SIGN 1 | WELCOME TO MY WORLD Come meet my family - the Trees! Along the first two miles of this trail I’ll share some information about us and our forest neighborhood. When you’ve finished your walk, you’ll have a better understanding of what it’s like to be me - a tree. Oh, by the way, you’ll need to know the size of an acre for some of the topics I cover. It’s about the size of a football field. Captions 1| My family portrait. (Image is of a forest) SIGN 2 | HEY! THAT HURTS! Show us a little respect, please. Don’t be thoughtless like the people who carved their names and initials in this beech tree’s bark. It ruins our “good looks” and can also lead to our death. Our outer bark is like the skin on your body - it protects the living cells inside. Wounds to our bark allow potentially destructive diseases, fungi and insects to enter our wood. The outer bark also protects our inner bark that transports food (sugar) from the leaves to the living cells in the branches, trunk and roots. It’s our “pipeline” to staying well fed. So, please, feel free to hug us, but don’t mug us! Captions 1| Michigan beech trees are now the target of a non-native, sap feeding, scale insect. These tiny creatures pierce the bark, which allows a deadly fungus to enter the living tissue. Within a few years the trees begin to die. The white streaks on this tree’s bark are thousands of scale insects. 2| Some foresters believe that 95 percent or more of Michigan’s beech trees will eventually die from this fungal disease. The subsequent loss of beechnuts will greatly affect the autumn food available to this ruffed grouse, and deer, wild turkeys, black bears and squirrels. SIGN 3| DWINDLING NUMBERS In one study of sugar maple trees, 2,671,000 seeds were dropped during autumn on an acre of land, but only one half sprouted the following spring. By late summer, just 79,500 seedlings remained. Two years later, only 14,200 of these little trees had survived. And of these, just a few managed to grow into full-sized trees. What happened to all the seeds and young trees? Think about it and I’ll tell you at the next sign. Captions 1| Pyramid of survival. (Diagram shows a triangle divided into three sections. At the base are hundreds of seeds. In the middle section is a handful of saplings, and at the top is one large tree.) 2| First-year sugar maple seedlings. SIGN 4 | lOTS OF LUCK Seeds are our children - they become new trees, but it’s a jungle out here and most don’t survive. Many seeds and young trees die from diseases or are eaten by insects, birds and mammals. Fires, droughts and floods eliminate others. And some just don’t have the strength to live. So, lots of seeds must be produced to insure that some will be lucky enough to grow into mature trees. Captions 1| It takes energy to make seeds, so trees with large seeds like oaks, hickories and walnuts produce fewer seeds than trees like birches, maples and elms. 2| On average, nearly 25 percent of all acorns are infected with weevil larvae or fungi before they fall to the ground. 3| Based on growing conditions, an acre of birch trees may produce from one to 35 million seeds per year. During high seed-bearing years, so much food energy goes into making seeds that branches may die. SIGN 5 | CLONE ALONG WITH ME I just heard that humans have learned how to clone animals. Big deal! Some trees have been cloning themselves for thousands of years. Willows may grow new trees from live, broken branches that fall onto stream banks. Tamarack branches touching the soil sometimes root to form new trees. And small aspen trees, like those in front of you, are usually root sprouts from larger aspen trees nearby. Captions 1| The largest tree clone is an aspen stand in Utah. The estimated 47,000 trees are actually one tree! They’re all connected to one root system that covers 107 acres. 2| Diagram of aspen root system with old and young trees. 3| Young beech sprout along the roots of an old beech tree. SIGN 6 | TRACES OF PAST TREES Look at the forest floor and notice all the small mounds and shallow depressions. What caused them? For a hint, look at the tree lying on the ground. When this tree fell, its roots pulled up a lot of soil, creating a small hole. As the roots rot, the soil they’re holding falls to the ground, making a mound. Eventually, the tree and its roots will rot away leaving only a pile of soil and a depression to mark the site where it once stood. For many years to come, the places where past trees once stood will still be visible by these earthly markers. Captions 1| (Three images of a fallen tree rotting away.) Going... Going.... Almost gone. 2| Rotting logs are shelters for many animals. (Images: spider, salamander, millipede) SIGN 7 | WINDOW OF OPPORTUNITY The maple tree that once stood here was cut down in 1999. Its trunk had split and it was ready to fall. If you look up, you’ll see the “light window” it left in the canopy. This section of open sky will eventually be filled by one of the smaller trees growing below. These “little guys” have been biding their time waiting for an opportunity like this. Captions 1| Sugar maple and beech seedlings can exist for years in the shade of other trees. They grow very little until they receive sufficient sunlight. 2| A light "window" throughout the seasons. (Four images: spring, summer, fall, winter) SIGN 8 | DRESSED FOR DINNER Our leaves are “food factories” that produce sugar to feed our living cells. Sunlight is the energy that runs these factories, but it does not reach all of our leaves at equal intensities. Therefore, many trees have two types of leaves; SUN leaves and SHADE leaves. Sun leaves are found in full sunlight, like at the top of the tree. They are thicker than shade leaves and tolerate the hot sun without drying out. Shade leaves are located in the center and lower branches. They are thinner and have more surface area than sun leaves and can manufacture sugar with less light. So, whether it’s cloudy or sunny, we can always make our “meals.” Captions 1| A sun and shade leaf from the same pin oak. Can you guess which is which? 2| Trees use oxygen for respiration too, but they release more oxygen through photosynthesis than they use. That’s good news for animals. (Diagram of photosynthesis: water+carbon dioxide+sunlight energy=sugar+oxygen. Diagram of respiration: sugar+oxygen=water+carbon dioxide=energy for living cells) SIGN 9 | OUR FEET ARE PLANTED FIRMLY IN THE GROUND Our roots anchor us to the ground and absorb water and nutrients from the soil. But they also store food, secrete chemicals, make organic compounds and sprout new trees. They’re so important that we have lots of them. Forest researchers measured 75 feet of roots, including microscopic ones, on a one-year-old white oak seedling (growing wild) and found 169 feet of roots on a four-month-old flowering dogwood (greenhouse grown)! Think of how many thousands of miles of roots there must be on one big tree. Captions 1| This is what a typical tree root system looks like. The roots of a tree may extend well beyond the spread of the limbs and nearly 85 percent of them are within the top 18 inches of the soil. 2| Few trees have root systems that look like this. (roots extending only to the spread of the limbs) SIGN 10 | OUR AUTOBIOGRAPHIES The life history of humans is recorded on paper made from wood. The life history of trees is recorded in our wood. As we grow, what we experience is “written” in the wood we produce. You just have to know how to read it. Naturally, by counting our rings you can tell how old we are. But you can also see scars from injuries, areas where we had decay, years that we grew well (or not so well), and places where insects tunneled through our bodies. Look at the photos to see what happened to some of my buddies. Captions 1| A maple sugar tap hole. New wood is not formed in the hole. 2| The interesting design in this red maple was created by a “blue stain” fungus. 3| This 87 year old bur oak is only six inches in diameter. It obviously had lots of competition from other trees for light and water. The wide rings were the better growth years. 4| The dark stains in this red maple are branches. They began to grow when the tree was about three years old. SIGN 11 | STRUCK FROM ABOVE Each year, on average, every square mile of Michigan is struck 10 to 15 times by lightning. That’s 700,000 strikes a year in this state! This wild black cherry tree before you is one of the casualties. Notice the long scar on its trunk. The bark was violently blown off as the electrical current ran through it. Some trees don’t survive lightning strikes, but only part of this tree was killed. However, observe how the exposed wood is rotting and being tunneled through by various insects. Even though this tree is trying to cover the wound with new wood and bark, its days are probably numbered. Captions 1| A spiral channel is common on trees struck by lightning. 2| On another black cherry you can see a half-inch wide groove in the center of the lightning channel. Two or more grooves indicate that the tree had multiple return strokes when hit. SIGN 12 | BURNING QUESTIONS Fire! There’s no running from it when you’re a tree! So, how do we cope? Will we survive? It all depends on the severity and type of fire and the age and variety of the tree. There are three types of forest fires - crown, surface and ground. Crown fires burn to the tops of trees and usually kill them. Surface fires burn leaves and branches lying on the ground. Ground fires smolder underground in dry organic matter and kill the roots of trees. Some trees, like mature bur oaks and black walnuts, have thick bark that insulates the living cells from fire. A light surface fire may only char the outer bark of these old trees, but may kill all the smaller trees around them. However, if their roots survive, the small trees may send up new shoots. Captions 1| Conifers are very susceptible to crown fires. 2| The thin bark of wild black cherry offers little protection from fire like the thick bark of black walnut. 3| In the 1930s, a fire burned through part of this area. The furrow before you is part of a firebreak that was cut to contain it. 4| The red lines show the locations of the firebreak. (Indian Springs nature trail map) SIGN 13 | UNSPORTSMANLIKE CONDUCT Trees are always competing with other plants for light, water and nutrients. As a competitive game tactic, some trees emit toxic chemicals from their roots or leaves that inhibit the growth of other plants. Among those that do this are black walnut, sugar maple, sassafras, and red and white oak. Naturally, some plants are immune to these chemicals and grow quite well next to these trees. But other plants can’t tolerate this “cheap shot.” Captions 1| Some crop plants, like sunflowers, release toxins to reduce competition from other plants. Scientists are trying to develop other crops that can naturally “weed out” their unwanted neighbors. SIGN 14 | WHAT'S EATING YOU? Sure, you know that lots of animals like to eat the fruits and seeds that trees produce. But, that’s not all that these creatures nibble on. Ruffed grouse and squirrels eat the buds on some trees. The larvae of many beetles feed on our wood. Aphids drink our sap. Deer devour our tender twigs. Rabbits gnaw the bark off young trees. And, numerous caterpillars munch on our leaves. So, the next time something is bothering you, just remember what we have to put up with! Captions 1| Over 500 organisms, from viruses and fungi to beaver and deer, feed on aspen trees. 2| Most trees can lose up to 30 percent of their leaves without being harmed. SIGN 15 | KNOTS ON WOOD The large bulge on my friend here is called a burl. It looks like he swallowed a giant egg. Although scientists have many theories as to how they form, no one really knows what causes them. They normally don’t harm us unless they begin to rot. Burls can be found on our trunks, roots and branches. The wood grain is often deformed, which creates an interesting appearance when the wood is cut. In fact, people often use our burls for bowls and veneers because of the unique look. Captions 1| A big "burly" guy. 2| Bowls turned from burls. 3| Walnut burl veneer on an antique dresser. SIGN 16 | "WOOD" YOU LIKE SOMETHING This old saw was used many years ago to cut some of my relatives into lumber for houses and barns. While most people associate trees with the production of lumber and paper, few realize that there are over 2,500 other tree products not related to these two uses. Nevertheless, if you had one cord of wood, look at the paper and wood items you could make. Captions 1| A cord is a woodpile four feet high by four feet wide by eight feet long. 2| One Cord of Wood = 7,500,000 toothpicks 61,000 standard envelopes 2,700 copies of an average daily newspaper 1,000-2,000 pounds of paper 1,200 copies of National Geographic 250 copies of the Sunday New York Times 30 Boston rockers 12 dining room tables 3| Some products made completely or partly from wood or wood by-products: Ping Pong Balls, Toothpaste, Artificial Sausage Casings, Turpentine, Rayon Clothing SIGN 17 | A BIG "FAMILY TREE" There are over 20,000 species of trees in the world and about 100 of them are indigenous to Michigan. In this park, you can find about 40 native varieties. Each tree has a common name and a scientific name. Common names can be confusing since different types of trees may be called by the same name. For example, several kinds of trees around the world are known as ironwood. So scientists have given each type of tree a scientific name, one that no other tree in the world has. The name has two parts - the genus, which is like your last name, and the species, which is like your first name. The scientific name often describes something unique about the tree. Captions 1| Common Name: Quaking Aspen, Scientific Name: Populus tremuloides Populus - Latin for aspen tree tremuloides - from Latin tremulus, meaning shaking or trembling, referring to the leaves that shake in the lightest of breezes 2| Common Name: Tulip Tree, Scientific Name: Liriodendron tulipifera Liriodendron - from the Greek words leiron for lily and dendron for tree, thus lily-tree tulipifera - meaning “tulip-bearing” in reference to the appearance of the flowers 3| Common Name: Bur Oak, Scientific Name: Quercus macrocarpa Quercus - Latin for oak macrocarpa - from the Greek words macros for large and karpos for seed, hence, large acorn SIGN 18 | KNOCK ON WOOD Knocking on wood for good luck arose from primitive European people who believed that friendly spirits lived in trees. They thought that if they gently tapped on a tree, the spirit would grant them a special favor or good luck. There are many other tree superstitions that people have created. Here’s a couple more. In ancient Scandinavia, the oak tree was believed to be the favorite of Thor, the Thunder God. People placed acorns in windows to show him respect with the hope that he wouldn’t strike their homes with lightning. Long ago, some people planted an evergreen tree in honor of a newborn child. Evergreens symbolized long life and were considered the beloved trees of the gods that watched over humans. Captions 1| Variations of the term, “knocking on wood” can be found throughout the world. Some versions include tapping the underside of furniture, knocking on unpainted wood or simply touching wood. 2| A painting of Thor, the Thunder God. SIGN 19 | LET ME POINT THE WAY Years ago, some American Indians would deliberately bend and tie small trees to the ground to mark trails. As the trees continued to grow, their tips would eventually turn upward, but their trunks would remain bowed. Or the tips might die and branches would then become the main trunks. The bent trees you see today, however, are the result of large trees falling on small trees. By the time the large trees rot away, the small trees will have permanently arched trunks. Captions 1| Crooked for life. 2| Here's how it begins... 3| Here's how it ends. SIGN 20 | I'VE GOT FRIENDS IN LOW PLACES “where the bacteria underground and the fungi chases my blues away.” Okay, so I’m no Garth Brooks, but trees couldn’t exist without the help of our “low-life” buddies. Bacteria break down leaves and wood into microscopic particles. This releases nutrients for us to reuse as we make more leaves and wood. Fungi also share in the duties of breaking down organic materials, but those that attach themselves to our roots are very important to us. They increase our ability to take in water and nutrients by 10 to 1,000 times! Captions 1| A teaspoon of soil may contain 50 million one-celled bacteria and a thimble of soil may have several miles of microscopic fungal filaments. 2| Worms recycle organic materials too, but Michigan’s forests evolved without them! The worms here are of European origin. They consume the leaf litter too fast which makes it difficult for the seeds of some plants to germinate. 3| The fruiting body of a fungus produces spores while the microscopic filaments obtain nourishment from organic materials. SIGN 21 | FASHION SHOW Trees are dressed in outerwear called bark and every type of tree sports its own unique look. This “look” is created by special cells called the cork cambium. The arrangement of these cells creates the patterns and designs seen in the bark. Some trees, like American beech, have a continuous ring of cork cambium that grows and expands at the same rate that new wood is being made. Thus, the bark is smooth. Other trees produce scaly, furrowed or peeling bark because the cork cambium is in random patches of various sizes and shapes. Since the tree produces wood faster than the cork cambium can produce bark, the bark is slowly pulled apart. Captions 1| Diagram pointint to parts of a cross-section of a tree: Wood, Primary Cambium, Inner Bark, Cork, Cambium 2| You’re eating bark when you eat cinnamon. 3| The blocky-looking bark of a red oak. 4| This is why this tree is called shagbark hickory. 5| The alligator-skin bark of the flowering dogwood. 6| Smooth is the look for the American beech. 7| Wild black cherry bark looks like black potato chips. SIGN 22 | THANKS FOR STOPPING BY I hope you enjoyed your visit to my “neck of the woods.” As you’ve seen, there are a lot of interesting things about trees and our forest neighborhood. Keep in mind, though, that forests are just one of many different types of habitats. Marshes, sand dunes, prairies, bogs, rivers and ponds are also important for the survival of many unique varieties of plants and animals. Please take some time to explore some of the other natural neighborhoods at Indian Springs. And now I’ll “leaf” you alone for the remainder of your walk. Bye, bye.