Lichens and Kipukas in Hawaii

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Whenever I visit the smooth, gray rocks on the North Shore of Lake Superior, I find myself crouching low to examine the colorful patchwork of lichens who have made their home in such a seemingly perilous place. I never expected to do the same thing on Hawaii!

Lichens on basalt with Lake Superior in the background. Photo by Emily Stone.

The basalt bedrock in the Northwoods hardened from lava that poured out of the Mid-Continent Rift 1.1 billion years ago. (If you want to learn more about the rift, visit our Northwoods Rocks exhibit!) While making plans to visit Hawaii last month, I knew that I’d be seeing much younger basalt, especially on the Big Island, where Kilauea erupted as recently as December 2022. What I didn’t expect was such an abundance of lichens that the rocks looked fuzzy!

Aptly named “the lava-colonizing lichen,” this pioneering organism is among the first to grow on basalt rocks after they cool from volcanic eruptions. Photo by Emily Stone.

Anytime I talk about lichens, I brag about how the symbiotic partnership between fungus and algae allows them to live where neither partner could survive alone, to colonize bare rock, and even to survive in outer space. The fungus provides a structure, and an anchor. The algae do photosynthesis and make food for them both out of sun, water, and air. Sometimes instead of algae, the partner is a cyanobacteria, who can do photosynthesis AND fix nitrogen out of the air. Plus, lichens are wind-dispersed, and as I wrote last week, wind is one of the main agents that brings new life to the Hawaiian Islands.

The first lichens I noticed weren’t growing on rocks, though, they were clinging to the trunks and branches of trees. The fuzzy, pale green strings were so dense they made the trees look like stuffed animals who had been loved and washed within an inch of their lives.

Fuzzy trees!

The trees were on a kīpuka, a vegetated hill in a sea of younger lava flows. Volcanoes erupted and formed the Hawaiian Islands. Over time forests grew, but the eruptions kept coming. Tongues of lava meandered across the flanks of the volcanoes, creating islands of older forest within a brand new landscape.

This view from a kīpuka on Mauna Kea in Hawaii highlights the age of the pale green lichen-covered forest in the foreground, with a background of newer lava flows. Photo by Emily Stone.

Kīpukas are essential reservoirs of biodiversity in Hawaii. Not only do they provide the source populations for revegetating fresh lava flows after volcanoes erupt, their isolation helps to protect them from invasive species. One kīpuka in Hawaii Volcanoes National Park is home to more native tree species per acre than any other forest in the park (and probably on the whole island). The diversity of lichens is far greater. Because they are sometimes hard to find and difficult to identify, the true number of lichen species in Hawaii may be impossible to ever measure, but it is likely more than 800 species, with at least 30 percent of those only existing in Hawaii.

Here you can see the forested kipuka in the background, with newer lava rocks in the foreground. Photo by Emily Stone.

While lichens make up a good part of the lushness and biodiversity in mature kīpukas, they are also key to helping life start over from scratch on the surrounding lava. On our way to explore a kīpuka along the Kaulana Manu Nature Trail, we passed by areas of younger lava rocks that weren’t yet covered in forest. They were, however, fuzzy with lichen! (see photo above)

The first species to arrive on freshly cooled lava flows is Stereocaulon vulcani, the lava-colonizing lichen. Fragments of lichen thalli (leaves) from other areas may break off and blow in, or the fungal partner within the lichen may produce dust-like spores that sail around the globe in the upper atmosphere. They especially thrive on the rugged a’a’ lava flows, where abundant surface area breaks down to release nutrients, and little holes left from gas bubbles collect rainwater.

These lichens can fix nitrogen—an essential ingredient for plant growth—while also breaking down rocks, building up soil, holding onto moisture, and providing cozy spots for other seeds and spores to germinate. The lichens shelter insects, which attract lizards and birds, the birds bring more seeds, and eventually a forest grows. The forest contains many more niches than the bare rock, so more and more species of lichens become established there, until they are carpeting the trees like the first ones I saw.

Lichens grow relatively quickly in the rainy areas of the islands. The ones I saw on the trees were sparkling with droplets swept out of thick clouds, which benefits the rest of the forest, too. They also enjoy the mild climate. Even though (according to one researcher,) at high elevations lichens experience “summer every day and winter every night,” I’m pretty sure that’s more conducive to growth than the Northwoods’ schedule of “winter for 6 months of the year.”

This looks just like our Usnea, or Old Man's Beard Lichen!

On the wave-washed, basalt shores of Lake Superior, it’s the bright orange Elegant Sunburst Lichen who first colonizes the rocks. Constant wave action prevents much more from growing there, for now. But if wave disturbance ever ceases, more and more lichens will move in there, too, building up soil and setting the stage for forests to grow. From afar, Hawaii seems really different from the Northwoods. Upon closer examination, I found all sorts of natural connections.

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too.

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Our exhibit: “The Northwoods ROCKS!” is open through mid-March. Our Winter/Spring Calendar of Events is ready for registration! Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.

Riding the Wind to Hawaii

From out of a vast, dark sea, a small area of lights appeared below. The landing went smoothly. As my parents and I descended the stairs onto the tarmac, steamy air made us regret our long pants and sleeves. With almost magical speed, we’d just arrived on the most isolated populated landmass in the world: Hawaii. As different as this tropical paradise is from the Northwoods, I still found plenty of natural connections.

My parents! Larry and Margaret Stone. It was raining in the rainforest on the Big Island when we arrived. After three days of rain, we flew to Maui, where it was windy. 

Several years ago we visited another remote island—Isle Royale in Lake Superior. While Isle Royale is much smaller and closer to the mainland, our trip to Hawaii was less strenuous and uncomfortable than the ferry ride across an angry, wave-tossed Lake Superior. Neither place is easy to visit. On that trip, I found myself asking everyone—human, plant, animal, and fungus— “How did you get here?” Now, on Hawaii, that question emerged again.

In preparation for the trip, I’d purchased a book titled Wind, Wings, and Waves: A Hawaii Nature Guide by Rick Soehren. Those are the means by which life began to inhabit the freshly cooled lava of these remote volcanic islands about 70 million years ago.

Our stay on Maui quickly highlighted the importance of wind to these unprotected islands. The Maalaea Harbor on Maui, where we launched for both a whale watch and snorkel tour, is one of the windiest harbors in the world. High surf warnings dominated my weather app for our entire stay, due to powerful gusts from the north. We stood in awe at huge waves crashing on the shore. Might that wind still bring new arrivals to the islands?

Big waves looking toward West Maui near the beginning of the Road to Hana.
Photo by Emily Stone.  

Being small and lightweight is key for wind dispersal, and the tiny spores of ferns are ideal. There are 200+ species of ferns on the Hawaiian Islands, but while the first ones blew in, many more evolved right there, and now occur nowhere else in the world. One of those 125 endemic species is ‘Ama’u, a beautiful fern that reminds me of our local cinnamon fern in the way that they grow in a beautiful vase-shaped cluster, and color their young fronds in a cinnamon shade to act as sunscreen. They are tough, and often stand as lonely pioneers on fresh, black lava flows.

‘Ama’u ferns on Hawaii can start growing on bare lava flows. They protect their young fronds with red pigment that acts like sunscreen. Hawaii Volcanoes National Park. Photo by Emily Stone.

Growing near the ‘Ama’u ferns are often ‘Ohi’a trees. Actually, it seemed like ‘Ohi’a trees were growing near everything! They were everywhere in Hawaii. A member of the Myrtle family, they and their cousins are some of the most widespread flowering plants in the Pacific. Lightweight seeds are easily dispersed on the wind, and despite their small size, they can survive below freezing temperatures and at least 30 days submerged in saltwater. The ‘Ohi’a lehua on Hawaii have evolved into new species, and occur nowhere else in the world.

Ohi’a trees join ‘Ama’u ferns in sprouting on rocks left by recent volcanic eruptions. The seeds and spores of each blew to Hawaii on strong winds, and still use wind to carry them to these fresh habitats. Hawaii Volcanoes National Park. Photo by Emily Stone

We spotted them on recent lava flows, often sprouting in cracks like you’d see a jack pine on much older lava on Isle Royale. In poor soil, Ohi’a stay shrubby. As their leaves add to the soil, and other plants move in, eventually the Ohi’a grow to full size trees and are an important component of forests.

'Ohi'a lehua shrub on a pretty recent lava flow. 

Even though we didn’t visit during their season of peak blooming, most of the Ohi’a trees we spotted had at least a few flowers gracing the ends of their twigs. A mass of red stamens makes them look fuzzy. And hiding among those flowers, sipping nectar, are two red birds who match the flowers perfectly! The ‘I’iwi and 'Apapane are two types of Hawaiian Honeycreepers, a group reminiscent of the Galápagos finches. Their ancestors arrived on wings (probably with the help of big storm winds!), but I’ll write more about them later.

Can you spot the bird in the red 'Ohi'a lehua flower? :-)

On Isle Royale, wind also brought ferns, as well as trees like aspen and birch, and 32 species of orchids with their dust-like seeds. Despite the fact that orchids are adapted for wind dispersal, Hawaii was not so lucky. There are only three native orchids on Hawaii. Several more have escaped from gardens.

Bamboo Orchid, native to Myanmar, India, Sri Lanka, Nepal, Thailand, Vietnam, the Ryukyu Islands, Malaysia, Singapore, China to Indonesia, the Philippines and New Guinea...but not Hawaii. The native orchids are super rare. Photo by Emily Stone. 

One group of critters you may not think of riding the wind to new places are spiders. They release little strands of silk, which first rise due to the Earth’s electrical fields and then catch the wind, and balloon away! Over 100 spiders are native to Hawaii. We peeked under hundreds of leaves to spot a famous “Hawaiian happy-face spider” with a cheesy red grin on their abdomen, but only ended up spotting several fog-dappled spider webs.

Spiders found their way to Hawaii more easily than most other animals. Spider silk acts like a balloon to help them catch a ride on the wind. Hawaii Volcanoes National Park. Photo by Emily Stone. P.S. There were SO MANY lichens in Hawaii! That might be another article...

These webs remind us of how everything is connected. Even the most remote islands in the world are linked by the transporters of wind, wings, waves, and ecological processes like evolution. One benefit of travel is that through finding those connections it helps us appreciate our own home.

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too.

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Our exhibit: “The Northwoods ROCKS!” is open through mid-March. Our Fall Calendar of Events is ready for registration! Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.

Iron and Life

The old road angled steeply up the hillside. Thick drifts of autumn leaves concealed loose rocks and little ravines. Saplings and brush crowded in from the sides, threatening to scratch cheeks already rosy from the cold. After several minutes of tough hiking, the road leveled out, and big concrete structures loomed among the trees.

From 1922 to 1924, the Pioneer Mining Company operated an open pit iron mine on Mt. Whittlesey near Mellen, Wisconsin, although pit doesn’t seem quite accurate. There’s no big hole, the hillside merely looks a bit sliced off. Mining and quarrying, along with fur trapping, logging, and attempts at farming have sculpted the landscape of the Northwoods since the late 1800s. But that history is influenced by far older events.

Continuing past the concrete ruins, my friend and I followed the scar of the old road to the top of a cliff. Smooth, dark rock peeked out from beneath dry leaves and grass. Kneeling for a better look, we found stripes of red, black, and gray with smooth, waxy, and sparkling surfaces. Crustose lichens had found toeholds in each tiny crack, so the surface was also decorated with little blobs in shades of brown, white, and yellow.

These lichens may be much younger than the outcrop, but the rock itself is no stranger to photosynthesizing friends. In fact, iron formations like this one record a major milestone in the history of life on Earth. Back in the day, and by that, I mean 1.9 billion years ago, the atmosphere was filled with carbon dioxide and methane, and the first inklings of life had only just begun. Volcanic activity in the early oceans, and erosion off the few continents, enriched the water with iron and silica.

As algae and cyanobacteria began turning water and carbon dioxide into sugar using energy from sunlight, they also emitted oxygen into the ocean where they lived. The oxygen reacted easily with the dissolved iron and silica, causing them to precipitate out of the water into the minerals hematite, magnetite, and jaspilite. Those minerals accumulated on the bottom of a shallow sea who sloshed between the shores of two early continents. Over time, the mineral mud hardened into stone. This stone. I pressed my hand to rock.

The minerals didn’t precipitate homogeneously, though, and built the rock in a series of bands with different colors, textures, and thickness. Seasonal fluctuations in algae growth may have contributed to some of the variation. The rise and fall of landforms on the early continents, and the weathering and erosion of different rocks, may also have altered the chemicals that fed into the sea. An even wilder source of the variation is that the early life hadn’t evolved with oxygen, and if ever the dissolved iron didn’t immediately clean up the oxygen they pumped into the water, the algae would have poisoned themselves, causing population fluctuations.

Banded iron formation is made up of layers of different minerals, mostly various combinations of iron, silica, and oxygen. Some of the layers are made of magnetite, and so a magnet sticks to the rock outcrop. Photo by Emily Stone.

I’m not a good enough geologist to tell you what conditions led to which bands, but I could see that some dark gray bands were smooth while others were rough and sparkling. And a few layers were a whimsical mash of red and gray polka dots in a darker matrix. The red dots were iron-stained quartz, sometimes called jasper or jaspilite. Geologists call this texture “granular iron formation,” and in this case, it represents sands broken out of slightly older iron formations that rolled back and forth in shallow waves before solidifying again.

Tiny red polka dots represent sand-sized pieces of iron formation that were rolled in waves before solidifying back into rock called granular iron formation. Photo by Emily Stone.

A billion years after precipitation stopped and the layers became rocks, intense tectonic activity in this region (the Mid-Continent Rift!) upended everything. Iron formations are sedimentary rocks, and therefore form in horizonal beds, flattened by the force of gravity. The action of the rift caused the center of Lake Superior to drop and the edges to curve upward like the pages of a book bent in a U. Rocks that once covered the bottom of a shallow sea now form narrow ridges at the surface and then dip steeply underground.

My friend and I descended the irregular, stair-like face of the cliff, vacillating between admiring the rock, the colorful lichens who clung in cracks, and the lush green mosses who soaked up trickles of water. Knowing the history beneath me, I was impressed by the sheer mass of iron that the early algae and cyanobacteria caused to precipitate out of the seawater. While there are a few iron formations older than this one, and some younger ones, too, iron formations of this age are notably abundant, especially in Minnesota and Michigan.

One of the final, amazing chapters in this saga is that the algae and cyanobacteria eventually evolved enzymes that allowed them to live with oxygen. No longer at risk of poisoning themselves with the element, they proliferated wildly, their oxygen waste sweeping most of the iron and silica out of the ocean water for good. Then excess oxygen, no longer tied up with iron, escaped into the air, and began creating the atmosphere we enjoy today.

My friend and I breathed deeply, grateful for the oxygen, the beautiful rocks, and the scientists whose research uncovers the Earth’s stories.

Author’s Note: You may have noticed that I refer to the sea, rocks, lichens and mosses as “who.” This is a deliberate choice in using a “grammar of animacy” and recognizing that not just humans possess the quality of life. I find that using this language causes a positive shift in the way I think about the more-than-human world. For more on this topic, I highly recommend an essay called “Speaking of Nature” by Robin Wall Kimmerer, available easily through an internet search.

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too.

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Our exhibit: “The Northwoods ROCKS!” is open through mid-March. Our Fall Calendar of Events is ready for registration! Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.

Birch Polypore

The rocky trail led up and over and around tree roots and boulders, and we hiked steadily to stay warm. As we navigated the stairs of a birch tree’s roots, my friend pointed out a pale grayish fungus poking out from the trunk like a small, fat Frisbee. “Birch polypore,” I offered reflexively, not needing to think at all about the name of this common and easily recognized species. Not having been on very many hikes with me, they were startled by this casual identification, and burst out in surprised laughter. This made me chuckle, and soon we were both giggling down the trail.

Birch Polypore

That laughter was good medicine, and fitting that it came from a mushroom with so many uses. Birch polypore, or Fomitopsis betulina is a bracket fungus who grows on birch trees around North America, the British Isles, Europe, and Asia. This fungi’s big moment of fame came with the discovery of Otzi the Iceman, a 5,300-year-old man frozen in the Italian Alps. Otiz was carrying two small lumps of birch polypore on a goat-skin thong around his neck.

Initially, some researchers put forth the idea that the fungus contains a laxative compound that Otzi was using to treat whipworms in his gut. While this sounds logical and interesting, and spread quickly throughout the internet, other scientists found no cultural or experimental evidence that chemicals in the fungus have that particular effect.

There are far more reliable reports in traditional medicine, especially in Europe, of birch polypore being used as an antimicrobial, anticancer, and anti-inflammatory agent. In Canada, a paper on Traditional Dene Medicine based on collaborative research with Indigenous knowledge holders, reports that the fungus was boiled into tea that could heal internal bleeding, ease heart pain, and more.

Traditional medicine, like those examples, is based on Indigenous science. While Western science uses short-term experiments that generally test one thing at a time, Indigenous science is practiced using trial and error over centuries, and is integrated into daily living. The knowledge gained through Indigenous science is valid and valuable. It can lose significance when taken out of its cultural context, though, such as by anthropologists without the full picture or a game of telephone on the internet.

While Indigenous science doesn’t need to be vetted by Western science to be valid, it often spurs research questions that lead to that outcome. In the case of birch polypore, pharmacological studies provide evidence for antiviral, anti-inflammatory, anticancer, neuroprotective, and immune tonic properties in the tea, and especially in an alcohol extraction of the fungus. Of course, none of those experiments contain the cultural context of how to treat a patient with this medicine.

Birch polypores aren’t just used for internal medicine. Slices of the fungi have been used as band-aids with built in styptic properties by people in Great Britain. Recently, this versatile fungus has proved useful for sharpening razors, polishing Swiss watches, soaking up sweat in hat bands, and by entomologists for mounting insects.

The pores on the underside of Birch Polypore are part of what make it so useful for soaking up sweat or stopping bleeding. 

Insects who haven’t been killed and mounted yet, mites, and even white-tailed deer, also rely on birch polypore as a source of food. Fungi are high in protein. The first time birch polypore caught my attention, it was because a deer had taken a nibble out of one right at my eye level in the Museum’s Wayside Wanderings Natural Play Area.

The fungus is an active player in the food web as well. Birch polypore may infect a wound in a birch tree and then just hang out for years, held at bay by the tree’s immune system, until the tree is weakened by other factors. Then the fungus begins to spread and eventually contributes to killing the tree.

As a brown rot fungi, birch polypore breaks down cellulose in the tree cells and turns it to sugar, but leaves the dark, woody lignin behind. According to Tim Adam’s PhD thesis, published the year I was born, wood being decomposed by birch polypore smells like green apples. Naturally I had to see for myself, so I set out on another hike, this time with a small folding saw in my pocket. Slicing a notch out of a birch trunk riddled with young polypores, I sniffed deeply. While the scent was a bit sour, I don’t believe I agree with Tim. Still, he spurred curiosity that got me outside on a sunny day.

From laughter, to curiosity, to other forms of internal medicine, birch polypore is a common fungus with a lot to offer.

Emily’s award-winning second book, Natural Connections: Dreaming of an Elfin Skimmer, is available to purchase at www.cablemuseum.org/books and at your local independent bookstore, too.

For more than 50 years, the Cable Natural History Museum has served to connect you to the Northwoods. Our exhibit: “The Northwoods ROCKS!” is open through mid-March. Our Fall Calendar of Events is ready for registration! Follow us on Facebook, Instagram, YouTube, and cablemuseum.org to see what we are up to.