrates, lizards, rodents, sloths, monkeys, and lemurs with paths across the forest. For example, in the Eastern tropical forests of Madagascar, many lemurs achieve higher mobility from the web of lianas draped amongst the vertical tree species. Many lemurs prefer trees with lianas for their roost sites. [2]
Lianas do not derive nutrients directly from trees but live on and derive nutrients at the expense of trees, thus they are parasites of trees. [3] [4] Specifically, they greatly reduce tree growth [5] and tree reproduction, [6] greatly increase tree mortality, [7] prevent tree seedlings from establishing, [5] alter the course of regeneration in forests, [8] and ultimately decrease tree population growth rates. [9] For example, forests without lianas grow 150% more fruit; trees with lianas have twice the probability of dying. [10]
Lianas are uniquely adapted to living in such forests as they use the host tree, for stability, to reach to top of the canopy. Lianas directly damage hosts by mechanical abrasion and strangulation, render hosts more susceptible to ice and wind damage,[ citation needed ] and increase the probability that the host tree falls.[ citation needed ] Lianas also provide support for weaker trees when strong winds blow by laterally anchoring them to stronger trees. [11] However, they may be destructive in that when one tree falls, the connections made by the lianas may cause many other trees to fall. [11] Because of these negative effects, trees which remain free of lianas are at an advantage; some species have evolved characteristics which help them avoid or shed lianas. [12]
Some lianas attain to great length, such as Bauhinia sp. in Surinam which has grown as long as 600 meters. [13] [14] Hawkins has accepted a length of 1.5 km for an Entada phaseoloides. [15] The longest monocot liana is Calamus manan (or Calamus ornatus) at exactly 240 meters. [16] One way of distinguishing lianas from trees and shrubs is based on the stiffness, specifically, the Young's modulus of various parts of the stem. Trees and shrubs have young twigs and smaller branches which are quite flexible and older growth such as trunks and large branches which are stiffer. A liana often has stiff young growths and older, more flexible growth at the base of the stem. [17]
Some families and genera containing liana species include:
A forest is an ecosystem characterized by a dense community of trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' Food and Agriculture Organization (FAO) defines a forest as, "Land spanning more than 0.5 hectares with trees higher than 5 meters and a canopy cover of more than 10 percent, or trees able to reach these thresholds in situ. It does not include land that is predominantly under agricultural or urban use." Using this definition, Global Forest Resources Assessment 2020 found that forests covered 4.06 billion hectares, or approximately 31 percent of the world's land area in 2020.
Rainforests are forests characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforests can be generally classified as tropical rainforests or temperate rainforests, but other types have been described.
A vine is any plant with a growth habit of trailing or scandent stems, lianas, or runners. The word vine can also refer to such stems or runners themselves, for instance, when used in wicker work.
In forestry and ecology, understory, or understorey, also known as underbrush or undergrowth, includes plant life growing beneath the forest canopy without penetrating it to any great extent, but above the forest floor. Only a small percentage of light penetrates the canopy so understory vegetation is generally shade-tolerant. The understory typically consists of trees stunted through lack of light, other small trees with low light requirements, saplings, shrubs, vines and undergrowth. Small trees such as holly and dogwood are understory specialists.
A savanna or savannah is a mixed woodland-grassland ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of grasses. According to Britannica, there exists four savanna forms; savanna woodland where trees and shrubs form a light canopy, tree savanna with scattered trees and shrubs, shrub savanna with distributed shrubs, and grass savanna where trees and shrubs are mostly nonexistent.
Rattan, also spelled ratan, is the name for roughly 600 species of Old World climbing palms belonging to subfamily Calamoideae. The greatest diversity of rattan palm species and genera are in the closed-canopy old-growth tropical forests of Southeast Asia, though they can also be found in other parts of tropical Asia and Africa. Most rattan palms are ecologically considered lianas due to their climbing habits, unlike other palm species. A few species also have tree-like or shrub-like habits.
Tropical forests are forested landscapes in tropical regions: i.e. land areas approximately bounded by the tropic of Cancer and Capricorn, but possibly affected by other factors such as prevailing winds.
A secondary forest is a forest or woodland area which has regenerated through largely natural processes after human-caused disturbances, such as timber harvest or agriculture clearing, or equivalently disruptive natural phenomena. It is distinguished from an old-growth forest, which has not recently undergone such disruption, and complex early seral forest, as well as third-growth forests that result from harvest in second growth forests. Secondary forest regrowing after timber harvest differs from forest regrowing after natural disturbances such as fire, insect infestation, or windthrow because the dead trees remain to provide nutrients, structure, and water retention after natural disturbances. Secondary forests are notably different from primary forests in their composition and biodiversity; however, they may still be helpful in providing habitat for native species, preserving watersheds, and restoring connectivity between ecosystems.
Acer circinatum, or vine maple, is a species of maple native to northwestern North America. Vine maple typically grows as a low-elevation costal tree in temperate areas of high precipitation such as the west coast of Oregon and northern California, as well as the rain forests of Washington State and British Columbia. Vine maples play an important role in conserving the biodiversity of lowland ecosystems by enriching upper soil layers and providing habitat for other organisms.
In biology, the canopy is the aboveground portion of a plant cropping or crop, formed by the collection of individual plant crowns. In forest ecology, canopy refers to the upper layer or habitat zone, formed by mature tree crowns and including other biological organisms. The communities that inhabit the canopy layer are thought to be involved in maintaining forest diversity, resilience, and functioning. Shade trees normally have a dense canopy that blocks light from lower growing plants.
A treefall gap is a distinguishable hole in the canopy of a forest with vertical sides extending through all levels down to an average height of 2 m (6.6 ft) above ground. These holes occur as result of a fallen tree or large limb. The ecologist who developed this definition used two meters because he believed that "a regrowth height of 2 m was sufficient" for a gap to be considered closed, but not all scientists agree. For example, Runkle believed that regrowth should be 10–20 m (33–66 ft) above the ground. Alternatively, a treefall gap is "the smallest gap [that must] be readily distinguishable amid the complexity of forest structure."
Mast is the fruit of forest trees and shrubs, such as acorns and other nuts. The term derives from the Old English mæst, meaning the nuts of forest trees that have accumulated on the ground, especially those used historically for fattening domestic pigs, and as food resources for wildlife. In the aseasonal tropics of Southeast Asia, entire forests, including hundreds of species of trees and shrubs, are known to mast at irregular periods of 2–12 years.
A seed bank stores seeds from plants and is significant in preserving plant genetic diversity. Seed banks can be categorized according to their location and the ecological functions they serve. The primary types include soil seed banks, which are found in terrestrial environments; wetland seed banks, located in aquatic habitats; and canopy seed banks, present in the upper layers of forest ecosystems. Each type of seed contributes uniquely to plant biodiversity, ecosystem resilience and human well-being. Also, they are unique in the way they retain their seed. For example, in canopy seed banks or aerial seed banks, the seeds are stored in the canopies of trees and plants.
Plant ecology is a subdiscipline of ecology that studies the distribution and abundance of plants, the effects of environmental factors upon the abundance of plants, and the interactions among plants and between plants and other organisms. Examples of these are the distribution of temperate deciduous forests in North America, the effects of drought or flooding upon plant survival, and competition among desert plants for water, or effects of herds of grazing animals upon the composition of grasslands.
Host–parasite coevolution is a special case of coevolution, where a host and a parasite continually adapt to each other. This can create an evolutionary arms race between them. A more benign possibility is of an evolutionary trade-off between transmission and virulence in the parasite, as if it kills its host too quickly, the parasite will not be able to reproduce either. Another theory, the Red Queen hypothesis, proposes that since both host and parasite have to keep on evolving to keep up with each other, and since sexual reproduction continually creates new combinations of genes, parasitism favours sexual reproduction in the host.
Simarouba amara is a species of tree in the family Simaroubaceae, found in the rainforests and savannahs of South and Central America and the Caribbean. It was first described by Aubl. in French Guiana in 1775 and is one of six species of Simarouba. The tree is evergreen, but produces a new set of leaves once a year. It requires relatively high levels of light to grow and grows rapidly in these conditions, but lives for a relatively short time. In Panama, it flowers during the dry season in February and March, whereas in Costa Rica, where there is no dry season it flowers later, between March and July. As the species is dioecious, the trees are either male or female and only produce male or female flowers. The small yellow flowers are thought to be pollinated by insects, the resulting fruits are dispersed by animals including monkeys, birds and fruit-eating bats and the seeds are also dispersed by leaf cutter ants.
Platypodium elegans, the graceful platypodium, is a large leguminous tree found in the Neotropics that forms part of the forest canopy. It was first described by Julius Rudolph Theodor Vogel in 1837 and is the type species of the genus. The tree has been known to grow up to 30 metres in height and have a trunk with a diameter up to 1 m at breast height. Its trunk has large holes in it, sometimes making it possible to see through the trunk. The holes provide a habitat for giant damselflies and other insects both when alive and once the tree has died and fallen over. It has compound leaves each of which is made up of 10–20 leaflets. Three new chemical compounds have been isolated from the leaves and they form part of the diet of several monkeys and the squirrel Sciurus ingrami. In Panama it flowers from April to June, the flowers contain only four ovules, but normally only one of these reaches maturity forming a winged seed pod around 10 cm long and weighing 2 g. During the dry season around a year after the flowers are fertilised, the seeds are dispersed by the wind and the tree loses it leaves. The seeds are eaten by agoutis and by bruchid beetle larvae. The majority of seedlings are killed by damping off fungi in the first few months of growth, with seedlings that grow nearer the parent trees being more likely to die. The seedlings are relatively unable to survive in deep shade compared to other species in the same habitat. Various epiphytes are known to grow on P. elegans with the cactus Epiphyllum phyllanthus being the most abundant in Panama. Despite having holes in its trunk which should encourage debris and seeds to collect, hemiepiphytes are relatively uncommon, meaning that animals are not attracted to it to feed and then defecate. It has no known uses in traditional medicine and although it can be used for timber, the wood is of poor quality.
Gap dynamics refers to the pattern of plant growth that occurs following the creation of a forest gap, a local area of natural disturbance that results in an opening in the canopy of a forest. Gap dynamics are a typical characteristic of both temperate and tropical forests and have a wide variety of causes and effects on forest life.
Seasonal tropical forest, also known as moist deciduous, semi-evergreen seasonal, tropical mixed or monsoon forest, typically contains a range of tree species: only some of which drop some or all of their leaves during the dry season. This tropical forest is classified under the Walter system as (i) tropical climate with high overall rainfall and (ii) having a very distinct wet season with dry season. These forests represent a range of habitats influenced by monsoon (Am) or tropical wet savannah (Aw/As) climates. Drier forests in the Aw climate zone are typically deciduous and placed in the Tropical dry forest biome: with further transitional zones (ecotones) of savannah woodland then tropical and subtropical grasslands, savannas, and shrublands.
In ecology, a light gap is a break in forest canopy or similar barrier that allows young plants to grow where they would be otherwise inhibited by the lack of light reaching the seedbed. Light gaps form predominantly when a tree falls, and thus produces an opening in the forest canopy. Light gaps are important for maintaining diversity in species-rich ecosystems.
A parasite is an organism that lives on or in a host organism and gets its food from or at the expense of its host.
{{cite book}}: |first= has generic name (help){{cite book}}: CS1 maint: location missing publisher (link) quoting: Prof. Melchior Treub, Observations surles Plantes Grimphantes de Jardin Botanique Buitenzorg, ANNALES de JARDIN BUITENZORG (1883) p. 175| Subdisciplines | |||||||||||
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