Tree

===Bark===
[[File:CorkOakStripped.jpg|thumb|upright|Recently stripped cork oak (''[[Quercus suber]]'')]]
{{further|Bark (botany)}}

[[Cork (material)|Cork]] is produced from the thick bark of the cork oak (''[[Quercus suber]]''). It is harvested from the living trees about once every ten years in an environmentally sustainable industry.<ref>{{cite web |url=http://www.azom.com/news.aspx?newsID=4951 |title=Cork Flooring is Environmentally Sustainable |date=27 February 2006 |publisher=AZoM.com |access-date=26 July 2012 |archive-date=7 November 2012 |archive-url=https://web.archive.org/web/20121107104856/http://www.azom.com/news.aspx?newsID=4951 |url-status=live }}</ref> More than half the world's cork comes from Portugal and is largely used to make stoppers for wine bottles.<ref name=cork>{{cite web |url=http://people.uwec.edu/ivogeler/Travel/Portugal/cork-article2.htm |title=The cork industry in Portugal |author1=Calheiros e Meneses |author2=J. L. |publisher=University of Wisconsin |access-date=26 July 2012 |archive-date=14 September 2014 |archive-url=https://web.archive.org/web/20140914040935/http://people.uwec.edu/ivogeler/Travel/Portugal/cork-article2.htm |url-status=live }}</ref> Other uses include floor tiles, bulletin boards, balls, footwear, cigarette tips, packaging, insulation and joints in woodwind instruments.<ref name=cork/>

The bark of other varieties of oak has traditionally been used in Europe for the [[Tanning (leather)|tanning]] of hides though bark from other species of tree has been used elsewhere. The active ingredient, [[tannin]], is extracted and after various preliminary treatments, the skins are immersed in a series of vats containing solutions in increasing concentrations. The tannin causes the hide to become supple, less affected by water and more resistant to bacterial attack.<ref>{{cite web |title=3. Tanneries, Description of the Tanning Process |access-date=26 July 2012 |publisher=Food and Agriculture Organization of the United Nations |url=http://www.fao.org/WAIRDOCS/LEAD/X6114E/x6114e05.htm#b1-3.1.%20Description%20of%20the%20tanningprocess |archive-date=22 August 2011 |archive-url=https://web.archive.org/web/20110822080512/http://www.fao.org/WAIRDOCS/LEAD/X6114E/x6114e05.htm#b1-3.1.%20Description%20of%20the%20tanningprocess |url-status=live }}</ref>

At least 120 drugs come from [[medicinal plant|plant sources]], many of them from the bark of trees.<ref name=rainforest>{{cite web |url=http://rainforest-database.com/plants/plantdrugs.htm |title=Plant Based Drugs and Medicines |author=Taylor, Leslie |date=13 October 2000 |work=The Healing Power of Rainforest Herbs |access-date=27 July 2012 |archive-date=29 June 2012 |archive-url=https://web.archive.org/web/20120629144821/http://rainforest-database.com/plants/plantdrugs.htm |url-status=live }}</ref> [[Quinine]] originates from the cinchona tree (''[[Cinchona]]'') and was for a long time the remedy of choice for the treatment of [[malaria]].<ref>{{cite web |title=Guidelines for the treatment of malaria |publisher=World Health Organization |url=http://apps.who.int/iris/bitstream/10665/162441/1/9789241549127_eng.pdf?ua=1&ua=1 |year=2006 |access-date=26 July 2012 |archive-date=13 October 2015 |archive-url=https://web.archive.org/web/20151013193459/http://apps.who.int/iris/bitstream/10665/162441/1/9789241549127_eng.pdf?ua=1&ua=1 |url-status=live }}</ref> [[Aspirin]] was synthesised to replace the [[sodium salicylate]] derived from the bark of willow trees (''[[Salix]]'') which had unpleasant side effects.<ref>{{Cite journal |last1=Sneader |first1=W. |title=The discovery of aspirin: A reappraisal |journal=BMJ (Clinical Research Ed.) |volume=321 |issue=7276 |pages=1591–1594 |year=2000 |pmid=11124191 |pmc=1119266 |doi=10.1136/bmj.321.7276.1591}}</ref> The anti-cancer drug [[Paclitaxel]] is derived from taxol, a substance found in the bark of the Pacific yew (''[[Taxus brevifolia]]'').<ref>{{cite book |last1=Goodman |first1=Jordan |last2=Walsh |first2=Vivien |title=The Story of Taxol: Nature and Politics in the Pursuit of an Anti-Cancer Drug |publisher=Cambridge University Press |year=2001 |isbn=978-0-521-56123-5 |page=[https://archive.org/details/storyoftaxolnatu00jord/page/17 17] |url=https://archive.org/details/storyoftaxolnatu00jord/page/17 }}</ref> Other tree based drugs come from the paw-paw (''[[Carica papaya]]''), the cassia ([[Cassia (genus)|''Cassia'' spp.]]), the cocoa tree (''Theobroma cacao''), the tree of life (''[[Camptotheca acuminata]]'') and the downy birch (''[[Betula pubescens]]'').<ref name=rainforest/>

The papery bark of the white birch tree (''[[Betula papyrifera]]'') was used extensively by [[Indigenous peoples of the Americas|Native Americans]]. [[Wigwam]]s were covered by it and [[canoe]]s were constructed from it. Other uses included food containers, hunting and fishing equipment, musical instruments, toys and sledges.<ref>{{cite web |url=http://www.nativetech.org/brchbark/brchbark.htm |title=Uses for birch bark |author=Prindle, Tara |year=1994 |publisher=NativeTech: Native American Technology and Art |access-date=27 July 2012 |archive-date=18 September 2012 |archive-url=https://web.archive.org/web/20120918040348/http://www.nativetech.org/brchbark/brchbark.htm |url-status=live }}</ref> Nowadays, bark chips, a by-product of the timber industry, are used as a mulch and as a growing medium for epiphytic plants that need a soil-free compost.<ref>{{cite web |url=http://www.orchid-growing-secrets.com/choosing-the-right-potting-media-for-your-orchid/ |archive-url=https://web.archive.org/web/20121115211019/http://www.orchid-growing-secrets.com/choosing-the-right-potting-media-for-your-orchid/ |archive-date=15 November 2012 |title=Choosing the right potting media for your orchid |author=Johnson, Aidan |date=25 January 2011 |work=Orchid growing secrets |access-date=27 July 2012 |url-status=dead }}</ref>

[[File:Fontaine-l'Eveque JPG01c.jpg|thumb|left|[[Avenue (landscape)|Alleé]] of [[Platanus × acerifolia|London plane trees (''Platanus'' × ''acerifolia'')]] in garden]]