One more tree species bites the dust…

a longer post than usual.

How can a tiny bacteria, fungus or insect wipe out a whole species in a short amount of time? The most destructive forest insect to ever invade the U.S. is in our forest now, and most of the ash trees are dying or already dead. Painful as it is to see, there is nothing we can do. This isn’t the first time an exotic organism surged through our forests and took out a keystone tree species. To better understand why this happens, lets look at some of the earlier tragedies.

Once upon a time, the American chestnut was a mainstay of eastern forests, reaching great height and girth. In the early years of the 20th century we learned the true price of global trade, when the pathogenic fungus Cryphonectria parasitica got off the boat from Japan in a wood shipment. It proceeded to kill almost every American chestnut, a species of great economic and wildlife value (there were as many as four billion trees). Cankers erupted from the bark of infected trees and quickly resulted in death due to chestnut blight disease.

Chestnuts growing in isolated locales were spared from the wave, and they became the starting point for recovering the species through breeding with resistant asian chestnuts. Current research focuses on genetic modification, by adding a gene from wheat that protects against the fungus. It’s a complex process that’s taken over ninety years, but healthy resistant trees are now being grown.

resistant 15/16th American chestnut  at the LNC- there are three,  planted and tended by the American Chestnut Foundation

Time for some science – what exactly does “resistant” mean? For a species to develop resistance to a pathogen, a huge number of non-resistant individuals have to die. This leaves the lucky few with resistant genetics to repopulate. In the case of the Chestnut blight, we can assume the fungus causing it has preyed upon chestnut trees in Asia for a very long time, long enough for resistance to develop (the chestnut genus Castanea is at least 65 million years old, and likely originated in Asia). That’s why scientists turned to the genetics of asian chestnuts to “fast forward” the work of restoring the American chestnut – they fought that battle long ago and survived.

What’s left of an American elm, near post #19 in our forest

In our forest the next major wave was Dutch elm disease, which occurred in my lifetime. I can still remember the grand old American elm that landed on my father’s car when I was a teen. The pathogen in this disease is also a fungus (Ophiostoma nova-ulmi), but it is harbored and spread by  bark beetles, both native and exotic.

 The skeletons of these elms still rear up here and there in our forest, and their large limbs continue to fall off, adding to the abundant supply of downed wood. The species is not all gone. Thanks to resistance shown by cultivars, which over time will cross with typical natives, we may see a recovery of the American elm.

But the worst is still to come.

Because this innocent looking little hole….

 

 

 

means the death of this huge ash tree, and hundreds more like it in our forest. And who knows how many millions, eventually billions in the whole eastern US. You’ve heard of it by now – EAB, short for Emerald ash borer. Unlike many of the other tree plagues, there are no fungi involved here. The larva of the beautiful iridescent beetle Agrilus planipennus does the damage all by itself.

EAB infestation was first noticed in Michigan in 2002, some time after larvae had arrived from Asia in a wood shipment. (If you’ve noticed the Asia connection for invasive pathogens, there is a reason. Pangaea, Big ice, and north -south mountain ranges explain most of it. Our Midwest flora has much more in common with China than the western U.S. A story to explore in a future post)

EAB larvae tunnel and feed throughout the living cambial layer, starting high in the trees and moving lower each year. So infestations are often not noticed until the tree is nearly dead. It only takes a few years to kill a tree when ash borers reach peak abundance in a forest.

 

Our forest, which is rich in ash trees of all sizes, is likely  near that stage now. Older ash trees are particularly abundant on the floodplain – depending on the site, ash species comprise 40% to 80% of the midsize and larger trees.

White and Green ash have a distinctive bark pattern that’s easy to spot

But there may be a silver lining, if you can call it that. Over the last 50 years our forest trees have continued to close the canopy, with less light going to the understory. Sadly, an invasive shrub invasion was underway too, with shade tolerant species like privet and honeysuckle coming into dominance. Now the opposite is occuring – invasive species removal plus EAB death equals a lot more light. The site of just one old ash tree’s demise can be considered a forest “gap”, the place where regeneration takes place. Some ash trees are already dismembering, as in the photo below, where one half the tree slabbed off in high winds.

So is this an opportunity or a nightmare? That depends on our actions as forest managers over the next few decades. All this sunlight pouring in could help revive an understory community of young trees, and gap colonizers like Pawpaw (Asimina triloba) and Spicebush ( Lindera benzoin). Or the invasives could all grow back with renewed vigor. Likely it will be both scenarios, with increased growth rates of native and invasive plants, and continual vigilance needed to keep the revival on track.

Pawpaw fruits in our forest

But something good is trying to happen – Spicebush regeneration from seed, documented by all those little red flags – is occurring at a surprising rate in some places. Scores of tiny ones may surround a large Spicebush that is a copious seed producer.

Spicebush berries in October

Very young spicebush are so abundant in spots that we’ll be transplanting some to a nursery site near the LNC, to “grow out” in sunlight and great soil. These plants will return to the forest when 2 to 3 feet tall, to areas where no spicebush currently grows.

Though Spicebush is adapted to grow in understory shade, with increased light it produces berries much more abundantly. Only female plants grow them, but an eight foot or taller bush can make hundreds of deep red berries. So the increase in light levels will speed up a Spicebush revival. And this is a great plant to have more of – unbrowsed by deer, it’s one of the most common shrubs of moist eastern forests. The lipid-rich berries are fuel for migrating thrushes, in particular.

 

Of course we cannot really understand all the complex interactions that will be altered by the loss of our ash trees.

Though there are few positives with such a huge forest die-off, in our particular case it may be a chance to revive an understory community that was overwhelmed by invasive plants. It’s good to remember that in nature, change means opportunity. And for woodpeckers at least, it’s a real windfall.

 

One of the great things about spending time in the natural world is getting to experience its ever-changingness. New surprises pop up daily, even in our small fragment of a forest.

Here’s a chance to test your nature interpretation skills, with some photos from the past few months. Guess what the picture is about, and check your answers below.

 

 1. Hint – the snow free area is about 3.5 feet at the widest.

 

 

2. The two pics above are feathers from the same unfortunate bird – what is it?

 

 

3. I kicked this organism to produce the dusty looking brown cloud

 

 

4. Yes it’s a deer skull, but there’s something different about it.

 

 

5.  Another unfortunate bird – the yellow color is a hint

 

 

6. Hint – this strange pattern was hidden by the bark of a tree.

 

 

Answers:

 

1. It’s a deer bed. Deer spend plenty of time lying around – it helps them conserve energy when it’s cold and stay comfortable when it’s hot.

 

 

2. Note red feathers on the back of the head, and  bl. and wh. barred wing feathers of a male Downy Woodpecker. Why would anything bother with such a tiny bird and how would they catch it, since the Downy is not a perching bird? Likely suspects – Cooper’s Hawk or Screech Owl.

 

 

3.  Lovely in its youth, this giant puffball, Calvatia gigantea,  must fulfill its purpose in life by turning into a spongy brown mass of spores.

 

4.  The flat-top knobs on the deer skull are “pedicles”, not antlers. This little guy died in his first year. We know this because pedicles must develop first, before antlers can grow from them. These are the pedicles of a young buck.

 

 

5.  A Yellow-shafted Flicker also was eaten. See the little streak of yellow feather shaft peeking out from the wing. I have observed a number of piles of these lovely yellow feathers over the years. Not sure if Flickers get eaten more, or if I just notice their feathers more.

 

 

6.  The hieroglyphic looking marks are the larval feeding paths of the Emerald Ash Borer beetle. It kills an ash tree by feeding on the living part of the inner bark that moves sugar and nutrients. Over time this layer is so disrupted that it can no longer function.

 

So how many did you know? Four or more and you earn the title of “naturalist”. Less than three – it’s time to get out in the woods more!

 

Having just finished a post about wildly colorful fungi,  it’s time to go to the opposite extreme. Be forewarned – this post is as much about art as it is about nature.

 I have a confession to make – I’m getting bored and irritated by pictures of nature. Often they have a color-saturated fantasy look about them, as if the reality isn’t good enough. I have been guilty myself on these pages, of amping the colors in a photo to make it more eye-grabbing. But I’m also a big fan of going backward to the black and white image.

(Viewing this through your email? Consider going to the blog itself for a better image appearance.)

 

 

 

 

 

 

If you’re following this blog you know I used to take black and white photos and print them in my darkroom. Yes, the old-fashioned way with smelly chemicals. So much easier to just turn on the “edit” feature, and make an ordinary color pic into something else. These are not actually “black and white” – rather they are toned, so  there is still a hint of color to indicate the warmth or coolness of the light.

Every forest is different of course. Having spent so much time in this one I’m getting to know its unique character. Somehow monotone images capture this better than color, maybe by eliminating some of the element of distraction.  Trees and fungi, with the way they grab the light, are well suited to this approach.

 

 

 

 

The visible presence of fungi is an important part of the character of this forest. Wave after wave of windstorm, disease, and infestation have laid many an old tree on the ground. And then the fungi come to feed, spreading their hyphae deep into the fallen trunks. What we see above ground is just the “tip of the mushroom” – the fruiting bodies that produce spores.

 

 

 

 

 

In a monotone image, fungi are distanced from our ordinary perception and revealed as truly astounding ghostly eruptions.

 

 

One of the joys of winter woods – afternoon filtered light on tree trunks. This pic is sepia toned and softened to give the feel of an old photo. It would be amazing to have an actual old photo or two of this place from back in the day. Just 100 years ago there was likely very little forest here, just scattered trees, grazing livestock, even fields of corn.

 

Imagine scrolling through the centuries in our time machine, in this one place, as forests rise and fall and rise again.

 

Speaking of rise and fall, the pic below introduces the next post, still being written. Can you guess what it will be about?

 

 

 

this velvety red fungus has yet to be ID’ed

Though winter woods are beautiful and so revealing, by this time of year I am longing for more color. Not just the green of madly photosynthesizing leaves, but the rarer hues.

In our forest the brightest pigments pop up unexpectedly – in the fruiting bodies of fungi. I never hunt for fungi, but find them in the course of doing something else. Another one of the perks of being off-trail a lot cutting or pulling invasive plants.

But what is the purpose of fungal pigments? Very few fungi need to attract the services of insects, since they don’t engage in cross pollination. One group that does advertise are the stinkhorns. With the color of flesh and smell of rotting meat, plus a coating of nasty brown slime called the “gleba”, there is no doubt who the customers are. Flies walk on and eat the spore containing slime, then act as dispersers.

though young and fresh, this Mutinus caninus is already attracting flies

 

It’s harder to understand why the color pink would be needed by the  life form pictured below, part of a kingdom so ancient that it predates insects.

If you did a search by typing in “fungus that looks like bubble gum” you’d get a lot of pictures of this. Except that it isn’t a fungus at all, it’s the bubble gum slime mold in its spore-producing stage. This one is a cosmopolitan species, meaning you can spot it in South Africa, Scotland and Alaska. I was lucky enough to spot it on a rotten log in our forest.

Not even close to fungi, slime molds have their own kingdom, the Protoctista. A slime mold you may have seen is the equally descriptively named “dog vomit slime mold”, its neon yellow plasmodium often creeping over front yard mulch in search of food. The sporangia stage that it changes into overnight is not nearly so attractive, hence the name.

 

 

Leucocoprinus birnbuamii

According to my internet search, this vivid mushroom is most likely to pop up in a flowerpot or a green house, though I photographed it in our forest. The “yellow houseplant mushroom” as it’s called in North America, could be considered an invasive species since it has traveled out of the tropics with the help of humans.

 

 

cut honeysuckle limb turned over to expose Terana caerulea,

Back to the question of colors – how does science explain the shockingly bright hue of the cobalt crust fungus? (It really defines the color “cobalt blue”- the first time I saw one, was sure that someone had been busy with a can of spray paint!)

The cobalt crust, also described as “blue velvet on a stick” is relatively common in our forest. It shelters on the underside of dead limbs, enjoying the wealth of new habitat found on cut bush honeysuckle. And the blue pigment is much more than color – it’s a biochemical weapon and defense system, particularly against bacteria. Since this fungus occurs in Europe too, it has been well studied, and the antibiotic cortalcerone is made from it. In fact, bacteria also use pigments in this fashion and can be disabled in the lab by having their colors removed.

These pigments are found throughout living systems, another example of our close relatedness with all life.  Melanin, which shelters us from ultraviolet radiation, is found in fungi too – researchers refer to it as “fungal armor”

So when you next see a shockingly colorful mushroom – ruminate on the wealth and potency of the biochemical compounds we call pigments. And isn’t it humbling to realize how much we share with fungus?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Sometimes the one that gives shelter needs sheltering

Smilax, we almost let you down. In our zeal to cut down all those big bush honeysuckles, we didn’t notice you were protected by some of them. Your vines happily streaming up to the sky from the center of an impossible tangle, ringed round by impenetrable bush honeysuckle and privet.

With the thickets of invasives gone, you were open to attack from big-eyed herbivores. Young tender shoots disappeared one by one, and the glorious spiny tangles began to shrink.

That’s unfortunate, since smilax patches give shelter to small creatures, young trees, and ground nesting birds. And shelter is scarce where we have removed invasive plants, since almost nothing else was growing there. It’s an awkward time, still a long way from the dense understory of native shrubs like spicebush that can be found in more intact forests.

But shelter can be created too..

Note the green ropes of a Smilax hispida clonal patch, with brush and limbs strategically placed to prevent entry by deer. This technique is part of the “revival” – to actively encourage the return and survival of native plants in our forest.

 You’d think these thorns would be enough to discourage anything.

If you have been reading this blog you know I am fascinated by vines. All kinds of vines, even the invasive ones like porcelainberry and wintercreeper. They’ve hit on a great way to get off the ground in a hurry – dispense with the upright woody architecture. It takes time for plants to grow woody stems, and while they’re short there’s a good chance of being shaded out or eaten. But vines grab onto the stems surrounding them, and climb away. Tendrils are one of the more popular adaptations for climbing –  the twining fingers of vines.

 

If I haven’t yet convinced you of the amazingness of smilax, I have one last thing to offer..

 

         The Turbulent Phosphila

Yes, that is truly the common name of Phosphila turbulenta, a species of moth that feeds only on smilax. The caterpillars cluster together for safety in numbers, and what looks like their head is their rear (a common caterpillar ploy).

Though in their other life they are dull brown moths, the glory of a cluster of phosphila caterpillars is something we should all get to experience. Watch for them this summer –  the smilax revival is underway.

 

 

 

In our forest especially…

This young hickory was squeezed in its youth by a Japanese honeysuckle vine. Thankfully it survived – but  with a twist that will last all its days. I’ve never seen a mature tree that was a victim of this vine. Does this mean the vine hasn’t been in our forest that long, or that trees subjected to this treatment don’t live a long time?

Another squeezed tree, a sassafras. In this case the strangulation inspired side shoots to emerge, perhaps anticipating the death of the upper part of the trunk. I removed the vine from this one several years ago, in an ongoing effort to rescue as many small trees as possible from a viney grasp.

 

Japanese Honeysuckle is a twiner, and once it finds a tree to climb its entire stem behaves like a spiraling tendril. It’s racing for the light up high, to flower and make fruit. Note the green leaves in February – with this mild winter it gets a longer growth period.

 

Black cherry revival – before and after. The vines were removed and drooping side branches trimmed, resulting in a relatively undamaged tree, just with a bit of a lean.

 

Another way to not grow old – a young black cherry and hackberry, both buck rubbed. Bucks do quite a bit more than rub their velvet off on trees. Under a heavy dose of testosterone they spar with, shove, and batter saplings and trees up to 4 or 5 inches wide. They trade scents, leaving their own, and taking with them the aroma of cedar, spicebush, black cherry or sassafras (favorites for rubbing).

 

Black cherries in particular are all the rage for rubbing during this season’s rut,  I’ve seen at least 15 of this size. When more than half the cambium is removed the tree is done for. Even if it’s less than that, the future tree is quite compromised and may succumb to rot. Easy prediction – between browsing and rubbing, no more black cherry making it past youth in this forest.

 

Rubbed oaks are seldom seen in our forest, likely because young oaks are so very few. Was enjoying the colors on this young red oak, when I noticed the bare white wood at the base of the trunk. It was already done for.

The last category of unfortunate trees has no images to go with it. These heavily deer browsed trees under 4 feet tall are so tiny and spindly I did not succeed in getting a good picture of one. Though they are small, it’s likely they may be much older than they look. We’ll just have to imagine them thriving in some faraway forest where the hazards are fewer.