''Populus'' is a genus of 25–30 species of
deciduous
In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, aft ...
flowering plant
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...
s in the family
Salicaceae
The Salicaceae is the willow family of flowering plants. The traditional family (Salicaceae ''sensu stricto'') included the willows, poplar, aspen, and cottonwoods. Genetic studies summarized by the Angiosperm Phylogeny Group (APG) have greatly ...
, native to most of the
Northern Hemisphere
The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...
. English names variously applied to different species include poplar (), aspen, and cottonwood.
The western balsam poplar (''
P. trichocarpa'') was the first tree to have its full DNA code determined by
DNA sequencing
DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. Th ...
, in 2006.
Description
![Trembling Aspen](https://upload.wikimedia.org/wikipedia/commons/c/cd/Trembling_Aspen.jpg)
The genus has a large genetic diversity, and can grow from tall, with trunks up to in diameter.
The
bark
Bark may refer to:
* Bark (botany), an outer layer of a woody plant such as a tree or stick
* Bark (sound), a vocalization of some animals (which is commonly the dog)
Places
* Bark, Germany
* Bark, Warmian-Masurian Voivodeship, Poland
Arts, ...
on young trees is smooth, white to greenish or dark gray, and often has conspicuous
lenticel
A lenticel is a porous tissue consisting of cells with large intercellular spaces in the periderm of the secondarily thickened organs and the bark of woody stems and roots of dicotyledonous flowering plants. It functions as a pore, providing a ...
s; on old trees, it remains smooth in some species, but becomes rough and deeply fissured in others. The shoots are stout, with (unlike in the related
willow
Willows, also called sallows and osiers, from the genus ''Salix'', comprise around 400 speciesMabberley, D.J. 1997. The Plant Book, Cambridge University Press #2: Cambridge. of typically deciduous trees and shrubs, found primarily on moist s ...
s) the terminal bud present. The
leaves
A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...
are spirally arranged, and vary in shape from triangular to circular or (rarely) lobed, and with a long
petiole; in species in the sections ''Populus'' and ''Aigeiros'', the petioles are laterally flattened, so that breezes easily cause the leaves to wobble back and forth, giving the whole tree a "twinkling" appearance in a breeze. Leaf size is very variable even on a single tree, typically with small leaves on side shoots, and very large leaves on strong-growing lead shoots. The leaves often turn bright gold to yellow before they fall during autumn.
[Meikle, R. D. (1984). ''Willows and Poplars of Great Britain and Ireland''. BSBI Handbook No. 4. .][Rushforth, K. (1999). ''Trees of Britain and rope''. Collins .]
![Populus (Populier zaadpluis en zaden)1](https://upload.wikimedia.org/wikipedia/commons/f/f8/Populus_%28Populier_zaadpluis_en_zaden%291.jpg)
The
flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...
s are mostly
dioecious
Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproductio ...
(rarely
monoecious
Monoecy (; adj. monoecious ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system alongside gynomonoecy, andromonoecy and trimonoecy.
Monoecy is conne ...
) and appear in early spring before the leaves. They are borne in long, drooping, sessile or pedunculate
catkin
A catkin or ament is a slim, cylindrical flower cluster (a spike), with inconspicuous or no petals, usually wind-pollinated (anemophilous) but sometimes insect-pollinated (as in ''Salix''). They contain many, usually unisexual flowers, arranged cl ...
s produced from buds formed in the axils of the leaves from the previous year. The flowers are each seated in a cup-shaped disk which is borne on the base of a scale which is itself attached to the rachis of the catkin. The scales are obovate, lobed, and fringed, membranous, hairy or smooth, and usually caducous. The male flowers are without
calyx or
corolla, and comprise a group of four to 60
stamen
The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10
Morphology and terminology
A stamen typically consists of a stalk called the filame ...
s inserted on a disk; filaments are short and pale yellow;
anther
The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10
Morphology and terminology
A stamen typically consists of a stalk called the filam ...
s are oblong, purple or red, introrse, and two-celled; the cells open longitudinally. The female flower also has no calyx or corolla, and comprises a single-celled ovary seated in a cup-shaped disk. The style is short, with two to four stigmata, variously lobed, and numerous ovules. Pollination is by wind, with the female catkins lengthening considerably between pollination and maturity. The
fruit
In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering.
Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...
is a two- to four-valved
dehiscent
Dehiscence is the splitting of a mature plant structure along a built-in line of weakness to release its contents. This is common among fruits, anthers and sporangia. Sometimes this involves the complete detachment of a part; structures that op ...
capsule, green to reddish-brown, mature in midsummer, containing numerous minute light brown
seed
A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...
s surrounded by tufts of long, soft, white hairs aiding wind dispersal.
Classification
The genus ''Populus'' has traditionally been divided into six sections on the basis of leaf and flower characters; this classification is followed below. Recent genetic studies have largely supported this, confirming some previously suspected reticulate evolution due to past hybridisation and introgression events between the groups. Some species (noted below) had differing relationships indicated by their nuclear DNA
Nuclear DNA (nDNA), or nuclear deoxyribonucleic acid, is the DNA contained within each cell nucleus of a eukaryotic organism. It encodes for the majority of the genome in eukaryotes, with mitochondrial DNA and plastid DNA coding for the rest. It ...
(paternally inherited) and chloroplast DNA
Chloroplast DNA (cpDNA) is the DNA located in chloroplasts, which are photosynthetic organelles located within the cells of some eukaryotic organisms. Chloroplasts, like other types of plastid, contain a genome separate from that in the cell nu ...
sequences (maternally inherited), a clear indication of likely hybrid origin.[Hamzeh, M., & Dayanandan, S. (2004). Phylogeny of ''Populus'' (Salicaceae) based on nucleotide sequences of chloroplast TRNT-TRNF region and nuclear rDNA. ''Amer. J. Bot''. 91: 1398-1408. Availabl]
online
/ref> Hybridisation continues to be common in the genus, with several hybrids between species in different sections known. There are currently 57 accepted species in the genus.["''Populus'' L.". ''Plants of the World Online'', Kew Science. Accessed 8 September 2021]
/ref>
Phylogeny
The oldest easily identifiable fossil of this genus belongs to ''Poplus wilmattae
mySociety is a UK-based registered charity, previously named UK Citizens Online Democracy. It began as a UK-focused organisation with the aim of making online democracy tools for UK citizens. However, those tools were open source, so that the ...
'', and comes from the Late Paleocene
The Thanetian is, in the International Commission on Stratigraphy, ICS Geologic timescale, the latest age (geology), age or uppermost stage (stratigraphy), stratigraphic stage of the Paleocene epoch (geology), Epoch or series (stratigraphy), Serie ...
of North America about 58 million years ago.
Selected species
* ''Populus'' section ''Populus'' – aspen
Aspen is a common name for certain tree species; some, but not all, are classified by botanists in the section ''Populus'', of the ''Populus'' genus.
Species
These species are called aspens:
*'' Populus adenopoda'' – Chinese aspen (China ...
s and white poplar (circumpolar subarctic and cool temperate, and mountains farther south, white poplar warm temperate)
** ''Populus adenopoda
''Populus adenopoda'', known commonly as the Chinese aspen, is a species of poplar found in the subtropical regions of China. The trees can reach a maximum height of 30 metres, and occur on mountain slopes at elevations of 300–2500 metres. Woo ...
'' – Chinese aspen (eastern Asia)
** ''Populus alba
''Populus alba'', commonly called silver poplar,Webb, C. J.; Sykes, W. R.; Garnock-Jones, P. J. 1988: Flora of New Zealand. Vol. IV. Naturalised Pteridophytes, Gymnosperms, Dicotyledons. 4. Christchurch, New Zealand, Botany Division, D.S.I.R. si ...
'' – white poplar (southern Europe to central Asia)
*** ''Populus'' × ''canescens'' (''P. alba × P. tremula'') – grey poplar
** ''Populus davidiana
''Populus'' is a genus of 25–30 species of deciduous flowering plants in the family Salicaceae, native to most of the Northern Hemisphere. English names variously applied to different species include poplar (), aspen, and cottonwood.
The we ...
'' – Korean aspen (eastern Asia)
** ''Populus grandidentata
''Populus grandidentata'', commonly called large-tooth aspen, big-tooth aspen, American aspen, Canadian poplar, or white poplar, is a deciduous tree native to eastern North America.
Name
The name ''Populus'' is from the Latin for poplar, and ' ...
'' – bigtooth aspen (eastern North America)
** ''Populus luziarum
''Populus'' is a genus of 25–30 species of deciduous flowering plants in the family Salicaceae, native to most of the Northern Hemisphere. English names variously applied to different species include poplar (), aspen, and cottonwood.
The we ...
'' – Jalisco
Jalisco (, , ; Nahuatl: Xalixco), officially the Free and Sovereign State of Jalisco ( es, Estado Libre y Soberano de Jalisco ; Nahuatl: Tlahtohcayotl Xalixco), is one of the 31 states which, along with Mexico City, comprise the 32 Federal En ...
, Mexico[
** '']Populus primaveralepensis
''Populus'' is a genus of 25–30 species of deciduous flowering plants in the family Salicaceae, native to most of the Northern Hemisphere. English names variously applied to different species include poplar (), aspen, and cottonwood.
The we ...
'' – Jalisco
Jalisco (, , ; Nahuatl: Xalixco), officially the Free and Sovereign State of Jalisco ( es, Estado Libre y Soberano de Jalisco ; Nahuatl: Tlahtohcayotl Xalixco), is one of the 31 states which, along with Mexico City, comprise the 32 Federal En ...
, Mexico
** ''Populus sieboldii
''Populus'' is a genus of 25–30 species of deciduous flowering plants in the family Salicaceae, native to most of the Northern Hemisphere. English names variously applied to different species include poplar (), aspen, and cottonwood.
The we ...
'' – Japanese aspen (eastern Asia)
** ''Populus tremula
''Populus tremula'' (commonly called aspen, common aspen, Eurasian aspen, European aspen, or quaking aspen) is a species of poplar native to cool temperate regions of Europe and Asia, from Iceland and the British IslesJames KilkellIrish native ...
'' – aspen, common aspen, Eurasian aspen, European aspen, quaking aspen (Europe, northern Asia)
** ''Populus tremuloides
''Populus tremuloides'' is a deciduous tree native to cooler areas of North America, one of several species referred to by the common name aspen. It is commonly called quaking aspen, trembling aspen, American aspen, mountain or golden aspen, tr ...
'' – quaking aspen or trembling aspen (North America)
* ''Populus'' section ''Aigeiros'' – black poplars, some of the cottonwoods (North America, Europe, western Asia; temperate)
** ''Populus deltoides
''Populus deltoides'', the eastern cottonwood or necklace poplar, is a Populus sect. Aigeiros, cottonwood Populus, poplar native to North America, growing throughout the eastern, central, and southwestern United States as well as the southern Ca ...
'' – eastern cottonwood (eastern North America)
** ''Populus fremontii
''Populus fremontii'', commonly known as Frémont's cottonwood, is a cottonwood (and thus a poplar) native to riparian zones of the Southwestern United States and northern through central Mexico. It is one of three species in ''Populus'' sect. ...
'' – Fremont cottonwood (western North America)
** ''Populus nigra
''Populus nigra'', the black poplar, is a species of cottonwood poplar, the type species of section ''Aigeiros'' of the genus ''Populus'', native to Europe, southwest and central Asia, and northwest Africa.Flora Europaea''Populus nigra''/ref>
...
'' – black poplar (Europe), placed here by nuclear DNA; cpDNA
Chloroplast DNA (cpDNA) is the DNA located in chloroplasts, which are photosynthetic organelles located within the cells of some eukaryotic organisms. Chloroplasts, like other types of plastid, contain a genome separate from that in the cell nuc ...
places it in sect. ''Populus'' (including ''Populus afghanica'')
*** ''Populus'' × ''canadensis'' (''P. deltoides'' × ''P. nigra'') – hybrid black poplar
*** ''Populus'' × ''inopina'' (''P. nigra'' × ''P. fremontii'') – hybrid black poplar
* ''Populus'' section ''Tacamahaca'' – balsam poplars (North America, Asia; cool temperate)
** ''Populus angustifolia
''Populus angustifolia'', commonly known as the narrowleaf cottonwood, is a species of tree in the willow family (Salicaceae). It is native to western North America, where it is a characteristic species of the Rocky Mountains and the surrounding ...
'' – willow-leaved poplar or narrowleaf cottonwood (central North America)
** ''Populus balsamifera
''Populus balsamifera'', commonly called balsam poplar, bam, bamtree, eastern balsam-poplar, hackmatack, tacamahac poplar, tacamahaca, is a tree species in the balsam poplar species group in the poplar genus, '' Populus.'' The genus name ''Populu ...
'' – Balsam poplar (northern North America) (= ''P. candicans'', ''P. tacamahaca'')
** ''Populus cathayana
''Populus'' is a genus of 25–30 species of deciduous flowering plants in the family Salicaceae, native to most of the Northern Hemisphere. English names variously applied to different species include poplar (), aspen, and cottonwood.
The we ...
'' – (northeast Asia)
** ''Populus koreana
''Populus suaveolens'', called the Mongolian poplar, Korean poplar and Japanese poplar, is a species of flowering plant in the genus '' Populus'', native to all of northern Asia, the Korean peninsula, the Kurils, and northern Japan. It is a tree ...
'' J.Rehnder – Korean poplar (northeast Asia)
** ''Populus laurifolia
''Populus laurifolia'', the laurel poplar, is a species of flowering plant in the family Salicaceae, native to Kazakhstan, the Altai, Mongolia, and Xinjiang
Xinjiang, SASM/GNC: ''Xinjang''; zh, c=, p=Xīnjiāng; formerly romanized as S ...
'' – laurel-leaf poplar (central Asia)
** ''Populus maximowiczii
''Populus suaveolens'', called the Mongolian poplar, Korean poplar and Japanese poplar, is a species of flowering plant in the genus '' Populus'', native to all of northern Asia, the Korean peninsula, the Kurils, and northern Japan. It is a tree ...
'' A.Henry – Maximowicz' poplar, Japanese poplar (northeast Asia)
** ''Populus simonii
''Populus simonii'', Simon's poplar, Simon poplar, or Chinese cottonwood, is a species of Populus, poplar native to northeast China and to Mongolia, and commonly planted as a street tree in cool temperate areas of Europe. There have been introduc ...
'' – Simon's poplar (northeast Asia)
** ''Populus suaveolens
''Populus suaveolens'', called the Mongolian poplar, Korean poplar and Japanese poplar, is a species of flowering plant in the genus ''Populus
''Populus'' is a genus of 25–30 species of deciduous flowering plants in the family Salicaceae, ...
'' Fischer – Mongolian poplar (northeast Asia)
** ''Populus szechuanica
''Populus'' is a genus of 25–30 species of deciduous flowering plants in the family Salicaceae, native to most of the Northern Hemisphere. English names variously applied to different species include poplar (), aspen, and cottonwood.
The we ...
'' – Sichuan poplar (northeast Asia), placed here by nuclear DNA; cpDNA
Chloroplast DNA (cpDNA) is the DNA located in chloroplasts, which are photosynthetic organelles located within the cells of some eukaryotic organisms. Chloroplasts, like other types of plastid, contain a genome separate from that in the cell nuc ...
places it in sect. ''Aigeiros''
** ''Populus trichocarpa
''Populus trichocarpa'', the black cottonwood, western balsam-poplar or California poplar, is a deciduous broadleaf tree species native to western North America. It is used for timber, and is notable as a model organism in plant biology.
Desc ...
'' – western balsam poplar or black cottonwood (western North America)
** ''Populus tristis
''Populus'' is a genus of 25–30 species of deciduous flowering plants in the family Salicaceae, native to most of the Northern Hemisphere. English names variously applied to different species include poplar (), aspen, and cottonwood.
The we ...
'' (northeast Asia), placed here by nuclear DNA; cpDNA
Chloroplast DNA (cpDNA) is the DNA located in chloroplasts, which are photosynthetic organelles located within the cells of some eukaryotic organisms. Chloroplasts, like other types of plastid, contain a genome separate from that in the cell nuc ...
places it in sect. ''Aigeiros''
** '' Populus ussuriensis'' – Ussuri poplar (northeast Asia)
** ''Populus yunnanensis
''Populus yunnanensis'', the Yunnan poplar, is a species of flowering plant in the family Salicaceae, native to south-central China. It has found use as a street tree, particularly in Australia.
Subtaxa
The following varieties are accepted:
*''P ...
'' – Yunnan poplar (east Asia)
* ''Populus'' section ''Leucoides'' – necklace poplars or bigleaf poplars (eastern North America, eastern Asia; warm temperate)
** ''Populus heterophylla
''Populus heterophylla'', also known as downy poplar, swamp poplar and swamp cottonwood, is a large deciduous poplar belonging to the ''Populus'' genus of the family ''Salicaceae''. This species can grow on sites that have too much water for oth ...
'' – downy poplar (southeastern North America)
** ''Populus lasiocarpa
''Populus lasiocarpa'', commonly called the Chinese necklace poplar, is a species of poplar native to humid forests of China. It is closely related to ''Populus wilsonii'', Wilson's poplar.
Description
''Populus lasiocarpa'' is known for its la ...
'' – Chinese necklace poplar (eastern Asia)
** ''Populus wilsonii
''Populus wilsonii'' (Wilson's poplar) is a species of deciduous poplar tree found in China's Gansu, Hubei, Shaanxi, Sichuan, Xizang and Yunnan provinces. The tree has elliptical leaves wider at the base than at the tip, and can grow to up to ...
'' – Wilson's poplar (eastern Asia)
* ''Populus'' section ''Turanga'' – subtropical poplars (southwest Asia, east Africa; subtropical to tropical)
** ''Populus euphratica
''Populus euphratica'', commonly known as the Euphrates poplar, desert poplar, diversiform-leaved poplar, or poplar diversifolia, is a species of poplar tree in the willow family.
Description
The Euphrates poplar is a medium-sized deciduous ...
'' – Euphrates poplar (North Africa, southwest and central Asia)
** ''Populus ilicifolia
''Populus ilicifolia'' (Tana River poplar) is a species of poplar in the family Salicaceae. It is found in Kenya and Tanzania from 1°N to 3°S latitude, 37°E to 41°E latitude, at altitudes of 10–1,200 m; it is the southernmost member of its ...
'' – Tana River poplar (East Africa)
* ''Populus'' section ''Abaso'' – Mexican poplars (Mexico; subtropical to tropical)
** ''Populus guzmanantlensis
''Populus guzmanantlensis'' is a species of plant in the family Salicaceae. It is endemic to Mexico. This species is native to the Sierra de Manantlán
Sierra (Spanish for "mountain range" and " saw", from Latin '' serra'') may refer to the fol ...
'' (Mexico)
** ''Populus mexicana
''Populus'' is a genus of 25–30 species of deciduous flowering plants in the family Salicaceae, native to most of the Northern Hemisphere. English names variously applied to different species include poplar (), aspen, and cottonwood.
The we ...
'' – Mexico poplar (Mexico)
* Intersectional hybrids
** ''Populus × acuminata
''Populus'' × ''acuminata'' or ''Populus acuminata'', the lanceleaf cottonwood, is a species of '' Populus'' native to the Rocky Mountains of North America. It is a naturally occurring hybrid of narrowleaf cottonwood, '' Populus angustifolia'', ...
'' (''P. angustifolia × P. deltoides'') – lanceleaf cottonwood
** ''Populus'' Pacific Albus (North America)
Ecology
Poplars of the cottonwood section are often wetlands or riparian
A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the terrestrial biomes of the Earth. Plant habitats and communities along the river margins and banks ar ...
trees. The aspens are among the most important boreal
Boreal may refer to:
Climatology and geography
*Boreal (age), the first climatic phase of the Blytt-Sernander sequence of northern Europe, during the Holocene epoch
*Boreal climate, a climate characterized by long winters and short, cool to mild ...
broadleaf trees.
Poplars and aspens are important food plants
A crop is a plant that can be grown and harvested extensively for profit or subsistence. When the plants of the same kind are cultivated at one place on a large scale, it is called a crop. Most crops are cultivated in agriculture or hydroponics ...
for the larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
The ...
e of a large number of Lepidoptera
Lepidoptera ( ) is an order (biology), order of insects that includes butterfly, butterflies and moths (both are called lepidopterans). About 180,000 species of the Lepidoptera are described, in 126 Family (biology), families and 46 Taxonomic r ...
species. ''Pleurotus populinus
''Pleurotus populinus'', the aspen oyster mushroom, is a Agaricales, gilled fungi, fungus native to North America. It is found on Wood-decay fungus, dead wood of aspen and cottonwood trees (genus ''Populus''). Although Morphology (biology), morp ...
'', the aspen oyster mushroom, is found exclusively on dead wood of ''Populus'' trees in North America.
Several species of ''Populus'' in the United Kingdom and other parts of Europe have experienced heavy dieback
Dieback may refer to a number of plant problems and diseases including:
* Forest dieback caused by acid rain, heavy metal pollution, or imported pathogens
* The death of regions of a plant or similar organism caused by physical damage, such as from ...
; this is thought in part to be due to '' Sesia apiformis'' which bores into the trunk of the tree during its larval stage.
Cultivation
Many poplars are grown as ornamental tree
Ornamental plants or garden plants are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars that i ...
s, with numerous cultivar
A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture, ...
s used. They have the advantage of growing to a very large size at a rapid pace. Almost all poplars take root readily from cuttings or where broken branches lie on the ground (they also often have remarkable suckering abilities, and can form huge colonies from a single original tree, such as the famous '' Pando'' forest made of thousands of ''Populus tremuloides
''Populus tremuloides'' is a deciduous tree native to cooler areas of North America, one of several species referred to by the common name aspen. It is commonly called quaking aspen, trembling aspen, American aspen, mountain or golden aspen, tr ...
'' clones).
Trees with fastigiate (erect, columnar) branching are particularly popular, and are widely grown across Europe and southwest Asia. However, like willow
Willows, also called sallows and osiers, from the genus ''Salix'', comprise around 400 speciesMabberley, D.J. 1997. The Plant Book, Cambridge University Press #2: Cambridge. of typically deciduous trees and shrubs, found primarily on moist s ...
s, poplars have very vigorous and invasive root systems stretching up to from the trees; planting close to houses or ceramic water pipes may result in damaged foundations and cracked walls and pipes due to their search for moisture.
A simple, reproducible, high-frequency micropropagation protocol in eastern cottonwood ''Populus deltoides'' has been reported by Yadav et al. 2009.
India
In India, the poplar is grown commercially by farmers, mainly in the Punjab
Punjab (; Punjabi: پنجاب ; ਪੰਜਾਬ ; ; also romanised as ''Panjāb'' or ''Panj-Āb'') is a geopolitical, cultural, and historical region in South Asia, specifically in the northern part of the Indian subcontinent, comprising ...
region. Common poplar varieties are:
* G48 (grown in the plains of Punjab, Haryana, UP)
* w22 (grown in mountainous regions, e.g., Himachal Pradesh, Pathankot, Jammu)
The trees are grown from ''kalam'' or cuttings, harvested annually in January and February, and commercially available up to 15November.
Most commonly used to make plywood
Plywood is a material manufactured from thin layers or "plies" of wood veneer that are glued together with adjacent layers having their wood grain rotated up to 90 degrees to one another. It is an engineered wood from the family of manufactured ...
, Yamuna Nagar
Yamunanagar (), is a city and a municipal corporation in Yamunanagar district in the Indian state of Haryana. This town is known for the cluster of plywood units and paper industries. It provides timber to larger industries. The older town is ...
in Haryana
Haryana (; ) is an Indian state located in the northern part of the country. It was carved out of the former state of East Punjab on 1 Nov 1966 on a linguistic basis. It is ranked 21st in terms of area, with less than 1.4% () of India's land ar ...
state has a large plywood industry reliant upon poplar. It is graded according to sizes known as "over" (over ), "under" (), and "sokta" (less than ).
Uses
Although the wood from ''Populus'' is known as poplar wood, a common high-quality hardwood "poplar" with a greenish colour is actually from an unrelated genus ''Liriodendron
''Liriodendron'' () is a genus of two species of characteristically large trees, deciduous over most of their populations, in the magnolia family (Magnoliaceae).
These trees are widely known by the common name tulip tree or tuliptree for their ...
''. ''Populus'' wood is a lighter, more porous material.
Its flexibility and close grain make it suitable for a number of applications, similar to those of willow. The Greeks and Etruscans made shields of poplar, and Pliny the Elder
Gaius Plinius Secundus (AD 23/2479), called Pliny the Elder (), was a Roman author, naturalist and natural philosopher, and naval and army commander of the early Roman Empire, and a friend of the emperor Vespasian. He wrote the encyclopedic '' ...
also recommended poplar for this purpose. Poplar continued to be used for shield construction through the Middle Ages and was renowned for a durability similar to that of oak, but with a substantial reduction in weight.
Food
In addition to the foliage and other parts of ''Populus'' species being consumed by animals, the starchy sap layer (underneath the outer bark) is edible to humans, both raw and cooked.
Manufacturing
* In many areas, fast-growing hybrid
Hybrid may refer to:
Science
* Hybrid (biology), an offspring resulting from cross-breeding
** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species
** Hybridity, the property of a hybrid plant which is a union of two dif ...
poplars are grown on plantation
A plantation is an agricultural estate, generally centered on a plantation house, meant for farming that specializes in cash crops, usually mainly planted with a single crop, with perhaps ancillary areas for vegetables for eating and so on. The ...
s for pulpwood
Pulpwood is timber with the principal use of making wood pulp for paper production.
Applications
* Trees raised specifically for pulp production account for 15% of world pulp production, old growth forests 9% and second- and third- and more gener ...
* Poplar is widely used for the manufacture of paper
Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, rags, grasses or other vegetable sources in water, draining the water through fine mesh leaving the fibre evenly distributed ...
.
* It is also sold as inexpensive hardwood timber
Lumber is wood that has been processed into dimensional lumber, including beams and planks or boards, a stage in the process of wood production. Lumber is mainly used for construction framing, as well as finishing (floors, wall panels, wi ...
, used for pallet
A pallet (also called a skid) is a flat transport structure, which supports goods in a stable fashion while being lifted by a forklift, a pallet jack, a front loader, a jacking device, or an erect crane. A pallet is the structural foundat ...
s and cheap plywood
Plywood is a material manufactured from thin layers or "plies" of wood veneer that are glued together with adjacent layers having their wood grain rotated up to 90 degrees to one another. It is an engineered wood from the family of manufactured ...
; more specialised uses including matches and match
A match is a tool for starting a fire. Typically, matches are made of small wooden sticks or stiff paper. One end is coated with a material that can be ignited by friction generated by striking the match against a suitable surface. Wooden matc ...
boxes and the boxes for Camembert cheese
Camembert (, also , ) is a moist, soft, creamy, surface-ripened cow's milk cheese. It was first made in the late 18th century in Camembert, Normandy, in northwest France. It is sometimes compared in look and taste to brie cheese, albeit with ...
.
* Poplar wood is also widely used in the snowboard
Snowboards are boards where the user places both feet, usually secured, to the same board. The board itself is wider than most skis, with the ability to glide on snow."snowboarding." Dictionary.com Unabridged (v 1.1). Random House, Inc. 17 Mar ...
industry for the snowboard core, because it has exceptional flexibility, and is sometimes used in the bodies of electric guitar
An electric guitar is a guitar that requires external amplification in order to be heard at typical performance volumes, unlike a standard acoustic guitar (however combinations of the two - a semi-acoustic guitar and an electric acoustic gui ...
s and drum
The drum is a member of the percussion group of musical instruments. In the Hornbostel-Sachs classification system, it is a membranophone. Drums consist of at least one membrane, called a drumhead or drum skin, that is stretched over a she ...
s.
* Poplar wood, particularly when seasoned, makes a good hearth for a bow drill
A bow drill is a simple hand-operated type of tool, consisting of a rod (the ''spindle'' or ''drill shaft'') that is set in rapid rotary motion by means of a cord wrapped around it, kept taut by a bow which is pushed back and forth with one han ...
.
* Due to its high tannic acid
Tannic acid is a specific form of tannin, a type of polyphenol. Its weak acidity ( pKa around 6) is due to the numerous phenol groups in the structure. The chemical formula for commercial tannic acid is often given as C76H52O46, which correspon ...
content, the bark has been used in Europe for tanning leather.[
* Poplar wood can be used to produce ]chopsticks
Chopsticks ( or ; Pinyin: ''kuaizi'' or ''zhu'') are shaped pairs of equal-length sticks of China, Chinese origin that have been used as Kitchen utensil, kitchen and List of eating utensils, eating utensils in most of East Asia, East and Southe ...
or wooden shoes
Clogs are a type of footwear made in part or completely from wood. Used in many parts of the world, their forms can vary by culture, but often remained unchanged for centuries within a culture.
Traditional clogs remain in use as protective fo ...
.
* Baking moulds from peeled poplar may be used in the freezer, oven, or microwave oven.
In Pakistan, poplar is grown on a commercial level by farmers in Punjab, Sindh, and Khyber Pakhtunkhwa Provinces. However, all varieties are seriously susceptible to termite attack, causing significant losses to poplar every year. Logs of poplar are therefore also used as bait in termite traps for biocontrol of termites in crops.
Energy
Interest exists in using poplar as an energy crop
Energy crops are low-cost and low-maintenance crops grown solely for energy production by combustion (not for food). The crops are processed into solid, liquid or gaseous fuels, such as pellets, bioethanol or biogas. The fuels are burned to g ...
for biomass
Biomass is plant-based material used as a fuel for heat or electricity production. It can be in the form of wood, wood residues, energy crops, agricultural residues, and waste from industry, farms, and households. Some people use the terms bi ...
, in energy forestry
Energy forestry is a form of forestry in which a fast-growing species of tree or woody shrub is grown specifically to provide biomass or biofuel for heating or power generation.
The two forms of energy forestry are short rotation coppice and short ...
systems, particularly in light of its high energy-in to energy-out ratio, large carbon mitigation potential, and fast growth.
In the United Kingdom, poplar (as with fellow energy crop willow) is typically grown in a short rotation coppice
Short rotation coppice (SRC) is coppice grown as an energy crop. This woody solid biomass can be used in applications such as district heating, electric power generating stations, alone or in combination with other fuels. Currently, the leading ...
system for two to five years (with single or multiple stems), then harvested and burned - the yield of some varieties can be as high as 12 oven-dry tonnes per hectare every year.
In warmer regions like Italy this crop can produce up to 13.8, 16.4 oven-dry tonnes of biomass per hectare every year for biannual and triennial cutting cycles also showing a positive energy balance and a high energy efficiency.
Fuel
Biofuel
Biofuel is a fuel that is produced over a short time span from biomass, rather than by the very slow natural processes involved in the formation of fossil fuels, such as oil. According to the United States Energy Information Administration (E ...
is another option for using poplar as bioenergy supply. In the United States, scientists studied converting short rotation coppice
Short rotation coppice (SRC) is coppice grown as an energy crop. This woody solid biomass can be used in applications such as district heating, electric power generating stations, alone or in combination with other fuels. Currently, the leading ...
poplar into sugars for biofuel (e.g. ethanol) production.
Considering the relative cheap price, the process of making biofuel from SRC can be economically feasible, although the conversion yield from short rotation coppice (as juvenile crops) were lower than regular mature wood. Besides biochemical conversion, thermochemical conversion (e.g. fast pyrolysis) was also studied for making biofuel from short rotation coppice poplar and was found to have higher energy recovery
Energy recovery includes any technique or method of minimizing the input of energy to an overall system by the exchange of energy from one sub-system of the overall system with another. The energy can be in any form in either subsystem, but mos ...
than that from bioconversion.
Art
Poplar was the most common wood used in Italy for panel painting
A panel painting is a painting made on a flat panel of wood, either a single piece or a number of pieces joined together. Until canvas became the more popular support medium in the 16th century, panel painting was the normal method, when not paint ...
s; the ''Mona Lisa
The ''Mona Lisa'' ( ; it, Gioconda or ; french: Joconde ) is a half-length portrait painting by Italian artist Leonardo da Vinci. Considered an archetypal masterpiece of the Italian Renaissance, it has been described as "the best known ...
'' and most famous early Italian Renaissance
The Italian Renaissance ( it, Rinascimento ) was a period in Italian history covering the 15th and 16th centuries. The period is known for the initial development of the broader Renaissance culture that spread across Europe and marked the trans ...
paintings are on poplar. The wood is generally white, often with a slightly yellowish colour.
Some stringed instrument
String instruments, stringed instruments, or chordophones are musical instruments that produce sound from vibrating strings when a performer plays or sounds the strings in some manner.
Musicians play some string instruments by plucking the st ...
s are made with one-piece poplar backs; viola
The viola ( , also , ) is a string instrument that is bow (music), bowed, plucked, or played with varying techniques. Slightly larger than a violin, it has a lower and deeper sound. Since the 18th century, it has been the middle or alto voice of ...
s made in this fashion are said to have a particularly resonant tone. Similarly, though typically it is considered to have a less attractive grain than the traditional sitka spruce
''Picea sitchensis'', the Sitka spruce, is a large, coniferous, evergreen tree growing to almost tall, with a trunk diameter at breast height that can exceed 5 m (16 ft). It is by far the largest species of spruce and the fifth-larg ...
, poplar is beginning to be targeted by some harp
The harp is a stringed musical instrument that has a number of individual strings running at an angle to its soundboard; the strings are plucked with the fingers. Harps can be made and played in various ways, standing or sitting, and in orche ...
luthier
A luthier ( ; AmE also ) is a craftsperson who builds or repairs string instruments that have a neck and a sound box. The word "luthier" is originally French and comes from the French word for lute. The term was originally used for makers o ...
s as a sustainable and even superior alternative for their sound boards: in these cases another hardwood veneer is sometimes applied to the resonant poplar base both for cosmetic reasons, and supposedly to fine-tune the acoustic properties.
Land management
Lombardy poplar
''Populus nigra'', the black poplar, is a species of cottonwood poplar, the type species of section ''Aigeiros'' of the genus ''Populus'', native to Europe, southwest and central Asia, and northwest Africa.Flora Europaea''Populus nigra''/ref>
...
s are frequently used as a windbreak
A windbreak (shelterbelt) is a planting usually made up of one or more rows of trees or shrubs planted in such a manner as to provide shelter from the wind and to protect soil from erosion. They are commonly planted in hedgerows around the edges ...
around agricultural fields to protect against wind erosion.
Agriculture
Logs from the poplar provide a growing medium for shiitake
The shiitake (alternate form shitake) (; ''Lentinula edodes'') is an edible mushroom native to East Asia, which is now cultivated and consumed around the globe. It is considered a Medicinal fungi, medicinal mushroom in some forms of tradition ...
mushrooms.
Phytoremediation
Poplar represents a suitable candidate for phytoremediation
Phytoremediation technologies use living plants to clean up soil, air and water contaminated with hazardous contaminants. It is defined as "the use of green plants and the associated microorganisms, along with proper soil amendments and agronomi ...
. This plant has been successfully used to target many types of pollutants including trace element
__NOTOC__
A trace element, also called minor element, is a chemical element whose concentration (or other measure of amount) is very low (a "trace amount"). They are classified into two groups: essential and non-essential. Essential trace elements ...
(TEs) in soil and sewage sludge
Sewage sludge is the residual, semi-solid material that is produced as a by-product during sewage treatment of industrial or municipal wastewater. The term "septage" also refers to sludge from simple wastewater treatment but is connected to si ...
, Polychlorinated Biphenyl
Polychlorinated biphenyls (PCBs) are highly carcinogenic chemical compounds, formerly used in industrial and consumer products, whose production was banned in the United States by the Toxic Substances Control Act in 1979 and internationally by t ...
(PCBs), Trichloroethylene
The chemical compound trichloroethylene is a halocarbon commonly used as an industrial solvent. It is a clear, colourless non-flammable liquid with a chloroform-like sweet smell. It should not be confused with the similar 1,1,1-trichloroethane, ...
(TCE), Polycyclic Aromatic Hydrocarbon
A polycyclic aromatic hydrocarbon (PAH) is a class of organic compounds that is composed of multiple aromatic rings. The simplest representative is naphthalene, having two aromatic rings and the three-ring compounds anthracene and phenanthrene. ...
(PAHs).
Culture
Two notable poems in English lament the cutting down of poplars, William Cowper
William Cowper ( ; 26 November 1731 – 25 April 1800) was an English poet and Anglican hymnwriter. One of the most popular poets of his time, Cowper changed the direction of 18th-century nature poetry by writing of everyday life and scen ...
's "The Poplar Field" and Gerard Manley Hopkins
Gerard Manley Hopkins (28 July 1844 – 8 June 1889) was an English poet and Jesuit priest, whose posthumous fame placed him among leading Victorian poets. His prosody – notably his concept of sprung rhythm – established him as an innovato ...
' "Binsey Poplars
"Binsey Poplars" is a poem by Gerard Manley Hopkins (1844–1889), written in 1879. The poem was inspired by the felling of a row of poplar trees near the village of Binsey, northwest of Oxford, England, and overlooking Port Meadow on the ban ...
felled 1879".
In Billie Holiday
Billie Holiday (born Eleanora Fagan; April 7, 1915 – July 17, 1959) was an American jazz and swing music singer. Nicknamed "Lady Day" by her friend and music partner, Lester Young, Holiday had an innovative influence on jazz music and pop si ...
's "Strange Fruit
"Strange Fruit" is a song written and composed by Abel Meeropol (under his pseudonym Lewis Allan) and recorded by Billie Holiday in 1939. The lyrics were drawn from a poem by Meeropol published in 1937. The song protests the lynching of Black ...
", she sings "Black bodies swinging in the southern breeze/Strange fruit hanging from the poplar trees…".
The Odd Poplars Alley, in Iași
Iași ( , , ; also known by other alternative names), also referred to mostly historically as Jassy ( , ), is the second largest city in Romania and the seat of Iași County. Located in the historical region of Moldavia, it has traditionally ...
, Romania, is one of the spots where Mihai Eminescu
Mihai Eminescu (; born Mihail Eminovici; 15 January 1850 – 15 June 1889) was a Romanian Romantic poet from Moldavia, novelist, and journalist, generally regarded as the most famous and influential Romanian poet. Eminescu was an active membe ...
sought inspiration in his works (the poem "Down Where the Lonely Poplars Grow"). In 1973, the 15 white poplars still left (with age ranges between 233 and 371 years) were declared natural monuments.
References
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Dioecious plants
Salicaceae genera
Taxa named by Carl Linnaeus