A Walk in the Winter Woods

This week I had a chance to go on a field trip with the Georgia Botanical Society to observe some of the native woody plants in their winter garb.  I like to observe plants in the winter – without the distraction of leaves and flowers you can appreciate some of the other characteristics of the plant.  In fact there are a few plants that I can identify faster in the winter!

Amelanchier sp. bud in winter

We started out by looking on the ground for clues that would help us understand some of the trees that were there.  The ground was covered with oak leaves, acorns, acorn caps, small twigs that had fallen to the ground; even though the trees soared above us, these items helped us figure out what they were.  There were 3 types of oak leaves: southern red oak (Quercus falcata), scarlet oak (Quercus coccinea) - later confirmed by acorns found - and white oak (Quercus alba).  We talked about the variable leaf shapes (especially on the southern red oak which had various numbers of lobes on different leaves), how the sinuses can be deeper on leaves that grow at the top of the tree where sunlight is more plentiful, and how oaks in the red oak group of the genus have bristle tips.  We also discussed acorn differences such as the early sprouting white oak acorns and the differences in the caps.  Later we found some sprouting scarlet oak acorns and observed the distinctive rings around the base of the acorn.  We also found some black oak acorn caps (Quercus velutina) and leaves from chestnut oak (Quercus montana). Someone also found an old flower spray from a sourwood (Oxydendrum arboreum).  The ground has a lot of clues!

We walked along and found some young trees that were small enough for us to examine their twigs.  Twigs are the most recent growth on the branch.  Leaf arrangement on a woody plant is a key identifier – all good tree identification books have keys, and leaf arrangement is usually the second question (first question is whether it is evergreen). Even without leaves, leaf arrangement is visible not only from the leaf buds but also from the branching structure of the tree.  We looked at the shape of the leaf buds and the leaf scars that were left behind from the previous year’s leaves.  Sometimes the leaf scar is no longer clear enough to make out characteristics like bundle scars; we ripped off one of the leaf buds on a tuliptree (Liriodendron tulipifera) so that we could get a look at the bundle scars.  One of the young trees we found was a black cherry (Prunus serotina) so we were able to examine the smooth bark with the numerous lenticels that is so distinctive of this very common species.

Something gets a closer look

We found a pair of young pine trees close together.  Because they were different species, we could compare the differences in the length of the needles as well as the number of needles found in each bundle.  Loblolly pine (Pinus taeda) has 3 needles per bundle while Virginia pine (Pinus virginiana) usually only has two; in addition, the Virginia pine’s shorter needles are a bit twisted.  Later, someone found a branch from shortleaf pine (Pinus echinata) on the ground and we were able to see the needles were similar to the Virginia pine but not twisted and a little bit longer.

As we walked further we found two plants growing so close together that it was a good reminder to make sure you separate the branches before trying to key it out.  This pair was a native azalea (Rhododendron sp.) with fat bloom buds, and a dogwood (Cornus florida) with no bloom buds.  The dogwood has opposite leaf arrangement while the azalea has alternate - you'd be going down the wrong key if you picked the wrong branch.

Hamamelis virginiana

Next we found some witch hazel (Hamamelis virginiana) which opened up the topic of bud scales.  Witch hazel leaf buds have no scales – what you see are the leaves themselves.  We were fortunate to find one that had bloomed in November – we could still see the flower structure as well as seed pods from the previous year.  Witch hazel seeds take a full year to develop – a rather unusual characteristic.  Nearby there were two species of hickory growing side by side.  Using our hand lens we found the distinctive yellow (some say “silvery”) dots on the slender twig and bud scales of sand hickory, Carya pallida.  The stout twigs and buds of the mockernut hickory (Carya alba) needed no hand lens to identify!

Viburnum acerifolium

Leftover fruit is a good way to identify things.  We found a mapleleaf viburnum (Viburnum acerifolium) that had a few fruits still clinging to the leftover umbel-like structure that was the flower.  This was helpful in distinguishing this opposite-branching plant from the more common red maple (Acer rubrum) which is also present in the area.  The viburnum also had some plump terminal buds that were clearly going to become flowers, another difference from the maple.  Nearby was another plant with fruit as well as some old leaves: sparkleberry (Vaccinium arboreum), the most tree-like of the blueberries.

Just a bit further was a young sweetgum (Liquidambar styraciflua).  The bright green twigs and shiny green buds were the only part of the tree not covered in thick corky growth.

We also had a chance to see some perennials – evergreen ones like heartleaf ginger (Hexastylis arifolia), the cranefly orchid (Tipularia discolor) and ferns like Christmas fern (Polystichum acrostichoides).  Everybody likes a little green in the winter!

So while you’re waiting for spring to come along, have a walk in the woods and see what’s there.  Don’t be intimidated by the lack of leaves! Identification clues are there for those that look.

P.S. The state and national parks are great places for a hike.

Folks compare notes during the walk