Editing Elm (section)

==Cultivation==
[[File:Camperdown Elm Prospect Park Brooklyn.jpg|thumb|right|Camperdown elm ([[Ulmus glabra 'Camperdownii'|''Ulmus glabra'' 'Camperdownii']]), cultivated in Prospect Park, [[Brooklyn, New York]]]]
[[File:English Elm avenue.jpg|thumb|right|An avenue of elm trees in [[Fitzroy Gardens]], [[Melbourne]]]]
{{See also|List of elm cultivars, hybrids and hybrid cultivars}}

One of the earliest of ornamental elms was the ball-headed graft [[Ulmus minor 'Umbraculifera'|narvan elm, ''Ulmus minor'' 'Umbraculifera']], cultivated from time immemorial in [[Iran|Persia]] as a shade tree and widely planted in cities through much of south-west and central Asia. From the 18th century to the early 20th century, elms, whether species, hybrids, or [[cultivars]], were among the most widely planted ornamental trees in both Europe and North America. They were particularly popular as a street tree in [[Avenue (landscape)|avenue]] plantings in towns and cities, creating high-tunnelled effects. Their quick growth and variety of foliage and forms,<ref name=Elwes>Elwes, H. J. & Henry, A. (1913). ''[http://fax.libs.uga.edu/QK488xE4/1f/trees_of_britain_and_ireland_vol_7.pdf The Trees of Great Britain & Ireland] {{webarchive|url=https://web.archive.org/web/20160303174627/http://fax.libs.uga.edu/QK488xE4/1f/trees_of_britain_and_ireland_vol_7.pdf |date=3 March 2016 }}''. Vol. VII. 1848–1929. Republished 2004 Cambridge University Press, {{ISBN|9781108069380}}</ref> their tolerance of air-pollution, and the comparatively rapid decomposition of their [[leaf litter]] in the fall were further advantages.

In North America, the species most commonly planted was the American elm (''U. americana''), which had unique properties that made it ideal for such use - rapid growth, adaptation to a broad range of [[climate]]s and soils, strong wood, resistance to wind damage, and vase-like growth habit requiring minimal [[pruning]]. In Europe, the [[Ulmus glabra|wych elm (''U. glabra'')]] and the [[Ulmus minor|field elm (''U. minor'')]] were the most widely planted in the countryside, the former in northern areas including Scandinavia and northern [[Great Britain|Britain]], the latter further south. The hybrid between these two, [[Ulmus × hollandica|Dutch elm (''U. × hollandica'')]], occurs naturally and was also commonly planted. In much of England, the [[Ulmus minor 'Atinia'|English elm]] later came to dominate the horticultural landscape. Most commonly planted in hedgerows, it sometimes occurred in densities over 1000/km<sup>2</sup>. In south-eastern [[Elms in Australia|Australia]] and New Zealand, large numbers of English and Dutch elms, as well as other species and cultivars, were planted as ornamentals following their introduction in the 19th century, while in northern Japan [[Ulmus davidiana var. japonica|Japanese elm (''U. davidiana'' var. ''japonica'')]] was widely planted as a street tree. From about 1850 to 1920, the most prized small ornamental elm in parks and gardens was the [[Ulmus glabra|'Camperdown' elm (''U. glabra'' 'Camperdownii')]], a contorted, weeping [[cultivar]] of the wych elm grafted on to a nonweeping elm trunk to give a wide, spreading, and weeping fountain shape in large garden spaces.

In northern Europe, elms were among the few trees tolerant of saline deposits from sea spray, which can cause "salt-burning" and die-back. This tolerance made elms reliable both as shelterbelt trees exposed to sea wind, in particular along the coastlines of southern and western Britain<ref>Edlin, H. L., ''Guide to Tree Planting and Cultivation'' (London, 1970), p.330, p.316</ref><ref>'Salt-tolerant landscape plants', countyofdane.com/myfairlakes/A3877.pdf</ref> and in the Low Countries, and as trees for coastal towns and cities.<ref>dutchtrig.com/the_netherlands/the_hague.html</ref>

This ''[[belle époque]]'' lasted until the [[World War I|First World War]], when the elm began its slide into horticultural decline. The impact of the hostilities on [[Germany]], the origin of at least 40 cultivars, coincided with an outbreak of the early strain of DED, ''[[Ophiostoma ulmi]]''. The devastation caused by the [[World War II|Second World War]], and the demise in 1944 of the huge [[Späth nursery]] in [[Berlin]], only accelerated the process. The outbreak of the new, three times more virulent, strain of DED ''[[Ophiostoma novo-ulmi]]'' in the late 1960s, brought the tree to its nadir.

Since around 1990, the elm has enjoyed a renaissance through the successful development in North America and Europe of cultivars highly resistant to DED.<ref name="Heybroek"/> Consequently, the total number of named cultivars, ancient and modern, now exceeds 300, although many of the older clones, possibly over 120, have been lost to cultivation. Some of the latter, however, were by today's standards inadequately described or illustrated before the pandemic, and a number may survive, or have regenerated, unrecognised. Enthusiasm for the newer clones often remains low owing to the poor performance of earlier, supposedly disease-resistant Dutch trees released in the 1960s and 1970s. In the Netherlands, sales of elm cultivars slumped from over 56,000 in 1989 to just 6,800 in 2004,<ref name=Hiemstra>{{cite book|last1=Hiemstra|first1=J.A.|display-authors=etal|title=Belang en toekomst van de iep in Nederland|trans-title=Importance and future of the elm in the Netherlands|date=2007|publisher=Praktijkonderzoek Plant & Omgeving B.V.|location=Wageningen, Netherlands|url=http://edepot.wur.nl/21797|access-date=26 October 2017|url-status=live|archive-url=https://web.archive.org/web/20140928031627/http://edepot.wur.nl/21797|archive-date=28 September 2014|df=dmy-all}}</ref> whilst in the [[UK]], only four of the new American and European releases were commercially available in 2008.

[[File:Scripps College Elm Tree Lawn.jpg|thumb|A row of [[Princeton elm]] trees, which are moderately resistant to Dutch elm disease, at [[Scripps College]] in [[Claremont, California]].<ref name="Scripps elm news">{{cite news |date=14 April 2008 |title=Elm Tree Lawn Begins New Life |language=en |work=Scripps College News |publisher=[[Scripps College]] |url=https://www.scrippscollege.edu/news/features/elm-tree-lawn-begins-new-life |access-date=18 February 2021}}</ref>]]

Efforts to develop DED-resistant cultivars began in the Netherlands in 1928 and continued, uninterrupted by World War II, until 1992.<ref name="Burdekin">{{cite journal |last1=Burdekin |first1=D.A. |last2=Rushforth |first2=K.D. |date=November 1996 |others=Revised by J.F. Webber |title=Elms resistant to Dutch elm disease |url=https://www.trees.org.uk/kenticotrees/Trees.org.uk/files/90/90f2d2f6-3d77-459c-8288-d951b0bf9782.pdf |url-status=live |journal=Arboriculture Research Note |location=Alice Holt Lodge, Farnham |publisher=Arboricultural Advisory & Information Service |volume=2/96 |pages=1–9 |issn=1362-5128 |archive-url=https://web.archive.org/web/20171026105302/https://www.trees.org.uk/kenticotrees/Trees.org.uk/files/90/90f2d2f6-3d77-459c-8288-d951b0bf9782.pdf |archive-date=26 October 2017 |access-date=26 October 2017 |df=dmy-all}}</ref> Similar programmes were initiated in North America (1937), Italy (1978) and Spain (1986). Research has followed two paths:

=== Species and species cultivars ===
In North America, careful selection has produced a number of trees resistant not only to DED, but also to the droughts and cold winters that occur on the continent. Research in the United States has concentrated on the American elm (''U. americana''), resulting in the release of DED-resistant clones, notably the [[cultivar]]s [[Ulmus americana 'Valley Forge'|'Valley Forge']] and [[Ulmus americana 'Jefferson'|'Jefferson']]. Much work has also been done into the selection of disease-resistant Asiatic species and cultivars.<ref name="Ware">Ware, G. (1995). Little-known elms from China: landscape tree possibilities. ''[http://www.ces.ncsu.edu/fletcher/programs/nursery/metria/metria8/m87.pdf Journal of Arboriculture] {{webarchive|url=https://web.archive.org/web/20071130221822/http://www.ces.ncsu.edu/fletcher/programs/nursery/metria/metria8/m87.pdf|date=30 November 2007}}'', (November 1995). International Society of Arboriculture, Champaign, Illinois, US.</ref><ref name="Biggerstaffe">Biggerstaffe, C., Iles, J. K., & Gleason, M. L. (1999). ''Sustainable urban landscapes: Dutch elm disease and disease-resistant elms''. SUL-4, Iowa State University</ref>

In 1993, Mariam B. Sticklen and Mark G. Bolyard reported the results of experiments funded by the US [[National Park Service]] and conducted at [[Michigan State University]] in [[East Lansing, Michigan|East Lansing]] that were designed to apply [[genetic engineering techniques]] to the development of DED-resistant strains of American elm trees.<ref>{{cite book|last1=Bolyard|first1=Mark G.|last2=Sticklen|first2=Mariam B.|editor-last1=Sticklen |editor-first1=Mariam B. |chapter-url=https://books.google.com/books?id=avvxBwAAQBAJ&pg=PA171 |chapter=Chapter 13: Strategies for the Production of Disease-Resistant Elms |editor-last2=Sherald |editor-first2=James L.|title=Dutch Elm Disease Research: Cellular and Molecular Approaches |publisher=Springer-Verlag |year=1993 |isbn=9781461568728 |location=New York |pages=171–183 |lccn=93017484 |oclc=851736058 |access-date=26 December 2024|via=[[Google Books]]}}</ref> In 2007, A. E. Newhouse and F. Schrodt of the [[State University of New York College of Environmental Science and Forestry]] in [[Syracuse, New York|Syracuse]] reported that young [[Transgene|transgenic]] American elm trees had shown reduced DED symptoms and normal [[mycorrhiza]]l colonization.<ref>{{cite journal |last1=Newhouse |first1=A. E. |last2=Schrodt |first2=F |last3=Liang |first3=H. |last4=Maynard |first4=C. A. |last5=Powell |first5=W. A. |year=2007 |title=Transgenic American elm shows reduced Dutch elm disease symptoms and normal mycorrhizal colonization |journal=Plant Cell Rep. |volume=26 |pages=977–987 |doi=10.1007/s00299-007-0313-z |pmid=17310333 |number=7 |bibcode=2007PCelR..26..977N |s2cid=21780088}}</ref>

In Europe, the European white elm (''U. laevis'') has received much attention. While this elm has little innate resistance to DED, it is not favoured by the vector bark beetles. Thus it becomes colonized and infected only when no other elms are available, a rare situation in western Europe. Research in Spain has suggested that it may be the presence of a [[triterpene]], [[alnulin]], which makes the tree bark unattractive to the beetle species that spread the disease.<ref name="Martín-Benito">Martín-Benito D., Concepción García-Vallejo M., Pajares J. A., López D. 2005. "[http://pubs.nrc-cnrc.gc.ca/rp/rppdf/x04-158.pdf Triterpenes in elms in Spain] {{webarchive|url=https://web.archive.org/web/20070628155809/http://pubs.nrc-cnrc.gc.ca/rp/rppdf/x04-158.pdf|date=28 June 2007}}". ''Can. J. For. Res.'' 35: 199–205 (2005).</ref> This possibility, though, has not been conclusively proven.<ref name="Pajares">Pajares, J. A., García, S., Díez, J. J., Martín, D. & García-Vallejo, M. C. 2004. "[http://www.revicien.net/abstract.php?ID=1712&Revista=7&PHPSESSID=63aad7e1b38034d0dcce46090b63a5c3 Feeding responses by Scolytus scolytus to twig bark extracts from elms] {{webarchive|url=https://web.archive.org/web/20081007035942/http://www.revicien.net/abstract.php?ID=1712&Revista=7&PHPSESSID=63aad7e1b38034d0dcce46090b63a5c3|date=7 October 2008}}". ''Invest Agrar: Sist Recur For.'' 13: 217–225.</ref> More recently, field elms ''Ulmus minor'' highly resistant to DED have been discovered in Spain, and form the basis of a major breeding programme.<ref name="Martin, a">{{cite journal |last1=Martín |first1=JA |last2=Solla |first2=A |last3=Venturas |first3=M |last4=Collada |first4=C |last5=Domínguez |first5=J |last6=Miranda |first6=E |last7=Fuentes |first7=P |last8=Burón |first8=M |last9=Iglesias |first9=S |last10=Gil |first10=L |date=2015-04-01 |title=Seven Ulmus minor clones tolerant to Ophiostoma novo-ulmi registered as forest reproductive material in Spain |journal=IForest - Biogeosciences and Forestry |publisher=Italian Society of Sivilculture and Forest Ecology (SISEF) |volume=8 |issue=2 |pages=172–180 |doi=10.3832/ifor1224-008 |issn=1971-7458 |doi-access=free}}</ref>

=== Hybrid cultivars ===
Owing to their innate resistance to DED, Asiatic species have been crossed with European species, or with other Asiatic elms, to produce trees that are both highly resistant to disease and tolerant of native climates. After a number of false dawns in the 1970s, this approach has produced a range of reliable hybrid cultivars now commercially available in North America and Europe.<ref>{{cite web |title=Scientific Name: Ulmus x species |url=http://www.hort.cornell.edu/uhi/outreach/recurbtree/pdfs/08Ulmus%20x.pdf |archive-url=https://web.archive.org/web/20081217195926/http://www.hort.cornell.edu/uhi/outreach/recurbtree/pdfs/08Ulmus%20x.pdf |archive-date=17 December 2008 |access-date=26 May 2018}}</ref><ref name="Santini2004">Santini A., Fagnani A., Ferrini F., Mittempergher L., Brunetti M., Crivellaro A., Macchioni N., "[http://www.inia.es/gcontrec/pub/179-184-(15)-Elm_breeding_1161943564468.pdf Elm breeding for DED resistance, the Italian clones and their wood properties] {{webarchive|url=https://web.archive.org/web/20071026213739/http://www.inia.es/gcontrec/pub/179-184-%2815%29-Elm_breeding_1161943564468.pdf|date=26 October 2007}}". ''Invest Agrar: Sist. Recur. For'' (2004) 13 (1), 179–184. 2004.</ref><ref name="Santamour">Santamour, J., Frank, S. & Bentz, S. (1995). Updated checklist of elm (Ulmus) cultivars for use in North America. ''Journal of Arboriculture'', 21:3 (May 1995), 121–131. International Society of Arboriculture, Champaign, Illinois, US</ref><ref name="Smalley">Smalley, E. B. & Guries, R. P. (1993). Breeding Elms for Resistance to Dutch Elm Disease. ''Annual Review of Phytopathology'' Vol. 31 : 325–354. Palo Alto, California</ref><ref name="Heybroeka">{{cite journal |last=Heybroek |first=Hans M. |date=1983 |editor-last=Burdekin |editor-first=D.A. |title=Resistant elms for Europe |url=http://www.forestry.gov.uk/pdf/FCBU060.pdf/$FILE/FCBU060.pdf#page=118 |url-status=live |journal=Forestry Commission Bulletin (Research on Dutch Elm Disease in Europe) |location=London |publisher=HMSO |pages=108–113 |archive-url=https://web.archive.org/web/20170215025124/http://www.forestry.gov.uk/pdf/FCBU060.pdf/$FILE/FCBU060.pdf#page=118 |archive-date=15 February 2017 |number=60 |df=dmy-all}}</ref><ref name="Heybroekb">{{cite book |last1=Heybroek |first1=H.M. |title=Dutch Elm Disease Research |date=1993 |publisher=Springer-Verlag |isbn=978-1-4615-6874-2 |editor1-last=Sticklen |editor1-first=Mariam B. |location=New York, USA |pages=16–25 |chapter=The Dutch Elm Breeding Program |access-date=26 October 2017 |editor2-last=Sherald |editor2-first=James L. |chapter-url=https://books.google.com/books?id=avvxBwAAQBAJ&pg=PA16 |archive-url=https://web.archive.org/web/20171026164004/https://books.google.co.uk/books?id=avvxBwAAQBAJ&pg=PA16&lpg=PA16 |archive-date=26 October 2017 |url-status=live |df=dmy-all}}</ref><ref name="Mittempergher2004">{{cite journal |last1=Mittempergher |first1=L |last2=Santini |first2=A |date=2004 |title=The history of elm breeding |url=http://www.inia.es/gcontrec/Pub/161-177-(14)-The_history_1161943529015.pdf |url-status=live |journal=Investigacion Agraria: Sistemas y Recursos Forestales |volume=13 |issue=1 |pages=161–177 |archive-url=https://web.archive.org/web/20170211155148/http://www.inia.es/gcontrec/Pub/161-177-(14)-The_history_1161943529015.pdf |archive-date=11 February 2017 |df=dmy-all}}</ref> Disease resistance is invariably carried by the female parent.<ref name="Martin, b">Martin, J., Sobrina-Plata, J., Rodriguez-Calcerrada, J., Collada, C., and Gil, L. (2018). Breeding and scientific advances in the fight against Dutch elm disease: Will they allow the use of elms in forest restoration? ''New Forests'', 1-33. Springer Nature 2018. [https://doi.org/10.1007/s11056-018-9640-x]</ref>

Some of these cultivars, notably those with the Siberian elm (''[[Ulmus pumila]]'') in their ancestry, lack the forms for which the iconic American elm and English elm were prized. Moreover, several exported to northwestern Europe have proven unsuited to the [[maritime climate]] conditions there, notably because of their intolerance of anoxic conditions resulting from ponding on poorly drained soils in winter. Dutch hybridizations invariably included the Himalayan elm (''[[Ulmus wallichiana]]'') as a source of antifungal genes and have proven more tolerant of wet ground; they should also ultimately reach a greater size. However, the susceptibility of the cultivar 'Lobel', used as a control in Italian trials, to [[elm yellows]] has now (2014) raised a question mark over all the Dutch clones.<ref name="Mittempergher2000">Mittempergher, L., (2000). Elm Yellows in Europe. In: ''The Elms, Conservation and Disease Management.'' pp.
103-119. Dunn C.P., ed. Kluwer Academic Press Publishers, Boston, USA.</ref>

Several highly resistant ''Ulmus'' cultivars have been released since 2000 by the Institute of Plant Protection in Florence, most commonly featuring crosses of the Dutch cultivar [[Ulmus 'Plantyn'|'Plantijn']] with the Siberian elm to produce resistant trees better adapted to the Mediterranean climate.<ref name="Santini2004" />

====Cautions regarding novel cultivars====
Elms take many decades to grow to maturity, and as the introduction of these disease-resistant cultivars is relatively recent, their long-term performance and ultimate size and form cannot be predicted with certainty. The [[National Elm Trial]] in North America, begun in 2005, is a nationwide trial to assess strengths and weaknesses of the 19 leading cultivars raised in the US over a 10-year period; European cultivars have been excluded.<ref>(1) {{cite web |year=2018 |title=National Elm Trial |url=http://bspm.agsci.colostate.edu/national-elm-trial/ |work=Bioagricultural Sciences & Pest Management |publisher=[[Colorado State University College of Agricultural Sciences]]: [[Colorado State University College of Agricultural Sciences#Academic Departments|Department of Agricultural Biology]] |location=[[Fort Collins, Colorado]] |access-date=8 February 2021 |archive-date=30 March 2018 |archive-url=https://web.archive.org/web/20180330152322/http://bspm.agsci.colostate.edu/national-elm-trial/ |url-status=dead }}.<br />(2) {{cite journal |last1=Griffin |first1=Jason J. |last2=Jacobi, E. |first2=William R. |last3=McPherson |first3=Gregory |last4=Sadof |first4=Clifford S. |last5=McKenna |first5=James R. |last6=Gleason |first6=Mark L. |last7=Gauthier |first7=Nicole Ward |last8=Potter |first8=Daniel A. |last9=Smitley |first9=David R. |last10=Adams |first10=Gerard C. |last11=Gould |first11=Ann Brooks |display-authors=4 |year=2017 |title=Ten-Year Performance of the United States National Elm Trial |url=https://webdoc.agsci.colostate.edu/bspm/NationalElmTrial/AUF2017.pdf |journal=Arboriculture & Urban Forestry |publisher=[[International Society of Arboriculture]] |volume=43 |pages=107–120 |doi=10.17660/ActaHortic.2018.1191.5 |issn=0567-7572 |oclc=7347020445 |access-date=February 7, 2021 |first12=Christian R. |last12=Cash |first13=James A. |last13=Walla |first14=Mark C. |last14=Starrett |first15=Gary |last15=Chastagner |first16=Jeff L. |last16=Sibley |first17=Vera A. |last17=Krischik |first18=Adam F. |last18=Newby |number=3 }}</ref> Meanwhile, in Europe, American and European cultivars are being assessed in field trials started in 2000 by the UK charity [[Butterfly Conservation]].<ref name="Brookes">Brookes, A. H. (2013). ''Disease-resistant elm cultivars, Butterfly Conservation trials report, 2nd revision, 2013.'' Butterfly Conservation, Hants & IoW Branch, England. {{cite web |title=Archived copy |url=http://www.hantsiow-butterflies.org.uk/conservation/2013%20Elm%20Report%20Sept%202013.pdf |url-status=dead |archive-url=https://web.archive.org/web/20140529181302/http://hantsiow-butterflies.org.uk/conservation/2013%20Elm%20Report%20Sept%202013.pdf |archive-date=29 May 2014 |access-date=2014-01-30 |df=dmy-all}}</ref>

===Landscaped parks===
====Central Park====
[[File:USA-NYC-Central Park-The Mall.JPG|thumb|right|American elm trees along the Mall and Literary Walk in New York City's  [[Central Park]] (2013)]]
The oldest American elm trees in New York City's [[Central Park]]  were planted in the 1860s by [[Frederick Law Olmsted]], making them among the oldest stands of American elms in the world. Along the Mall and Literary Walk four lines of American elms stretch over the walkway forming a cathedral-like covering. A part of New York City's [[urban ecology]], the elms improve air and water quality, reduce erosion and flooding, and decrease air temperatures during warm days.<ref>[[Central Park Conservancy]]. [http://www.centralparknyc.org/things-to-see-and-do/attractions/mall-literary-walk.html The Mall and Literary Walk] {{Webarchive|url=https://web.archive.org/web/20160510085304/http://www.centralparknyc.org/things-to-see-and-do/attractions/mall-literary-walk.html |date=10 May 2016 }}.</ref>

While the stand is still vulnerable to DED, in the 1980s the [[Central Park Conservancy]] undertook aggressive countermeasures such as heavy pruning and removal of extensively diseased trees. These efforts have largely been successful in saving the majority of the trees, although several are still lost each year. Younger American elms that have been planted in Central Park since the outbreak are of the DED-resistant 'Princeton' and 'Valley Forge' cultivars.<ref>Pollak, Michael. ''The New York Times''. "[https://www.nytimes.com/2013/01/13/nyregion/answers-to-questions-about-new-york.html?_r=0 Answers to Questions About New York] {{Webarchive|url=https://web.archive.org/web/20160401141020/http://www.nytimes.com/2013/01/13/nyregion/answers-to-questions-about-new-york.html?_r=0 |date=April 1, 2016 }}." 11 January 2013.</ref>

====National Mall====
[[File:Defense.gov photo essay 060911-D-7203T-018.jpg|thumb|right|200px|Rows of American elm trees line a path south of the [[Lincoln Memorial Reflecting Pool]] on the National Mall in Washington, DC (November 11, 2006)]]

Several rows of American elm trees that the National Park Service (NPS) first planted during the 1930s line much of the {{convert|1.9|mi|km|adj=mid|-length|abbr=off|sp=us}} of the [[National Mall]] in Washington, DC. DED first appeared on the trees during the 1950s and reached a peak in the 1970s. The NPS used a number of methods to control the [[epidemic]], including [[sanitation]], [[pruning]], injecting trees with [[fungicide]], and replanting with DED-resistant cultivars. The NPS combated the disease's local insect [[Vector (epidemiology)|vector]], the smaller European elm bark beetle (''[[Scolytus multistriatus]]''), by trapping and by spraying with [[insecticide]]s. As a result, the population of American elms planted on the Mall and its surrounding areas has remained intact for more than 80 years.<ref>{{cite book|last=Sherald |first=James L |url=http://www.nps.gov/nationalmallplan/Documents/Studies/ElmsoftheMonuCore_HistandMgmtPlan_122009.pdf |title=Elms for the Monumental Core: History and Management Plan |id=Natural Resource Report NPS/NCR/NRR--2009/001 |place=Washington, D.C. |publisher=Center for Urban Ecology, National Capital Region, [[National Park Service]] |date=December 2009 |access-date=2010-10-14|archive-url=https://web.archive.org/web/20101129074707/http://www.nps.gov/nationalmallplan/Documents/Studies/ElmsoftheMonuCore_HistandMgmtPlan_122009.pdf|archive-date=2010-11-29}}</ref>