- What Trees Lose Their Leaves Seasonally?
- What does a leaf do?
- Why do trees lose their leaves?
- What trees lose their leaves seasonally?
- Why Do Leaves Fall in Autumn?
- Comparing Conifers and Deciduous Trees
- When do evergreen trees lose their old leaves?
- Why Are My Trees Shedding or Losing Leaves in Spring?
- Two Common Causes of Spring Leaf Drop
- What Are Examples of Deciduous Trees?
- What Are Deciduous Trees And Shrubs: Types Of Deciduous Trees And Shrubs
- What are Deciduous Trees and Shrubs?
- Why Do Deciduous Plants Lose Their Leaves in Autumn?
- Caring for Deciduous Plants
- Types of Deciduous Trees
- Deciduous Shrub Varieties
What Trees Lose Their Leaves Seasonally?
Each year, as the days get shorter and cooler, certain types of trees begin a spectacular transformation. They slowly begin to shed the green from their leaves and turn different colors. This is a process called senescence, which is induced at certain times a year by photoperiodism, the process by which a tree regulates its life cycle and prepares for winter.
Broadly speaking, there are two major types of trees: evergreens and deciduous trees. Evergreen trees, like firs and junipers, keep their needles all year round. Many of these trees grow needles or scale-like leaves. Because they don’t lose their needles in the fall, they stay green, thus the name evergreen.
Deciduous trees, like maples, oaks, and beech trees, operate in the opposite way. The word “deciduous” means “tending to fall off,” and as you might guess, these trees lose their leaves during the colder months of the year. Unlike evergreen trees, deciduous trees don’t typically grow needle-like leaves, but larger, broader, flat leaves.
There are exceptions to this rule, however. Oaks, a deciduous tree, do eventually shed their leaves each year, but not generally until new growth occurs in spring. Tamaracks, an evergreen tree, sheds its needles every fall.
What does a leaf do?
Leaves may seem like a relatively small part of a tree, but without leaves, a tree can’t grow. Leaves are responsible for producing the food that a tree requires in order to survive. Leaves engage in a process called photosynthesis, which turns light energy from the sun into food.
Each leaf has a series of stomatas, pore-like structures, that allow the leaves to “breathe” in carbon dioxide, a necessary ingredient for photosynthesis, and “breathe” out oxygen, a waste product of photosynthesis. Leaves also exhale excess water, sort of like sweating. This exhaling of water increases humidity near the tree and can help cool the air in the summer. Trees are like giant green air conditioners!
Why do trees lose their leaves?
Even though the leaf is one of the most important parts of a tree, it is important for a tree’s health for those leaves to be shed each year. Unlike evergreen trees, whose needles tend to be small and narrow, deciduous trees generally have large, broad leaves. During windier winter months, these leaves would undoubtedly become damaged and could increase the likelihood of the tree being toppled.
Shedding leaves also helps conserve both water and energy during dry, colder months. Instead of relying on leaves all year long, it stores some of the food the leaves produce during spring and summer and subsists on that through winter.
When the time comes for the leaves to fall, the tree begins a process called abscission. During abscission, the tree grows specialized cells at the point where the leaf’s stem meets the branch of the tree. Eventually these cells will sever the leaf from the tree.
What trees lose their leaves seasonally?
Any tree that falls under the ‘deciduous’ umbrella will lose its leaves at some point in its annual photoperiodism. Some trees, like maples, beech, and ash trees, will lose their leaves during the autumn season. Oak trees are a bit different, often holding onto their leaves until new growth begins in the spring. Ash trees are often the first to lose their leaves, while sycamores will usually wait until midwinter to drop their leaves.
Want to learn more about why leaves change their colors in the fall? Check out our blog that explains it!
Why Do Leaves Fall in Autumn?
In temperate regions of the world, autumn is marked by the brightly colored foliage that slowly drops from trees and shrubs to carpet the ground. But why do some plants shed their leaves before winter? It turns out autumnal leaf drop is a form of self-protection. While evergreen plants in cold climates have thick waxes and resins to protect their leaves from freezing and fracturing, deciduous species generally have thin leaves that are susceptible to cold temperatures. Since water expands when frozen, the tender leaf cells would rupture during the winter, making them useless for photosynthesis. Without dropping these leaves, such a tree would be stuck with thousands of unproductive appendages and no way to make food! As if that weren’t reason enough, the surface area of all those leaves would also pose a threat to the plant’s physical integrity. Winter months are often windier than other seasons, and the wind against the broad leaves on a cold, brittle tree could cause major breakage. The same goes for the weight of snow collecting on all those leaves. Finally, by the end of summer, many leaves are insect-eaten, diseased, or otherwise damaged. Dropping them gives the plant a fresh start in the spring, and the nutrients from the decaying leaves are recycled to help grow the next leafy generation.
Interestingly, autumn leaves are not simply blown off trees but are separated from the plants in a highly controlled process. As day length shortens and temperatures cool, hormones within the plant are activated to begin the abscission process. Chlorophyll production stops and the pigment starts to degrade, often revealing showy reds and yellows that were masked by green. The vessels that carry water to the leaf and sugars to the rest of the plant are closed off, and a layer of cells, known as the abscission layer, starts to grow between the leaf stalk and the twig holding it. These cells serve to slowly cut the leaf from the plant without leaving an open wound. As the leaves fall, the plant enters dormancy, saving its energy for the great bud burst of spring.
Comparing Conifers and Deciduous Trees
As noted above, deciduous leaves have greater photosynthetic ability than do coniferous ones. That is partly because of their greater surface area, and partly because they invest more nitrogen in leaf building to begin with.
High-nitrogen leaves photosynthesize more efficiently (This is a broad statement based on observed correlations. One reason for the correlation between foliage nitrogen levels and photosynthetic efficiency may be that photosynthesis requires nitrogen-containing enzymes.) They are also more costly to maintain, being better stocked with proteins and other energy-demanding components.
So, it makes sense for the tree to shed them at the start of the cold season and produce new ones in the spring…if there is an adequate supply of nutrients with which to create those new leaves, that is.
Where nutrients are in short supply, the evergreen habit may be more efficient. That is at least part of the reason conifers tend to predominate at higher elevations in the Methow.
Long-lasting leaves represent a smaller annual investment of nitrogen, which can be a limiting factor in cold or dry places. The cuticle that coats conifer leaves also helps keep nutrients in the leaves; they are less likely to be leached by precipitation than are the nutrients in deciduous leaves, at least in the short run.
In the course of a needle’s life, it may lose as many nutrients as a deciduous leaf would in its few months on the tree, but in a single year, it will lose much less nitrogen.
Finally, conifers and broadleaved trees use different mechanisms to conduct water. In conifers, water moves in structures called tracheids. In broadleaved trees, water moves in more efficient structures called vessels as well as in tracheids, further supporting faster growth and larger leaves.
All of those adaptations add up to improved ability to survive and reproduce in a particular environment.
Here in the Methow, both conifers and deciduous trees have found niches. Deciduous trees generally predominate close to reliable water sources—where resources are plentiful, their adaptations have given them the edge.
Conifers may also grow in riparian areas, but they are also able to survive in upland environments. It is there that their ability to weather harsher conditions becomes a real advantage.
Other environments are dominated by either coniferous or deciduous trees.
The maritime northwest is an example of an area dominated by conifers. It appears that the northwest’s dry summers give conifers an advantage.
Photosynthesis may stop or slow way down as trees close the stomata in their leaves to reduce evapotranspiration—a real hindrance to trees that only bear leaves for a few months a year. In the winter, temperatures are generally mild enough that conifers can keep photosynthesizing, and, of course, there is plenty of rain to fuel growth.
At the opposite end of the spectrum are tropical rainforests, which tend to be dominated by broadleaved evergreen trees. When conditions are favorable, broad leaves are more efficient than the needles and scales of conifers.
Conditions in tropical rainforests are favorable in two respects: neither temperature nor moisture limits growth. In places where the growing season is not interrupted by cold winters, even angiosperms can photosynthesize all year round—and they don’t need tough needles and scales to do it. Neither do they need to conserve water, so leaf forms that limit surface area and evapotranspiration are not needed.
On the other hand, nutrients are likely to be limiting in tropical rainforests—the high rainfall leaches them from the soil—so an evergreen habit confers another advantage, allowing leaves to make use of nutrients for a longer period as well as take advantage of the sunlight year-round. The vessels that angiosperms use to transport water may even help their seedlings get off to a faster start than those of conifers.
The very harsh winter environments found at high altitudes and high latitudes are a third extreme, and one that has led to a specialized adaptation: deciduous conifers. The larches, mentioned earlier, are the best known example; a few other genera occur world-wide.
Larches rely on needles rather than broad leaves and they grow new needles every year (although the needles of juvenile trees may survive the first winter—perhaps protected by the forest canopy above).
How do they do it? First, they grow in areas where there is little competition—other trees are not adapted to the harsh environments in which larches have established themselves. And second, they rely on efficient form and efficient use of nutrients to capture light and grow leaves and structural components.
Come winter, the view from my window will alter. The pines will stand out, cinnamon-orange bark and green needles highlighted by snow. The beauty of the deciduous trees will be starker, the riparian stand more easily penetrated by the eye. Those trees will stand stiller and less colorful. They’ll be waiting.
Gower, Stith T., and James H. Richards. “Larches: Deciduous conifers in an evergreen world.” Bioscience, v. 40, no. 11 (December, 1990).
“Larix laricina—Tamarack: Adaptations.” Accessed March 5, 2012 at .
Mathews, Daniel. 1999. Cascade-Olympic natural history: A trailside reference. Portland: Raven Editions.
“The taiga or boreal forest.” Accessed March 5, 2012 at http://www.marietta.edu/~biol/biomes/boreal.htm.
Wikipedia—various articles, including:
Deciduous and evergreen are two opposite types of trees. They are categorized by the pattern and seasonality of their foliage growth. Plants between deciduous and evergreen are known as semi-deciduous trees. They have characteristics of both. In this article, we’ll tell you the main differences between an evergreen and a deciduous tree.
What are deciduous trees?
Deciduous is a term that refers to trees which seasonally shed their unnecessary parts, such as leaves, from their structure. Most deciduous trees are broad leaf trees. Because of the structure of the leaves and the pattern of leaf arrangement, the effectiveness of photosynthesis is very high in deciduous trees. Unfortunately, deciduous trees have both positive and negative aspects to them. Since they shed their leaves seasonally (during autumn and winter usually), they are very susceptible to wind and other winter weather conditions.
The falling of the leaves helps them prepare for winter conditions. It ensures better survival in winter as well as high water conservation and protection against predatory actions. Deciduous tree characteristics are observable in many woody trees like oak and maple. There are two characteristic deciduous forests where the majority of trees shed their foliage at the end of their typical growing season. These are temperate deciduous forests and tropical (and subtropical) deciduous forests. Trees in temperate deciduous forests are sensitive to the seasonal temperature variations whereas the tropical deciduous trees respond to seasonal rainforest patterns.
What are evergreen trees?
The evergreen tree is a complete contrast to the deciduous tree. As the name implies, an evergreen’s foliage remains on the tree throughout the entire year. There is no seasonal leaf shedding. Evergreen plants have a huge deviation within them. They include most conifers and angiosperms such as hemlock, cycads, and eucalyptus trees.
This does not mean that evergreens never shed their foliage. Old leaves of evergreen trees are replaced by new growth as they age. Evergreen trees favor warm, temperate climates. Many tropical rainforests are considered evergreens.
What are the differences between a deciduous and an evergreen tree?
There are several important differences between a deciduous and an evergreen tree. We will list them for you here:
- Deciduous and evergreen trees are opposite each other. Deciduous trees shed their leaves seasonally and evergreen trees keep their foliage throughout the year.
- Deciduous trees are adapted to tolerate cold and dry weather conditions by shedding their leaves while evergreens do not.
- Evergreens can survive with low soil nutrients. A huge portion of internal nutrients is removed during the defoliation of deciduous trees.
- Nutrient requirements of evergreens are somewhat higher than those of deciduous trees during bad weather because of the need for foliage maintenance. In deciduous trees, it is high after harsh weather when the foliage is renewed.
- Deciduous trees are more sensitive to temperature and rain fall than evergreen trees.
We hope that this article has helped you to better understand deciduous and evergreen trees, especially their differences. If you have questions on what types of trees you have, you should contact a certified arborist. They can help you identify your trees.
When do evergreen trees lose their old leaves?
The term ‘evergreen’ can be a bit misleading as all leaves eventually wear out and give way for others. The sole purpose of a leaf is to capture sunlight which can then be converted into food through a process known as photosynthesis, and when that leaf gets shaded out by a new flush of growth, it is discarded. A good example of this is seen in Pine which grows once per year in May/June with extension growth in whorls about 60 centimetres in length. You can read a Pine like a book and trace back these whorls to count how many years old it is! The new shoots grow from the tips of the old so the older needles get shaded out by the new flush of growth and go yellow/brown, before dropping through the middle of the tree to the ground below. This leaves the tree quite stark in the late summer with this so called ‘evergreen’ tree going brown inside out until only the last two years growth remains green. This is nothing to worry about; it is just the tree’s way of keeping efficient.
A deciduous tree can act in the same way over a shorter time. For example, a Silver Birch tree can put on extension growth of over a metre in one growing season and every centimetre or so is furnished with a new leaf. So the leaf created in May is well and truly crowded out by the leaf on the same shoot that is created in August. This older leaf is routinely jettisoned after fading to yellow, whilst the outer edge of the tree is still green and flourishing. The tree is not stressed; it is just discarding inefficient leaves.
Sometimes leaves are retained on deciduous plants even when they are dead. You see this mostly on Beech or Hornbeam with the tree holding onto brown leaves in the winter for the first two metres or so of its height. This is to protect the new season’s juicy buds from grazing animals through the winter as the rough dead leaves are unpleasant to eat. From two metres up the tree a Beech will not hold onto its leaves because the threat from deer has gone; they can’t reach that high!
The evergreen native tree Holly has evolved with a similar trick to defend itself against herbivorous grazers. We all know that Holly leaves are spikey but you look further up the tree and from about eight foot above ground level the leaves are smooth. It doesn’t need to grow spikes at this height as nothing can reach it! No giraffes in the UK!
We are full of these interesting facts about trees at Barcham! Best not to end up talking to one of us at a party, we could keep talking trees for hours!!!
Why Are My Trees Shedding or Losing Leaves in Spring?
In springtime, you expect your tree to put on a show–bursting full of fresh leaves or beautiful blooms to ring in the season.
But what if the new leaves that should be gracing your tree’s branches are scattered across your lawn?
Below, find out why tree leaves fall in spring and if you should help your tree with its spring leaf drop.
Two Common Causes of Spring Leaf Drop
Some trees tend to hang on to a portion of their leaves through the winter, making spring leaf drop perfectly normal. We usually think of fall as the season for shedding, but there are a few tree species that go against the grain.
But if you don’t have a tree that naturally loses its leaves in spring, your tree could have an infection. First, see what type of tree you have. Then, examine its fallen leaves to see if they’re curled and brown instead of smooth and green.
What are the trees that naturally lose their leaves in spring?
If your tree is dropping leaves that look green and healthy, all is probably good! You likely just have a tree that naturally sheds in spring. Below are the most common trees that do this.
Common Trees That Lose Their leaves in Spring
- Live oak
- Southern magnolia
I don’t have one of those trees, so why are my tree’s leaves falling in spring?
If your fallen tree leaves appear curled, spotted, or brown, anthracnose could be the issue. Anthracnose is the catch-all name for different fungal diseases that attack all kinds of trees. Plus, it’s most common in damp, cool springtime weather.
What if my ash tree is losing leaves in spring? Is it likely anthracnose or something else?
Ash trees, particularly white and green ash, are often affected by anthracnose. You’ll see the same signs as listed above.
What treatment is there for anthracnose?
Fortunately, most tree types–including ash– can easily shake off anthracnose. While the fungus can cause some leaves to fall, a flush of fresh leaves should come in within a few months.
While you wait, the best thing to do is get rid of the branches seriously affected and reboot your tree’s health.
What Are Examples of Deciduous Trees?
Examples of some of the most common deciduous trees are oak, maple, beech and sycamore. Deciduous trees are trees that shed their leaves annually.
Deciduous trees belong to the flowering plant group, angiosperms, and they are also called leaf trees, broad-leaved trees or foliage trees. There are more types of deciduous trees than there are conifers, or evergreens, which do not shed their leaves on an annual basis. In most North American latitudes, deciduous trees shed their leaves in autumn to avoid becoming parched during winter.
The most common method of tree identification is by noting the shapes of the leaves, which are typically oval, narrowly oval with a pointed tip (lanceolate), triangular, round or heart-shaped. The edges of the leaves are important identifiers too. For instance, apple, birch and aspen trees have dentate (tooth-like) edges, while beech tree leaves are serrated and oak leaves have lobed edges.
Besides leaves, deciduous trees also can be identified through their buds, bark, blossoms and fruit. During winter, when the trees have shed their leaves, identification is usually made through bark characteristics. White poplars and birch trees are readily recognizable by their light grayish bark that sometimes appears flaky.
When deciduous trees are in bloom, their fruits can make identification easier, as in the case of apple, pear or cherry trees. Nut trees are also deciduous (beechnut and acorn, for instance), as are trees with air-borne fruit and with wing-shaped seeds, such as maple and ash.
What Are Deciduous Trees And Shrubs: Types Of Deciduous Trees And Shrubs
Caring for deciduous plants in the landscape isn’t difficult. These interesting shrubs and trees add vibrant blooms in spring and summer, colorful foliage in fall and then drop their leaves prior to a restful winter’s nap. Keep reading to learn more about the life cycle of deciduous plants and what are deciduous trees and shrubs grown for.
What are Deciduous Trees and Shrubs?
Deciduous trees and shrubs are some of the most beautiful elements in the home landscape. They range in size, form and color and shed their leaves each fall before they go to sleep for the winter. The term deciduous is a fitting name for these plants as the word means, “tending to fall off.” Deciduous shrub varieties and trees shed the part that they no longer need to survive for the season.
Many types of deciduous trees add a great deal of interest to the landscape and serve a number of practical roles that include providing shade and reducing soil erosion.
Why Do Deciduous Plants Lose Their Leaves in Autumn?
The life cycle of deciduous plants includes a growing season and a dormant season. Warm spring temperatures and rainfall wake deciduous plants from their slumber and they begin to form new leaf buds. As temperatures continue to warm, the leaves develop more fully and reach maturity by the time summer arrives.
Leaves produce food for the plant and help with respiration. As temperatures begin to cool, deciduous plants instinctively begin to shut down food production and leaves change colors due to the lack of chlorophyll and drop to the ground.
It is due to this stage of the lifecycle that we get to enjoy the spectacular display of color each fall. Cold temperatures and a lack of moisture force deciduous plants into a deep slumber. This dormancy protects deciduous plants from extreme winter weather.
Caring for Deciduous Plants
Fall is the best time to plant deciduous plants as this gives them plenty of time to become acclimated before hot and dry weather arrives. Many deciduous plants including shrubs, fruit and ornamental trees require pruning in order to thrive. It is imperative that you understand the pruning needs of your particular plants so that you can help them reach their full growing potential.
Early spring fertilization also helps give deciduous plants a seasonal boost and often encourages prolific blooms on flowering varieties. Provide plenty of water during dry spells for new deciduous plants and check regularly for pest infestation or disease.
Types of Deciduous Trees
When selecting deciduous trees for your landscape, be sure that you choose varieties that are suitable for your growing region. Although many deciduous trees such as maples, birch, willow, oak and hickory are big, there are a number of smaller or ornamental deciduous trees that make an excellent addition to the home landscape.
Popular flowering trees include crepe myrtle, dogwood and redbud. Fruit trees such as apple, pear, plum and peach make a lovely and tasty addition to any garden and are often available in dwarf size, perfect for those with limited space.
Deciduous Shrub Varieties
Deciduous shrubs are often planted for their seasonal interest, color and texture. Popular use of many deciduous shrub varieties includes windbreaks, privacy screens or wildlife habitats. Popular deciduous shrub varieties include barberry, butterfly bush, and azalea.