Ed, all; Dale and I had this same discussion a few weeks back and here's what I sent him:
I asked my advisor [Donald Leopold], who's as good with tree id as anyone I've met, and he said he goes by four characteristics for separating red and pignut (I hope I'm remembering correctly here): bark scaliness, leaflet number, fruit dehisence, and fruit shape. Pignut is more likely to have bark that stays attached to the trunk, five leaflets, husks that do not split, and pear shaped fruits. Red hickory has narrow scales of bark that flip away from the trunk, seven leaflets, husks that split freely to the base, and subglobose fruits. He said he has not noticed habitat difference for them, and that they can grow intermixed on the same site. He also said that both trees with intermediate characteristics and trees that are consistent for all four characteristics occur. I think I tend to see pignuts, or at least hickories with tight bark and pear shaped fruits, more commonly on acidic sites or ridgetops. I believe red hickory is also supposed to have more aromatic leaves; I'm not sure if that's where the name odorata comes from when its classified as the variety Carya glabra var. odorata. One other character that I've seen occasionally mentioned is that the petiole (leaf stem) may be red on top, hence the name, but I don't think that's a very reliable characteristic. Jess On Wed, Dec 17, 2008 at 10:54 AM, Edward Frank <[email protected]> wrote: > ENTS, Will, > > Red Hickory (Carya ovalis) vs Pignut Hickory (Carya glabra) > > > Will, You said Jess has a good grasp on the red hickory vs. pignut hickory > question. I ma glad someone does, because I find myself a mite perplexed. > > In my Audubon Field Guide to Trees under Pignut (there is no separate entry > for Red Hickory): > > Red Hickory (var. odorata (Marsh.) Little), a variety with nearly the same > range, has the fruit husks spitting to the base, usually 7 leaflets, and > often shaggy bark. > > > In my Peterson's Filed Guide to Eastern Trees under Pignut (there is no > separate entry for Red Hickory): > > [Similar species... Shagbark Hickory, Sand Hickory, Black Hickory, Mockernut > Hickory] Intergrades occur between these several species. Sweet Pignut > Hickory (C. ovalis), with fully splitting nut husks, is no longer > separated. > > > So I am wondering if Red Hickory is a separate species, subspecies, variety, > or what. Peterson's indicates it is no longer considered as a separate > species, but it is listed elsewhere as one. The most definitive > characteristic seems to be how the nut splits. > > Here are some hickory Links: > > http://ohioline.osu.edu/b700/b700_23.html > Red Hickory–Carya (Hicoria) ovalis > > The red hickory tree is very similar to the pignut hickory. It thrives in > the same areas as the pignut, and is often hard to distinguished from the > pignut hickory. Many people consider red hickory to be a northern ecotype of > the pignut hickory. At maturity, the red hickory attains a height of 50—80 > feet with a trunk diameter of from 2—3 feet. The crown is narrowly oblong > with rather short, spreading branches. Lower branches are drooping. The > trunk extends straight into the crown and is often forked. > > Buds are small and only 1/4—1/2 inch (6—13 mm) long. Branchlets and leaflets > are scarcely pubescent. The bark is dark gray, fissured, and closely held on > young trees. Mature bark separates into narrow, shaggy plates on older > trunks, but even these plates are more tightly held than shagbark and > shellbark hickories. This character give rise to the name of false-shagbark > hickory. > > The leaves are 8—12 inches (20—30 1/2 cm) long. They are composed of five to > seven leaflets which are oblong or rounded to lance-shaped, 3—5 inches (7 > 1/2—13 cm) long, and 1—2 inches (2 1/2—5 cm) wide. Leaflets sharply taper at > the apex and are finely serrate, or toothed, along the margin. > > Flowers are monoecious. Male flowers are catkins and showy, while the female > flowers are green and inconspicuous. Flowering occurs in May. The fruit is > subglobose, from 4/5—1 inch (20—25 mm) long, and four-channeled from the > apex to the base. Fruits are light brown and scaly when ripe. The husk is > thin and is difficult to split. The nut is brownish in color with a small, > sweet kernel. > > This tree is found on lower slopes of southeastern Ohio rather than the > ridges where the pignut hickory is found. Red hickory is particularly common > on southern and western exposures. The wood is heavy, strong, and hard. It > is reddish-brown in color which gives this plant its local name of red > hickory. It is said to be somewhat inferior to the other hickories but is > used for the same purposes. > > http://athenstrees.com/champ_24_red_hickory.php > > Bark: A gray-brown developing rounded ridges forming an irregular > diamond-shaped pattern, and on older trees, tends to appear shaggy. > > Notes: Red hickory is found occasionally throughout the hardwood forests of > the southern piedmont. It is similar in appearance to both pig nut and shag > bark hickory, such that "false shag bark hickory" is often used as a common > name. The bark is the one visible clue in identification. In young trees, > the bark is tight and similar to Pig Nut, but tends to shag with age, giving > a shag bark/pig nut appearance (see bark illustration above). Like the other > hickory's, the tree makes a good specimen tree where it has room to grow. > The commercial uses of this species is the same as the other hickory's and > in the timber business, little differentiation is made between them, and > like the other hickory's, its use as a source of hard mast for wildlife is > limited. > > http://www.dof.virginia.gov/trees/hickory-pignut.shtml > > Pignut Hickory: Early settlers named the species "pignut" because their > hogs loved to eat the nuts. A related species, red hickory (Carya ovalis) > differs from pignut hickory by slight differences in the fruit and bark. > Many hickories hybridize with each other, making exact identification > difficult even for experts. > > > http://www.cnr.vt.edu/DENDRO/dendrology/syllabus/factsheet.cfm?ID=19 Pignut > Hickory > > http://plants.usda.gov/java/county?state_name=Pennsylvania&statefips=42&symbol=CAOV3 > Red > Hickory Distributions in PA > > http://en.wikipedia.org/wiki/Red_Hickory > > The bark of the Red Hickory is composed of sharp, furrowed bark with deep > crevices in between the scales. On younger trees, the bark becomes very > tight but can also for sections the scales occasionally curl up vertically > away from the trunk, much like the Shagbark Hickory (Carya ovata). Middle > aged trees have tight, shallow furrowed bark that is composed of tough > interlocking scales. The coloring can range from grayish to dark brown with > reddish highlights in between scales. > > http://www.cas.vanderbilt.edu/bioimages/species/caov3.htm Carya ovalis > images > > http://www.fw.vt.edu/dendro/dendrology/syllabus2/factsheet.cfm?ID=826 Carya > ovalis fact sheet > > http://www.natureserve.org/explorer/servlet/NatureServe?searchCommunityUid=ELEMENT_GLOBAL.2.684405 > > Comments about a forest species association from northern VA. Quercus rubra > - Carya ovalis / Collinsonia canadensis - Impatiens pallida Forest > > > These are the best links I found on the species. I could not fins any good > photos of older trees showig the bark characteristics. > > Ed Frank > > > > > > > Join me in the Eastern Native Tree Society at > http://www.nativetreesociety.org > and in the Primal Forests - Ancient Trees Community at: > http://primalforests.ning.com/ > > > > --~--~---------~--~----~------------~-------~--~----~ Eastern Native Tree Society http://www.nativetreesociety.org You are subscribed to the Google Groups "ENTSTrees" group. To post to this group, send email to [email protected] To unsubscribe send email to [email protected] For more options, visit this group at http://groups.google.com/group/entstrees?hl=en -~----------~----~----~----~------~----~------~--~---
