In a world where climate change is an unavoidable reality, the search for sustainable solutions is more crucial than ever. Every action counts, including in our gardens. Among the many ways to attenuate the effects of climate change, tree planting plays a key role. Among them, a champion from Asia stands out: Paulownia, a tree with exceptional carbon capture properties.
What is Paulownia?
Paulownia is a deciduous tree distinguished by its large heart-shaped leaves and clusters of purple flowers. It can reach an impressive height of 10 to 25 metres in its natural habitat, making it a majestic addition to any landscape or large garden. Here in France, it will typically reach between 8 to 12 metres tall depending on the growing conditions.
It is native to Asia, particularly China and Japan, where it is known as "the emperor tree". Paulownia has been introduced to other parts of the world, including Europe and North America, where it has adapted well to various climatic conditions.
This tree is traditionally used for its wood, which is both lightweight and strong. Additionally, its ability to grow quickly makes it a popular choice for reforestation and ecological gardening projects. It is also used in traditional Asian medicine.
Note: the genus Paulownia includes six different species. However, the two most commonly cultivated species are Paulownia tomentosa and Paulownia fortunei.
The carbon capture properties of Paulownia
Paulownia is often referred to as the "carbon capture champion", and for good reason. According to scientific studies, this tree can sequester an impressive amount of carbon dioxide (CO2) from the atmosphere. In fact, an adult Paulownia can absorb up to 48 kilograms of CO2 per year, which is about 10 times more than most other trees commonly used in reforestation projects.
This exceptional capability is partly due to its rapid growth. Paulownia can reach maturity in 10 years, meaning it starts to have a positive impact on the environment much more quickly than other trees.
When compared to other trees like oak or pine, which are typically used in reforestation projects, Paulownia stands out significantly. For example, an oak can take up to 30 years to reach maturity and captures on average only 4 to 5 kilograms of CO2 per year. Pine, although faster growing than oak, captures on average 10 to 20 kg of CO2 per year, but it still does not reach the levels of Paulownia.
Finally, Paulownia is also noted for its ability to regenerate from its stump after cutting, an asset that can promote rapid new growth and continuous carbon capture. However, this capability varies greatly depending on soil conditions, climate, and forestry management practices.
Additional benefits of Paulownia
In winter, its large, nutrient-rich leaves decompose quickly and enrich the soil. This is an additional asset for mulching, composting, and permaculture.
Resilient, Paulownia is a robust tree that easily adapts to a wide range of climatic conditions and soil types. It is also resistant to diseases and pests, making it a sustainable choice for any garden or reforestation project.
Further reading
To learn more about this tree, read our sheet on Paulownia, Imperial Tree: planting, growing, and care.
In a world where climate change is an unavoidable reality, the search for sustainable solutions is more crucial than ever. Every action counts, including in our gardens. Among the many ways to attenuate the effects of climate change, tree planting plays a key role. Among them, a champion from Asia stands out: Paulownia, a tree […]
In an increasingly environmentally conscious world, efforts are being made to develop more sustainable agricultural systems. One of the ways we seek to achieve this goal is through permaculture - a holistic approach to agriculture that aims to work with nature rather than against it. Among the many questions that arise, one often comes up: what are the best trees to use in these systems? Among them, the Paulownia - a robust and fast-growing tree native to Asia - is of particular interest. Its resilience, ability to improve soil quality, and rapid growth indeed make Paulownia a promising candidate to become "the tree of the future" for permaculturists. But is this really the case? We will find out.
What is this tree?
The Paulownia tomentosa, often referred to as "the emperor tree", is a tree species native to Asia, known for its rapid growth and spectacular fragrant flowers. This giant, which can reach heights of 15 to 25 metres, not only has undeniable aesthetic appeal but also significant ecological value. Its ability to fix nitrogen in the soil, resist diseases and pests, and thrive in various soil and climate conditions has made it a popular choice for many reforestation and permaculture projects. Furthermore, Paulownia wood is lightweight, strong, and of high quality, making it a valuable resource for the timber industry. Therefore, Paulownia is increasingly recognised as a tree with immense potential to contribute to a more sustainable future.
Nota bene: there are 6 species in the genus Paulownia, but the most commonly cultivated are Paulownia tomentosa and Paulownia fortunei. The latter is distinguished from the Emperor Tree by its earlier flowering, but retains the same qualities.
Paulownia has many advantages
In the context of permaculture, Paulownia presents several notable advantages that make it interesting for sustainable agriculture projects:
- Rapid growth: Paulownia is one of the fastest-growing trees in the world. In just a few years, it can reach several metres in height, which is particularly interesting for reforestation and permaculture projects that seek to establish a forest cover quickly.
- Soil improvement: Paulownia has the ability to fix nitrogen, an essential element for plant growth, in the soil. This ability contributes to the improvement of soil quality and fertility, which is crucial in a permaculture system. The nutrient-rich leaves decompose quickly in the soil or compost, which is an additional asset.
- Resistance: These are robust trees that can withstand a wide range of climatic conditions and soil qualities. They are also resistant to diseases and pest attacks.
- High wood yield: Paulownia wood is lightweight, strong, and of high quality. It can be used for a variety of products, including furniture, musical instruments, and construction wood. It is also a species that can be used for biomass production due to its rapid growth.
- Carbon storage: Thanks to its rapid growth, Paulownia is capable of sequestering a large amount of CO2, making it an important asset in the fight against climate change.
- Shade tree and support for climbing plants: Paulownia quickly becomes an excellent shade tree, but its straight and sturdy stems can also serve as support for climbing plants. It is worth noting that the Emperor Tree is also excellent in a windbreak hedge.
A concrete example of using Paulownia in permaculture
The use of Paulownia as a "windbreak" is one of the most common examples in permaculture. Due to its rapid growth, it can provide a protective barrier against strong winds for more delicate plants or livestock. Its dense foliage can help reduce soil erosion caused by wind while retaining more moisture in the soil, which is beneficial for other plants in the system.
Moreover, Paulownia produces a large amount of biomass in a short period, which can be useful for producing mulch or compost. Its leaves are nutrient-rich and can help improve soil quality when they fall and decompose.
Can Paulownia impact local biodiversity?
Paulownia is an exotic and pioneering species. Beware of its potentially invasive character!
Paulownia is indeed a fast-growing species, which can make it competitive with local species. If its spread is not controlled, it may eventually dominate a landscape, reducing the diversity of native tree species.
Furthermore, although Paulownia can provide habitat for certain species of insects, birds, or small mammals, it is not always suitable for local wildlife. Most insects, for example, have co-evolved with specific plant species. If Paulownia replaces these trees, these animals will lose their natural habitat.
That said, it is also possible that Paulownia may have beneficial effects on local biodiversity. Its flowers attract and nourish many pollinators, and its nutrient-rich leaves can improve soil fertility when they fall and decompose.
However, it is important to keep in mind that, in general, the introduction of non-native species should be done with caution, as they can have unforeseen and potentially negative impacts on local ecosystems. It is preferable to plant native species whenever possible, as they are often in harmony with local flora and fauna.
The particular case of pioneer trees
Paulownia tomentosa and Paulownia fortunei are not the only trees that multiply some of the advantages mentioned earlier. This is the case for many so-called pioneer trees, such as Aspen, birches, Pinus pinaster, Goat willow, or Black locust. Pioneer trees are tree species that are among the first to colonise disturbed or degraded lands. They play a crucial role in restoring ecosystems, as they help stabilise the soil, improve its fertility, and prepare the ground for the arrival of other plant species. Pioneer trees are generally characterised by rapid growth, a great ability to spread by seeds, and a capacity to tolerate difficult environmental conditions, such as poor soil or extreme temperature and humidity conditions.
In an increasingly environmentally conscious world, efforts are being made to develop more sustainable agricultural systems. One of the ways we seek to achieve this goal is through permaculture – a holistic approach to agriculture that aims to work with nature rather than against it. Among the many questions that arise, one often comes up: […]
We love variegated foliage... or not. But in any case, it never fails to leave gardeners indifferent. You can find perennials, trees or shrubs with variegated or marbled foliage in white, cream, yellow, or another colour... Sometimes simply marginate, sometimes almost entirely devoid of green... But the question we are asking today is: what causes this foliage or another part of the plant to become bicoloured or multicoloured?
What is a variegated foliage?
We refer to variegation when a part of a leaf, flower, or even fruit appears "discoloured." These discoloured parts are completely or partially devoid of chlorophyll, the pigment that gives the green colour and enables photosynthesis.
It is important to know that a green leaf contains chlorophyll (we should even say chlorophylls, as there are several types), but also a certain amount of other pigments that are more or less hidden: carotin, xanthophyll, anthocyanin... When chlorophyll disappears, the other pigments become visible. This is what gives the yellow, orange, red, or brown colours of leaves in autumn when chlorophyll naturally fades. For variegations, it works on a similar principle, except that it is not the decrease in light that causes chlorophyll to disappear, but other reasons. When chlorophyll partially disappears, we end up with white, cream, yellow... and sometimes even pink or red spots.
Where do these variegations come from?
Variegations in a leaf can arise from various causes:
The most common case is mutation-induced variegation. A young seedling or part of a plant mutates and suddenly becomes variegated. Since the variegation is not stable, and therefore not sexually reproducible, these plants should be propagated vegetatively (cuttings, layering, grafting). Be on the lookout for such mutations in your own garden. You never know, you might obtain a remarkable new variety.
Variegations can also be caused by a virus. This is rarer, but it does happen. A benign virus infects the plant, which in response produces variegated parts (leaves, flowers, fruits). This is the case with most variegated-leaved Hibiscus, such as Hibiscus 'Summer Ruffle', or with bicoloured tulip varieties;
Finally, some variegations are entirely natural. Indeed, certain plant species have evolved to develop variegated or punctate parts. Botanists do not have explanations for all these species. However, it can be said that the natural variegation of certain species is a defence mechanism, as seen in Hypoestes which produce leaves speckled with small dots or in Adelonema walisii which reveals very variegated leaves of yellow-cream. The former gives the illusion that the plant has already been eaten by an insect, while the latter is camouflaged in the decor to avoid being browsed by herbivores. Some species may also use variegations to more effectively attract pollinators, as seen in Euphorbia marginata.
But is it serious, doctor?
As mentioned, even if variegation is caused by a virus, this virus is completely benign. However, having a low chlorophyll content within a leaf can lead to reduced vigour. In other words, a variegated variety will often grow a little slower than its green-leaved counterpart. But don’t let that stop you from planting them!
One small note, however: some variegated mutations are so low in chlorophyll that it would be impossible to propagate them by cuttings, as the cutting would not have enough energy to produce roots. These mutations are therefore propagated by grafting (which significantly increases the purchase price).
A bit of botany
We find Latin terminologies in some species names or the names of old variegated varieties such as: variegata, marginata, pulverulenta...
- Variegata for variegation: meaning variegated, as in Cornus controversa 'Variegata';
- Maculata: meaning maculate, thus a large coloured spot, as in Phlox maculata or Begonia maculata;
- Marginata: meaning marginate, thus bordered by a fine coloured band, as in Agave angustifolia 'Marginata';
- Striata : meaning striate or marbled, thus marked by coloured bands of varying widths, as in Bletilla striata;
- Punctata : meaning punctate, thus sprinkled with small coloured dots or spots, as in Lysimachia punctata;
- Pulverulenta : meaning it seems to have been sprinkled with a lighter substance, as in Catalpa speciosa 'Pulverulenta';
- Reticulata : which colouring follows the pattern of the veins, as in Iris reticulata;
- Crotonifolia : with Croton-like leaves (a famous houseplant - Codiaeum variegatum), thus exhibiting irregular discolouration, as in Aucuba japonica 'Crotonifolia'.
Did you know? Since 1956, breeders have not been able to use Latin to name new varieties and cultivars. The choice has mainly fallen on the English language, although exceptions exist. This is why we find words like 'Gold', 'Silver', 'Rainbow', 'Cream'... in the names of plant varieties featuring variegations.
We love variegated foliage… or not. But in any case, it never fails to leave gardeners indifferent. You can find perennials, trees or shrubs with variegated or marbled foliage in white, cream, yellow, or another colour… Sometimes simply marginate, sometimes almost entirely devoid of green… But the question we are asking today is: what causes […]
With climate change, we regularly hear about hot and dry summers that cause suffering to plants, including trees (and not just them!). However, we also forget that plants need a period of rest, winter. If this winter is not cold enough, it can lead to detrimental consequences for the health of trees and bushes. Let's take stock!
Meteorological observations
One year is not like another, especially in our time. However, it is now not uncommon to encounter temperatures well above seasonal averages, whether in the south or further north. What specialists sometimes refer to as "non-winters". And this is unlikely to improve, that much is certain. Indeed, throughout history, humans have experienced exceptional years, some with particularly mild winters. The problem is that the exceptional is becoming the norm and that practically every year winters are getting less and less cold. With climate change, the same ocean winds of the past are bringing more air, and this air is warmer because the ocean water is also warmer. Furthermore, the reduction in snow-covered areas will amplify the effect by no longer performing its cooling function. In other words, the effect will accelerate in the coming years.
Also read: researchers at CNRS have developed a method to determine whether an extreme weather event is due to climate change or not.
What consequences for trees?
If temperatures are mild, sap will start to circulate again, some plants will come out of dormancy and begin to bud. This would not have such serious repercussions if a period of severe frost did not systematically follow in the weeks after. This frost will destroy the buds, flowers, and even part of the young foliage. No flowers, no fruits! And if the foliage is destroyed, the tree will exhaust itself trying to form another. Once is fine! Every year: hello damage! Note that some trees, bushes, or spring-flowering bulbs are adapted to winter cold, even late cold. For these, like the male dogwood or snowdrops: cold? Not a problem!
The tree's cycle can also be completely disrupted. Indeed, many plants need a period of cold to come out of dormancy, which is called vernalisation. This vernalisation will trigger a process of flower formation. It is the transition between the vegetative stage and the reproductive stage. However, if this cold period does not occur (or not at the right time), the tree will not produce flowers with all that this implies. For example: cherry trees need an average of just over 1000 hours at a temperature below 7°C to start flowering, while apple and pear trees need between 200 and 1400 hours.
Are we heading towards a fruit shortage within 100 years?
Hard to say... But this climate warming is acting so quickly that plants cannot evolve fast enough to cope with these changes. Fruit trees and bushes are indeed at risk of no longer being able to flower or producing stunted flowers that yield misshapen or small fruits. Additionally, pollinating insects are also affected. They often emerge too early at the end of winter, at a time when trees are not yet in bloom. When we know that a large majority of insects have co-evolved with specific plant species (in other words, a particular insect species is capable of pollinating a specific plant), these trees are doomed to disappear along with the insects that depend on them. In short: the future does not look bright...
With climate change, we regularly hear about hot and dry summers that cause suffering to plants, including trees (and not just them!). However, we also forget that plants need a period of rest, winter. If this winter is not cold enough, it can lead to detrimental consequences for the health of trees and bushes. Let’s […]
Trees or woody plants (which produce wood) are fascinating in many ways. So fascinating that they are even the subject of a science in its own right: dendrology. But what exactly is dendrology? What does a dendrologist study and why? Let's clarify in this short article.
Dendrology in a nutshell
Dendrology, from the Greek "dendron" meaning tree and "logos" meaning study, is the science that studies woody plants (trees, bushes, shrubs, and lianas). The term was coined in 1688 by an Italian naturalist Ulisse Aldrovandi. A person who studies this science is a dendrologist. They may work in forestry operations or wood processing, within government agencies or nature conservation organisations.
In France, there is the French Society of Dendrology and in Belgium, you can find the Belgian Society of Dendrology.
Dendrology is a multifaceted science
In dendrology, various species of trees are studied: botanical classification and species recognition by morphology, such as the shape of leaves for example (the classical classification known as Cronquist) or by common evolution among species (phylogenetic classification). The boundary between plant taxonomy and dendrology is relatively blurred, but dendrology also deals with many other areas beyond botanical classification.
However, dendrology has several other branches (which is fitting when studying... trees): dendrochronology, which can determine the age of a tree or date a piece of wood using growth rings (or tree rings), and dendrometry, which allows for measuring the diameter, height, and volume of a tree, as well as its age or the thickness of its bark. There is also dendrogeomorphology, which studies geological and climatic processes through the observation of tree growth rings.
Nota bene: in archaeology, dendrochronology is often used to date an element, as well as xylology, a science that studies wood as a material and its physical and chemical properties. The two disciplines are complementary and help determine what type of wood was used, thus providing insights into the flora surrounding our ancestors. The science that studies fossilised wood is called paleoxylology.
What is the purpose of dendrology?
Dendrology, and especially dendrometry, serves various fields:
- Forestry (wood exploitation): calculating the size, age, shape... of cultivated trees (such as poplar plantations) and in forests, general tree management;
- Forest management and protection: combating diseases and wood-eating pests, protection against fires...;
- Wood industry: calculating volume (dendrometry) and studying the physical properties of wood;
- Ecology: studying the distribution and range of botanical species as well as the evolution of wooded environments, and also studying forest ecosystems and their evolution in the face of climate change;
- Archaeology: dating and determining the wood present at an excavation site, allowing for dating and gaining insights into the flora and lifestyle of people who once lived in that area;
- Customs: through the identification of a wood species in the context of combating deforestation and the importation of protected or prohibited species;
- Judicial: a (almost) personal anecdote, one of my botany professors was called in a homicide investigation (in the 1980s) to determine the exact species of a log that had been used to commit a murder. When we say that dendrology leads to everything... Nowadays, forensic police have botanical experts in their ranks.
Trees or woody plants (which produce wood) are fascinating in many ways. So fascinating that they are even the subject of a science in its own right: dendrology. But what exactly is dendrology? What does a dendrologist study and why? Let’s clarify in this short article. Dendrology in a nutshell Dendrology, from the Greek “dendron” […]
Failing to plant a tree is easier than it seems. Despite their general robustness compared to annuals or perennials, with a bit of know-how, you can manage it quite well. Follow our step-by-step advice and soon you too will be able to successfully mess up the planting of your trees and bushes!
Lesson 1: Don't neglect the preparation of the planting hole
The purists of the spade and the hoe who succeed in their plantings recommend digging a hole 2 to 3 times larger than the root ball and adding compost, drainage materials and other permaculture tricks that promote root development. To mess up properly, here are the steps to follow:
- Dig a small hole in a hurry, using a pick, hoe, trowel, or even a teaspoon. As narrow and shallow as possible.
- Place the roots, which you will have previously left to dry in the open air and sun for a whole day. Form a compact mass and do not trim the damaged ends, as this is the best way for fungi to develop and parasitise your tree.
- VERY IMPORTANT: Bury the collar well! You know, that part that separates the roots from the trunk. This is the key gesture to successfully mess up your planting. Bury it more than 3-4 cm underground; the roots will no longer be able to breathe, and the tree will die more or less quickly in spring or during the summer. This method is especially reserved for large trees: oaks, beeches, birches, etc.
- If your soil is wet or poor, do not add drainage materials or compost, NEVER!
- Do not compact! And above all, do not water to keep as many air pockets in the soil as possible, thus suffocating the roots.
This is a method that has proven effective and that we recommend. A small planting hole is also the best technique for the roots to form a girdle and suffocate themselves. Guaranteed failure!
Lesson 2: plant anytime!
"At Saint Catherine, all wood takes root," is often heard from the mouths of French gardeners. And only they would put their hands in the soil at the end of November, when it’s grey and cold, while common sense tells us to stay warm under the duvet (or in front of the fire with a good book) all winter...
If you want to mess up with style, first plant when YOU feel like it. Starting with bare-root trees, which you will install in spring, just when they are producing their new roots and their branches are filled with sap. This will block their growth and surely make them wither.
Temperatures above 25°C and the sun shining? Put on your best shorts, flip-flops, and rush to the garden... And don’t forget to go on holiday right after, for at least three weeks. This is the express method to fail! You will indeed have the chance to have a tree that cannot acclimatise to your soil, nor take the time to root and seek water deeply. If by miracle the tree survives, then go directly to lesson 5.
Lesson 3: skip the staking!
Fanatical gardeners, obsessed with everything growing straight, may tell you that it is essential to stake any tree planted in the wind. These same eccentrics will also tell you that this stake must be sized according to the height of the tree. They will use strange terms, bordering on dialect, such as "oblique stakes", "bipod stakes", or even "tripod stakes". They will talk about a wild technique called "guying" that allows for strong anchoring of large trees.
To properly mess up the planting of trees exposed to wind or planted in loose soil, of course, banish any support. Dig, plant, and let nature take its course. With the first gusts, the tree will lean and eventually lie down. And for a lovely twisted growth, besides the absence of a stake, do not compact the soil during planting. What could be more charming than a tree that crawls on the ground after the first gust of wind?
Lesson 4: select any varieties!
"Consider your soil, climate, exposure, and know-how for successful planting," can be read on Plantfit, the new app that seasoned gardeners use without moderation.
To mess up your plantings, plant what YOU want! Do you live in Strasbourg and think that this lovely azalea would look wonderful in your beds? Plant it! The foliage of this acid-soil shrub will yellow upon contact with alkaline soil and will eventually languish and die. Well done! Tired of growing Mediterranean climate plants in your beautiful city of Avignon? Succumb to the charm of tree ferns and plant them in spring, when the mistral is blowing. Their bright green foliage will quickly turn a lovely brown colour. Decorative effect guaranteed.
So when choosing your trees and shrubs, completely forget to "plant appropriately" according to your garden and know-how: this is the best way not to see them grow, or to have to rely heavily on fertilisers and other nutrients, which are oh so responsible!
Lesson 5: water from time to time, if you think of it!
If your tree is still alive, it’s because you’ve pampered it too much. The chlorophyll addicts who succeed in their plantings often quote excerpts from their esoteric literature. It can be read that the first year is crucial for the resumption of vegetation in trees: it is necessary to water regularly to develop their root system, create a planting basin around the root ball to create an essential water reserve, preventing the tree from suffering in summer, or even spread ramial chipped wood (known as RCW) at the base of your trees to keep the root ball cool during the summer period.
Forget all this! To mess up the planting, forget your tree! Let it live its life and fend for itself!
Good luck!
-> Find all our varieties of trees here.
Failing to plant a tree is easier than it seems. Despite their general robustness compared to annuals or perennials, with a bit of know-how, you can manage it quite well. Follow our step-by-step advice and soon you too will be able to successfully mess up the planting of your trees and bushes! Lesson 1: Don’t […]
“ Should trees always be staked ?” Now, that’s a good question! For ages, the answer was quite clear: You plant a tree. You stake it. End of story. However, recent research suggests that trees may not always need it. Worse still! Some even argue that unstaked trees may actually establish better than their staked counterparts.
The reasons are numerous, but the first ones fall on the gardener themselves...
Be cautious when staking your trees!
You shouldn’t stake just any way, nor with any material! Here are the main mistakes to avoid:
- driving the stake in like a brute through the root ball or even into the roots: when you decide to stake a young tree, avoid injuring the roots. Make sure to place the stake well outside the root ball! The easiest way is to place it before planting the tree.
- using ties that can injure the bark of the young tree : only use natural materials if possible or “ soft ” materials for the bark! There are systems designed for this purpose, but rubber from old inner tubes is an excellent solution. Absolutely avoid wire or other rigid materials and don’t tighten too much! The tree should be supported but not strangled, so don’t hesitate to move and loosen the ties as it grows.
- forgetting to remove the stake: I have personally removed dozens of old stakes from trees and shrubs in my garden that had been forgotten there for decades (and they were rusty metal bars tied with plastic string...). Never forget to remove your stake no later than a year after installation! If you wait longer, you risk injuring the tree's roots.
Staking is not always welcome
Recent studies have shown that staking a tree too firmly shortly after planting can sometimes be detrimental. Indeed, young trees need to move a bit with the wind. This allows them to create a very strong root system with roots that will anchor deeper into the soil.
Moreover, the tree will develop a thicker and more resilient trunk against various external threats. It will also produce more branches from a young age. Another proof that staking is not obligatory, on the contrary.
To avoid staking, simply plant well! That is, properly set the root ball or roots at the bottom of the hole you’ve dug and compact the soil afterwards. If you do this, your tree won’t sway too much in the wind, and even if it seems a bit tilted in the first year, it’s very likely to straighten up later.
But staking can sometimes be necessary
Let’s not kid ourselves, staking can be necessary in certain circumstances :
- if the ground has a slope worthy of the Beille plateau or the Aubisque pass: good staking will allow the tree to grow straight regardless of the slope.
- if your garden is so swept by the wind that you need to stake the gardener too
- if you are planting a large specimen with a root system reduced compared to its branches, this is particularly the case for trees presented with bare roots. In this situation, your tree, if unstaked, will find itself like a person with a big head and small feet. It will topple at the slightest breeze!
- if the “ top ” is already high on a very (too!) thin trunk : this is a bit of a case-by-case situation, but sometimes you will quickly realise that if you don’t stake your young tree, it will break in two at the first gust (which can be good if you want a coppice). Always check at purchase that your tree is well balanced.
A little word from Oli: if you are patient, frugal, or both like me, you can also adopt very young trees. They are obviously less expensive to buy but that’s not their only quality. Indeed, planting is a traumatic experience for a tree, especially if it has been uprooted from a nursery gauge. If planting is done in its early years, it will have a better chance of recovering. Moreover, a young tree will not have the root ball problem that can be found in container-grown specimens. It will also be less sensitive to the elements and will anchor better in the soil. Lastly, it is also easier to plant and transport a small one-year-old than a large five-year-old specimen. Ultimately, we think we save time by planting already large trees, but young trees planted at the same time will soon catch up with their older siblings in size and spread while being less temperamental in their recovery.
For further reading
Find Oli's tips, or rather his article on how to fail at planting your trees in 5 lessons.
“ Should trees always be staked ?” Now, that’s a good question! For ages, the answer was quite clear: You plant a tree. You stake it. End of story. However, recent research suggests that trees may not always need it. Worse still! Some even argue that unstaked trees may actually establish better than their staked counterparts. The […]
Planting trees to combat climate change may seem like a very simple solution. Fortunately, it is!
At a time when more trees are being cut down than planted, every tree you can plant in your garden will prove beneficial in various ways.
One of the causes of climate change is the excessive release of carbon dioxide (CO2), so the most obvious solution that comes to mind is to plant trees, as they absorb this CO2.
Why planting trees?
Plants in general, but trees in particular, have an incredible capacity to absorb CO2. This is simply a result of photosynthesis. The tree absorbs CO2 from the air and transforms it into carbon and oxygen. The oxygen is released into the air for our benefit, while the carbon is stored and gradually released. Forests thus represent the second largest carbon sink after the oceans.
But that's not all; trees are also useful for:
- regulating temperature and humidity: they are true living air conditioners;
- filtering wind and dust, thereby improving air quality;
- fixing certain pollutants such as pesticides or heavy metals;
- improving soil by adding biomass (wood, leaves...) and combating erosion.
Which trees to plant to combat climate change?
1) Native trees first
There are two huge advantages to planting native species:
- they are perfectly adapted to the climate and soil
- they nourish and provide shelter for local wildlife
The list of native trees is long, but here are a few examples:
- For the North: Field Maple, Glutinous Alder, Downy Birch, Common Hornbeam, Male Dogwood, Common Ash, Holly, Trembling Aspen, Field Elm...
- For the South: Strawberry Tree, Montpellier Maple, Corsican Alder, Chestnut, Olive, Holm Oak...
- For the mountains: Hop Hornbeam, Mountain Elm, Mountain Pine...
- For the Coast: Tamarisk, Sea Buckthorn, Bohemian Olive, Maritime Pine, Field Maple...
2) Natives, but not only...
Some natives are suffering from climate change while others, more exotic or southern species, seem to be making their way north. For instance, Pines, across all species, are suffering from repeated attacks by Pine Processionary caterpillars. Meanwhile, Common Beech, spruces, and even Pectinate Fir can no longer withstand our hot and dry summers. All these trees have also become less resistant to diseases.
On the other hand, some trees are seeing their original range shift. This is not surprising: it has always been the case! Plants grow where they thrive best. This is why we have issues with certain invasive exotic plants that turn out to be more suited than natives in some natural environments. Or the fact that oak forests are regaining ground over beech forests as they did... only two thousand years ago.
Some examples of trees that have adapted to climate change
- Holm Oak - Quercus ilex: once confined to the Mediterranean climate, it is now moving further north. It now thrives along the Atlantic coast up to Brittany and will continue its progression towards the centre.
- Turkey Oak - Quercus cerris: previously only found in the southeast of the country, it is now moving categorically north, even reaching Belgium...
- Pubescent Oak - Quercus pubescens: a species particularly adapted to drought that has been thriving in recent years.
- Montpellier Maple - Acer monspessulanum: often found in nature alongside Holm Oak, it is following the same trend, progressing up to Vendée.
- Flowering Ash - Fraxinus ornus: a cousin of Common Ash but significantly less sensitive to ash dieback, it is gradually moving away from its native Corsica and Maritime Alps to further north.
- Pride of India - Koelreuteria paniculata: native to China and Korea, this tree proves to be perfectly resistant to drought and urban pollution.
- Maritime Pine - Pinus pinaster: originally found around the Mediterranean and along the coast, it continues its spread westward and northward.
- Black Locust - Robinia pseudoacacia: this exotic tree is gradually becoming the "king of the forest". It withstands heat, drought, and flooding and is adapted to poor soils as it has the ability to fix nitrogen. It is thus gradually taking the place of other tree species.
For your information: the National Forestry Office is currently conducting trials of Bornmuller Fir (Abies bornmuelleriana) in forests, a species more suited to drought than Pectinate Fir. Meanwhile, in Belgium, trials are being conducted in forests with Turkey and Pubescent Oaks and even... Corsican Pines.
General characteristics of trees resistant to climate change
Trees that exhibit natural resistance to drought and high summer temperatures often share common characteristics:
- Small and numerous leaves: the larger the leaf, the more water evaporates. Small leaves are thus a result of adaptation to drought;
- Waxy and/or fuzzy foliage: if the leaf is thick or equipped with small hairs, it will retain water more effectively;
- Next, it is important to check the tree's region of origin: if it originates from the Scandinavian taiga, it is likely to suffer in summer... Conversely, mediterranean and central European species will be particularly well-suited.
In conclusion
Due to the accelerating climate changes in recent decades, we will need to reassess our approach regarding native species adapted to regions. Some, whose survival requires moisture and distinct seasons, will disappear in favour of less water-demanding species that do not require harsh winters. In any case, planting trees will be beneficial as long as we choose species that can thrive optimally with minimal care. So in conclusion: let’s plant trees!
To learn more
Some researchers express doubts about the effectiveness of tree planting to combat climate change. In reality, it is mainly the notion that CO2 is the sole culprit of climate change that they question, as well as the belief that we will (according to them) need even more agricultural land to feed the population. The ideal would also be to stop deforestation rather than just replanting a few trees here and there. If you wish to learn more and form your own opinion on the matter, read this article (in French): Forests: a solution to the climate crisis?
And if you haven't seen it yet, here are the main results of our survey on climate change and gardening.
Planting trees to combat climate change may seem like a very simple solution. Fortunately, it is! At a time when more trees are being cut down than planted, every tree you can plant in your garden will prove beneficial in various ways. One of the causes of climate change is the excessive release of carbon […]
Every autumn, many trees and shrubs reveal their finest colours, offering a true spectacle: the leaves take on scarlet, coppery or golden hues before falling... Although it amazes us, this phenomenon is the result of a real strategy implemented by plants to protect themselves in winter. They go into dormancy, marking a necessary pause that allows them to resume growth in spring. We invite you here to discover this mechanism that explains the flamboyant colours of autumn!
Liquidambar styraciflua is one of the finest trees for autumn foliage! (photo: Frank Vincentz)
Where does the green color of the leaves come from?
The leaf helps the tree capture sunlight. In spring and summer, the leaves are green because they contain chlorophyll. This is a pigment that allows the plant to capture light energy, and to use it to synthesise organic molecules from water (taken up from the soil) and CO2 (taken up from the atmosphere). Thanks to chlorophyll, leaves absorb, from light, blue and red wavelengths, but not green ones... The green colour is therefore reflected by the leaf, which is why we perceive it. Other pigments are present in the leaf, but they are masked by chlorophyll.
Why does the colour change in autumn?
When the length of the day decreases, the tree seeks to go into dormancy and conserve its energy. It will therefore block the sap supply to the leaves, producing at their base a small cork plug. Thus, the leaves no longer receive water and minerals, chlorophyll pigments are no longer renewed and eventually disappear... As they were responsible for the green colour of leaves, these then change colour. However, the other pigments present in the leaves remain – xanthophylls (yellow) and carotin (orange) – with the disappearance of chlorophyll, they become apparent, which gives the leaves superb orange tones!
The red colours, on the other hand, are due to new pigments that are synthesised in autumn, from the sugars present in the leaf: anthocyanins (responsible for deep red, violet and purple colours). At the same time they help protect the leaves from solar radiation, and at the same time prevent insects and other animals from attacking the plant: the red colour repels them, as in nature this hue signals toxicity.
In autumn, not all trees take on the same colour, but several factors cause the colour of the foliage to vary: soil pH, moisture and drought, genetics (the colour varies depending on species and varieties), the age of the plant... Each colour depends on the specific proportions of each pigment, and on how they are expressed!
In North America and Asia, red colours (due to anthocyanins) are particularly marked, while in Europe autumn leaves are more often yellow or orange.
Winged euonymus (photo: Jean Jones), bloodtwig dogwood, Ginkgo biloba, American sweetgum and Japanese maple
Leaves eventually fall...
As they are no longer fed with sap, the leaves dry out, turn brown and eventually fall. This is a way for the tree to save its energy and go into dormancy, awaiting milder temperatures. Its metabolism slows, conserving its water and mineral elements. Leaves are thin and tender tissues; in cold weather they would be prone to freezing and dropping... so there is no point for the tree to try to keep them! Evergreen plants, on the other hand, generally have thicker, tougher leaves able to withstand cold temperatures. They continue to photosynthesise in winter, but even for them the metabolism slows.
When they fall, the leaves of deciduous trees bring organic matter to the soil. They protect the soil, support insects and microorganisms, and as they decompose, they enrich and improve the soil texture, aiding humus formation. While the ground is covered with a coloured carpet, the falling leaves allow us to admire the tree's entire architecture! This highlights the colour and texture of its bark, branches and branching.
In spring, with longer days, the roots will again draw water and minerals from the soil, which will then circulate in the tree's sap. This “sap rise” will enable bud burst and the appearance of new leaves... allowing photosynthesis through to the next autumn!
Every autumn, many trees and shrubs reveal their finest colours, offering a true spectacle: the leaves take on scarlet, coppery or golden hues before falling… Although it amazes us, this phenomenon is the result of a real strategy implemented by plants to protect themselves in winter. They go into dormancy, marking a necessary pause that […]
