poplar

Populus

Foliage of Populus tremula

Scientific classification

Kingdom: Plantae

(unranked): Angiosperms

(unranked): Eudicots

(unranked): Rosids

Order: Malpighiales

Family: Salicaceae

Tribe: Saliceae[1]

Genus: Populus

L.

Type species

Populus tremula

Species

See text

Male catkins of Populus

canadensis

A group of four poplars on a hill

through the seasons, April,

September, October, February

(Germany).

PopulusFrom Wikipedia, the free encyclopedia

(Redirected from Poplar)

Populus is a genus of 2535 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 (/pp.lr/), aspen, and cottonwood.In the September 2006 issue of Science, it was announced that the Western Balsam Poplar (P. trichocarpa) was the first tree to

have its full DNA code sequenced.[2]

Contents

1 Description

2 Ecology

3 Classification

3.1 Selected species

4 Cultivation

4.1 The Poplar in India

5 Uses

5.1 Manufacturing

5.2 Energy

5.3 Art

5.4 Land management

5.5 Agriculture

6 References

Description

The genus has a large genetic diversity, and can grow from anywhere between 1550 m (50 to 165 ft) tall, with trunks of up to

2.5 m (8 ft) diameter.

The bark on young trees is smooth, white to greenish or dark grey, often with conspicuous

lenticels; 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 willows) the terminal

bud present. The leaves 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.[3][4]

The flowers are mostly dioecious (rarely monoecious) and appear in early spring before the leaves. They are borne in long,

drooping, sessile or pedunculate catkins produced from buds formed in the axils of the leaves of 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, usually caducous. The male flowers are without calyx or

corolla, and comprise a group of 460 stamens inserted on a disk; filaments short, pale yellow; anthers oblong, purple or red,

introrse, two-celled; cells opening 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 24 stigmas, variously lobed, and numerous ovules. Pollination is by

wind, with the female catkins lengthening considerably between pollination and maturity. The fruit is a two to four-valved

dehiscent capsule, green to reddish-brown, mature in mid summer, containing numerous minute light brown seeds surrounded by

tufts of long, soft, white hairs which aid wind dispersal.[3][5]

Ecology

Poplars of the cottonwood section are often wetlands or riparian trees. The aspens are among the most important boreal broadleaf trees.[3]

Poplars and aspens are important food plants for the larvae of a large number of Lepidoptera species - see List of Lepidoptera that feed on poplars. Pleurotus populinus, the aspen oyster mushroom, is found exclusively on dead wood of Populus trees in North America.

Classification

The genus Populus has traditionally been divided into six sections on the basis of leaf and flower characters;[4][6] 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 (paternally inherited) and chloroplast DNA sequences (maternally

inherited), a clear indication of likely hybrid origin.[7] Hybridisation continues to be common in the genus, with several hybrids

between species in different sections known.[3][8]

Selected species

Populus section Populus aspens and White Poplar. Circumpolar subarctic and cool temperate, and mountains farther

south (White Poplar warm temperate)

Populus tremula Common Aspen, Trembling Aspen or Eurasian Aspen (Europe, northern Asia)

Populus adenopoda Chinese Aspen (Eastern Asia)

Populus alba White Poplar (Southern Europe to central Asia)

Populus canescens (P. alba P. tremula) Grey Poplar

Populus spp. X Pacific Albus (North America)

Populus davidiana Korean Aspen (Eastern Asia)

Populus grandidentata Bigtooth Aspen (Eastern North America)

Populus sieboldii Japanese Aspen (Eastern Asia)

Populus tremuloides Quaking Aspen or Trembling Aspen (North America)

Page 1 of 3Populus - Wikipedia, the free encyclopedia

02-Apr-12http://en.wikipedia.org/wiki/Poplar

Populus nigra in autumn

Leaves of Populus lasiocarpa

A fastigiate Black Poplar cultivar of

the Plantierensis Group, in Hungary.

Poplars dominate the flora of Khorog

City Park, GBAO, Tajikistan

Popular-G48 in Punjab, India; Jhalli

Farms Village Niara/Hoshiarpur (20-

March-2011)

Populus section Aigeiros black poplars, some of the cottonwoods. North America, Europe, western Asia; temperate

Populus deltoides Eastern Cottonwood (Eastern North America)

Populus fremontii Fremont Cottonwood (Western North America)

Populus nigra Black Poplar (Europe) Placed here by nuclear DNA; cpDNA places in sect. Populus. (Including

Populus afghanica.)

Populus canadensis (P. nigra P. deltoides) Hybrid Black Poplar

Populus inopina (P. nigra P. fremontii) Hybrid Black Poplar

Populus sect. Tacamahaca balsam poplars. North America, Asia; cool temperate

Populus angustifolia Willow-leaved Poplar or Narrowleaf Cottonwood (Central North America)

Populus balsamifera Ontario Balsam Poplar (Northern North America) (= P. candicans, P. tacamahaca)

Populus cathayana (Northeast Asia)

Populus koreana J.Rehnder Korean Poplar (Northeast Asia)

Populus laurifolia Laurel-leaf Poplar (Central Asia)

Populus maximowiczii A.Henry Maximowicz' Poplar, Japanese Poplar (Northeast Asia)

Populus simonii Simon's Poplar (Northeast Asia)

Populus suaveolens Fischer Mongolian Poplar (Northeast Asia) Populus szechuanica Sichuan Poplar (Northeast Asia) Placed here by nuclear DNA; cpDNA places in sect.

Aigeiros.

Populus trichocarpa Western Balsam Poplar or Black Cottonwood (Western North America)

Populus tristis (Northeast Asia) Placed here by nuclear DNA; cpDNA places in sect. Aigeiros.

Populus ussuriensis Ussuri Poplar (Northeast Asia)

Populus yunnanensis Yunnan Poplar (East Asia)

Populus section Leucoides necklace poplars or bigleaf poplars. Eastern North America, eastern Asia; warm temperate

Populus heterophylla Swamp Cottonwood (Southeastern North America.

Populus lasiocarpa Chinese Necklace Poplar (Eastern Asia)

Populus wilsonii Wilson's Poplar (Eastern Asia)

Populus section Turanga subtropical poplars. Southwest Asia, east Africa; subtropical to tropical

Populus euphratica Euphrates Poplar (Southwest Asia)

Populus ilicifolia Tana River Poplar (East Africa)

Populus section Abaso Mexican poplars. Mexico; subtropical to tropical

Populus guzmanantlensis (Mexico)

Populus mexicana Mexico Poplar (Mexico)

Cultivation

Many poplars are grown as ornamental trees, with numerous cultivars used. They have the advantage of growing very big, very

fast. Almost all poplars take root readily from cuttings or where broken branches lie on the ground.

Trees with fastigiate (erect, columnar) branching are particularly popular, and are widely grown across Europe and southwest

Asia. However, like willows, poplars have very vigorous and invasive root systems stretching up to 40 m 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 [3] (http://www.springerlink.com/content/553472252334p7kq/fulltext.pdf)

The Poplar in India

In India, the poplar is grown commercially by farmers, mainly in the Punjab region. Popular poplar varieties are as follows:

1. G48 (grown in the plains of Punjab, Haryana, UP)

2. w22 (grown in mountainous regions, i.e. Himachal Pradesh, Pathankot, Jammu)

The poplar is grown from "kalam" (cuttings), harvested annually in January and February, and is commercially available up to 15

November.

This most common use of poplar is in plywood. Yamuna Nagar in state of Haryana has a large plywood industry reliant upon

poplar. It is graded according in sizes known as "over" (over 24 inches in girth), "under" (18-24 inches), and "sokta" (less than

18 inches).

Punjab Agriculture University in Ludhiana has published a package of practices for

poplar cultivation.

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. Populus wood is a lighter, more porous material.

In modern society poplar is not readily associated with many uses beyond biomass. This

poor reputation is undeserved, as its flexibility and close grain give it a balance of

properties that have made it highly desirable for a number of applications (similar to

those for willow) since antiquity. Notably the Greeks and Etruscans made shields of

poplar, and Pliny also recommended poplar for this purpose.[9] Poplar continued to be used for shield construction through the

middle ages and was renowned for a durability similar to that of oak, but at a substantial reduction in weight.

Manufacturing

In many areas, fast-growing hybrid poplars are grown on plantations for pulpwood

Poplar is widely used for the manufacture of paper.[10]

It is also sold as inexpensive hardwood timber, used for pallets and cheap plywood; more specialised uses include matches and

the boxes in which camembert cheese is sold.

Poplar wood is also widely used in the snowboard industry for the snowboard core, because it has exceptional flexibility, and is

sometimes used in the bodies of electric guitars and drums.



Traditional Pamiri House

Poplar wood, particularly when seasoned, makes a good hearth for a bow drill.

Due to its high tannic acid content, the bark has been used in Europe for tanning leather.[5]

Poplar wood can be used to produce chopsticks.

Energy

There is interest in using poplar as an energy crop for biomass or biofuel, in energy forestry systems, particularly in light of its

high energy-in / 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 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 every year[11]

Art

Poplar was the most common wood used in Italy for panel paintings; the Mona Lisa and indeed most famous early renaissance Italian paintings are on poplar. The wood

is generally white, often with a slightly yellowish color.

Some stringed instruments are made with one-piece poplar backs; violas 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, poplar is beginning to be targeted by some harp luthiers as a sustainable and even superior

alternative for their soundboards:[12] 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 Poplars are used as a windbreak around agricultural fields to protect against wind erosion.

Agriculture

Logs from the poplar provide a growing medium for Shiitake mushrooms.[13]

References

1. ^ "Genus Populus (poplars)" (http://www.uniprot.org/taxonomy/3689) . Taxonomy. UniProt. http://www.uniprot.org/taxonomy/3689. Retrieved 2010-02-04.

2. ^ Joint Genome Institute: Populus trichocarpa (http://genome.jgi-psf.org/Poptr1_1/Poptr1_1.home.html)

3. ^ a b c d Meikle, R. D. (1984). Willows and Poplars of Great Britain and Ireland. BSBI Handbook No. 4. ISBN 0-901158-07-0.

4. ^ a b Rushforth, K. (1999). Trees of Britain and Europe. Collins ISBN 0-00-220013-9.

5. ^ a b Keeler, H. L. (1900). Our Native Trees and How to Identify Them. New York: Charles Scriber's Sons. pp. 410412.

6. ^ Eckenwalder, J.E. (1996). "Systematics and evolution of Populus" (http://books.google.com.mx/books?

id=HvuTJC32C3YC&pg=PR1&source=gbs_selected_pages&cad=3#v=onepage&q&f=false) . In R.F. Stettler; H.D. Bradshaw; P.E. Heilman; T.M. Hinckley. Biology of Populus

and its implications for management and conservation. Ottawa: NRC Research Press, National Research Council of Canada. http://books.google.com.mx/books?

id=HvuTJC32C3YC&pg=PR1&source=gbs_selected_pages&cad=3#v=onepage&q&f=false.

7. ^ 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. Available online (http://www.amjbot.org/cgi/content/full/91/9/1398)

8. ^ Eckenwalder, J.E. (2001). "Key to species and main crosses". In D.I. Dickmann; J.G. Isebrands; J.E. Eckenwalder; J. Richardson. Poplar culture in North America. Ottawa: NRC

Research Press. pp. 325330. ISBN 978-0-660-18145-5.

9. ^ [1] (http://books.google.co.uk/books?

id=6LUcuGdJF30C&pg=PA69&lpg=PA69&dq=greek+shield+poplar&source=bl&ots=QwHVY5pBbo&sig=mHrOh_hjrGxAvuc9M3eLoDvvVys&hl=en&ei=G4oNTvLBDoK0-

Qa02bXqDQ&sa=X&oi=book_result&ct=result&resnum=6&ved=0CDAQ6AEwBQ#v=onepage&q=greek%20shield%20poplar&f=false) The Cambridge Companion to Archaic

Greece, p.69.

10. ^ Poplar cultivation in Europe (http://www.peupliersdefrance.org/indexGB.htm/)

11. ^ Aylott, Matthew J.; Casella, E; Tubby, I; Street, NR; Smith, P; Taylor, G (2008). "Yield and spatial supply of bioenergy poplar and willow short-rotation coppice in the

UK" (http://www3.interscience.wiley.com/journal/119394739/abstract) (PDF). New Phytologist 178 (2 fvhc): 358370. doi:10.1111/j.1469-8137.2008.02396.x

(http://dx.doi.org/10.1111%2Fj.1469-8137.2008.02396.x) . PMID 18331429 (http://www.ncbi.nlm.nih.gov/pubmed/18331429) .

http://www3.interscience.wiley.com/journal/119394739/abstract. Retrieved 2008-10-22.

12. ^ [2] (http://traditionalharps.com/Old_Rees_Harps_Site/HarpsGeneralTonewoods.html) Rees Harps Website, "Harp Myth #8".

13. ^ Shiitake growth studies performed by RMIT (http://www.mtg.unimelb.edu.au/Shiitake.htm)

Retrieved from "http://en.wikipedia.org/w/index.php?title=Populus&oldid=484379371"

Categories: Populus Plants with dehiscent fruit Dioecious plants

This page was last modified on 28 March 2012 at 14:34.

Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. See Terms of use for details.

Wikipedia is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.



poplar

Documents