Creature: Soil Sponge

Organisms like fungi and plant roots that build soil structure and enhance water retention.

Featured Creature: ‘Ōhi’a Lehua

What tree has adapted to grow directly in lava rock and is a keystone species of the Hawaiian watershed?

‘Ōhi’a Lehua (Metrosideros polymorpha)!

Image Credit: Kevin Faccenda via iNaturalist 

The first time I saw the vibrant blossoms of the ‘ōhi’a lehua tree, I was walking on a dirt path in Kauai’s Waimea Canyon State Park, gaping down at the most colorful red and green gorges I had ever seen. Needing a breather from the steep visual plunge, I looked up from the canyon and noticed bright red flowers on the side of the path. As I got closer and could see the plant more clearly, the first thought that popped into my head was how similar the flowers looked to those fiber optic light toys I had played with as a kid. (If you don’t know what fiber optic light toys look like, look them up. You’ll see exactly what I mean.) 

After my trip to Waimea Canyon, I saw ‘ōhi’a lehua everywhere. When I drove along the coast between the beach and the sloping mountains, when I hiked the volcanic craters of Haleakala, and when I visited parks and gardens across the islands that protect native plants and animals. ‘Ōhi’a lehua is the most common native tree in Hawaii, so seeing its fiery red, orange, or yellow blossoms every day felt so very ordinary. But ‘ōhi’a lehua is far from ordinary.

Image Credit: Ed Sharron via iNaturalist 

Let Me Introduce You to My New Friend, ‘Ōhia Lehua

Endemic to the six largest islands of Hawaii, ‘ōhi’a lehua is the dominant tree species in native forests, present in approximately 80% of the total area of these ecosystems and covering close to one million acres of land across the state. Depending on where exactly it grows, its size can vary widely, from a small shrub to a large tree. Found only in the Hawaiian archipelago, ‘ōhi’a lehua grows at elevations from sea level to higher than 9000 feet, and in a variety of habitats like shrublands, mesic forests (forests that receive a moderate amount of moisture throughout the year), and more wet, or hydric, forests.

You can easily identify the ‘ōhi’a lehua blossoms by their mass of stamens – the part of the flower that produces pollen – which are slender stalks with pollen-bearing anthers on the end. It’s what made me think the ‘ōhi’a lehua looked exactly like those fiber optic light toys. These powder puff-like flowers are most often brilliant shades of red and orange, but yellow, pink, and sometimes even white ones can be found.

‘Ōhi’a lehua grows slowly, reaching up to 20-25 meters (66-82 feet) in certain conditions.

With a little help from the wind, the seeds of ‘ōhi’a lehua travel from the tree and settle in cracks in the ground of young lava rock. It is, in every sense, a true pioneer plant. As one of the earliest plants to colonize and grow in fresh lava fields, ‘ōhi’a lehua stabilizes the soil and makes it more habitable for other species.

Even though ‘ōhi’a lehua can blanket Hawaii’s native forests, this flowering tree also grows alone, as you can see in the photograph below. Plants like ‘ōhi’a lehua fill me with happiness because they are able to grow in the most harsh, barren, and disrupted places, and they make it possible for other species to do the same. Plants like ‘ōhi’a lehua fill me with surety that even though sometimes poorly treated, the natural world will continue to be strong. Plants like ‘ōhi’a lehua make me believe in the resilience of nature.

Arid, rocky, Mediterranean coast. (Via Pexels)

How ‘Ōhi’a Lehua Cares for the Hawaiian People

Biodiversity forms the web of life we depend on for so many things – food, water, medicine, a stable climate, and more. But this connection between human beings and natural life is not always clear, understood, or appreciated. But there is a concept in Hawaiian culture called aloha ‘āina, or love of the land, which teaches that if you take care of the land, it will take care of you. The ‘ōhi’a lehua in particular takes care of the Hawaiian people in a pretty special way. 

One of the most important characteristics of this flowering evergreen tree is that it’s a keystone species, protecting the Hawaiian watershed and conserving a great amount of water. The way I see it, ‘Ōhi’a lehua is an essential glue that holds Hawaii’s native ecosystems together. The leaves of ‘ōhi’a lehua are excellent at catching fog, mist, and rain, replenishing the islands’ aquifers and providing drinking and irrigation water for Hawaiian communities. ‘Ōhi’a lehua’s ability to retain water, particularly after storms, not only makes that water accessible for other plants, but it helps mitigate erosion and flooding. The tree provides food and shelter for native insects, rare native tree snails (kāhuli), and native and endangered birds like the Hawaiian honeycreepers (‘i’iwi, ‘apapane, and ‘ākepa). ‘Ōhi’a lehua trunks protect native seedlings and act as nurse logs, providing new plants with nutrients and a growing environment.

‘I’iwi, the Scarlet Hawaiian Honeycreeper, perched on an ‘ohi’a tree (Image Credit: Nick Volpe)

The Myth of ‘Ōhi’a Lehua

‘Ōhi’a lehua may have a disproportionately large effect on Hawaii’s ecosystems as a keystone species, but its presence as a meaningful part of Hawaiian culture could be even larger. There are many versions of mo’olelo (story) about the origin of the ‘ōhi’a lehua tree, but the most common one is about young lovers named Ōhi’a and Lehua. Pele, the goddess of the volcano, changed herself into a human woman and tried to entice ‘Ōhi’a. When he denied her, Pele became enraged and transformed ‘Ōhi’a into a tree. When Lehua found out, she was so heartbroken that she prayed to the gods to somehow help her reunite with him. Answering her prayers, the gods transformed Lehua into a flower and placed her on the ‘ōhi’a tree’s limbs. To this day, it’s believed that whenever a lehua flower is picked, the skies will open up and rain will fall, because the lovers have been separated.

‘Ōhi’a Lehua as a Cultural Symbol

In Hawaiian culture, the ‘ōhi’a lehua is a symbol of love, resilience, and ecological harmony. The transformation of Ohia and Lehua into tree and flower represents the inseparable bond between two people who love each other, and between the tree and its flowers. The term pua lehua, or lehua flowers, is often used to describe people who express the same grace, strength, and resilience of the ‘ōhi’a lehua. Pilina, a Hawaiian word that means “connection” or “relationship,” is an important value in Hawaiian culture because it is a critical way for people to connect with and understand the world around them. The ‘ōhi’a lehua tree is a symbol of pilina, and embodies this relationship between the Hawaiian landscape and its people.

Hula dancers performing at the Merrie Monarch Festival
Thomas Tunsch (CC BY-SA )

The ‘ōhi’a lehua is also incredibly important to hula. Hula is the narrative dance of the Hawaiian Islands, and it is an embodiment of one’s surroundings. Dancers use fluid and graceful movements to manifest what they see around them and tell stories about the plants, animals, elements, and stars. ‘Ōhi’a lehua trees and forests are considered sacred to both Pele, the goddess of the volcano as you may recall, and Laka, goddess of hula. To enhance their storytelling and evoke the gods, dancers traditionally wear lehua blossoms or buds in lei, headbands, and around their wrists and ankles.

The Dependability of ‘Ōhi’a Lehua 

‘Ōhi’a lehua has long been a part of daily life. Historically, the hardwood of the tree was used for kapa (cloth) beaters, papa ku’i ‘ai (poi pounding boards), dancing sticks and ki’i (statues), weapons, canoes, and in the construction of houses and temples. Today, the tree’s wood is used for flooring, furniture, fencing, decoration, carving, and firewood. ‘Ōhi’a lehua blossoms decorate altars for cultural ceremonies and practices. Flowers, buds, seeds, and leaves form the base of medicinal teas that can stimulate appetite and treat childbirth pain.

Threats to ‘Ōhi’a Lehua

As a native tree, ‘ōhi’a lehua competes with invasive species for moisture, nutrients, light, and space. Plants like the strawberry guava plant (Psidium cattleyanum) grow in dense thickets and block the growth of ‘ōhi’a seedlings. The invasive fountain grass (Pennisetum setaceum) can dominate barren lava flows, making it difficult for ‘ōhi’a to compete. ‘Ōhi’a lehua is also threatened by non-native animals. Hooved animals like pigs, cattle, goats, and deer disturb the soil, eat sensitive native plants, and trample the roots of ‘ōhi’a lehua trees.

The most dangerous threat to ‘ōhi’a lehua is a virulent fungus called Ceratocystis fimbriate, which attacks the tree’s sapwood, preventing it from uptaking water and nutrients, and killing the tree within weeks. It’s been given the name Rapid Ohia Death (ROD) because of how quickly it suffocates the tree, turning the leaves yellow and brown and the sapwood black with fungus. Infections spread through a wound in the bark, which can be caused by animals trampling roots, lawn mowing, or even pruning, and can be present in the tree for up to a year before showing symptoms. ROD is spread by an invasive species of wood boring Ambrosia beetle that infests the tree and feeds off the fungus. When colonizing trees, the beetle produces a sawdust-like substance made of excrement and wood particles called frass, which can contain living fungal spores that get carried in wind currents and spread by sticking to animals and human clothes, tools, and vehicles. 

Since its discovery in 2014, ROD has killed more than one million ‘ōhi’a lehua trees across 270,000 acres of land, making it a significant threat to biodiversity and cultural heritage. The International Union for Conservation of Nature (IUCN) classifies ‘ōhi’a lehua’s conservation status as vulnerable, and has recorded a decline in mature trees since 2020. Because ROD can spread long distances, it has the potential to wipe out ‘ōhi’a lehua across the entire state. If ‘ōhi’a lehua disappears, it will lead to a collapse of the Hawaiian watershed and radically change the ecosystem.

How the Hawaiian People Care for ‘Ōhi’a Lehua

Scientists, researchers, and native Hawaiians are working together to ensure the long-term health and resilience of ‘ōhi’a and Hawaii’s native forests by mitigating the spread of Rapid Ohia Death. Hawaii’s Forest Service monitors the land to track the spread of ROD and mortality of trees, has developed sanitation and wound-sealing treatments, and collaborates with hunters and game managers to reduce disease transmission. Scientists rigorously test ‘ōhi’a trees to understand the disease cycle, find out how it can be broken, and to identify trees resistant to the infection that could be used in potential reforestation efforts. 

To prevent the spread, Hawaii has announced quarantine restrictions, travel alerts, and sanitation rules. If you are shipping vehicles between islands, you should clean the entire understory with strong soap to remove all mud and dirt from the tires and wheel wells. People who go into ‘ōhi’a forests are advised to avoid breaking branches or moving wood around, to clean their shoes and clothes, and to decontaminate any tools used with alcohol or bleach to kill the fungus. Even hula practitioners are forgoing the use of ‘ōhi’a lehua.

Orange ‘ōhi’a lehua blossom (Image Credit: Joan Wasser via National Park Service)

Mālama the ‘āina

Mālama the ‘āina is a phrase that means to care for and honor the land. ‘Ōhi’a lehua is a wonderful representation of the interconnection between people and nature and I hope learning about this beautiful tree has encouraged you to appreciate the relationship we have with the Earth and what the natural world does for us. 

Remember, if you take care of the land, it will take care of you.

Abigail

Abigail Gipson is an environmental advocate with a bachelor’s degree in humanitarian studies from Fordham University. Working to protect the natural world and its inhabitants, Abigail is specifically interested in environmental protection, ecosystem-based adaptation, and the intersection of climate change with human rights and animal welfare. She loves autumn, reading, and gardening.

Sources and Further Reading:

Featured Creature: Stone Pine

What Mediterranean tree is uniquely equipped to withstand wildfires with armor-like bark and high, out of reach, branches?

The stone pine!

The stone pine in Casa de Campo, Madrid. (image by author)

In his 1913-1927 novel, In Search of Lost Time, French writer Marcel Proust described the power of a soft, buttery madeleine cookie dipped in tea to transport the story’s narrator back to his childhood, unlocking a flood of vivid memories, emotions, and senses. Since then, the term “Proustian memory” has come to describe the sights, smells, sounds, or tastes that bring us back to a particular place in time, one that reminds each of us that we are home.

This is how my partner talks about the stone pine (Pinus pinea) in Spain. Raised in Madrid, she moved to the U.S. when she was twenty-three. For the next decade she’d go long stretches without returning home (blame grad school, work, a global pandemic, and high airfare).

But on those occasions where she was able to return home for a visit, before that first sip of cafe con leche, it was the stone pines flickering past the taxi cab window that brought her back to the youth she’d spent running beneath them, and told her soul that she was home.

There are few markers more reliable than the stone pine to remind you that you are in the Mediterranean. Its branchless trunk rises 25-30 meters from the dry ground. Deep grooves run up the thick, rugged bark in shades of rust and ash-gray. It is bare all the way up to a rounded crown that seems to hover above the landscape. Branches bearing clusters of slender needles splay out horizontally and cast large soft shadows on the ground, giving the tree its nickname, the parasol (umbrella) pine. Its high canopy offers nesting sites and vantage points for many birds of the Med, like Eurasian Jays and Red Kites.

The stone pine’s unique silhouette foreshadows its individuality among its relatives in the genus Pinus. 

stone pine bark detail. (Photo by dmcd25)(CC-BY-NC via iNaturalist)

The Parasol Pine

It is a resilient tree with few natural predators. High branches keep its cones away from most ground-dwelling herbivores, and that hardy bark helps shield against both prying insects and wildfire, perhaps its most common threat in the Mediterranean. The clustering of branches high above the brush also helps it withstand fire events more successfully than other species in the area. That said—it’s important to understand that pests (like the pine tortoise scale) and runaway fires do remain serious threats, even if the stone pine is better prepared to meet them. 

The tree also stands apart from other species of pine in its lack of hybridization—that is, its failure to crossbreed with other pine species, despite existing in close proximity. It does not demonstrate a tendency to interbreed with its neighbors like Pinus halepensis (Aleppo pine) or Pinus pinaster (maritime pine), and that is unusual among pines. It’s really just out here doing its own thing.

This pattern of genetic isolation is a product of circumstances. The stone pine’s pollination window doesn’t often line up with other species and, even when they do, the tree’s genetic makeup has remained distinct enough (while others have hybridized) that fertilization is increasingly improbable.

And unlike other pine species, stone pine seeds are not effectively dispersed by the wind, perhaps contributing to this isolation. Instead, they rely on the few animals that can reach them, particularly birds, to shake them free and drop them elsewhere.

Arid, rocky, Mediterranean coast. (Via Pexels)

Digging Deeper

I hope we’ve established that the stone pine is one tough, rugged cookie, designed from the root up to thrive in a variety of ecosystems around the Mediterranean. But what’s going on below the surface?

To really understand any tree, you’ve got to look down. When we talk about “siliceous” soils, we’re talking about soils that are made up mostly of silica—essentially a mineral of silicon and oxygen that comes from rocks like quartz and sandstone. These soils are characteristically sandy and drain water quickly, but offer fewer nutrients—making them less fertile and more inhospitable for many trees. They also tend to be more acidic. 

On the other half of the pH scale (which measures the acidity of acids on one end, and alkalinity of bases on the other) are what are known as “calcareous” soils—that is, soils rich in calcium carbonate from sources like limestone or chalk, but light on most other important nutrients.

Understanding pH and soil. Ann McCauley et al. 2017, Montana State University

Both of these types of soil are found along the rocky Mediterranean. And while its preference is for the former, more siliceous soils, the stone pine does well in both. In fact, it’s this ability to thrive in these rocky soils that earned the tree its name, the stone pine. Of course, the tree’s deep roots alone are not always enough to survive in these nutrient-deficient soils. Like other pines around the world, Pinus pinea benefits from ectomycorrhizas, the symbiotic relationship between the tree and fungi in the ground that help facilitate nutrient exchange in soils where they are harder to come by. It’s a fascinating relationship that certainly deserves its own essay, but it is important to understand the critical role Ectomycorrhizal fungi (EMF) play in maintaining thriving forest ecosystems. They form mutually beneficial relationships with trees, where the fungi exchange those coveted soil nutrients for carbon compounds produced by the trees during photosynthesis. This natural partnership supports nutrient cycling and enhances tree health and growth, allowing pines just like the stone to survive under more challenging soil conditions. 

Explore visualizations of how Ectomycorrhizal fungi support forest growth.

In the course of human events

We know quite a bit more about where the stone pine is, rather than where it’s from. Pinpointing its native range has proven difficult because the tree has been harvested, traded, and replanted by human since prehistory—first for their edible pine nut seeds, then by later civilizations like the Romans for their ornamental status. Even today, it is common throughout the region to find a street or garden lined with the distinctive tree.

Today, pine nuts from the stone pine remain big business, and their cultivation has been seen as an alternative crop in regions where the arid soil would make other agricultural endeavors too difficult.

Pine nuts served on a dish of roasted peppers. Via Pexels.

I’ve realized there is more to learn about the stone pine than I could ever hope to fit on a page. In my naivety or ignorance, I did not expect that. Its deceptively simple silhouette belies a complex story of resilience, symbiosis, and ancient history and, for at least one Spaniard, a reminder that she’s home.

Brendan began his career teaching conservation education programs at the Columbus Zoo and Aquarium. He is interested in how the intersection of informal education, mass communications and marketing can be retooled to drive relatable, accessible climate action. While he loves all ecosystems equally, he is admittedly partial to those in the alpine.  

Sources and Further Reading:

Featured Creature: Sphagnum moss

What bog-builder can hold 15-20 times its dry weight in water?
Sphagnum moss!

by David McNicholas

The distinctive brown color of Sphagnum beothuk forming a large hummock on a raised bog. (Photo courtesy David McNicholas)

As an ecologist working on Ireland’s peatland restoration, I’ve seen firsthand the profound transformation of re-wetting former industrial peatlands, and its capacity to enhance biodiversity and carbon storage. Working as a member of the Bord na Móna Ecology Team with funding provided by the EU’s Recovery and Resilience Facility as part of Ireland’s National Recovery and Resilience Plan, I’ve have seen more than 60 peatland sites undergo this incredible transformation. Following extensive ecological, hydrological and engineering studies to create the optimal conditions for Sphagnum moss establishment, it is exciting to now move towards the active planting of Sphagnum moss back onto these peatlands. This will accelerate the establishment of Sphagnum-rich bog vegetation that will have greater biodiversity and climate benefits at scale.

Raised bog formation

Sphagnum moss species are key plants in the development and existence of bog habitats. Some species can hold 15 to 20 times their dry weight in absorbed water and tolerate very harsh conditions such as nutrient deficiency, high acidity and waterlogged environments. This ability of Sphagnum to hold water creates the quaky surface conditions that are characteristic of raised bogs in good condition. Bogs simply would not exist as we know them without Sphagnum.

Raised bogs begin to develop in wet shallow depressions, often shallow lakes. Over time, wetland vegetation such as reeds, rushes and other plants leave dead matter behind in the substrate. As the amount of dead vegetation accumulates, the layer of growing vegetation on top is eventually lifted above the influence of the local groundwater. At this point, this layer has become ombrotrophic (exclusively rain fed). The result, in wetter climates, is the development of a wet, nutrient poor and acidic environment in which Sphagnum species thrive. Sphagnum is known as an “ecosystem engineer”. This moss can change its environment, making it wetter and more acidic, suiting these mosses and creating perfect peat-forming raised bog. As the living plants grow upward, the Sphagnum tissue beneath the living surface of the bog is submerged beneath the weight of the growing layer above. This dead material does not completely decay in the anoxic, waterlogged conditions. Instead, it will become peat over time, while the living material will continue to grow, driving the formation of a raised bog dome.

Sphagnum cuspidatum occurring within a bog pool. This species occurs in pools and the wettest parts of peatlands. (Photo courtesy David McNicholas)

Sphagnum’s role in carbon sequestration

The growth habit of Sphagnum is directly responsible for the development of one of nature’s most efficient carbon traps. A metre squared of intact, good quality raised bog sequesters a small amount of carbon annually, but over time these peatlands can accumulate and store much more carbon than the same area of other ecosystems like tropical rainforest. As such, Sphagnum moss is very important to help tackle climate change by taking in carbon and by creating peat-forming conditions to secure this carbon in the ground within healthy peatlands.

The ability of Sphagnum to store water also plays an important role in regulating heavy rainfall events within a catchment. Healthy peatlands can store water in Sphagnum moss, then slowly release this water over time, thereby helping to mitigate potential downstream impacts associated with sudden heavy rainfall.

Sphagnum papillosum, with round leaved sundew growing on top. (Photo courtesy David McNicholas)

Sphagnum as an indicator species

Different Sphagnum species can be used as valuable indicators of peatland type and their overall condition. However, Sphagnum mosses are widely believed to be tricky to identify and so many ecologists simply aggregate them, classifying them as “Sphagnum species”. In doing so, ecologists are forfeiting valuable information on nutrient availability, hydrology and habitat condition that these species provide. Like any other plant group, there are generalist and specialist Sphagnum species. For example, Sphagnum rubellum can be found on nearly any bog habitat in Ireland. Small red cushions and hummocks can be found from relatively dry cutover bog to the wettest parts of an active raised bog.

Sphagnum beothuk has a very characteristic chocolate brown colouring and is one of the prettiest raised bog species. While S. austinii has a range of colours, the large size of the individual capitulums (the top of the plant) and the relative compactness of the hummocks as a whole can be used to reliably identify the species. Both species generally inhabit the wetter parts of a bog and if abundant and healthy, can be used as an indicator of raised bogs in good condition. Sphagnum cuspidatum is one of the most aquatic species and is generally found in the acidic bog pools in the wettest parts of the bog. Interestingly, it can be found within the drainage ditches of industrially harvested bogs where no other Sphagnum species may be present. There are some Sphagnum mosses that are found in less acidic and more nutrient rich, fen conditions. To get to know Sphagnum species is to open a large encyclopaedia on the various natural history processes and conditions of our peatlands. However, don’t be put off getting to know the more readily identifiable species and build on this. Knowing just a few species can really add to the satisfaction of exploring our unique peatlands.

Moss growth (courtesy David McNicholas)

Use of Sphagnum moss in peatland restoration

Planting Sphagnum moss across re-wetted cutaway bog as a rehabilitation technique is a key objective of the Peatlands and People LIFE Integrated Project (IP). We’re on track to plant one million Sphagnum plugs across over 270 hectares of rehabilitated peatland by November 2024, with ambitious plans for further planting in 2025 and beyond.

Revegetating these areas provides new and more resilient habitat over the longer term. Sphagnum moss will recolonise these sites naturally in time; however, the work we’re doing aims to speed up this trajectory, and we’re establishing a network of peatland sites to develop best practices in restoration and rehabilitation. This involves the design of robust methodologies to monitor and analyse Sphagnum and carbon storage.

While monitoring is ongoing and we have a lot of research ahead of us, initial evaluations of the planted Sphagnum material is already showing positive survival and growth rates.

As I continue my work with Bord na Móna, we’re grateful for the support provided by the European Union’s Recovery and Resilience Facility as part of Ireland’s National Recovery and Resilience Plan, a key instrument at the heart of NextGenerationEU. The primary aim of this scheme is to optimize climate action benefits of rewetting the former industrial peat production areas by creating soggy peatland conditions that will allow compatible peatland habitats to redevelop.

David McNicholas is an Ecologist at Bord na Móna where he works with a multidisciplinary team to deliver an ambitious peatland restoration programme, post-industrial peat production. As a member of the Bord na Móna Ecology Team, David is involved in rehabilitation planning and implementation, while also planning and undertaking monitoring and protected species surveys.

Sources and Further Reading:

Featured Creature: Northern Red Oak

What statuesque organism is a champion of beauty, hardiness, and capacity to nurture life around it?

The Northern Red Oak!

Image by iris4me from Pixabay

In the lush landscapes of North America, the Northern Red Oak stands as a timeless symbol of strength, resilience, and enduring beauty. Revered for its towering stature, vibrant foliage, and essential ecological contributions, this iconic species holds a cherished place in both natural ecosystems and human communities.

The state tree of New Jersey, the Northern Red Oak is sometimes referred to as the “champion oak,” and it certainly qualifies as a biodiversity and climate champion!

Image by Manfred Richter from Pixabay

The Northern Red Oak, or Quercus rubra, is an impressive hardwood tree that graces the forests of Eastern and Central North America. Its grandeur is exemplified by its towering height, often reaching between 70 to 90 feet, and its robust, straight trunk. Adorned with deeply lobed, glossy green leaves, the Northern Red Oak undergoes a breathtaking transformation in the autumn, as its foliage turns into a symphony of red, russet, and orange hues, captivating onlookers and adding a burst of color to the landscape. 

I got to know my oaks over the past few years as I’ve dived more deeply into the native ecology of New England. Like maples and tulip trees, oaks have fairly recognizable leaves, and make an accessible place to start with species identification. It took me a bit longer to discern between different types of oaks, from the sharp edged Northern Red Oak leaves to the rounded edges of the Swamp White Oak leaves, but it’s a satisfying journey to take to get to know these hallmarks of the landscape better. As I learn trees’ names, patterns, life cycles, and roles, I get to establish a greater kinship with these beings, and witness the beautiful ways they interact with the people, birds, insects, and animals in the ecosystem.

Image by Hans from Pixabay

Ecological Support Star

Beyond its visual allure, the Northern Red Oak plays a crucial role in maintaining the health and balance of its ecosystems. Its extensive root system helps prevent soil erosion, and improves the soil sponge for water infiltration, buffering against the intensifying drought and flood cycles affecting our environments. These trees also provide essential food and habitat for a biodiverse array of wildlife. 

As many scientists and foresters are beginning to recognize in greater numbers, the more we can preserve and plant keystone native species of our ecosystems, the more deeply and powerfully those ecosystems can mitigate the extreme effects of climate change and global warming. Healthy ecosystems are full of complexity, and in part it is the relationships between different species of vegetation, fungi, microbes, and wildlife that make the whole so successful. Northern Red Oaks are particularly valuable bulwarks of the forest ecosystems of the Eastern and Central US, where they support almost 500 different of butterfly and moth species, which in turn feed the larger food chain. These trees’ acorns also directly supply vital sustenance for many types of wildlife, including blue jays, woodpeckers, turkeys, squirrels, raccoons, and deer. Finally, as old trees begin to decay and die, their trunks and branches go on to house many animals’ dens and nests, continuing to provide throughout the stages their life cycle. 

The Northern Red Oak has traditionally been valued for its economic significance, which characterizes a lot of the information you can find on this beautiful tree. Revered for its durable wood, the Northern Red Oak is a prized timber species, notable for its strength, durability, and attractive grain pattern. Its wood can be found in various woodworking applications, including furniture, cabinetry, flooring, and veneer. So next time you see a product boasting its oak hardwood, imagine the long history of that material that lies beneath the surface.

Image by Nicholas A. Tonelli from Northeast Pennsylvania, USA, CC BY 2.0 via Wikimedia Commons

Vital and Versatile

Adaptability is another hallmark of the Northern Red Oak, as these trees thrive in a wide range of soil types and environmental conditions. From lush forests to urban parks, this resilient species can flourish in diverse habitats, underscoring its importance as a cornerstone of biodiversity.

In urban forestry and landscaping, Northern Red Oaks are treasured for providing shade, natural beauty, and environmental benefits to parks, streetscapes, and residential areas. Sometimes, biodiversity value and hardiness to poor soil conditions and urban stressors are thought of as tradeoffs that urban foresters must navigate. However, the Northern Red Oak (and many other remarkable trees) prove that sometimes, you can have it all. 

Northern Red Oak sapling in our Danehy Park Miyawaki Forest
(Image by Maya Dutta)

Despite its resilience, the Northern Red Oak faces threats from pests, diseases, and habitat loss from logging, degradation, and fragmentation, underscoring the need for transforming our relationship to forests and vegetation, these powerful systems for cooling and carbon sequestration. By protecting and preserving Northern Red Oak populations, prioritizing biodiversity and holistic ecosystem health in our climate resilience efforts, we can make a cooler, greener, healthier world for ourselves and the many species we share our home with.

May we make that dream a reality,

Maya

Maya Dutta is an environmental advocate and ecosystem restorer working to spread understanding on the key role of biodiversity in shaping the climate and the water, carbon, nutrient and energy cycles we rely on. She is passionate about climate change adaptation and mitigation and the ways that community-led ecosystem restoration can fight global climate change while improving the livelihood and equity of human communities. Having grown up in New York City and lived in cities all her life, Maya is interested in creating more natural infrastructure, biodiversity, and access to nature and ecological connection in urban areas.

Sources and Further Reading:
https://en.wikipedia.org/wiki/Quercus_rubra
https://forestry.ca.uky.edu/sites/forestry.ca.uky.edu/files/northern_red_oak_factsheet.pdf
https://gobotany.nativeplanttrust.org/species/quercus/rubra/
https://hort.ifas.ufl.edu/database/documents/pdf/tree_fact_sheets/queruba.pdf
https://ufi.ca.uky.edu/treetalk/ecobot-red-oak
https://forestry.com/trees/oak-tree/red-oak-tree/
Wild Seed Project’s Native Trees for Northeast Landscapes (2021)

Featured Creature: American Chestnut

Photo by Jean Mottershead flickr.com

What tree, the “Redwood of the East,” once dominated the forests of the Eastern United States, and the cultural landscape as well?

The American Chestnut!

Photo by Jean Mottershead flickr.com

What Nat King Cole, Mel Torme’ and Bing Crosby Were Singing About

According to legend, songwriter Robert Wells, trying to stay cool during the hot summer of 1945, put to paper his favorite parts of winter, eventually turning those thoughts into “The Christmas Song.” First on his list – “chestnuts roasting on an open fire.”

Now maybe, if you are like me, you find that a curious choice. Were chestnuts really that important to the Christmas experience? Before yuletide carols and Jack Frost? Before turkeys and mistletoe and tiny tots who can’t sleep because “SantaSantaSanta?” Why, when penning his favorite parts of winter, did his first thought turn to chestnuts?

Which brings us to the Columbian Exchange.

What is the Columbian Exchange?

The Columbian Exchange, for those who don’t know, refers to the massive transfer of plants, animals, germs, ideas, people, and more that occurred in the wake of Christopher Columbus’ arrival in the Americas. While a detailed analysis of all the impacts of the Columbian Exchange is far beyond the scope of this piece, from a strictly biological standpoint, it began a fierce evolutionary battle as previously unseen species entered new territory for the first time.

One of the most notable victims of this exchange turned out to be the American Chestnut Tree.

Photo from getarchive.net

For more than 2,000 years, the American Chestnut dominated the mountains and forests of the Eastern United States, allowing adventurous squirrels to travel, according to legend, from Georgia to New England without ever touching the ground or another species of tree. Each year it provided much of the diet for many species, including black bears, deer, turkeys, the (now extinct) passenger pigeon and more. 

The chestnuts, which grew three at a time inside the velvety lining of a spiny burr, contained more nutrients than other trees in the East, making them especially valuable to Indigenous peoples who relied on them as a food source and used them in traditional medicines. Europeans would later use the nuts as feed for their animals, or forage to use them for food or trade. In addition, since the trees grew faster than oak and were highly resistant to decay, the lumber was highly-prized for construction—to this day American chestnut, reclaimed from older buildings, is sometimes used to create furniture.

Harvesting an American chestnut at TACF’s Meadowview Research Farms
Open bur of an American chestnut
Young green burs at Meadowview Research Farms
Wild American chestnut seedling in NY

The chestnuts were, in fact, such a staple that, in the late fall and early winter after the trees had delivered their harvest, city streets would be lined with carts roasting the nuts for sale. They are reported to be richer and sweeter than other varieties of chestnut and were a much sought-after wintertime treat. Today, roasted chestnuts are typically imported, and either European or Chinese chestnuts are used and, if our great-grandparents are to be believed, those species are just not as good. In addition, the loss of the American Chestnut deprived the United States of an important export.

So, What Happened?

After Columbus arrived, a fella by the name of Thomas Jefferson danced into his Virginia home-sweet-home with some European chestnuts to plant at Monticello. Somebody else imported Chinese chestnuts and, before too long, ink disease had practically eliminated the American chestnut in the southern portion of its range.

Then, in 1876, Japanese chestnuts were introduced into the United States in upstate New York and, a few decades later, a blight was discovered at the Bronx Zoo (then known as New York Zoological Park) that, by 1906, had killed 98% of the American chestnuts in the borough. Since Asian chestnuts, and to a lesser extent European chestnuts, had evolved alongside the blight, they were able to survive. But the American Chestnut tree (and its cousin the Allegheny Chinquapin) could not. Over the coming decades the airborne fungus, which could spread 50 miles in a year and kill an infected American Chestnut within ten years, had rendered the American Chestnut functionally extinct.

Canker and blight
Blight on young chestnut trees.

What Does That Mean, “Functionally” Extinct?

While the American Chestnut may be “functionally” extinct, that is not the same as being extinct. The root systems of the trees in many cases have survived, as the blight only kills the above-ground portion, and the below-ground components remain. Every so often a new shoot will sprout from the roots not killed when the main tree stem died. These shoots are only able to grow for a few years before they are infected with the blight, and they never reach a point of bearing fruit and reproducing, but they do grow. For that reason, the tree is classified as “functionally” extinct, but not extinct. In addition, isolated pockets of the species have been found, or planted, west of the trees’ historical range where the blight has not yet reached.

A Tufted Titmouse sits on the limb of an American chestnut
Red-spotted purple butterfly on an American hybrid
Gray Tree Frog in Chestnut Tree

Will I Ever Get to Eat a Roasted American Chestnut?

While you probably won’t get to have the full roasted chestnuts experience as Robert Wells once did, there is hope for this species and hope that maybe your grandchildren will enjoy them as your great-grandparents once did. Programs at several universities such as the University of Tennessee and the State University of New York along with the USDA, US Forest Service and some non-profits like the American Chestnut Foundation are actively working to bring the species back by either cross pollinating blight-resistant specimens or combining them with more resistant species. You can learn more about these efforts toward resilient chestnuts by exploring the sources below.

Ho ho ho,

Mike

Mike Conway is a part-time freelance writer who lives with his wife, kids, and dog Smudge (pictured) in Northern Virginia. 

Sources:
American chestnut – Wikipedia
Home | The American Chestnut Foundation (tacf.org)
How to grow an American chestnut | US Forest Service (usda.gov)
The Great American Chestnut Tree Revival – Modern Farmer
What it Takes to Bring Back the Near Mythical American Chestnut Trees | USDA
Sowing the Seeds for a Great American Chestnut Comeback | NPR
Uncredited photos in this blog from tacf.org

Featured Creature: Lichen

Which creature is a combination of two other organisms, comes in bright colors, and helps us measure air quality?

Lichen!

Image by Jerzy Górecki from Pixabay

Master of Symbiosis

Though we know lichens as creatures in and of themselves, lichens are actually a result of symbiosis, a mutually beneficial relationship between two or more species. In the lichen’s case, algae and fungi come together to form a new creature. No two lichens are alike. They vary in form, color, and which type of algae they have – either green, blue-green, or both.

The fungus gives the lichen a majority of its traits, including shape and anatomy. The algae determines the color, from orange to yellow to neon green. The fungus partners with the algae out of necessity for food. Since the algae, or cyanobacteria, can photosynthesize, they provide food for the fungus in exchange for shelter. Therefore, each party relies on the other for survival.

Image by Emmi Nummela from Pixabay

Abundant yet Unique

From hot deserts and windy coastlines to the arctic tundra, lichen are found around the world. In North America alone, there are thought to be 3600 different species! They grow on trees, rocks, and soil. They can even grow on things made out of one of the above, such as a house made out of wood. If a sand dune remains stable for long enough, soil crusts will form and lichens will begin to appear along the crusts. Essentially, all lichens need is something solid to hang onto. 

Lichens require a stable habitat because they take a long time to grow. Every year, they only grow 1-2 mm. To promote their growth cycle, lichens will often partner with moss, adding yet another organism to the party. Mosses are simple plants (meaning they lack roots, stems, and leaves) that retain water, and since lichens have two creatures to sustain (the algae and fungi), this water source is a welcomed one. This partnership is so common that if you look up ‘lichen’ on the internet, a majority of pictures will contain both lichen and moss. They are truly geniuses of cooperation!

The lichen Letharia vulpina at Mt. Gleason, CA (Photo by Jason Hollinger from Wikipedia, CC BY-SA 3.0)

Welcomed by All

At first glance, it may look like lichens harm trees. (After all, if you or I had something bright green or orange growing on our limbs, we should call the doctor). But fear not – lichens don’t harm any plants they attach themselves to. On the contrary, they benefit many other species, such as birds that use lichen as nesting material. Numerous invertebrates see lichen as a source for food and shelter and, as a result, the more lichen in a forest, the more organisms the ecosystem can sustain. 

Humans have reaped the benefits of lichen, too. We have used them for clothing, decorations, and food. They are also highly valued for their antibiotic properties. Today, we use them in toothpastes, salves, deodorants, and other products. So you can thank lichens for helping us stay clean and healthy!

Cup Lichen (Image by Jürgen from Pixabay)

A Climate Helper

Since the algae in lichen photosynthesize, lichens contribute to the important function of converting carbon dioxide in the atmosphere to oxygen. The fungus in lichen contribute to this function, too, by allowing algae to live in places they wouldn’t be able to on their own. By providing a form of shelter, the fungus gives an opportunity for more algae to exist and thrive, and that means we have more creatures sequestering carbon and stabilizing the climate.

Lichens also play a vital role in soil formation and development by helping to break down solid minerals like rock. This process creates pockets in the soil – perfect for larger organisms to thrive in. It also creates pathways for nutrients to sink deep into the Earth, where they will later benefit plants and other creatures. As we like to say at Bio4Climate, healthy soil makes for a healthy planet.

Last but not least, lichens give us an insight on the amount of pollution in their respective area. Lichens absorb everything around them – including air, nutrients, water, and pollutants. Scientists study lichens in order to understand the type of toxins present in the environment and their levels. This information gives us insights on the root causes of disease and environmental degradation. With that knowledge, we can address issues affecting human and wildlife communities – creating a cleaner environment for us all. 

That’s all for now, but I hope you’re lichen this series!
Tania

Tania graduated from Tufts University with a Master of Science in Animals and Public Policy. Her academic research projects focused on wildlife conservation efforts, and the impacts that human activities have on wild habitats. As a writer and activist, Tania emphasizes the connections between planet, human, and animal health. She is a co-founder of the podcast Closing the Gap, and works on outreach and communications for Sustainable Harvest International. She loves hiking, snorkeling, and advocating for social justice.

Sources:
https://www.deschuteslandtrust.org/news/blog/2016-blog-posts/five-fun-facts-about-lichen
https://www.fs.fed.us/wildflowers/beauty/lichens/about.shtml
https://www.woodlandtrust.org.uk/blog/2019/04/what-is-lichen-seven-types-of-lichen-found-on-trees/
https://digitalcommons.humboldt.edu/cgi/viewcontent.cgi?article=1078&context=ideafest

Featured Creature: Slime Mold

Photo Credit: Yamaoyaji/Shutterstock

What brainless creature can learn, problem solve, and even hold down a job? 

The slime mold!

Photo by Bernard Spragg (CC0 via Wikimedia Commons)

Slime molds are eukaryotic organisms (a type of organism with membrane bound organelles, like nuclei) that can live either as single-celled individuals or clumped together in large aggregates, called plasmodial slime molds. These strange creatures have long fascinated humans, and it’s no surprise why. 

The individuals of the species Physarum polycephalum live as solitary cells for a period of time and then come together as plasmodial slime molds, before splitting again to reproduce. Because of this strange cellular structure across their life cycle, they have been a challenge to classify, and were previously grouped as fungi. There are over 900 different species of slime molds, which come in different shapes, sizes, and colors.

Since they are single-celled organisms, slime molds do not form nervous systems or organs like a brain. However, when they live as plasmodial slime molds, the many nuclei form a network within a single cell membrane that can process sensory information independently and share that information with each other. In this way, they have been shown to learn where displeasing or toxic substances are within an area and then avoid that area in the future, remembering such stimuli and passing it on. They can play the world’s most successful game of “telephone”!

Pretzel Slime Mold (Photo from Nativeplants Garden, CC BY-SA 4.0 via Wikimedia Commons)

How have slime molds become known for problem solving? 

Because of their ability to group together and send out strands of slime, slime molds are adept problem solvers. They can sense the chemical traces of food sources in the air the way that we sniff out food with our senses of smell, and pulse out toward that signal. 

Researchers have set up experiments where they placed oat flakes, a food greatly enjoyed by slime mold, at different points in a dish, and observed the slime mold find the shortest route between them. Slime molds can map out the most efficient network of pathways between dozens of different points of interest, organically figuring out the solution to a problem of tremendous computational complexity. In different experiments, they have mimicked the Tokyo train network, as well as British and Iberian road networks.

Take a look at their movement and decision making:

What else can slime molds do?

Scientists fascinated by slime molds’ power have wondered about the possibility of “computing” with slime molds. A graduate student in the UK has powered a microchip with a slime mold sample, and other British researchers have created a robot that is controlled by a slime mold at its center reacting to light, which it likes to avoid. 

Perhaps strangest still is the decision by Hampshire College to give slime mold a faculty appointment. A sample of Physarum Polycephalum is the school’s resident non-human scholar, and it does research on problems posed to it by students modeling various policy questions. 

Though their intelligence is quite different from our own, it is certainly worthy of respect, and can teach us a thing or two. For more interesting looks at slime mold, check out the work of Heather Barnett, who spoke at our Voices of Nature conference in 2018, and recorded a popular TED Talk on the subject. As research on this intriguing creature reminds us, intelligence comes in many life forms.

Off to learn some more,
Maya

Maya Dutta is an environmental advocate and ecosystem restorer working to spread understanding on the key role of biodiversity in shaping the climate and the water, carbon, nutrient and energy cycles we rely on. She is passionate about climate change adaptation and mitigation and the ways that community-led ecosystem restoration can fight global climate change while improving the livelihood and equity of human communities. Having grown up in New York City and lived in cities all her life, Maya is interested in creating more natural infrastructure, biodiversity, and access to nature and ecological connection in urban areas.

Sources and Further Reading:
https://www.pbs.org/wgbh/nova/article/slime-mold-smart-brainless-cognition/
https://www.vox.com/science-and-health/2018/3/6/17072380/slime-mold-intelligence-hampshire-college
https://en.wikipedia.org/wiki/Physarum_polycephalum
https://www.newscientist.com/article/dn11875-bio-sensor-puts-slime-mould-at-its-heart/
https://www.newscientist.com/article/dn8718-robot-moved-by-a-slime-moulds-fears/