Tree flowers are usually wind-pollinated rather than insect-pollinated. This is because they produce large amounts of lightweight pollen that can be carried by the wind.
the making0606
The majority of a tree's roots (up to 90%) are located in the top 30-60 centimetres of soil. This shallow root system is important for absorbing water and nutrients.
the making0605
Birch trees can grow as tall as 18-24 meters and have a slender, often multi-trunked appearance. They are fast-growing and can colonize disturbed or cleared areas quickly.
the making0604
Some tree species have evolved leaves with adaptations that reduce water loss. For instance, some leaves are waxy or hairy, which helps to prevent water loss through transpiration
the making0603
A mature, healthy tree can evaporate anywhere from 40 to 400 liters of water per day during the summer months.
the making0602
Trees will often produce more fruits than they can realistically support to full maturity. This is a survival strategy - by creating an overabundance, the tree increases the odds that at least some of the fruits will successfully develop and drop to the ground, where the seeds can germinate and grow into new trees.
the making0601
Approximately a fifth of all animal and plant species rely on dead trees. A dead tree is a host of life and should not be removed from forests.
the making0531
Birch trees produce catkins, which are long, cylindrical clusters of small, inconspicuous flowers. The male catkins are pendulous and appear in early spring, while the female catkins are more upright and develop into small, winged fruits.
the making0530
The acorn caps (also called the cupule) that enclose the acorn nut are structurally fascinating. They are made up of overlapping, modified leaves that fuse together to form the protective cap. The number, shape, and texture of the scales on the acorn cap can help identify different oak species.
the making0529
Branches can communicate with each other through chemical signals, allowing the tree to coordinate its growth and respond to environmental stresses.
the making0528
Reductions in sea ice in the Arctic are helping white spruce trees move north and up mountainsides.
the making0527
Willow bark contains salicin, a key component of aspirin. Its quantity is small, however the multi-component active principle of willow bark provides a broader mechanism of action and is devoid of serious adverse events. For example, willow bark does not damage the gastrointestinal mucosa.
the making0526
Woodpeckers feed on insects that can damage or infest trees, but they also open cavities for their nests, often starting a long decay process that can kill their host.
the making0525
The bark is the first line of defence against external threat. When it is damaged, trees have different ways of coping. Some compartmentalize and isolate the damaged areas, others produce new bark tissue to cover over and heal the wound. Often, around the edges, the tree will form a callus - a raised ring of new tissue that gradually grows over the damaged area. Finally, many trees will produce sap or resin to seal and protect exposed areas of the inner bark and cambium layer after damage.
the making0524
From “the hidden life of trees”, by Peter Wohlleben. In 2009, tree researcher Dr. Martin Gosser, to document the richness of species present high up in the crown of trees, sprayed the oldest ( 600 years old) and mightiest tree in the Bavarian Forest National Park with pyrethum, an insecticide. He killed, and therefore counted, 2041 animals belonging to 257 different species.
the making0523
A tree cannot move, but its seeds can. Depending on their size, they travel in the air, using feathers and wings, or on land, helped by mice, squirrels, and birds, or floating on water.
the making0522
Trees have a series of thin roots that extend to the edge of the canopy. These roots catch the water that drips from the leaves on rainy days.
the making0521
A fast growth rate gives pioneer trees a chance to survive the appetite of large herbivores such as deer. They defend themselves by growing a thick, tough, rough trunk as quickly as possible.
the making0520
Approximately one third of the sugar and nutrients produced by trees is given to fungi, in exchange for their services.
the making0519
After all the old trees are felled, it takes from decades to centuries for a forest to regenerate.
the making0518
Trees need a well-developed root system and companions to withstand the effects of high winds and severe storms. Because of the sparse distribution of trees and the compact nature of the soil, commercial forests are more susceptible to damage.
the making0517
Roots and crown grow in balance. When a tree is severely pruned, the roots are deprived of the nutrients produced by photosynthesis and suffer and starve, while the wounds in the branches become an open invitation for fungi.
the making0516
Trees periodically stop producing seeds to reduce the population of animals that feed on them. Surprisingly, the same species several thousand kilometers away often suspend production in the same year, in synchrony.
the making0515
The chemical substances that trees use to communicate with each other have a direct effect on our blood pressure. According to Peter Wohlleben in his “The heartbeat of trees”, we experience beauty in forests when their effect on us lowers our blood pressure.
the making0514
In their early years, trees in forest grow very slow, under the shade of their mother tree. The slower they grow, the longer they will live and the harder their trunk will be. In managed forests, trees grow fast and their wood is less dense.
the making0513
Trees are nature's example of how life manages rigid constraints. Without the ability to move, and with very slow reactions, trees cannot plan against events that are infinitely faster and more mobile than they are. To adapt, they constantly produce low-cost, parallel "experiments" (their branches) and keep only those that are successful.
the making0512
When hot temperatures and drought combine, trees respond by reducing their perspiration to a minimum, sometimes even prematurely shedding their leaves. In both cases, they lose the ability to fotosynthesize and to produce wood, so they stop growing.
the making0511
The ash is one of the trees that most extends its roots. They can reach twice the distance of the trees’ height.
the making0510
Roots are the place where all chemical exchanges take place. However, the apex of each root also exchanges electrical impulses with the root itself. This electro-chemical exchanges are similar to what happens in our brains.
the making0509
A tree is governed by simple rules, encoded in its DNA. However it is impossible to predict how those simple rules will translate into concrete shape and size, because a tree co-evolves with its environment.
the making0508
Trees, like all living organisms, are complex entities that can at the same time host chaos, simplicity and complication.
the making0507
In a forest, planned obsolescence nourishes the soil and the organisms that live in it.
the making0506
Trees cannot plan their growth. They cannot fix a goal and reach it. Instead, they follow their disposition for as long as the environment allows.
the making0505
“Flowers with petals are more common on trees that are isolated or grow in small groups, like fruit trees. Wind-pollinated flowers are more common in forests.” Tristan Gooley - How to read a tree
the making0504
Exaptation. We can observe it every time an animal uses different parts of trees for purposes other than the intended. Holes in the trunk and twigs become home, thorns and spines become defense against predators.
the making0503
On a hot summer day, a mature beech tree can transpire up to 500 liters of water. In periods of drought, the only way it can conserve water is by shedding leaves.
the making0502
Leaves often have a pointed tip. This allows water to drip off as quickly as possible. In general, the pointier the tip of a leaf, the greater the chance of rain in that area.
the making0501
There are four main types of root systems: plate, sinker, heart and tap.
the making0430
The wood in the center of a tree is dead. However, if protected by the outer layers and bark, it will last for centuries as a supporting structure.
the making0429
Leaves and branches are alternating in poplars, cherries and oaks, while they are opposing in maples and ashes.
the making0428
A thin bark indicates that the tree has evolved to thrive in shady areas, such as the interior of forests. A thicker tree is more common in pioneer or solitary trees.
the making0427
Trees develop small, thick, and light-colored leaves for areas exposed to the sun and dark, thin leaves for areas in the shade.
the making0426
Warm and windless climates allow trees to grow a relatively small number of large leaves, while trees growing in windy, cold climates grow smaller leaves in greater numbers.
the making0425
“We notice more when we care about what we’re looking at.” Tristan Gooley – How to read a tree
the making0424
Water evaporating from trees and forests creates clouds that gradually move inland. This mechanism depends on coastal forests and allows water to move many kilometers from the sea to the interior of the continent. If there are no coastal forests, the water will not move toward the interior lands, which will dry up.
the making0423
In a forest, the thickness of the layer of humus and the quantity of water retained depend strictly on the amount of living and dead trees. Thinning has a detrimental effect on forests.
the making0422
A forest is capable of creating its own ideal habitat.
the making0421
If buds or leaves grow in opposite directions, so will the branches of that tree. In a tree, the patterns of growth remain consistent.
the making0420
Trees grow more branches on their southern side. They also shed a lot of branches on that same side as they grow taller.
the making0419
Tall trees often grow solitary “defender” branches close to the ground. The shadow these branches cast is enough to prevent other trees from growing too close to the main trunk.
the making0418
Trees help bring life to waterways by protecting them from excessive heat in the summer and by letting in light to prevent freezing in the winter.
the making0417
A tree is the result of radically distributed responses. Each part - leaf, bud, branch, root, or flower – senses the environment and responds according to its disposition.
the making0416
A fork in the tree structure is a potential weak point, as it is subject to cracking.
the making0415
Roots grow longer and larger against the direction of prevailing winds. Their section is shaped to resist tensile forces.
the making0414
Trees partner with fungi for many reasons, one of which is to increase their chance to collect water.
the making0413
While young trees may not have enough energy from the sun to synthesize sugar, they still receive some nutrients through their mother's roots.
the making0412
Only 3% of sunlight reaches the ground through the canopy of a mature forest. This light is barely enough for seedlings to survive, and under these conditions, an 80-year-old tree is only as tall as a person.
the making0411
Poplars can produce more than fifty million seeds a year. Before a mother three gives its space to a new tree to replace her, she will have produced more than a billion seeds.
the making0410
It takes 80 to 150 years for a beech to be sexually mature. Then, every five years, it will produce at least 30 thousand beechnuts.
the making0409
Blossoms are set the summer before. The abundance of fruit marks what happened in the previous year and does not give any insight into the years to come.
the making0408
At any given time, a tree grows in two opposite directions: downwards into the ground, and upwards towards the sky.
the making0407
A branch stops growing when its terminal bud develops a flower.
the making0406
Trees grow branches in opposite or alternating patterns.
the making0405
Branches that extend from both sides of a cleared path or road are similar to those that extend across a river. Both grow toward the light created by the clearing, but while the branches growing along roads can be cut back periodically, those along rivers can grow to extraordinary lengths.
the making0404
The growing ends of the branches are sensitive to light. That's why you rarely see two trees growing together: they stop when they sense shade. The thin line that marks the distance from one crown to another is called "crown shyness".
the making0403
The growing ends of the branches are sensitive to light. That's why you rarely see two trees growing into each other. The narrow line that marks the distance from a crown to another is called “crown shyness”
the making0402
Trees that seek light at the top of the forest shed their lower branches, usually in the shade of other trees. However, they still have buds ready to shoot if, for some reason, their lower trunk is exposed to light again.
the making0401
Pollarding is similar to coppicing. It’s the practice of cutting young stems from a tree, but instead of cutting it close to the ground, the stems are cut higher up, at about 1.8mt.
the making0331
Coppicing is the practice of harvesting the tree by cutting the trunks close to the ground. Done well, this practice does not kill the tree, in fact it is known to prolong its life.
the making0330
Epicornic sprouts are usually a sign of distress. They look like a burst of small branches from the base, trunk, or branches of a tree.
the making0329
The branches of a tree rarely cross and touch each other. When they do, it may be due to the wind, the action of an animal, a falling branch, or disease.
the making0328
The cross-section of a tree is rarely perfectly circular, as it narrows in the direction of the prevailing wind.
the making0327
All trees taper at the top and the ends, but they do so in different ways. Pioneers, standing alone against the wind, end up with very thin trunks. Climax trees, which grow slowly deep in the forest, maintain a certain level of thickness all the way to the top.
the making0326
Tall trees preserve only the branches at the top. If you walk in a pine forest, you will notice that the trunks at the lower levels have many spikes. These are the remnants of the branches the trees shed as they were growing up.
the making0325
Trees grow in two different ways. The first growth is in length, when a bud forms a green stem. The second is in diameter, after the bark forms. If you carve your initials on the bark of a young tree, you will find them at the same height no matter how tall the tree grows.
the making0324
The extension of a root system is twice the spread of the crown
the making0323
The apical bud of a tree sends chemical signals to the lower branches depending on the light it senses. If it is in the shade, it signals the tree to focus its energy on upward growth. As soon as it senses light, it signals the tree to slow vertical growth and start spreading out the lower branches.
the making0322
Trees have several mechanisms to avoid self-fertilization, like growing separate male and female individuals.
the making0321
While conifers spread their seeds every year, deciduous trees spread their seeds intermittently, but generally in unison, as a strategy to keep the animals that feed on their seeds under control.
the making0320
Each tree follows the directions of its apical bud, which influences the growth of all the branches through hormones. Conifers have the strongest apical buds.
the making0319
In a forest, it is quite possible to find either tall trees, or short ones. The tall trees have direct access to light from the top of the canopy while the short ones live on the light that filters from up above.
the making0318
Trees are in contact with each other and help each other, across species, beyond competition.
the making0317
Without the exchange of information that occurs in a healthy forest, a tree cannot know in advance and prepare for imminent threats, like drought, insects or fire.
the making0316
Trees warn each other about threats by communicating via chemical signals. The messages are passed through the fungal network that leaves around the tip of their roots.
the making0315
A tree can only be as strong as the forest around it
the making0314
Beeches can form friendships with other beeches and share nutrients. They go so far as to redistribute to those who have less, compensating for barren soils or lack of water. In this way, all trees grow at the same pace, almost in synchronicity.
the making0313
The scent of flowers is a kind of chemical signal. It is meant to attract pollinators, but we are also sensitive to it. Apparently, we have the same taste as insects when it comes to perfumes.
the making0312
Willows produce salicilic acid as a defence mechanism, to give their bark and leaves an unpleasant taste.
the making0311
Fallen trees create a gap in the canopy, allowing more light to reach the forest floor and creating new opportunities for other plants to grow.
the making0310
Migration is trees’ response to changing conditions in their environment. The future of forests on earth depends on their ability to migrate faster than the pace of climate change.
the making0309
Chloroplast contains chlorophyll, which captures and turns carbon dioxide, water, and sunlight into starches and sugars, providing the tree with energy. Chlorophyll also creates the leaves’ green color.
the making0308
Trees use changes in humidity to trigger the sudden release of their seeds over long distances through a mechanism called ballistic dispersal. The energy needed for propulsion is stored in the structure of the pods and released when a change in humidity makes a weak spot too brittle to withstand the tension.
the making0307
Because trees cannot move as individuals, they have developed sophisticated cooperative strategies to reproduce, obtain nutrients, and seek protection from threats. For example, they cooperate with us by giving us their fruit in exchange for our attention and care.
the making0306
A branch that grows two meters up from the forest floor will still be at the same height in five, ten, a hundred years. Branches may become thicker, but do not “travel upwards” with time.
the making0305
Trees manage their branches by self-pruning those that cannot contribute more resources than they consume.
the making0304
Branches grow in response to external conditions. The tree follows a trial-and-error strategy: it sends out several attempts, and only keeps the successful ones.
the making0303
There are approximately 20 basic shapes of trees. However the final shape of a tree is influenced by the exposure to light, the soil, the weather, animals, fungi… and many other factors.
the making0302
Birches have a lifespan that is very close to ours. They are pioneer trees: they grow fast but in the long run they leave way to the slower, sturdier climax trees.
the making0301
Salicilic acid, the substance from which aspirin is derived, is found naturally in willow bark. For fevers and headaches, a tea of willow bark may suffice.
the making0229
Chloroplasts are a tree’s powerhouse. They are found in each cell of a tree and provide the location for photosynthesis, which is how plants turn light into energy.
the making0228
Photosynthesis is the process by which light energy is converted to chemical energy in form of starch and sugars, plus oxygen and water vapour.
the making0227
Trees can sense the composition of the saliva of the insect that is biting them. They use this information to produce specific toxins or to attract the insects’ predators.
the making0226
The seeds of pioneer trees, like Birch, are usually small and are spread easily on large areas by the wind. Climax trees produce larger, heavier seeds and rely on animals to transport them.
the making0225
Trees can be divided in pioneers and climax. Pioneers colonize new spaces and grow fast, with relatively thin trunks. Climax trees tend to grow slower with larger trunks.
the making0224
Signals in plant travel at approximately one centimetre per minute. When an animal starts biting on a leaf, it takes approximately one hour for the plant to start releasing the toxins it needs to repel the animal.
the making0223
When trees are attacked, they release special scents that warn the surrounding trees. As a response, they start producing special toxins to repel the attacker.
the making0222
In a commercially planted forest, each individual arrives severed from the others, with roots that are often extremely damaged. In these conditions, trees cannot create bonds, cannot network and cannot cooperate like in a native forest. They are alone against diseases and adverse conditions.
the making0221
A native forest creates a protected ecosystem rich of water and humidity which allows its trees to live and thrive for hundreds of years.
the making0220
You can spot if two trees are “friends” by looking up where their branches meet. Friends don’t grow thick branches towards each other, to better share the light. They grow thick branches away from each other, towards other trees.
the making0219
In a forest, trees become a super-organism that mimics the structure of a single tree: smaller and shorter trees stay on the outside, while taller and stronger trees are on the inside.
the making0218
A tree can distinguish its roots from the roots of other species, and even of other individuals of its same specie.
the making0217
Most individual trees of the same species living in proximity are connected through their roots, and use the connections to balance the distribution of nourishment.
the making0216
If we can read patterns in trees, we can find the way out of a forest just by reading their roots.
the making0215
Conifers resist better to harsh conditions than broadleaves. For example, their vessels are narrower than those in broadleaves, which makes it harder for water to develop bubbles in freezing/de-freezing cycles.
the making0214
The oldest trees on earth belong to the gymnosperm family. They include conifers and protect their seeds inside cones. It took Nature two hundred million years to evolve a new family of trees, which we call angiosperms, that develops flowers and protects its seeds inside fruits.
the making0213
According to Tristan Gooley, the author of “How to read a tree”, it is far more important to recognize shapes and patterns, and their meaning, than trying to memorize the names of individual species. We can be content just by remembering tree families and their shapes.
the making0212
Mespilus germanica, known as the medlar or common medlar, is a large shrub or small tree in the rose family Rosaceae. The fruit of this tree, also called medlar, has been cultivated since Roman times, is usually available in winter and eaten when bletted.
the making0211
When you consider how seeds germinate in nature, it makes sense to sow seeds the same way. Winter sowing is the process of planting seeds outdoors in a container during the winter months. The container remains outdoors until the seedlings emerge in the spring. The container protects the seeds from animals and harsh weather, but the exposure to colder temperatures breaks dormancy and the seeds germinate.
the making0210
Some trees like many birches can survive temperatures well below -40C
the making0209
While trees have evolved amazing strategies for withstanding winter, if the cold arrives too fast for the trees to prepare, the life-sustaining sap can begin to freeze, expand, and put pressure on the bark, which can break and “explode”.
the making0208
A tree doesn’t have to keep all of its cells from freezing, just the living ones which are primarily the phloem cells. This is significant, since much of a tree’s living trunk is made up of cells that are dead, such as xylem cells. These dead cells can and do freeze
the making0207
Decomposing leaves add nutrients to the soil for new growth. Whole leaves take about two to three years to turn into compost.
the making0206
Dormant trees have already formed buds containing flowers and leaves for next spring.
the making0205
Some trees keep their dry, brown leaves throughout the winter in a process known as "marcescence". The abscission layer on these trees does not fully form until spring.
the making0204
The abscission layer grows between the branch and the stem of a leaf. It causes the leaves to shed and helps to protect this sensitive area from winter cold.
the making0203
We might be tempted to think that trees have a method to pump water upwards, based on how blood moves in our veins. In reality, trees can only generate a very small amount of pressure from the roots. Water is pulled up to the leaves by capillary action and transpiration.
the making0202
It can take more than a century for trees to develop cavities large enough to host wildlife. Cavities provide protection from cold weather and shelter from predators.
the making0201
Trees are capable of entering in a state of dormancy. In winter their metabolism slows down and they stop growing to conserve energy.
the making0131
Leaves have superficial microscopic openings that allow water to evaporate and leave the trees along with oxygen. In pine needles, the openings are not on the surface, but deep inside. This, along with their reduced surface area and a special coating wax as a barrier, allows pine trees to maintain their leaves (or needles) throughout the year.
the making0130
Trees protect their living cells from freezing by producing proteins called ice nucleators. They sit between the cells and are the first to freeze, attracting water. As the water leaves the cells, the concentration of sugars increases, constantly lowering their freezing temperature.
the making0129
In winter, cold and dry conditions make it impossible for some trees to transport nutrients and water to their leaves. So they drop their leaves to conserve energy and resources and avoid wasting water through transpiration.
the making0128
Trees cannot "move" as individuals, but they can move as a community. For example, in response to warming temperatures, European spruce has climbed 250 meters in the last fifty years, growing at higher altitudes than its usual range.
the making0127
Phenotypic plasticity is the term used to describe the plants’ ability to adapt their shape and shrink or grow their size based on their environment and on the availability of nutrients.
the making0126
Plants are decentralized organisms. They are made up of modules that distribute functions throughout their bodies, unlike animals, which concentrate specific functions in specific organs.
the making0125
Trees, like all plants, are capable of simultaneously perceiving light, temperature, gravity, chemical gradients, electric fields, touch, sound... and more. Their heightened sensitivity compensates for their inability to move.
the making0124
Plants represent more than 80 per cent of the biomass on Earth, a total of 450 billion tons. Humans account for 0.6 billion tons, less than 0.01 per cent. In other words, if all life on earth had your weight, humans will approximately be lighter than one of the banknotes you carry with you.
the making0123
Depending on the species, roots extend horizontally a minimum of 2.5 to 3 times the width of the crown.
the making0122
Trees are nurturers. They nurture each other and they nurture us.
the making0121
Trees, like us, cannot remain healthy under continuous stress. For a tree, compacted soil, limited space for the root system, air pollution and disrupted lighting patterns are all cause of stress.
the making0120
“Almost all the trees we plant in our cities come from forests somewhere in the world. What does that mean for the tree? How do our present planning and management strategies affect tree health and resilience?” @Naomi Zurcher, Connecting trees with people
the making0119
Root explore the underground based on the temperature of the soil and on the availability of oxygen, water and nutrients.
the making0118
An individual forest tree’s root system begins with the development of at least one order root in each of the four cardinal directions, forming the root system’s perennial framework.
the making0117
Forests occur over millennia. They are a process of succession and evolution.
the making0116
A forest is a complex-adaptive ecosystem formed by flora, funga, fauna, soil… and trees. A complex-adaptive ecosystem managed with linear, extractive, industrial practices loses its capacity to support biodiversity and, in the long run, to host life.
the making0115
Tree growth is the combined interaction of genetic potential and its ability to deliver on that potential, driven by the surrounding environment.
the making0114
Trees have living cells in their outermost structure (buds, roots, leaves) and use dead cells as their core structure. This is opposite of how we are structured: we are supported by living cells and use dead cells (hair, nails, and the skin surface) to protect us from the environment.
the making0113
Forest trees live in extended cooperative communities below ground. They share resources and information in cooperation with symbiotic fungi. This association (mychorriza) drives plant population and community biology.
the making0112
The Ginko biloba, the Maidenhair tree and conifers are the first trees to appear as plants that produce unenclosed seeds, or “naked” sees.
the making0111
In a tree, the crown architecture determines how light is captures and distributed for photosynthesis. The shape of the crown varies according to species and age.
the making0110
Branches that don’t produce more resources than they use, die. However they will only shed when all their resources have been reabsorbed into the tree.
the making0109
Trees can vary the architecture that they inherit from their specie to adapt to the environment. They may change the size of their leaves to respond to variations in temperature, or increase the amount of wood in parts that need it most, to support their weight.
the making0108
The earlier examples of vascular plants dates back approximately 420 million years. The form that we recognize as tree evolved during 360 million years.
the making0107
“There can be no life without soil and no soil without life; they have evolved together” – Charles Kellog
Soil can take millennia to evolve to the point where it can support a forest community.
the making0106
Trees and plants are the only organisms on earth that produce their own nourishment. Directly or indirectly, they feed all forms of life.
the making0105
Trees produce their own food and the material they need to grow. This is why they cannot grow beyond their possibilities.
the making0104
When we sweat, our body temperature goes down. When trees sweat, the water cycle starts, and the environment around them cools down.
the making0103
"Se la conoscenza del tutto (dell'unità) viene divisa in due e spiegata e successivamente queste due metà sono divise ulteriormente in tre o quattro e analizzate, non siamo affatto più vicini a capire il tutto rispetto a prima. Eppure, quando facciamo ciò siamo preda dell'illusione secondo cui la nostra conoscenza è aumentata."
M. Fukuoka, Sowing seeds in the desert
the making0102
Trees are the longest living organisms on Earth and never die of old age. Some of the oldest living trees, such as the bristlecone pines and giant sequoias in California, are 4,000-5,000 years old.
the making0101
