A Comparison of Two Common Hickories

Recently I spent a couple of hours observing the stems of two trees: Shagbark Hickory (Carya ovata) and Pignut Hickory (Carya glabra). The result of time spent with these trees was a thorough exploration of the details of their stems, leaf buds, leaf scars and other minor details. Distinguishing between the two has become quite easy.

My tools for observation and inquiry were pencil, pen, paper, pocketknife, fingers, nose, eyes, and hand lens. Here are the steps I took that allowed me to first determine if they were in fact hickory trees, and second, distinguish them from one another:

I walked through the woods looking for young trees (so I could reach the limbs) and used only a few tests to confirm whether I had in hand a limb from the Juglanaceae Family, which includes walnuts, hickories, and pecans.

First, and after a quick glance, determine if the leaf buds are opposite or alternating. Hickories are always alternate in their leaf presentation (notice the alternate pattern in both stems in the drawing).

Second, I looked for heart-shaped leaf scars and light colored lenticels (see "Leaf Scar Variety" sketch below).

Leaf scars are the marks left when last year's leaf drops off. In most deciduous trees, this leaves a mark just beneath new leaf buds.

Lenticels are tiny openings in the bark of the stem that allow for gas transfer (see the little spots on the stem in the drawing).

Third, and just for reassurance, I bend a branch...Hickories are particularly tough. They will not snap off, unless dead.

At this point, I know I have either a hickory, walnut, or pecan. Now to distinguish further.

Learning more requires one to look a little closer. Attempting to replicate the stem in a drawing, and in a way the represents great detail, challenges me to look closer...and it does a great job of imprinting the experience upon my brain. So, the next step:

First, ...look at the drawing of the stems...Are the lenticels round or elongated? (see close up of the stem drawing below) If they are elongated, the tree is a hickory. I ran into several trees that looked like hickory saplings to me, but they had round lenticels; which means they were walnut trees (curiously, walnut stems also have a pith that is in thin horizontal layers...pith is the different colored wood found at the very center of the stem.).

Second, and for reassurance only, I sliced the stem horizontally revealing a pentagon-shaped pith...an attribute that also distinguishes it from the walnut.

That is it. Having encountered several trees, I now knew which were hickories and which were not. It was my hope to find several different types, but alas, I only encountered two different varieties.

As already stated, one was Shagbark, one was Pignut.

Well, in this ecological province (Northern Piedmont) we have four regularly occurring native hickories: Shagbark, Pignut, Bitternut, and Mockernut. Occasionally, one finds a fifth, the Pecan (yes, a hickory), and most always it has been planted by human; placing it in or very near old and new human habitats.

The Pecan and the Mockernut have quite hairy twigs and the Bitternut has a very distinct terminal bud, being mustard-yellow in color and flattened. The Shagbark and Pignut have none of these attributes.

Based upon my observations, the following features distinguished the Shagbark and the Pignut hickories from one another (and you can see some of these attributes in the drawing):

Shagbark Hickory is different from Pignut Hickory in these ways:

• the terminal bud (at the end of the stem) is much larger, being 1/2" -1" long
• side buds extend at a shallow angle from the stem, where-as the side buds of the Pignut extend at nearly right angles
• bud scales around the base of the leaf buds are very dark colored
• the end bud is nearly odorless when crushed...the pignut bud smells wonderful, like a mixture of menthol, eucalyptus, and lavender (at least, that's what my nose tells me)
• the terminal bud of the shagbark is quite fuzzy, pignut appears smooth (but small hairs are visible with hand lens)

With some time spent in close observation with these two stems, I have confidently identified the trees they came from...all without considering leaves, bark or nut (which can be very misleading...the least of which is the nut). Being able to make a quick ID allows me to spend more time considering the bigger picture...ecological mixes, interdependencies, co-adaptation, habitat, and connections. It adds to the richness of the story that hides in the woods. Patterns and behaviors in one part of nature are always connected to patterns and behaviors in another part...reading the landscape and the life on it requires a certain amount of decoding.

Understanding our place within the story requires an ability to recognize details and the relationships between them. Otherwise, we are assuming in our interpretation of things, and doing so based upon a puzzle made mostly of missing pieces. This is why species distinction and identification is oh so important for understanding.

The Power of Sharing Stories

Well, ...unthinkable amounts of snow have blanketed much of the east, sending all animals into various states of surprise and frantic. Voles were spotted racing across the top of the deep snow, a dangerous dash. Songbirds jockeyed for positions at feeders. Large mammals could be seen partaking in a ritual of repositioning the snow...so they could reach their watering holes, their winter stores, and there markets. Amidst all the snowy chaos (and amid the complete demolition of the enormous and historic building near Belmont Bridge) I wonder about the hunter...the Cooper’s Hawk that was spotted a few weeks ago.

Does the contrast provided by the snow give it an advantage?

Does the gathering of birds into groups and clusters focused on scant food sources make the hunt easier?

Does the nearby demolition change the hawk's behavior?

I have not heard a single mention of the hawk of Belmont Bridge in about a week-n'-a-half...but of course, we’ve all been under the snow’s magic spell...and traveling. For a while there, word of the stealthy bird traveled about in small circles. Within a week of sharing the story of the Cooper’s Hawk another significant sighting surfaced. People had begun looking for it!

This is the power of sharing. Sharing with other people the things you discover and the things you learn while looking closer and learning more may be the primary way we all come to a deeper understanding of this world. So, I offer this story as an example of the power of sharing:

A couple of days after sharing the story of the mighty Cooper’s Hawk I received a phone call from someone with great excitement in her voice. She, her family, and some friends had happened upon a Cooper’s Hawk while it was having a meal. She said it was at the corner of Monticello Rd. and Graves St., within close proximity of the previous sighting.

Norah and I launched out of the house, knowing the hawk might be moving on soon. Upon arriving we inspected the area for remaining evidence of the "meal". It did not take long...the ground beneath a large evergreen tree was blanketed with pigeon feathers, some of them warm to the touch and fresh with blood. As we focused downward upon the fallen feathers, we noticed a small piece of fluffy feather spiraling down slowly. We both looked up, and there he was...about 5 feet away and above our heads... nestled in the densely packed limbs and foliage of the coniferous eastern redcedar (a wonderfully hardy native evergreen tree). Immediately he sprung from his position and took to the air, dropping his featherless food. The carcass nearly hit Norah in the head...a three-quarters eaten pigeon with few recognizable parts. She called it "meat", and said it looked like the chicken we get at the store...and you wonder "where on earth do they shop?". It was surprisingly similar, plucked feathers and pink bumpy skin.

After spending a moment prodding the guts and skin, we were off again, in hot pursuit of the hunter. It landed in a large red maple nearby, and we watched it there for about five minutes. What fun! A story shared had returned, and now it goes out again. Norah has been sharing the story of the hunter with others, as have I. Many folks have had similar experiences recently. Individuals have shared with me their observations over the past week; individuals living from the Piedmont of Pennsylvania to the Blue Ridge of SW Virginia (the Cooper's lives in most of the United States). The eight or so people that spotted the feeding hawk near Belmont Bridge have been sharing their stories. This is how it happens. This is how awareness grows. These are the seeds of appreciation and understanding.

So, when you discover something out there that inspires wonder and awe, that piques your interest, do not hesitate to share with others. The effort in doing so is tiny compared to what is gained in return!

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Related Story: A Master of the Hunt, the first encounter with the Cooper's Hawk of Belmont Bridge

Unsuspected beauty in snake plant flowers

It is hard to believe that anyone has not at some time had snake plants (Sansevieria) in their family households. The ability of this interesting but strange plant to survive almost any treatment made it popular around the world as a house plant.

Unfortunately in warmer areas such as Florida they ended up planted outside and have caused considerable problems since they are highly invasive, especially in shaded forest locations where native plants are crowded out by the snake plant. Removing them is problematic since the roots break into small pieces and generate many new plants.

I have fought a running battle with snake plants in our Florida yard since a former owner got them started. So I always considered them a big pest with no redeeming qualities. However I have now recognized that the regular Winter-time blooms of these plants are actually quite interesting from an ecological perspective (see photo). A spike of white tubular flowers emits a powerful fragrance and is actually quite beautiful, if you can get past the bad-boy image of this species. I am always interested in predicting what might pollinate specific flowers, based on flower color, shape and smell. I found out that this plant originated most likely from Western Africa but have not yet found out what pollinates it in its native habitat. However the white tubular flowers with a strong odor indicate pollination by a night-flying moth with a long tongue, possibly a sphinx/hawk moth whose larvae are often called horn worms.

I did find one article that determined that the primary sugar in the nectar of the common snake plant is sucrose, and predicted that this in conjunction with the flower structure would attract mainly sphinx moths. Note also that the authors found extra-floral sources of nectar and surmised these might satisfy creatures such as ants that might otherwise steal the flower nectar and limit the plant's ability to reproduce.
http://aob.oxfordjournals.org/cgi/content/abstract/58/4/541

So look around you with a renewed interest in plants and animals that you might have dismissed as unworthy of notice, and you may find unsuspected beauty and interest among the "bad boys" of the natural world.

Bill DunsonEnglewood,

FL & Galax, VA