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Often used by Hollywood, this bizarre looking member of the mostly subtropical agave family provides a striking silhouette standing tall with rigid arms extending in every direction against the orange Mojave Desert sky.
Named by 18th century Mormons after the biblical prophet Joshua, the plant also known as a yucca had special meaning for those wandering across the parched high desert in search of the Promised Lands. Its arms pointing towards heaven, as the story goes, confirmed that they were on course.
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Fire is an integral part of western forests and all forest types throughout North America, Australia and elsewhere have evolved and adapted to fire.
Three types of forest fires occur.
When treetops burn it is called a crown fire and its lethal for most trees. In California oaks and big cone Douglas-fir, for example can regenerate new leaves after being scorched.
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Nineteenth century author, naturalist and co-founder of the Sierra Club – John Muir called the giant Sequoia “the noblest of a noble race” for many worthy reasons.
These exquisite specimens date back to at least 150 million years ago to the Jurassic Period – a time when the great plant-eating dinosaurs ruled the land and the ocean was stocked with the great ichthyosaurs and the long-necked plesiosaurs.
Magnificent giant Sequioas once thrived from Alaska to the Midwest, from Europe to the Orient and even in Greenland.
Big trees, as they are affectionately known, have survived epic geologic upheavals and extreme climate changes. As a matter of fact, on Specimen Ridge in Yellowstone National Park, Wyoming, there’s a fossilized 26-foot Sequoia stump jutting up amongst 40 million year old volcanic debris.
About 18 million years ago the remaining giant Sequoia populations mostly occurred in southern Idaho and western Nevada. As the climate cooled and continued to dry-out the giant Sequoia were forced to migrate southwest. They managed to expand their range west into California before the Sierra Nevada range became the formidable backbone of the state. The mountains cut-off any moisture and the eastern population of big trees perished.
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Ants and human beings have much in common, including that both species have globally conquered the planet. We are both highly socialized creatures, agriculturalists and ruthless in warfare. Both depend on forests for sustenance.
Ants have been on Earth for more than 140 million years and evolving from wasps. There are about 12,000 species known and emeritus professor E. O. Wilson of Harvard University estimates there about another 9,500 kinds still to be discovered.
Currently there are about ten thousand trillion living ants. When combined, all ants on Earth would weigh about as much as all humans.
There are currently about a million known species of insects. There are about 15,000 species of highly social insects of which ants make up 12,000. Half the living tissue of insects is made up of just two per cent of the species that live in well organized colonies.
A worker ant is one-millionth the size of a human. Yet, a leaf-cutter ant, whose jaws can slice human skin, will not back down from a human.
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The amazing whitebark pine (Pinus albicaulis) reach ages in excess of 1,000 years old. It lives in the harsh environs of the Rocky Mountains and has cooperatively co-evolved with a bird – known for its extraordinary memory – called the Clark’s nutcracker.
White bark pines can reach heights of 65 feet, but more usually they are recognized as a stunted multi-stemmed tree. Named after its whitish bark with scaly plates on older trees, its needles grow in bundles of five and egg-shaped, sticky-with-resin purple cones, take two years to ripen. The wingless seeds are large and filled with high concentrations of fats and proteins. Cones mature in late August, but do not open widely enough for the seeds to fall out. If the seeds over-winter in the ripened cones, by springtime they become moldy and turn rancid. So how does viable seed get out of white bark pine cones?
Clark’s nutcrackers belong to the 113-member group called the Corvids. Corvids have unusually large brains compared to all the other 10,000 bird species. They eat some insects and occasionally a bit of carrion. But it’s their chisel-like bills that are specially adapted to ripping into white bark pinecones and with precision extracting the large protenacious seeds. These seeds, as a primary food source, enable the throaty squawks of resident Clark’s nutcrackers to live year-round in the otherwise inhospitable environment of the Rocky Mountain alpine (above tree line).
This is a story of a mutual relationship between bird and pine, offering insight into the marvels of Mother Nature. Together, Clark’s nutcrackers and white bark pines build high elevation ecosystems.
Nutcrackers start to feed on white bark pine seeds in mid-August. They chisel into the purple, pulpy cones and extract seeds, one at a time. They store the seeds in a sublingual pouch in the floor of their mouth, underneath the tongue. This pouch can hold as many as 80 seeds. The August and September seed harvest must sustain the birds and their offspring, for the coming 10 months.
The Clark’s nutcrackers then carefully deposit the seeds, one at a time and up to 15, 1 inch deep into the soil. Occasionally these caches are close to the tree where the harvest took place, but more often it’s up to 6 miles away. Seeds are buried in open areas and in recently burned-over high-elevation forests. Some of those openings remain windswept during the long winter months. Others can have over six feet of snow covering the cache and I have observed Clark’s nutcrackers burrowing into deep snowpacks to retrieve white bark seeds.
One bird can cache up to 98,000 seeds in over 30,000 sites. About half those seeds will be recovered by Clark’s nutcrackers. Multi-stemmed white bark pines denotes a cache was not retrieved and that several or more seeds sprouted at the same time and have grown together.
How does the Clark’s nutcracker locate all of its caches? Experiments have clearly demonstrated that these birds, like other Corvids, have excellent memories and in fact remember where they placed the seeds. They use a system of triangulation to reference where caches are located. That is, they use a tree, stump, rock, log or other landmark and remember the angles between the caches. Their memories, especially long-term, are remarkable, since they are able to recover seeds some 10 months after storing them. They must also use other cues to assist them because snow modifies the landscape.
White bark pine seeds are also an important food source for ground squirrels that also live full-time in the alpine of the Rocky Mountains. They too harvest the cones and take them to large caches called middens. In addition, ground squirrels raid Clarks’ caches and relocate seeds.
In the autumn and occasionally the springtime, black and grizzly bears raid ground squirrels middens. I have watched bears gingerly extracting the delectable white bark seeds. Prior to hibernation a sow must add about 7 inches of fat around her tummy or 99 pounds of body weight, in order to give birth – while she’s hibernating – to cubs. So the white bark pine seed is a very important food source for many different big and small alpine and subalpine animals.
Soon after the spring snow-melt, white bark pine seeds germinate and grow 8 inches deep tap roots. White bark pines require full sunlight – they are shade intolerant and cannot grow under other trees. White bark pines change the micro-climate, causing warmer winter and cooler summer under their cover. Over time, openings along the high elevation landscape are filled in by white bark pines and clumps of young trees form new forests high in the mountains.
In time, Englemann spruce, which require some shade, seeds itself into the under-story of the white bark pine forests. Other tree species like subalpine fir follow soon thereafter.
Some trees die young and their wood serves as a decomposing base to feed bacteria, fungus and wood boring insects, which assist in the breaking down of wood and making new soils. Other, like old white bark pines, become victims to pine bark beetles and die but remain standing upright for another 100 years. Woodpeckers, nutcrackers and other cavity-nesting birds use these trees for roosting and nesting. These forests are occasionally used by big game animals like mule deer. In the autumn, finches, siskins and crossbills forage in the Englemann spruce treetops.
In the wild, Clark’s nutcrackers can live for 12 years. They can fly at speeds of 30 miles per hour carrying a load of seeds than can exceed 20 percent of their body weight, for distances up to two miles. About 22 species of high elevation pines worldwide depend on a dozen or so Corvids to help disseminate their seeds, create forests and habitats for many animals.
Eventually, one hot and muggy summer afternoon a bolt of lightning ignites the forest. The assiduous Clark’s nutcracker will return to replant the forest, feed other animals, and recreate the tenacious forested mountain ecosystems of Rocky Mountains.
Text © by Dr Reese Halter 2012. All rights reserved.
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Portrayed throughout history as a villainous critter that wastefully kills, the wolf’s reputation precedes it. The traditional image, however, is unwarranted and incorrect.
Wolves are highly intelligent social animals. They are a critically important predator in the western food chain. When wolves eat, so to do a host of other animals including: wolverines, lynx, bobcats, mink, weasels, hares, porcupines, squirrels, mice, voles, shrews and ravens.
Wolves ancestory dates back to about 15 million years ago. They are related to foxes and domesticated dogs. There are two species in North America, the gray or timber wolf, and the red wolf. Wolves have the largest natural range of any animal on our continent and their main predator are human beings. Hence, they have been hunted and poisoned, at one point to near extinction. Thankfully, they are survivors.
The translation of the wolf’s Latin name is literally “dog wolf,” and for good reason. Wolves and dogs share common features. They both have a similar gestation time of about two months. And they both molt in the spring and grow winter coats in response to season differences in temperatures.
Wolves, however, do have distinct features. Their ears are relatively shorter, broad at the base and less pointy at the tip than those of most dogs. They have large heads with wide and heavy skulls which curves downward and blend into a broad but tapering muzzle that ends with a black nose. Their jaws have tremendous biting power.
They have longer legs than most dogs, with paws that are longer and wider in the front compared to the back. They have five frontal and four back toes. The fifth frontal toe is actually called a dewclaw and is used to help secure, hold and bring down prey. Because its not necessary for locomotion, many dog owners have dewclaws removed. Big springy feet assist wolves in attaining a top end speed of about 40 miles/hr (65 kilometers/hr). More usually though, they travel at 5 to 6 miles/hr (8 to 10 kilometers/hr) while tracking prey for hours on end.
Wolves are large critters, ranging in size from 5 to 6 feet (1.6 to 1.8 meters) in length with an average weight of 88 pounds (40 kilograms). Females are about 15 percent smaller than males.
One of the most remarkable aspects about wild animals, particularly in north country, is how they manage with cold winter temperatures. It has to do with their winter coats. And wolves have an exquisite two layered coat. The outer layer consists of guard hairs that shed moisture, keeping the coat free of dirt and burs because of the hard, smooth, slippery hairs. Their thick underfur contains an oily substance similar to sheep’s lanolin helping make it impermeable to cold temperatures.
Wolves, like human beings, are a very social animal. And not dissimilarly to us, they have a social hierarchy. Packs have between six and nine members but can be as large as 36. There is one dominant male and female, called alpha’s, in each pack. Order in the pack is achieved by various postures, stares and physical punishment. Status is shown by the way the other pack members carry tails, eyes and head positions. Subservience is demonstrated by bearing the throat, lifting the leg or exposing the groin.
Wolves howl; humans sing in the shower. Why? Because we both like too.
Wolves are fierce hunters relying upon their keen power of scent to track their prey. Moose, elk, caribou and deer are their preferred prey. They hunt in a pack. The alpha male will test the prey. If it stands its ground wolves will not challenge it. If it run the pack will quickly bring it down. Most wolf kills are old, unfit or young prey. Wolf digestive systems break down every bit of protein and their scats contain very little fecal matter.
Wolves are survivors, they will eat: beavers, snakes, porcupines, grouse, ducks, voles, mice, rabbits, vegetables, grasses, herbs, mushrooms, fruit and, when low in vitamin C, they will gnaw in the springtime on rich tree bark for its supplements.
Like humans, wolves enjoy playing and grinning. They have suffered from an unnecessary war that we have waged against them for centuries, and somehow managed to survive. Wolves are a symbol of courage, endurance, and admirable intelligence.
Text © by Dr Reese Halter 2012. All rights reserved.
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Most of the land mass that encircles the North Pole is covered with an evergreen crown. It is home to the giant northern or boreal forest of Earth. Its remarkable fauna and flora are well adapted to the harsh frigid environment.
The boreal forest is truly immense. It occupies 4.6 million square miles (12 million square kilometers) or roughly one and a quarter times the size of either Canada or the U.S.
In North America it stretches from Newfoundland across at least the northern part of every province and the southern part of the territory and most of Alaska. Across the Bering Strait it covers eastern Siberia and slivers of northern Mongolia and China, and it marches across a vast expanse of Russia eastward into most of Scandinavia.
Evergreen spruce, pine and fir needles’ must endure blasting ice shards and unimaginable freezing temperatures as low as minus 62 degrees Celsius. Thick coatings of wax and sunken pores or stomates that absorb CO2 for photosynthesis are but two important needle adaptations enabling these trees to thrive in this environment. Although larches are cone bearing or conifers they are deciduous preferring to grow new needles each spring.
Birches, alders, poplars and willows also make a living in these northern forests. As a matter of fact, European aspen which lives in the boreal forest is the most widespread of all the more than 80,000 species of trees on Earth.
Incidentally, the northern most treeline is determined by temperature; that is, the average temperature of the warmest month, July, must be greater than 50 degrees Fahrenheit (10 degrees Celsius).
In North America the boreal forest sits on top of the Canadian Shield -at over four billion years old it comprises some of the oldest known rock on the planet.
Lightning-induced fire plays an important role at resetting the biological clock and promoting diversity in the boreal forest. At average intervals of 150 years massive fires char the land. Jack pinecones are sealed shut awaiting the heat of the fire to melt the resin around the cone scales and release millions of seeds to quickly enable recolonization of the land. Jack pinecones are able to with stand fire temperatures of 1,292 degrees Fahrenheit (700 degrees Celsius) for three minutes.
Wood-hungry beetles attack smoldering trees and immediately assist in decomposing dead wood. Woodpeckers soon follow to feast on these beetles keeping their numbers in check.
Winter in the boreal forest is magic. I trained as an eco-tree-physiologist specializing in life in the cold and so each time I visit the boreal forest I cannot help but marvel at myriad adaptations of both animals and plants.
For instance, the diminutive muskrat remains active in cold water mostly under ice all winter long. In the fall they increase their blood volume and the amount of oxygen-binding myoglobin in their muscles. They build small winter lodges and create a number of feeding shelters nearby. As ice forms they gnaw through it and cache soggy vegetation under the snow where it freezes. They remember where the cavities are and revisit then to rest and eat throughout the winter.
Three species of chickadees, the smallest birds to reside permanently in the boreal forest, hoard seeds, berries and fossick for hibernating insects, pupae and egg clusters. They must eat every morning or they perish. A large portion of their brain, called the hippocampus, is dedicated to spatial memory. Remarkably, it increases and decreases seasonally.
Voles, mice, lemmings and shrews are also active all winter long on the forest floor underneath a blanket of snow. They gnaw on roots, bark, twigs, shoots and fungi.
The pygmy shrew – aptly named for its size of five grams or the weigh of a quarter – has a voracious appetite. It hunts insects, spiders, mites and must eat every two to three hours as it consumes 80 to 90 percent of its body weight each day. In order to cope with the winter it looses 45 percent of its body weight by shriveling up. Its skull and back-bone shortens, muscles thin out and its liver and spleen become smaller.
Spring peepers, the wood frog and the striped chorus frog have adapted to winter conditions in the far north by deliberately freezing solid with no perceptible heart-beat. As is by magic in the spring they thaw and soon after males in search of females peep over 4,500 times a night.
The onset of spring brings millions of migratory birds to the boreal forest. My favorite are the loons. There’s nothing more ethereal or hypnotic than the call of the loon on a lake. These birds are champion divers and fisherman attaining depths in excess of 266 feet (81 meters) and one record holder dove 201 times in three hours.
The spring also signals the hatch of billions of biting mosquitoes and slashing black-, deer- and horse-flies.
The boreal forest has millions of nutrient-poor stagnant bogs and slow-flowing fens. Sundews, pitcher plants, butterworts and bladderworts or carnivorous plants, live in the bogs and fens and feed on plentiful nutrient-rich bugs.
The effects of global warming are very apparent in the boreal forest. Spruce and mountain pine bark beetles are on a tear and have recently entered the southwestern boreal forest with an endless food supply of Jack pines stretching eastward across the continent. Warming soils are releasing methane, a greenhouse gas 23 times more potent at absorbing heat than CO2, five times faster than computer models predicted, and the soils are releasing one billion tons of CO2 a year. And nighttime summer temperatures have risen so dramatically in the last 10 years that some Alaskan forests have stopped growing.
Essentially the boreal forests have become the modern version of canaries in the coal mines. The boreal forest is obviously extremely sensitive to rising temperatures. We must conserve these exquisite forests and significantly reduce our dependency on coal, petroleum products and natural gas by promoting non-carbon alternative technologies now. Especially since the Arctic is now warming 4 times faster than the mean global temperature.
Text © by Dr Reese Halter 2012. All rights reserved.
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