How deep are tree roots
How Deep Do Tree Roots Really Grow?
Our 2010 blog entry by James Urban, FASLA, on the topic of how deep tree roots grow is consistently one of our most popular. Obviously there is a curiosity about this topic and a need for useful data about it. But the original post is a little technical and not as image-heavy as we’d like. So today we’re bringing you a new and improved version of the original post, with additional pictures and more simplified explanation of the factors that really influence how deep tree roots grow.
How deep tree roots grow depends on three simple factors. To answer this question I contacted Jim Urban, FASLA, a noted tree and soil expert. He contributed to the following post.
Roots require three things: water, oxygen, and soil compaction levels low enough (or with void spaces sufficiently large enough) to allow root penetration. If all these conditions are met, roots can grow to great depths. Under ideal soil and moisture conditions, roots have been observed to grow to more than 20 feet (6 meters) deep.
Early studies of tree roots from the 1930s, often working in easy-to-dig loess soils, presented an image of trees with deep roots and root architecture that mimicked the structure of the top of the tree. The idea of a deeply-rooted tree became embedded as the typical root system for all trees. Later work on urban trees that were planted in more compacted soils more often found very shallow, horizontal root systems. Urban foresters have successfully spent a lot of energy trying to make people understand that tree roots have a basically horizontal orientation, to the point that even many tree professionals now believe that deep roots in trees are a myth. The truth lies somewhere in between deep roots and shallow roots.
This totally horizontal root system formed on top of poorly drained soils. Photo courtesy of Miles Barnard.
Simply put, by Jim: “Trees are genetically capable of growing deep roots, but root architecture is strongly influenced by soil and climate conditions. ”
The most typical limitations to tree rooting in urban areas are soil compaction and poor drainage. These are often related, with a compaction layer creating a poorly-draining hard pan. This results in a perched water layer that restricts roots. Hard pans and perched water tables can also be found in nature. In fine-grained clay soils and fine-grained silty soils, pore space — and therefore and rooting depth — is often limited. Since these conditions are quite common in urban areas, shallow rooted trees are often seen as “typical.”
Six foot long sinker or striker roots in well-draining soils. Note the remnant of horizontal roots at the trunk flare. Photo courtesy of Miles Barnard.
Orjan Stahl, a tree researcher in Stockholm, made an exhaustive study of over 500 trees that had root and utility conflicts. He regularly found roots at depths of 7 to 9 feet (2.1 to 2.7 meters) and the deepest root he encountered was at 23 feet (7 meters). In their 1991 paper, “On The Maximum Extent of Tree Roots,” E. L. Stone and P.J. Kalicz summarized previous root depth studies of 49 genera and 211 species growing in a wide variety of soil types. They found numerous examples of trees reported to be growing roots to over 33 feet (10 meters), and one report of a tree that grew roots to a depth of 174 feet (53 meters). Clearly, a tree’s ability to grow deep roots is not a significantly limiting factor in soil design.
4 foot deep rooting in loam soil that was on top of a hard pan. Photo courtesy of James Urban.
Given all this, and the unpredictable site constraints of the urban environment, urban trees need flexible solutions that can enable roots to grow out or down. In some sites, increasing soil depth is not a problem, while expanding may be limited by other constraints. The opposite can also be true. This is why the Silva Cell system is flexible in all three dimensions to respond to different spatial limitations.
These roots go at least 4 feet deep. This tree fell over after the irrigation contractor installed a line on the up wind side. Photo courtesy of James Urban.
The designed maximum depth of the system is 45 inches (1150mm). This is a strategic compromise between the system’s structural requirements, soil volume, and cost and constructability issues. The Silva Cell was designed to provide a deep soil volume because roots will grow to these depths. For urban sites where deep excavation is limited, one- or two-layer systems can provide the same total soil volume across a shallower profile.
Two other factors are absolutely critical to the ability of roots to grow though the entire soil profile: the type of soil that is used, and designing the system to permit adequate water into and to drain out of the soil. These features must be designed to reflect the environment in which the Silva Cells are to be placed, the types of soil resources available and the project performance expectations of trees, soil and water.
Horizontal rooting to about 4 foot depth in loam soil over river wash till. Photo courtesy of James Urban.
How Far Down Do Tree Roots Go? The Fascinating Answer
Date May 29, 2022
Author David Gaona
When you look at a tree, the roots are out of sight and often out of mind. Some people say that tree roots can only grow as deep as the soil is thick, while others believe that they can reach down much further. So, what’s the answer? In this blog post, we’ll explore the fascinating world of tree root growth, from the impact of tree types and soil conditions to how to make sure yours grow strong and resilient!
How Do Tree Roots Grow?
Tree roots are amazing things. They are the unseen foundation of these massive plants, and they play a vital role in both the tree’s health and the health of the ecosystem around it. In order to understand how far down they can grow, we first need to take a look at how tree root growth happens in the first place.
Roots grow in response to a few different things, including the tree’s need for water and nutrients, gravity, and soil conditions. When a tree is first growing, its roots will typically grow down into the ground until they reach the water table. The roots will then begin to spread out horizontally in search of more water and nutrients.
Did you know: It can take anywhere from 3 months to over a year for tree roots to establish.
What are Invasive Roots?
Invasive roots are those that spread out horizontally and aggressively, often causing problems for nearby pipes and foundations. While not all tree roots are invasive, certain tree species are more likely to have them, including:
- Crepe Myrtle
- Willow trees
- Chinese Pistache
If you are concerned about the potential for damage from invasive roots, it’s best to consult with a Certified Arborist before planting.
What Affects How Far Tree Roots Can Grow?
The depth of the roots will also be affected by the type of tree. Trees that are native to areas with deep soils, like oaks and maples, will have roots that grow down to depths of 20 feet or more. Meanwhile, trees that are native to areas with shallow soils, like pines and firs, will have shallower roots.
Soil conditions also play a role in how deep tree roots can grow. If the soil is loose and easy to dig, the roots will be able to grow down deeper. If the soil is dense and hard, the roots will have a harder time growing down deep.
Are Long Roots A Sign of Good Tree Health?
While tree roots can grow to impressive depths, they don’t always need to go that deep in order to be healthy. In fact, tree roots often benefit from being closer to the surface of the soil. This is because they are able to get more oxygen and water from shallower soils.
In general, most tree roots can grow anywhere from two to six feet deep. However, there are some tree roots that have been known to grow much deeper than that. The world’s deepest tree root was found in South Africa, and it reached a depth of 24 feet!
How to Promote Healthy Root Growth
There are a few things you can do to promote healthy root growth in your trees, including:
- Choose the right tree species for your area. Some tree species are more likely to have invasive roots than others, so it’s important to choose wisely.
- Make sure the tree is getting enough water. A tree that is stressed from lack of water is more likely to have problems with its roots.
- Mulch around the base of the tree. This will help to keep the roots moist and the soil temperature balanced, which is ideal for root growth.
Concerned About Your Roots?
If you are concerned about the health of your tree’s roots, check with tree care experts to get the best results to help them grow strong and resilient. There are otherwise a few general things you can do to start.
First, as mentioned above, make sure that you’re watering your tree regularly. Tree roots need water to grow, so if the soil around your tree is dry, the roots will suffer.
Make sure that the mulch you add is no thicker than 2 to 4 inches and no closer to the trunk than 3 to 5 inches of a young tree and 8 to 12 inches of a mature tree. Otherwise, you risk constricting the oxygen supply to the roots below.
Finally, make sure that you’re not compacting the soil around your tree. Tree roots need loose, well-aerated soil in order to grow properly. If the soil is too compacted, the roots will have a tough time growing and they may even start to suffocate.
By following these tips, you can help your tree’s roots to grow strong and healthy. And when your roots are healthy, your tree will be healthy too! If you have any further questions about how to care for your tree, or if you need help with tree root removal, don’t hesitate to contact TreeNewal. We’re always happy to help!
If you need advice or assistance with tree growth or root care, get in touch with the ISA-Certified Arborists at TreeNewal and enjoy tailored tree care advice.
To learn more about How Far Down Do Tree Roots Go? The Fascinating Answer, call our Argyle and Southlake-based teams
at (817) 592-6846 or send us a message.
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Learn more about TreeNewal’s ISA Certified Arborists!
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How many meters do tree roots drop?
Tree roots are a true masterpiece of nature. From the first moment the seeds germinate, they go in search of much-needed water to keep the plant alive. Water containing minerals needed for growth. But not only that, but also, thanks to the rod, which is the thickest of all, is well fixed on the floor. Thus, no matter how strong the wind blows, it will be difficult to start it.
Although they also have a disadvantage, and this is that in the incessant search for water, depending on the type, it can damage pipes or any structure. To avoid this, I will tell you how many meters the roots of trees descend .
- 1 What are tree roots?
- 2 How many meters do they go down?
- 3 Deep tap root trees
- 3.1 Genus Ficus
- 3.2 Genus Pinus
- 3.3 Genus Eucalyptus
- 4 Non-invasive rooted trees
- 4.1 Genus Citrus
- 4.2 Genus Lagerstroemia
- 4.3 Genus Cercis
What are the roots of the trees?
Before moving on to the topic, it is important to first talk a little about the features of the root system of trees, as this will help you avoid problems. What you need to know is that the roots, from the moment the seeds germinate until almost the end of the plant's life, form a network in search of water.
This network initially has a distinct primary or main root, which is the so-called rotation, which is responsible for anchoring the trees to the ground, but as the trees grow, the roots become mostly superficial, and only a few of them continue to grow vertically. In fact, if we take a mature tree about 50 years old as an example, we can be sure that about 90% of the roots are in the first 50 centimeters of the ground. . But that's not all.
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And the fact is that the size of the entire root system of a tree tends to match (more or less) the size of its crown, which makes sense if we think that all these branches should receive the water that their roots receive. in most cases from the ground to produce leaves, flowers, fruits and seeds. This means that if we have a tree with a crown about 2 meters in diameter by 3 meters at the highest point, its roots will take up about 2 meters in diameter (in this case, the depth is not taken into account because it is difficult to go down a meter and more).
How many meters do they descend?
How deep the roots go depends on several things: soil type , plant species in question and the amount of water in the ground . As a rule, the wetter the soil, the longer its root system will be.
However, You should know that the vast majority of trees, namely 80% of them, as well as the vast majority of their roots, only go down to 60 cm. . From there, they lay out their roots horizontally. The roots of the remaining 20% can penetrate more than 2 m underground, so they will have to be planted away from any buildings.
Since you are probably wondering what these deep-rooted trees are, we couldn't end this article without mentioning the most important ones:
Image - Wikimedia / Forest and Kim Starr
Ficus are trees, shrubs or vines native to the intertropical zone of the world. Many species are used as house or garden plants, such as Ficus pumila , Ficus Benjamina o el Ficus robusta . Its height is variable, but can easily exceed 's 10 meters, and its roots extend several meters in all directions.
Image - Flickr / CARLOS VELAZCO
Pine (or pine) are woody or shrubby coniferous trees with a crown, usually pyramidal, and sometimes wide and round, which they can reach 30 meters . The best known and most commonly used types are Pinus Pinea , Pinus halepensis or common .
Eucalyptus (eucalyptus) - trees, especially growing in Australia and New Guinea. It has a fast growth and they can measure over 60 meters. . Its roots are not only unsuitable for growing in a small garden, but also prevent other plants from growing around them. Interesting species for very large plots are, for example, Eucalyptus deglupta for tropical climates or Eucalyptus camaldulensis .
Non-Invasive Root Trees
If you are looking for plants with a more shallow and non-invasive root system, I recommend more plants in these genera: 5 to 15 meters . They are native to tropical and subtropical Asia and there are many species that produce delicious fruits such as Citrus reticulata (mandarin), Citrus x Paradisi (grapefruit) or Citrus x sinensis (orange tree).
Image - Flickr / Joel Abroad
Lagerstroemia are trees and shrubs native to tropical regions of Asia. They can grow up to 10 meters. , and produce many purple or white flowers. The most famous species is Lagerstromia , popularly called the tree of Jupiter.
Image - Wikimedia / Batsv
Cerci are deciduous trees native to Europe, Asia and North America. They reach a small height, from 6 to 10 meters. , with a wide crown that fills with pink flowers in spring, like European purple o el Chinese purple .
Do you know other trees that are not invasive?
How to uproot trees: tips and tricks
Sat, 12/09/2015 - 13:03 | Comments: 0 | Author: OLCHUKS
Everyone who has had to get rid of tree stumps and roots on their site knows how difficult this process is. Knowing how to uproot trees quickly and inexpensively can be needed in a variety of situations: if the tree has already outlived its usefulness, if you need to free up a plot for construction, or just update the landscape design.
- Step-by-step instructions for removing tree roots
- Chemical uprooting
- Mechanical methods
Step-by-Step Guide to Remove Tree Roots
To complete this task, follow these steps:
- Estimate the scope of the work. The larger the tree, the more difficult it is to remove. The size of the roots often depends on the type of tree. Assess the terrain and soil where the tree is growing. All this will help you determine the next steps or estimate the costs if you contact a specialized company.
- Prepare all necessary equipment: shovel, hacksaw, axe, etc.
- If the trunk of the tree has a large enough diameter and is strong with strong roots, you will have to dig a hole around the trunk. Moreover, the pit should be 3 times larger than the trunk itself. Depth is determined individually. You will see the first roots, start cutting them off. It is very important to get to the main, central root. If it remains intact, pulling out the tree will be extremely difficult.
In the case when the previous point did not give any results, you can resort to the next step - to apply special equipment. If you have a tractor, it will be very easy to pull out an already dug up tree. Tie the rope to it, the other end to the tractor and pull. If the roots have already been cut, the tree is removed the first time. However, this effective method has its own characteristics. Firstly, not every site can bring a tractor. Not everywhere there is an entrance to the site. And secondly, the site itself must be large enough so that the tractor can then also turn around.
If the tractor is not brought to the site and the tree with roots is still in place, try to wash away the soil around the roots.
Fill the hole with water from a hose, then the soil will become loose, it will be easier to pull out the stump. But remember that you can’t get very close to the tree, there will be slippery liquid mud under your feet. There is a high chance of slipping and falling into a hole. In case of an unsuccessful fall, there is a possibility of fractures.
Chemical methods of tree removal do not require much effort. You won't have to drag, pull or cut anything. However, these methods have their own characteristics. For example, they do not act instantly. We'll have to wait until the chemical turns the roots into dust.
These methods are especially popular when removing trees in the city, where it is not possible to dig and pull special equipment. Basic methods:
- Potassium nitrate. This method does not require any effort at all and is inexpensive. But it will take a long time to wait. If the roots are very large and deep, like those of coniferous trees, it will take more than one year to wait for the complete removal of all roots. To uproot a tree in this way, cut the tree as close to the ground as possible, make holes in the soil around the trunk with a diameter of at least 5 cm, the depth will depend on the scale of the roots. Pour 100 g of saltpeter into each hole and fill with water. To prevent the substance from washing out, plug all the holes with a stopper. For a while, you can forget about the stump. It is better to do this in early summer and leave everything in this form until spring. And in the spring, if the tree was small, you can complete the procedure. Pour combustible material into the holes and set it on fire. The fire will destroy the remnants of the roots, it remains only to dig.
- Ammonium nitrate. Ammonium nitrate is good because it not only destroys the roots, but also fertilizes the soil well. The same procedure is carried out as described above, only nothing needs to be set on fire at the end. After the roots have dissolved, this soil can be used to grow flowers.
- Common salt. A simple and affordable means of removing unwanted roots. Take coarse table salt, pour it into the holes and leave it for the winter. A small stump will take about 300 grams of salt. Then just fill the area with earth. The stump will decompose itself. Nothing can be planted in this area, the soil is too salty. But for changing the landscape, this method is perfect.
- Special products from the store. You can buy a weed remover, pour it on a fresh cut of a tree and wrap it up for the winter. After about a year and a half, the remains of the stump can be easily removed. No new growth will appear.
Mechanical methods are more labor intensive, but you don't have to wait long. You can get rid of hated stumps quickly and immediately. To make the work efficient, get a pick, a special tool for uprooting. Ordinary shovels will dull quickly.
Methods of mechanical uprooting:
- Manual method. This method requires great strength and perseverance. However, among gardeners and gardeners, it remains the most popular due to its cheapness and availability. It does not require any special skills. You need to have time in reserve and strong assistants. The time of year doesn't matter. It is enough to dig and cut off the roots until the stump is pulled out. If you act correctly, even the deepest roots can be removed, and you do not have to wait a year for this. However, if there is no experience and skill, injuries are possible.
- Excavator. A very fast and efficient method. However, it is advisable to hire special equipment only if there are a lot of stumps and enough space on the site. For example, if we are talking about a park or an orchard, then this method can even be called economical. But in the event that there is not enough free space, there is a lawn, paths, fenced areas nearby, then it will be impossible to use such bulky equipment. If you do not plan to plant new trees, then the holes after the excavator will need to be covered with earth.
- Pneumatic crusher. A crusher is a device that enters the ground by about 30 cm and cuts the roots into small chips. For hard-rooted trees, this is a great way to remove. It is compact in size, acts quickly, does not dig deep holes. However, it enters the soil shallowly, roots may remain in the ground, which then sprout. If the site is contaminated with something, large debris, stones can lead to breakage of the crusher.
- Winch. This is almost a manual method of removal, but here a simple mechanism called a lever comes to the rescue. The stump needs to be dug up, some roots cut off. Then tie a cable to it, and wrap the other end around the tree and attach it to the winch, and then pull it. If the stump is dug very well, it will fly out of the pit quite unexpectedly and abruptly. So you have to be careful not to hit anyone. This method, although it sounds simple, but requires certain skills.