January 21, 2020

Of Porcupine Palms and Bears

Image by Bigfish

Needle Palm, Rhapidophyllum hystrix, is an interesting species patchily distributed in the Southeastern U.S. The sole member of the genus, it’s generally found in river floodplains and moist bottomlands. It’s scarce or endangered throughout most of its range. In Florida, where numerous populations occur, it can often be found on moist riverbanks, growing above water-loving Dwarf Palmetto, Sabal minor, and below Saw Palmetto, Serenoa repens, which thrive on higher, drier sites. Of course, “higher” when referring to topography in the Sunshine State, is a subtle descriptor.
Image by Bigfish
Needle Palm develops stubby, clustering trunks; highly dissected palmate leaves arise from stems that are armed with long black spines. 
Unripe Fruit
Image by Alan Cressler
Its flowers and musty or foul-smelling fruit are a formidable deterrent to larger creatures that might consume them. It seems that the species isn’t very good at reproducing. 
Male Inflorescence
Seedlings tend to germinate too close to the mother plants, thus most don’t thrive. Needle Palm is considered a relictual species, one whose ancestors were more widespread. It’s possible that extinct plant-feeders, such as giant ground sloths, were its primary seed-dispersers. Black Bears currently fill that ecological function.
 Characteristic of Needle Palms in habitat is the quantity of leaf litter that is in the dense spines. Perhaps this trait has evolved primarily to funnel nutrients to the plants’ roots as the debris decomposes.
Seedlings and Debris Trapped in Spines
Image by Bigfish
Maybe physical protection is a secondary effect. The spines don’t stop bears from consuming the ripe fruit; probably Giant Ground Sloths weren’t discouraged, either.  
Giant Ground Sloths were Peaceful Foragers except when Surprised

January 8, 2020

The Queen of the Andes

The biggest species, the tallest inflorescence, the longest-lived, perhaps the most dangerous? Puya raimondii is the leviathan of bromeliads, plants in the family Bromeliaceae. As an imposing organism growing in dramatic habitat, it’s an attention-getting member of a relatively unloved genus.

The species is native to the high Andes of Peru and Bolivia, found on rocky slopes between 9,800-15,700 feet. Exposed to harsh sun and extreme levels of ultraviolet light, freezing cold, and desiccating wind, the plants grow to 15 feet tall. When in flower, their spike-shaped inflorescences reach up to 50 feet.  

Huascaran National Park, Peru
Image by Urrola

Puya raimondii is well-adapted to its challenging environment. The slow-growing plants retain their dead fibrous leaves as an insulating skirt for their woody stems.Leaf edges are fiercely armed with sharp, hooked teeth that catch and resist releasing any vulnerable creature that attempts to investigate the plants.

Perhaps due to the hazard they might pose to livestock, or maybe just for amusement, the plants are often burned by locals. Increasingly intensive anthropogenic land use and long term climatological warming and drying is resulting in an overall decline of the species’ fragile populations. Most surviving populations are small and isolated, although a community of several hundred thousand plants is protected in Peru’s Hauascaran National Park.

Puya raimondii can take 80-100 years to bloom. After the hummingbird-pollinated flowers produce many thousands of seeds, the plants die.

Conditions in habitat are only occasionally favorable for germination and seedling survival. Although successful in a specific, challenging environment, its remarkably low level of genetic variation doesn’t bode well for adaptation to a changing world.
image by Wilmer




December 16, 2019

Ancient Trees: The Baldcypress, Part 2

Image by George Connor
Historically, old growth Baldcypress growing in the swamps, bottomlands, and along rivers of the Southeastern United States were commercially valuable. Individual trees were often huge, with straight, relatively unbranched trunks that could be cut into long, rot-resistant boards and shingles. 
Image by American Lumberman Magazine

By the nineteen twenties, nearly all  of the ancient giants had been logged out, and the unique ecology and species mix of their habitat also vanished. Fortunately, climatological conditions at the time were favorable for the germination and survival of a large group of seedlings. Many of today’s mature trees began their lives at that time.
Baldcypress populations are considered relatively stable for now, even though overall southern forest loss has accelerated. Coastal populations of the species, in particular, are threatened by rising sea levels and increasing salinity in the wet places where they grow. Trees of all ages are harvested to be shredded and sold as landscaping mulch, although production seems to have slowed recently. Clearcutting of the trees for wood pellet production to fuel European power plants is eliminating many acres of Baldcypress.
Baldcypress Clearcut.
 Image by the Dogwood Alliance
What grows on the cleared land is nothing like the former forest.  Increasing urbanization and more intensive land use and drainage also impact all three Baldcypress species (or varieties), in the United States and Mexico.

Ivory-Billed Woodpecker, 1935.
The largest North American woodpecker species, now extinct, fed and nested in Baldcypress.
Image by Arthur Allen

Locally, old growth trees of the Pond Cypress variety are found in the Big Cypress National Preserve and the Everglades. Venerable Baldcypress can be experienced in the Audubon Society’s Corkscrew Swamp Sanctuary, east of Naples, Florida. An impressive grove of large trees, not publicly accessible, is protected by the Seminole Tribe on its Big Cypress reservation.

Baldcypress at Pinecrest Gardens
 One  priceless group of old growth Baldcypress can be found in the Miami area, at Pinecrest Gardens. These coastal trees, growing slightly inland from mangroves along what was once Snapper Creek, were doubtlessly present when the first Spanish explorers made landfall. The aboriginal Tequesta people camped and fished beneath them. Weakened by European disease, converted to Christianity and transported to Cuba, the tribe vanished long ago, but the trees remain. 


December 9, 2019

Ancient Trees: The Baldcypress

Baldcypress along the  Arkansas River.
Image by Linda Tanner
The Baldcypress, Taxodium distichum, is an evocative symbol of southern lakes, river bottomlands, and swamps. These ancient members of the Cypress family occur as far north as Southern Illinois and Maryland and as far west as South-Central Texas.
The Famous Arbol del Tule Montezuma Cypress, Oaxaca, Mexico.
Image by Gengiskanhg
Baldcypresses, along with several related genera like the Redwood and Sequoia, were placed in their own family, the Taxodiaceae. Now, all are classified in the same family with a number of other conifer genera, such as true Cypress and Juniper. Surprisingly for such a well-known genus, it seems that its three members have hardly any genetic differences between them, and are either varieties of a single species or perhaps two. Baldcypress wood is extremely rot-resistant to water. Submerged trunks, lost during historical logging activities, are valuable, and often salvaged for milling. 
Along the Wacissa River, Jefferson County, Florida.
Image by Arnold Dent
I’ve seen the trunks of trees toppled during the terrible hurricanes of the nineteen twenties lying in shallow water in the Big Cypress Swamp.  The species, when not topped by storms or lightening, is the tallest tree east of the Rockies, potentially growing to more than 140 feet. Old growth Baldcypress can still be found outside of preserves. Some squat, misshapen trees with little commercial use were never cut. Other trees survived logging by growing in deep water along rivers. Trees commonly live for several centuries. The oldest living tree, still hearty along the Black River of North Carolina, has reached the incredible age of 2624 years. It’s the oldest Eastern U.S. tree, the oldest wetland tree, and the fifth oldest tree in the world.   

Dwarf Pond Cypress in the Florida Everglades.
Image by Daniel Kraft

November 21, 2019

Planting the Mangrove Forest

Mangroves are woody trees or shrubs belonging to several plant families. Their lifestyle allows them to live along tropical coastlines and the banks of rivers where salt and freshwater intermingle. Growing in dense stands and forests, tropical mangrove habitats are critical to provide proper ecosystem functions, the creation of new land, and in mitigating the effects of storms, flooding, and other disruptive effects of rising sea levels.
Image by Lanare Sevi
Each species commonly grouped together under the mangrove lifestyle has differing tolerances to saltwater; they use various strategies to block absorption or to excrete dangerous salt from their tissues. They also grow in slightly different environments. Mangroves don’t need saltwater to live, they just tolerate it much better than other plants. It’s a great advantage and an evolutionary strategy that rids them of competitors.  Some must have primarily freshwater or water that is only slightly brackish to survive.
National Park Service/Image by G. Gardner
Other mangroves are found closer to the sea, and some can grow in pure seawater. Many mangroves excrete excess salt via pores along the undersides of their leaves or from their twigs, while others have impermeable leaf surfaces that physically block the salt.
Mangrove forests are imperiled worldwide due to coastal development, harvesting for timber and fuel, and the catastrophic effects of increasingly powerful hurricanes. Mangroves have declined in most areas due to human activities, but the warming climate is allowing them to colonize places that, until recently, were too cold for them to survive.

National Park Service/Image by G. Gardner
The forests historically covered much of coastal South Florida, its offshore barrier islands, and the Keys. Rising sea levels will allow them to grow on land that was last submerged 2.5 million years ago. Drive along U.S. highway 41, the Tamiami Trail, west of the Big Cypress Swamp to see stunted Red Mangroves, the recent pioneers of a swamp that is gradually turning salty.

Sometime within this century, most, if not all, of low-lying South Florida will once again become submerged by a shallow sea, as it has been at least four previous times in the geological history of North America.

Pinecrest Gardens’ artist-in-residence, Xavier Cortada, has developed a conceptual project to remind us of this. As part of The Mangrove Project, he has distributed mangrove seedlings, painted a Garden mural depicting Red Mangroves, and collaborated with the Gardens to plant the world’s first upland mangrove forest. Hundreds of Red, Black, and White Mangroves have been installed adjacent to the mural. It’s thought that the cultivated mangrove forest will survive to grow, in the future, in the newly-returned sea. 

November 14, 2019

The Mangrove Palm

Image by Dr. Neahga Leonard
"If there are no mangrove forests, then the sea will have no meaning. It is like having a tree with no roots, for the mangroves are the roots of the sea."

 Unknown fisherman, Trang Province, Southern Thailand 

Mangroves are woody trees or shrubs that are salt-tolerant and grow along coasts in tropical and subtropical regions. Their distinctive and ecologically important communities consist of members of a number of plant families. Mangrove species can be said to have a common lifestyle, rather than being taxonomically related.
Image by Luis Argerich
The Nipa Palm, Nypa fruticans, is naturally distributed along Asian and Northern Australian rivers and brackish estuarian environments, often in dense stands that can extend for miles. In many areas the palm is a significant and sometimes dominant component of mangrove forests. It’s quite unusual, as palms go. Characteristic of the species is its mild salinity tolerance, which is generally uncommon among palms. The trees develop subterranean, horizontally branching trunks in their muddy, shallow-water habitat. Nipas form spiky clusters of fruit that resemble medieval weapons. Their seeds are designed to float, like coconuts. Sometimes the seeds will begin germinating before they settle in the mud or sand.
Image by Tanetahi

Nipa Palm is both ecologically and economically useful. It provides habitat for aquatic organisms; it stabilizes and protects land from storms and flooding, just like other mangroves. Its leaves make a durable building thatch; its copious sweet sap is harvested to make palm wine and syrup. The fruit is also popularly eaten. Because of the high sugar content of the plant’s tissues, it's an outstanding source of ethanol for fuel production. Nipa stands are environmentally sustainable and require no chemical fertilizer or pesticide inputs.

Male and Female Flowers

November 1, 2019

The Strangest Plant on Earth


“He wrote that he was so astonished that he knelt on the hot sand in bewilderment, thinking that his fantasies had taken flight.”
Chris Bornman, describing the reaction of Friedrich Welwitsch upon seeing Welwitschia mirabilis for the first time.

A fine candidate for the most world’s most biologically unique plant, Welwitschia mirabilis is the sole member of the family Welwitschiaceae. This strange cone-bearing plant was first brought to the attention of science by the plant explorer for whom it was named.

Friedrich Welwitsch was an Austrian, trained in medicine and botany, who disappointed his parents by not developing a law career. Instead, after briefly working as a physician, he pursued his interests in plants, working for important botanical gardens in Portugal and England. His African explorations resulted in the discovery of several new species. Welwitsch died in 1872 but left a fine collection of many thousands of dried herbarium specimens. Three hundred and twenty nine species of plants and animals have been named in his honor.

Namib Desert Fog. Image by Juliane Ziedler
Welwitschia is related to other cone-bearing plants, such as cycads and the relic family of trees and vines, the Gnetaceae. From evidence in the fossil record, the ancestors of Welwitschia diverged from other conifers at least 114 million years ago. The ancestral Welwitchias' forest habitat dried and vanished; the modern species seems like a fanciful creation from the imagination of Dr. Seuss. Welwitschia mirabilis is a woody, two-leaved dwarf “tree” that ekes out it existence in parts of the Namib Desert of Angola and Namibia in areas that can receive no rain at all for several consecutive years. As in western South America, the plant communities of the coastal Namib Desert have evolved to rely upon the nightly fogs that are generated by cold ocean currents. Welwitschia’s metabolism requires some foggy humidity to function, but the species ultimately survives by tapping into deeper soil moisture that is recharged by infrequent rainfall. 
Male and female plants bear cones  on short branches; the winged seeds need a bit of surface soil moisture to germinate. Consequently, the reproductive success rate is low. Outlandish claims are often made concerning Welwtschia’s longevity. More accurately, by measuring the growth rates of their leaves, it’s estimated that individual plants can live 500 to 1000 years.

Welwitschia seedling. Image by H. Maurer
 Welwitchia Seedlings grow two tough strap-like leaves that elongate throughout the plants’ lives. Desert winds twist and shred the long, tough leaves. After many decades the tangled, unkempt mature plants resemble dirty piles of rubbish.

Welwitschia near Swakopmund, Namibia. Image By Joh Henschel
Image by Thomas Schoch

October 17, 2019

Grapes, Plums, and Pigeons

Coccoloba is a large genus of Neotropical trees and shrubs belonging to the Buckwheat Family. Two species are found as far North as Southern Florida, where they are important and distinctive components of coastal plant communities.
Sea Grape, Coccoloba uvifera, is a broad-canopied tree commonly growing in sand or very sandy soil behind the first dune line on beaches or in coastal hammocks inland from mangroves. Sometimes it can be found along the shore just inland of the high tide line. The species is both salt and drought tolerant. Depending on location, Sea Grape can grow as a medium-tall tree with a mound-like shape, or be wind- sculpted and sand-blasted into a sparser, irregular form. It can also be found as a thicket or tall groundcover that helps anchor and stabilize beaches. Its dense branches and thick foliage shelter wildlife; it’s an important nectar source for several butterfly species. Female trees bear tasty fruit, a food source for birds and mammals.  The  fully ripe fruit can be eaten by people, too. It makes excellent jam or jelly.

Pigeon Plum, Coccoloba diversifolia, is a medium-sized coastal tree in South Florida. It’s less salt-tolerant than Sea Grape; typically found in coastal hammocks or behind protective dunes. Pigeon Plum is narrower and smaller leaved, too. 
Pigeon Plum Foliage
Mature trees are irregularly vase-shaped, less subject to being shaped by challenging environmental conditions.As indicated by the specific name of the species, diversifolia, Pigeon Plum leaves occur in various sizes. The blooming trees attract their own suite of butterflies. 

The small “plums” are extremely sought after by many birds, most notably the White-Crowned Pigeon, Patagioenas leucocephala. The birds also consume Sea Grape fruit. Declining populations of this frugivorous wild pigeon are extremely habitat and food source sensitive, and are subjected to hunting pressure in the Caribbean.     

White Crowned Pigeon in Sea Grape

 In the U.S., this elegant bird seems to be highly intolerant of disturbance and occurs only in extreme South Florida and the Keys. 

White-Crowned Pigeon, Patagioenas leucocephala


White Crowned Pigeon by John James Audubon




October 4, 2019

Planting Trees and the Complexities of Good Intentions

Iris atrofusca  on a Negev Hillside, image by Ori Fragman-Sapir
As humans, we often treat ourselves as though we are somehow separate from the rest of Nature. Yet everything that we do connects to the greater world. The growth and migration of human populations have profoundly influenced landscapes, species composition, and ecosystem functions for thousands of years. It’s only in our contemporary period of rapidly accelerating instability and destruction that efforts at environmental mitigation and restoration are being attempted. Many solutions seem straightforward; if a forest is logged, then replant. If the burning of fossil fuels causes climatological warming, then utilize renewable energy resources. We seek elegant, simple solutions to complex problems. Sometimes, the applied fixes exacerbate the negative conditions that need correction. 
Around the world, forests are being lost to the expansion of agriculture and cattle-grazing, wood-cutting for fuel and construction, mining, and the growth of cities. Replanted trees are often utilized as a renewable resource to be harvested. The selected species don’t always replicate the previous diversity, aren’t appropriate for all the sites being replanted, or are exotics, such as Eucalyptus.
Yatir Forest, image by KKL-JNF


 An example of unexpected results is the Yatir Forest in Israel’s Northern Negev region. This is an area where the desert and Mediterranean ecosystems meet; people have lived there for thousands of years. Unfortunately, the forest eliminates the habitat of rare dryland species. 
Yatir Forest, image by Yosef Segal
 The planted Aleppo pines, Pinus halapensis, while native to the greater geographical region, are growing at the driest limit of their range, with no natural seedling recruitment. Many adult trees have died due to increasing droughts. Measurements taken of the dark forest canopy show that it acts as a heat sink, increasing warming effects compared to the reflective, light-colored soils. When the trees die, the carbon that is stored in their wood is released back into the global environment. It’s estimated that the trees would have to grow for at least 80 years for their accumulated carbon to mitigate the warming effect of the forest canopy. It’s questionable that the pines will survive that long.

Iris atrofusca, image by Ori Fragman-Sapir
 The current biota is exquisitely attuned to the dry scrub or grassland environment that has developed with much human input over the centuries.

The new forest should correct longstanding environmental problems like overgrazing; it’s a bulwark against desertification and should mitigate the effects of the warming, drying climate.

Yatir Forest
Planting trees is an excellent environmental strategy, but to be effective, the local conditions and habitat of each planting site must be part of the overall plan. Effective efforts toward carbon sequestration won’t succeed when based on unsupported assumptions. Destroying existing habitats to create new ones is not a viable path to the future.


September 23, 2019

The African Tree of Life

“Wisdom is like a baobab tree; no individual can embrace it."

Some trees are strongly associated with the places in which they grow, so much that they become symbols of the places themselves; think of the Coast Redwoods of California, the Pehuen or Monkey Puzzle of the Andean foothills of Chile, or the various species of Australian Eucalyptus. One tree that is distinctly recognizable in the drier parts of sub-Saharan Africa is the Baobab, Adansonia digitata. Baobabs are naturally distributed from the Atlantic to the Red Sea, and to the northernmost part of South Africa. Like other organisms that are so well known that they have been taken for granted, the massive Baobabs still have secrets to reveal. Some of the trees might be a newly described species, Adansonia kilima, according to the latest genetic analysis. Baobabs provide significant environmental benefits to wildlife: safety and a nesting place for many creatures, nectar for the species’ fruit bat and insect pollinators, and a food and water source for elephants. Up to 75-80% of a Baobabs’ bulk is composed of water.
Elephants will often strip away bark and rip and chew through the trunks to satisfy their thirst. Even after many generations of damage, if not toppled, the trees continue to grow.

Elephant damage to a large Baobab
Baobabs also provide significant benefits for humans, especially in the driest areas where they grow. Honeybees utilize the hollow limbs; the trees have been used as various forms of shelter.  The fibrous bark makes excellent rope and nets. Leaves are harvested as fodder for cattle, goats, and camels. The pulpy fruit, commonly sold in markets across the continent, is peeled, sliced, and dried; it’s an excellent source of vitamin C. The seeds can be ground into a type of rich flour that is high in fat and protein. Young leaves can be cooked as a vegetable. All of the tree’s edible parts also contain valuable mineral nutrients. Historically, Baobabs were planted along the paths of the slave trade and can be found on the Arabian Peninsula and in the New World tropics.

 The Baobab prominently figures in many African myths and stories, especially in the explanation of the tree’s “upside-down” appearance. During the dry season, the species endures long periods of leaflessness, and the trees look as though they are growing upside down in the earth.