Editing Pinus jeffreyi (section)

==Description==
''Pinus jeffreyi'' is a large [[conifer]]ous evergreen tree, reaching {{convert|25|to|40|m|sp=us}} tall, rarely up to {{convert|53|m|abbr=on}} tall, though smaller when growing at or near [[tree line]].<ref name="silvics"/> The [[leaves]] are needle-like, in bundles of three, stout, [[glaucous]] gray-green, {{convert|12 to 28|cm|frac=4|sp=us}} long.<ref name="tktimb">{{Cite book |last1=Turner |first1=Mark |url=https://books.google.com/books?id=VLbAAwAAQBAJ |title=Trees & Shrubs of the Pacific Northwest |last2=Kuhlmann |first2=Ellen |date=2014 |publisher=[[Timber Press]] |isbn=978-1-60469-263-1 |edition=1st |location=Portland, OR |pages=78}}</ref> The [[conifer cone|cones]] are {{convert|12 to 30|cm|abbr=on|frac=4}} long,<ref name=":0">{{Cite book|last1=Arno|first1=Stephen F.|url=https://www.worldcat.org/oclc/1141235469|title=Northwest Trees: Identifying & Understanding the Region's Native Trees|last2=Hammerly|first2=Ramona P.|publisher=[[Mountaineers Books]]|year=2020|isbn=978-1-68051-329-5|edition=field guide|location=Seattle|pages=57–58|language=en|oclc=1141235469|orig-date=1977}}</ref><ref name="tktimb" /> dark purple when immature, ripening pale brown, with thinly woody scales bearing a short, sharp inward-pointing barb. The brownish seeds are {{convert|10|to|12|mm|frac=8|sp=us}} long, with a large wing,<ref name="tktimb" /> measuring {{convert|15|to|25|mm|abbr=on|frac=8}}.

''Pinus jeffreyi'' is closely related to ''[[Pinus ponderosa]]'' (ponderosa pine) and is similar in appearance. One way to distinguish between them is by their cones. Each has barbs at the end of the scales. The sharp ''P.&nbsp;jeffreyi'' cone scale barbs point inward, so the cone feels smooth to the palm of one's hand when rubbed down the cone. ''Pinus ponderosa'' cone scale barbs point outward, so feel sharp and prickly to the palm of one's hands. The memory device of 'gentle Jeffrey' and 'prickly ponderosa' can be used to differentiate between the species. Another distinguishing characteristic is that the needles of ''P.&nbsp;jeffreyi'' are glaucous, less bright green than those of ''P.&nbsp;ponderosa'', and by the stouter, heavier cones with larger seeds and inward-pointing barbs.<ref name="Moore2008">{{cite book |last1=Moore|first1=Gerry |last2=Kershner|first2=Bruce |first3=Craig|last3=Tufts |first4=Daniel|last4=Mathews |first5=Gil|last5=Nelson |last6=Spellenberg|first6=Richard |last7=Thieret|first7=John W. |first8=Terry|last8=Purinton |last9=Block|first9=Andrew|display-authors=4 |title=National Wildlife Federation Field Guide to Trees of North America |publisher=Sterling |location=New York |year=2008 |page=86 |isbn=978-1-4027-3875-3}}</ref> ''Pinus jeffreyi'' can be somewhat distinguished from ''P.&nbsp;ponderosa'' by the relatively smaller scales of reddish-brown bark as compared to the larger plates of orangish ponderosa bark.<ref name=":0" />

The scent of ''P. jeffreyi'' is variously described as reminiscent of vanilla, lemon, pineapple, violets, apple,<ref>{{cite web|url=http://www.enature.com/flashcard/show_flash_card.asp?recordNumber=TS0040|title=Jeffrey Pine|work=enature.com|archive-url=https://web.archive.org/web/20110614142314/http://www.enature.com/flashcard/show_flash_card.asp?recordNumber=TS0040|archive-date=2011-06-14}}</ref> and, quite commonly, butterscotch.<ref>{{cite book|title=Wild Plants of the Sierra Nevada|first1=Ray S.|last1=Vizgirdas|first2=Edna M.|last2=Rey-Vizgirdas|year=2006|publisher=University of Nevada Press|location=Reno, Nevada}}</ref> This scent may be sampled by breaking off a shoot or some needles, or by simply smelling the resin's scent in between the plates of the bark. This scent is related to the very unusual composition of the resin, with the [[volatile organic compound|volatile]] component made up almost entirely of pure [[heptane|n-heptane]]. It is because of this peculiarity that the trees are sometimes known as '''gasoline trees'''. Easy availability of this hydrocarbon in pure form made it the basis of the modern [[octane rating]] in the late 1920s.<ref>{{Cite book |last=Hill |first=Cary Le Roy |url=https://books.google.com/books?id=hAsRvdX33p8C&pg=PA13 |title=Experiments in the Production of Heptane by the Tapping of Jeffrey Pine in California |date=1932 |publisher=California Forest Experiment Station |pages=13 |language=en}}</ref><ref>{{Cite book |last=Arno |first=Stephen F. |url=https://books.google.com/books?id=DDTm1_9Pdy8C&pg=PA11 |title=Discovering Sierra Trees |date=1973 |publisher=Yosemite Natural History Association |isbn=978-0-939666-04-1 |pages=11 |language=en}}</ref>

The largest specimen, by trunk volume, is the Eureka Valley Giant, in the [[Stanislaus National Forest]]. Its trunk contains {{convert|129|m3|abbr=on}} of wood, is {{convert|59|m|abbr=on}} tall, with a diameter of {{convert|2.5|m|ftin|abbr=on}}.<ref>{{cite book|title=Forest Giants of the Pacific Coast|url=https://archive.org/details/forestgiantsofpa0000vanp|url-access=registration|first=Robert|last=Van Pelt|year=2001|page=[https://archive.org/details/forestgiantsofpa0000vanp/page/108 108]|publisher=Global Forest Society}}</ref>