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 that 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 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.















September 13, 2019

Living on the Edge: the Cottontop Cactus

image by Zdenek Richter

The Cottontop Cactus, Echinocactus polycephalus, is a moderate-sized barrel cactus that lives in some of the driest areas of North America. There are two similar subspecies: polycephalus, the most widespread, found in parts of California, Nevada, Utah, Arizona and northern Mexico, and xeranthemoides, found near the Grand Canyon in southeastern Nevada and Northern Arizona. “Way over to Hell and gone” is an apt description of the species’ habitat. It occurs from the spectacularly desolate mountains overlooking Death Valley to the wretchedly arid flats of the Cabeza Prieta National Wildlife Refuge.
Cottontop Cactus grow in arid or hyper-arid landscapes that usually receive no more than 5 inches of precipitation per year. In the Mojave Desert the species must survive exclusively on winter rainfall, but plants in the Sonoran Desert occasionally experience summer thunderstorms during the monsoon season. In the stony wastes in which they grow, the sparse rains quickly drain away or evaporate in the heat.

The barrels grow to about 2 feet or so, gradually branching from the base to form clumps of up to 50 heads. Thick, fierce spines give the heads the appearance of medieval weapons. Rainfall temporarily turns the spines brilliant red. Given the slow rate of growth, it’s thought that large plants are over 100 years old. New growth tends to occur in Spring, months after the Winter rains have ended, and flowering takes place during the scorching heat of Summer.

The ripening fruit is embedded in a dense mass of tough, white fiber, thus the name "Cottontop".

image by Michael Thomas Bogen

Packrats and other rodents have to chew through the protective spines and fiber to get to the fruit.
Seeds found in ancient packrat middens indicate that the species has been dancing around its current range for the past 30,000 years. Favorable conditions for seed germination are infrequent occurrences, and seedling growth is very slow. With increasing temperatures and the long term prognosis of climatological drying of the Southwest, the survival of this tough, tough species in its exquisite environmental niche is, unfortunately, in question. 
image by Michael Thomas Bogen


August 27, 2019

Bananaquits in our Gardens

Image by Matt Magillivray
Recently, a pair of modestly colored, unusual birds have moved into the entrance area at Pinecrest Gardens. Occasionally found in South Florida, they most likely have flown here from the Bahamas. They are quite noticeable, actively flitting from shrub to signpost to roofline to trees. Their frequent singing is loud and pleasant; we hope that they stay and perhaps nest here.                                                         

The Bananquit, Coereba flaveola, is a small bird of the New World tropics. The species belongs to the large avian group known as perching birds, a taxonomic order that includes many of the best known and liked songbirds, including their close relatives, the Tanagers. Bananaquits are small and mostly grey, with white or bright yellow breasts and white-striped heads. They are inhabit a wide geographical range that includes much of the South American tropics and subtropics east of the Andes Mountains, parts of Central America and Mexico, and Caribbean and Antillean islands. They live in diverse habitats, including open forests and scrub, and also live and nest in gardens in urban areas.
Bananaquits consume some insects. Mostly, they use their slender, down-curved bills to pierce flowers for their nectar and eat sweet fruit, their primary foods. Although it is a poor food source, people often use granulated sugar or syrup to attract them to bird feeders. They are bold creatures that seem comfortable around human noise and activity.

Like so many other organisms, there are unanswered mysteries about the birds. One question concerns their distribution: why are Bananaquits only found in some places, but not others, e.g. Cuba, that would seem to have suitable habitat? How often do they occur in Florida? What accounts for the great variability in the physical appearance of different populations? Off the Venezuelan coast and on some other islands, for example, the birds are nearly entirely black. It seems that what biologists classified as a single species might actually be several different birds!
To hear a Bananaquit singing, open this YouTube video:

August 22, 2019

Olive Trees in South Florida! Hold On, You’re Getting Excited for the Wrong Reason


Talk of olive trees in South Florida and people tend to think of the Black Olive, Terminalia buceras, a tree in the family Combretaceae, the White Mangrove family. Naturally found in the Caribbean, Central America, and Northern South America, there is some public confusion over its identity as the cultivated edible olive species. It ain’t. It’s doubtlessly called Black Olive due to the similiarity in the appearance and staining properties of the ripe fruit.

To see a real olive tree, visit Pinecrest Gardens, where a 125 year old specimen has been planted in one of the dry garden areas. With its silvery leaves and thick, gnarled trunk, it looks just like the individuals that one might encounter on a Greek island, the Andalusian countryside, or a Lebanese mountain.
Olive at Pinecrest Gardens
The Common Olive, or just plain Olive, Olea europaea var. europaea, is a tree that originated in the Mediterranean Basin region. It’s one of many members of the family Oleaceae, the Olive family, but the only species that is widely grown for its fruit. The Olive is an ancient cultivated crop that was domesticated from the wild Oleaster, Olea europaea var. sylvestris, about 6000 years ago; the earliest evidence of olive use is 19,000 years ago from an archeological site in Northern Israel. To be edible, olive fruit must be fermented (pickled) by allowing the natural bacterial community found on their skins to grow, or by processing them with lye.
Old Olives near Chalkio, Greece
Olives are mostly grown for oil production. Established groves having productive trees are often hundreds of years old. The species also has fine, durable wood that is rot-resistant and excellent for carving.
Olives develop heavily gnarled trunks 
Olives were brought to the New World by the Spanish. In Florida, olives were planted at St. Augustine and New Smyrna Beach. Currently, the University of Florida is encouraging commercial planting in the central and northern parts of the state, where cooler winters make fruiting possible. Olives do best in Mediterranean-type climates, where Winters are mild and moist and Summers are long, hot, and dry. They are an adaptable species but require full sun, perfect drainage, and no irrigation once established.   

August 15, 2019

Ah, the Romance, the Exoticism, the Colonialism, the Breadfruit!

Image by Ryderfoot
Breadfruit, Artocarpus altilis, is a strictly tropical-growing tree in the same family that includes figs, mulberries, and Jackfruit, the Moraceae. It’s a fairly large, big-leaved tree that bears a starchy edible fruit. Originating in New Guinea and the Philippines, its wild ancestor was spread throughout the Pacific during the times of the great Austronesian and Polynesian ocean voyages, starting 3000 years ago. Breadnut, Artocarpus camansi, is still cultivated, especially in New Guinea for its edible seeds. The domesticated breadfruit is mostly seedless. The unripe fruit is eaten after being boiled, baked, roasted, or fried. It tastes somewhat like potato or bread. It's quite popular across Polynesia and many countries around the world where it is cultivated.  
Breadfruit is also an example of botanical imperialism, as depicted in Mutiny on the Bounty. Young plants were transported by the British to the New World, providing an easily grown, calorie rich food for slaves working on the island colonies.
Image by Pxleyes
Breadfruit is quite adaptable in cultivation, but prefers rich, well drained soils in areas with high rainfall. It’s strictly tropical in its temperature requirements and won’t tolerate any but the mildest of cool weather. In some places it has escaped to the wild and has become a bit of an invasive pest.

Image by NTBG

Breadfruit is a very attractive landscaping tree. Its large, deeply incised leaves make a decidedly tropical statement. In the past, Breadfruit was nearly impossible to cultivate long-term in South Florida except in the most protected of locations. With increasing temperatures and mild winters, chances have greatly improved for success in warm locations near the coast. 

July 31, 2019

Sealing Wax Palms, Species Conservation, and Environmental Change

photo by David J.Stang

The Red Sealing Wax Palm, Cyrtostachys renda, is a slender, medium-sized clustering palm with pinnate (feather-shaped) leaves found in tropical peat swamp forests in Southern Thailand, Peninsular Malaysia, Sumatra, and Borneo. Of unique and striking appearance, the species is widely grown in the world’s tropical regions.

And what an appearance!  One of the world’s most beautiful palms, the tree’s graceful, thin, green-ringed trunks support dazzlingly red or orange crownshafts and colorful feathery leaves.  Outside of the tropics, it’s considered a “holy grail” plant for gardeners; a palm that is both difficult to find, to accommodate, and to grow in a non-greenhouse setting. If you’ve ever visited a public garden or park in the tropics or a large conservatory in more temperate zones, the species can frequently be found planted en masse or prominently displayed as a specimen. The Sealing Wax Palm is commonly used as a landscape tree in wet tropical climates.

Having so much horticultural value, many plants have been removed from the wild. The International Union for the Conservation of Nature (IUCN) listed the species as threatened in 1995, thus motivating Indonesia to pass protective legislation. Cyrtostachys renda was no longer considered at risk by the IUCN in 2000. 
Cyrtostachys renda in habitat
 Unfortunately, IUCN listing or delisting often does not predict an organism’s survivability in the current age of rapidly increasing environmental stress. It’s not possible to assess the conservation status of all of the world’s species; many thousands are undescribed and doubtlessly pass from the biological stage without our ever knowing of them. Assessments are based upon field surveys that can only give a snapshot of a species’ populational health and abundance. In some instances, all it takes is a forest to be logged out, cut, or burned for agricultural conversion, drainage of a marsh for construction of a new housing project, the local loss of a specific pollinator, or sustained harvesting or poaching to result in a species’ extinction. Of course, underlying most environmental stressors is the big one that “rules them all”: climate change inevitably disrupts the subtle and complex phenology of entire biological communities. It’s difficult to ascertain just how stable wild Sealing Wax Palm populations really are. It should be assumed that since the species’ habitat is highly threatened, especially by conversion to Oil Palm plantations, then the palm probably is, too.

Forest clearance and road construction for Oil Palm cultivation

An "island" of forest remnant

Miles of Oil Palm monoculture

Primary forest
The peatlands or peat swamp forests are highly threatened ecoregions in Southeast Asia. They function as huge carbon sinks, holding the accumulation of thousands of years of plant growth. Dead plants don’t break down easily in the water-laden, oxygen deficient ground, and the carbon in their bodies remains naturally stored as peat. Peatlands are ancient, biodiverse, and store more carbon than other types of tropical forests, including the better-known rainforests. When they are drained and set ablaze for clearing, immense amounts of carbon dioxide are released into the atmosphere, adding to global warming.

Peat forest burning

Fire-induced air pollution