Delicious, Deadly & Decorative Decay: The Fungus Among Our Trees

On a regular basis, foresters are called out to investigate decay in trees to assess whether the decay poses a hazard to the tree and/or people. Trees suffer from decay fungi in several ways, with brown rot causing lack of flexibility, and white rot causing lack of structural stability, and often a combination of the two.

The science of detecting decay is still fairly young and the decision-making process to condemn decayed trees is complex and requires thorough risk assessment. Our interactions with mushrooms are not new, however, and many of the native species of tree decay fungi serve other functions. Here are some common fungi decaying trees, and how they also provide sustenance and even inspiration for art.

Hen of the Woods

Hen of the woods on an oak tree in Arlington. Photo courtesy of Rachel Jackson.

Hen of the Woods (Grifola frondosa)

  • Identification: Usually at the base of oak trees in Arlington or on the ground. Brown/gray, frilly fruit 1-2.5 inches in width. Single colonies can grow up to 50 pounds.
  • Causes white rot in tree roots. Can cause instability in trees.
  • Also known as maitake. Highly valued in Japanese cuisine. Significant medicinal value. The flavor is very nutty, similar to portobello. Becomes unpalatable when older.
Chicken of the Woods

Chicken of the woods. Photo courtesy of Wikipedia.

Chicken of the Woods (Laetiporus sulphureus)

  • Identification: Tan or yellow-colored shelf fungus, growing in overlapping clumps. Highly variable in size. Generally found on the trunk of trees.
  • Causes major brown rot in trees, compromising their trunk structure. Once the fruiting bodies show, trees are generally significantly compromised.
  • Chicken is the best comparison as far as taste goes. This fungus has the texture and flavor of white meat, and can be used as a great vegetarian alternative.
Artist Fungus.

Artist fungus. Photo courtesy of Wikipedia.

Artist Fungus (Ganoderma applanatum)

  • Identification: Large, hard, gray-brown shelf fungi, generally growing from the trunk of trees (beech and poplar in particular).
  • Rots the dead and the living parts of trees, mostly through white rot. Fruiting bodies are often an indicator of major structural damage.
  • This fungus is inedible, but is commonly used by artists to create intricate designs on the bottom of the shelf fungus.
Honey Mushroom

Honey mushroom. Photo courtesy of Wikipedia.

Honey Mushroom (Armillaria mellea)

  • Identification: Generally a honey-colored cap with a long white stem. Grows in clumps near the base of trees.
  • One of the major killers of trees in the region. Causes major decay in oaks and other hardwoods, and has even been found on conifers. If the fruiting body is found, it’s often an indicator of imminent tree demise.
  • The caps can be eaten, but need to be prepared properly, using parboiling to remove bitter taste and chemicals that may upset the stomach.

Keep in mind it’s very important to know you’re certain you’re working with a species of mushroom that is edible. Consult with mushroom literature or a mycologist to ensure proper food safety. It’s also a general rule that any mushroom shouldn’t be consumed in large quantities, as they can be hard to digest.

Some sources of mushroom identification and preparation:

“Fruit of the Gods”

This post first appeared on Capital Naturalist.

An American persimmon tree.

American Persimmon (Diospyros virginiana), the “Fruit of the Gods.” Photo courtesy of Alonso Abugattas.

Few trees have as much lore and ethnobotany surrounding them as the American persimmon (Diospyros virginiana). Though best known for its delicious edible qualities — but only when completely ripe — it has so many other traits. It is, however, hard to get past the wonderful taste of the fruits of this genus of small trees. The name Diospyros translates to “Fruit of the Gods” and many would say that is indeed a fitting name.

Even when not full of fruit — and since this tree is dioecious, only female trees produce flowers resulting in fruit — the flat, corky rectangular bark is often enough to identify American persimmon. It’s a member of the ebony family, with very dense, strong, and almost black heartwood.

Bark of a persimmon tree.

Rectangular bark typical of a persimmon. Photo courtesy of Alonso Abugattas.

Urn shaped flowers of a persimmon.

Urn shaped flowers. Photo courtesy of Alonso Abugattas.

The leaves are nondescript, and the flowers, though fragrant, aren’t often noticed. It seems as though the only time people notice these small trees (growing less than 70 feet at most) is when they are loaded down with fruits.

A persimmon fruit.

A ripe ‘simmon ready for eating. Photo courtesy of Alonso Abugattas.

Although many would say it’s deservedly called the “fruit of the gods” when ripe, few things compare to biting into a green persimmon. They are astringent and tart to the extreme. They so completely dry out your mouth that it’s quite a memorable experience for all the wrong reasons — and a favorite prank to play on people who are uninitiated and then tricked into biting into an unripe fruit. Captain John Smith, while near Jamestown, Va., in the early 1600s wrote: “If it be not ripe, it will draw a man’s mouth awrie with much torment.” The puckered mouth is said to last up to a full day (or at least it seems that way for those of us who have tried to eat one). So astringent is the green fruit that Francis Peyre Porcher in his treatise that is often referred to as the “Confederate Ethnobotany” says that it’s better than oak for tanning.

Persimmon fruit pulp and seeds.

Sweet, colorful pulp and seeds of a ripe persimmon. Photo courtesy of Alonso Abugattas.

A fully ripe persimmon is something else altogether though, considered delicious by most. Some compare the flavor to that of dates. Although many believe that ‘simmons are not edible until they have been hit by hard frosts, this is not true. While the cold does reduce some of the tannins and makes the fruit slightly sweeter, if the persimmon falls off the tree with only a slight pull or by shaking the tree, they should be good to eat. They should be slightly squishy and have lost most of their green coloration as well.

The fruits are full of vitamin C, can be eaten raw, and are used to make puddings, breads and cakes, or made into alcoholic drinks. In fact, Porcher, in his aforementioned Civil War manual, lists not one, but three different recipes for using persimmon to make beer. He also mentions that they can make a “particularly fine brandy.”

Porcher also notes that various parts of persimmon can be used to treat fevers, diarrhea, dysentery and sore throats. Other sources report Confederate soldiers using the roasted seeds as a coffee substitute and the seeds for buttons. Similarly, various tribes used persimmon not only for food, but for other purposes as well. The Cherokee, for example, used it to treat diarrhea, sore throats, heart burn and even hemorrhoids. The Rappahannocks made a strong spirit similar to beer as well. Oil from the seeds is said to taste similar to peanuts.

One of the most unusual uses for persimmons though deals with folklore claiming that one can predict how harsh the winter will be by cutting a seed in half. Legend says that if you look at the split seed, you should see one of three objects. If you see a spoon, then you will be shoveling lots of snow. If you see a knife, then it will be icy cold and the wind will cut like a knife. Finally, if you see what looks like a fork, then the winter will be mild and there will plenty to eat.

I must admit, the seeds are not easy to slice and the insides not that easy to interpret. Having said that, below is one I cut today and which I think resembles a knife. Let’s see if that prognostication has any merit.

Persimmon seeds.

Persimmon seed prediction for winter 2014-2015: the cold will cut like a knife. Photo courtesy of Alonso Abugattas.

Animals of course also make use of persimmon trees. Forty-six different species of caterpillars have been documented feeding on them. The fruits are consumed by numerous animals, though seem to be a favorite of raccoons and foxes in particular. In fact, their scat often have persimmon seeds in them this time of year and they are likely the main dispersers of these trees.

I thoroughly love to eat persimmons. They can hang on the trees for most of the winter. Though they may be shriveled, they still are quite tasty and a nice surprise on what might be an otherwise dreary day.

Water-Loving Trees and Their Adaptations

Tree roots stream side.Trees grow in all types of environments, and stream side or wetland areas can be some of the most challenging environments for trees to grow. While trees do need water, they face several challenges in a wet environment:

  • While they also use water and sunlight, trees need oxygen. Trees share at least 60 percent of genetic information with humans, and breathe and use oxygen for energy. A flooded or very wet soil has little oxygen, so this makes root growth and function difficult.
  • Wet environments are perfect for certain decay organisms to break down and damage trees.
  • Periodically flooded or flowing streams and lakes face more disturbance, with wet and dry periods during the year increasing the stress to the surrounding trees. While a tree in a flat field may suffer from temperature changes, the environment around water changes more drastically, requiring much hardier trees.

Trees growing near water with a view of Rosslyn.In Arlington, we have a lot of species that work well in this environment. Trees native to our County and in the region have adapted to these stresses in various ways:

  • Some trees adapt to wet soils by having very superficial roots. These roots exchange oxygen at the top layer of soil and help the tree survive in a high water table. Species that characterize this include maples, sweetgum, magnolias and elms. Great examples of these superficial roots can be found in Bon Air Park along Four Mile Run, near the shelter, where we have some of our native red maple stands.
  • The most common strategy to wet soils is to grow faster than any decay that may form, and heal over wounds caused by disturbance quickly. Eventually, these trees lose this battle, but they often pair the strategy by reproducing early in their age. These trees can be structurally unsound and often contain significant decay. Examples of trees like this are silver maple, American elm, and green ash. Barcroft Park is a great place to find many of these species along Four Mile Run throughout the park.
  • Slow-growing, rot-resistant wood is one of the more long-term strategies to deal with the high disturbance of a waterlogged environment. The species using this strategy tend to be found in older environments where they have waited patiently, growing slowly, to take over the shorter-lived species over time. Some of these trees are the longest-living species in eastern North America, and include black tupelo, black locust, baldcypress (longest-living tree species in the east, up to 2,000 years) and arborvitae. While baldcypress and arborvitae aren’t directly native to Arlington, you can find blackgum and black locust growing along Ballston Pond.

Trees growing in water.Because of all their adaptations and their resistance to disturbance, many species that can handle tough environments like this can be appropriate trees for urban, compacted planting as well. Arlington uses many species commonly found along streams to beautify our streets and improve our tree canopy. We also plant many of these species to restore existing streams to improve retention of soil and clean our water in the short- and long-term.

To learn more about trees in Arlington, including our tree programs, proper practices and recommended trees for planting, visit environment.arlingtonva.us/trees.