In the past five years an odd phenomenon has been observed on the bark of over twenty species of trees in New England — an intense reddish-orange coloration. It’s been determined that this is due to the presence of a microscopic green algae (Chlorophyta), tentatively identified as belonging to the genus Trentepohlia. A branching mat of thick-walled algal cells containing a bright orange-red pigment alters the color of the bark.
Red Bark Phenomenon is especially prevalent on White Pine, Eastern Hemlock, Red Oak and American Beech trees. Affected trees appear to be of varying ages and are often, but not exclusively,observed near bodies of water, such as swamps and rivers. Frequently (as pictured) only one side of a tree is affected.
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Because tree buds tend to swell and increase greatly in size in the spring, this is often the season when we first notice them and assume that this is when they are produced. However, if you look in the axils of leaves on any deciduous tree right now, you will see full-size buds that were formed this summer. These little packages of miniature leaves, branches and sometimes flowers, will remain on trees all winter, tightly closed and often protected from the elements by modified leaves called bud scales. Come spring, when trees are once again taking up quantities of water, their buds will swell, scales will fall off (leaving bud scale scars), and tiny, pristine leaves or flowers will appear. (Photo is of American beech, Fagus grandifolia, bud.)
Just a quick reminder that the NC Calendar ordering deadline is November 10th.
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In winter it is common to use the pattern by which branches and buds are arranged on a deciduous tree as a first, quick clue to the tree’s identity. There are two large groups of trees, those with alternate and opposite patterns, and a third less common pattern, whorled. Trees with alternate arrangement have only a single leaf/bud/branch attached at one location (node) on a branch. Those with opposite arrangement have two leaves/buds/branches attached at a node, opposite one another on either side of the branch. When more than two leaves/buds/branches arise from a node (rare) this is called a whorled arrangement.
At this time of year, when deciduous trees are bare, you can see the arrangement of buds, branches and leaf scars (where leaves have fallen off) clearly. Relatively few trees have opposite branching – Maples, Ashes, Dogwoods, and Horse Chestnuts – while a majority have alternate branching. More characteristics are needed to narrow a tree down to species, but noting its arrangement is an easy and quick way to eliminate certain species.
Striped Maple (Acer pensylvanicum), named after the vertical white streaks on its bark, is often associated with Moose and White-tailed Deer, both of which feed on its bark. In some places it goes by the name “Moosewood” for this very reason. The shape of its leaves give it another common name, “Goosefoot Maple.” In the spring when Striped Maples are nearly in full leaf, bright yellow bell-shaped flowers appear on long, pendulous strings, or racemes. (The flower stalks of the similar Mountain Maple also materialize after the leaves have matured, but these flower clusters are upright, held above the surrounding leaves.)
Striped Maples have the unusual ability to change sexes repeatedly over their lifetime (as does Jack-in-the-Pulpit), a phenomenon called gender diphasy. Among five study populations located in New Jersey, approximately one in four trees exhibited a change in the sex of its flowers between flowering seasons. The flowers of most Striped Maples are predominantly male. If changes occur in the canopy and new conditions seem favorable, a predominantly male tree can become predominantly female (and vice versa, if conditions deteriorate). Size, injury, and carbohydrate reserves are thought to impact the frequency and direction of gender change. Another unusual trait of Striped Maples is that the final sex of a flower is determined within one month of flowering, in contrast to most woody perennials which set buds the previous year.
In 1935 Walter Rogers wrote a book on tree flowers (Tree Flowers of Forest, Park and Street) in which he described White Ash (Fraxinus americana) in the following words. “The Ashes are important trees with interesting features of form and foliage, but their flowers are among the least interesting.” I am of a different opinion, at least regarding White Ash’s male, or staminate, flowers.
White Ash is dioecius – individual trees have all male or all female flowers. Just before and as the tree is leafing out, the flower buds, located on the shoots of the previous season, begin to open. Male flowers are more noticeable than female flowers, partly because of the size of their clusters — there are between 200 and 300 flowers in each cluster – and their vibrant color (which resembles the fall color of some White Ash leaves). Being wind-pollinated, White Ash’s flowers lack petals as they would impede pollination. The stamens are a purplish-red, raspberry-like color until they mature, at which time the pollen’s yellow color is predominant. The flowers are soon hidden by emerging leaves, so now is the time to see if you agree with Mr. Rogers!
There are two trees, both in the Birch family, which, due to the similarity of their common names, are occasionally mixed up with each other. One is known as American Hornbeam (Carpinus caroliniana) and the other as American or Eastern Hophornbeam (Ostrya virginiana). Due to the hardness of their wood, they also both go by the name Ironwood, adding to the confusion. A perfect example of when Linnaeus’s binomial system, which gives each species two scientific names, one of which is unique to each species, is helpful.
While the fruits and leaves of both species are superficially similar, their respective bark is very different. Carpinus caroliniana’s bark resembles flexed muscles (see https://naturallycuriouswithmaryholland.wordpress.com/2012/10/30/american-hornbeam/ ), earning it yet another common name, Musclewood, while Ostrya virginiana’s bark (pictured) has a “shreddy” appearance, with the bark broken into small, narrow plates which curve away from the trunk. Look for C. caroliniana in valleys and along streams, and O. virginiana on well-drained slopes and ridges.
Partridgeberry (the fruit is eaten by partridges, or ruffed grouse, as well as wild turkey, mice, foxes, skunks and deer) is a woody vine found creeping along the forest floor, often in large colonies. At this time of year there are bright red berries interspersed among the paired evergreen leaves. If you look closely at a berry, you will see two indentations at its tip. These are the result of the flowers’ unusual structure and the fruit’s development.
In late spring a pair of white flowers appears which share a set of sepals. Each small, fragrant flower has four white hairy petals that join to form a tube. The unusual aspect of these flowers is that they both must be pollinated to obtain a single berry. Each berry is the result of the fusion of the ovaries of the pollinated pair of white flowers. This fusion is what accounts for the two indentations on the surface of each fruit.