Trees in Paved Surfaces: Structural Stability vs Rootable Soil

Posted by Shane Carpani on Oct 15, 2015

http://blog.greenblue.com/

 

 

Soil structure is fundamental for the planting of trees, as well as the stability of roads, buildings, and other infrastructure. It refers to two things:

1. the arrangement of soil particles including silt, sand, and clay that aggregate together
2. the void pore spaces between these aggregate particles

In this article, we discuss why appropriate soil structure is critical to healthy tree establishment, and what landscape architects and other specifiers can do to ensure newly planted urban trees receive the conditions they need to thrive, so they can provide the many benefits that mature trees offer. 

Why We Need Soil Structure

Not every soil is conducive to the growth of trees and other plants, urban soils least of all. Tree growth and fertility are strongly influenced by soil structure, as it defines whether the tree will have rootable soil available and affects the movement of air, water, and other nutrients required for trees to flourish. 

Effectively the 'architecture of the soil', soil is usually the most critical element for the success or failure of urban trees. A well structured soil functions like a reservoir, enabling the tree to accept, store, and transmit water and nutrients, provide room in which roots can propagate, and allow the space required for life and the necessary biochemical exchanges for growth. 

Trees & Compacted Soil

Too often, trees are planted in cramped planting pits and poor subsoil, resulting in retarded growth, with roots tending to colonize the area immediately underneath paved surfaces, leading to structural pavement damage. 

Root colonization immediately underneath the paving stone roadway causing pavement damage 

There are different types of roots associated with tree establishment. Anchor roots function as a structural element to the tree and hold the tree in place in the soil. 

Fibrous roots (or feeder roots) are roots that intake nutrients, and typically grow in the top 6" of the soil. They can be directed lower to avoid damage to paved surfaces, if appropriate irrigation and aeration are ensuring the required nutrients are reaching lower levels. This "feeder zone" can extend between two and seven times the diameter of the canopy drip line. 

The feeder zone of any tree must be protected from compaction in order to ensure root establishment. 

"Resistance to root penetration due to soil compaction will affect
root establishment and the ultimate health of the tree"

Tree roots are opportunistic and seek out favorable growing conditions. Moisture and air trapped between impermeable pavements and compacted soil attracts nutrient-starved roots to grow into those areas. The resulting colonization of those roots causes subsequent pavement heave and infrastructure damage. 

These trees died prematurely due to unavailable rooting volume caused by soil compaction 

So how can urban trees be adequately provided for in their city settings, without compromising or damaging the structural integrity of paved surfaces? The answer is structural soil cells. 

How Soil Cells Work

As we discussed in last week's article, urban soil rarely provides the favorable environment trees need to grow and flourish. Hard compaction, lack of aeration, poor drainage, low nutrient levels, and the existence of pollutants in soil stunt root growth and make it nearly impossible for urban trees to thrive. Landscape architects, arborists, engineers, and other specifiers have the availability of strong soil support systems that, while conducive to root growth, also offer adequate support for roads and sidewalks. 

The concept behind soil cells was first developed by GreenBlue in 1992, when our UK branch installed the first tree pit using soil cells to provide uncompacted soil volume for root growth underneath a paved surround. 

Suitable for parking lots and sidewalks, soil cells prevent the topsoil in tree pits from becoming compacted by the pressure of surrounding hardscapes, amongst other things. They allow trees in urban settings to have large, healthy root systems, thriving in quality uncompacted soil.  

These modular units are assembled into a skeletal framework (or matrix) with over 90% void space to provide large volumes of soil within the tree pit for the healthy growth of roots - all while also supporting pavement loads. 

Designed to highly advanced engineering specifications in order to support heavy vertical and lateral loads, StrataCells bring tree root systems closer to the pavement surface. Engineers have calculated that with only 12" (300mm) of granular pavement depth, a StrataCell matrix can support maximum traffic loads, while providing over 94% of void space for root growth. 

With both vertical and lateral forces considered in the engineering make-up of tree pits, soil cell modules lock together, forming a monolithic framework with excellent modular strength. Highly secure connectors allow for modules to click together fast and simply, while it's enormous growth zone allows for plenteous root establishment. 

Structural Integrity of Soil Cells

GreenBlue soil cells are crush tested during manufacturing as part of our rigorous quality control standards. Whilst FEA (Finite Element Analysis) computer load testing was also conducted during the initial design stages to project the loading capacity laterally and vertically, physical laboratory tests were then used to clarify the cells actual loading capabilities. 

This physical load testing is part of an ongoing development and research program, and is the only true measure of structural integrity. GreenBlue soil cells are made using 100% recycled polypropylene, and have the highest structural integrity of any large soil cell. 

Fatigue Testing

As manufacturer of the world’s strongest soil cell, GreenBlue has subjected our soil cells to extraordinary laboratory tests, including fatigue testing. In one test, a university applied a load of 8.6 tonnes to a StrataCell® tower 10,000 times. The tower was then crushed to measure whether the ultimate load had been diminished by the cyclic loading. The high strength modules had lost no strength, verifying the design of this remarkable system. 

In closing, our streets do not have to be a battle between trees and pavement. They can coexist together, if specifiers and professionals consider the site conditions and provide an appropriate soil structure to suit both tree planting and infrastructure construction. 

Please consider sharing this article, and download our free eBook on the Soil Requirements of Urban Trees. 

Written by Shane Carpani

Shane Carpani is the Creative Director and Manager of Content Strategy at GreenBlue Infrastructure Solutions. Connect with Shane on LinkedIn or follow @ThinkGreenBlue on Twitter.

http://blog.greenblue.com/trees-in-paved-surfaces-structural-stability-vs-rootable-soil

 

 

 

 

7 Thoughtful Uses of Dead Tree Leaves

 

While we don’t have the traditional fall leave drop in South Florida, we do have trees dropping leaves at many different times during the year so this advice is still useful!  --Gene

 

Home Improvement Writer: Kathy Hatter

 

As the cycle of seasons moves forward, each season brings with it new developments in a landscape. In the autumn of the year, you may find that you have more dead leaves than you can easily handle. This may be where some creativity and ingenuity comes in. Sure, you could rake them all up and burn them or throw them away – but perhaps there’s something more creative to do with dead tree leaves.

 

As you consider your options, take a passing glance at what the Department of Natural Resources has to say about the benefits of dead tree leaves in the environment. Dead tree leaves provide nutrients for the soil as well as shelter and cover for animals.

 

With a fresh mindset, use seven thoughtful uses of dead tree leaves to use the materials nature gives you for a positive purpose.

 

<![if !supportLists]>1.       <![endif]>Winter Mulch

As you clean up your yard in the autumn, raking and gathering dead leaves that fall from the trees, save the leaves for a winter purpose. Many perennial plants and shrubs need winter protection of their roots to keep them from damage from cold subzero temperatures. Dead leaves can make an ideal winter mulch. Mound the leaves in a 4 to 6-inch layer around the base of shrubs. Extend the leaf mounds out to the drip line of the shrubs to ensure that you cover the root system completely. Cover perennial plants and flowers with a thick layer of dead leaves as well.

 

One caveat – make sure you place the dead leaves around plants after the ground freezes and remove the leaves before the ground warms up too much the next spring to ensure that you keep the roots from overheating in the soil.

 

<![if !supportLists]>2.       <![endif]>Lawn Fertilizer

When leaves litter your lawn, you may think it’s time to get out the rakes and collect them all for disposal. Instead of rakes, what you need is simply your lawn mower. While leaving whole leaves on the lawn would not be healthy for the grass because they would smother it, there is another option. Mow the lawn in standard fashion to chop up the leaves on your lawn. By chopping up the leaves, you break them into tiny pieces that will decompose more quickly. This keeps the grass exposed to air and sun but enables the leaves to decompose and add nitrogen to the soil. You may even find that your lawn no longer needs synthetic fertilizers when you use chopped up leaves as fertilizer.

 

<![if !supportLists]>3.       <![endif]>Brush Pile

If you wish to create an inviting habitat for creatures in your yard, make a large brush pile for the critters. Choose an out-of-the-way spot where you can create the brush pile without anything or anyone disturbing it. Don’t create the brush pile near the foundation of a building, however, because the brush pile might lead to animals burrowing under the foundation. Start the brush pile with a base of large branches, criss-crossed across each other. Add smaller branches over and around the large branches, leaning the smaller branches to make the brush pile look like a teepee. Add dead leaves in and around the branches to finish the brush pile and make it cozy. Once you finish your brush pile, watch for small animals like rodents, chipmunks, garter snakes, lizards, box turtles and wild birds.

 

<![if !supportLists]>4.       <![endif]>Compost

Adding dead leaves to a compost pile is an effective way to increase the nitrogen content of the compost. Add leaves regularly to the compost and then turn the contents of the compost pile to mix the materials well. With regular mixing and turning, leaves added to compost will result in rich compost within three to six months. Once you have compost, you’ll be ready to return it to your landscape as a soil enhancer and natural fertilizer.

 

<![if !supportLists]>5.       <![endif]>Aquaria Supplement

If you have an aquarium with fish, you might add dead leaves to the water in the aquarium to enhance the environment. You will notice that the water color changes almost immediately after you place dead leaves into the aquarium water. Dead leaves release tannins into the water. These tannins lower the pH level of aquarium water, which makes the water healthier for fish. Dead leaves can also fight bacteria and fungi in aquariums as well as reduce the heavy metal content of the aquarium water. If fish in the aquarium are stressed due to illness or they are new additions to the aquarium, dead leaves can improve the health of fish. Some fish may even eat the dead leaves in an aquarium.

 

<![if !supportLists]>6.       <![endif]>Flowers

If you find colorful dead leaves on the ground, scoop them up to use for a bouquet. You can easily make beautiful fall roses out of a few colorful maple leaves. Take one maple leave and fold it in half from top to bottom, leaving the stem on the leaf. Roll up the folded leaf from left to right to create a tight bundle that will become the center of the flower. Fold another leaf in half in the same fashion and wrap it around the center leaf to make an outer layer. Continue folding leaves in half and wrapping them around the flower to make additional layers. Add as many layers as you wish to make the flower as full as you desire. Once you have the flower you want, wrap floral wire around the base of the flower to hold the layers tightly together. Continue wrapping the floral wire tightly down the stems of the leaves to hold them together. The stems of the leaves will become the stem of the flower.

 

<![if !supportLists]>7.       <![endif]>Pressing

A few perfect leaves on the ground in vivid fall colors can make lasting mementos of the autumn season. Collect leaves and place them between sheets of newspaper in a heavy book for about one day. Next, place the leaves between two sheets of waxed paper and press them with a medium hot iron for approximately 10 seconds. Let the waxed paper cool and cut around the leaves. Display the pressed leaves in a scrapbook or photo album.

 

Once you learn to view dead leaves with a different perspective, you may never burn or throw them away again! Swing by the Red Beacon website for more ideas to put your autumn leaves to good use.

Read more: http://www.redbeacon.com/hg/7-thoughtful-uses-dead-tree-leaves/#ixzz3p0wGqKqT

 

 

 

9 Reasons Our Cities Need Mature Urban Trees

 

GreenBlue Blog - Sustainability in the Urban Landscape

 

Posted by Shane Carpani on Aug 28, 2015

 

 

Trees improve the livability of urban areas for many reasons. However for several years now, tree canopy in our cities and towns has been diminishing. Large mature trees which reach the end of their lives are frequently replaced with smaller species, or not at all. Then, replanted trees often struggle to establish and reach maturity due to the demands of engineered surfaces around them. 

In this article, we outline nine of the main reasons why our cities need trees, and touch briefly on the systems available to specifiers and designers to help ensure new tree plantings have the chance to thrive. Landscape architects, urban planners, developers, and local authorities - listen up! 

 

As time has gone on, more and more research has confirmed the value and benefits that mature urban trees offer our cities. Organizations such as 'American Forests' and 'Trees Forever' actively campaign in support of trees in urban areas. And the more mature the tree, the greater the benefits - so it's critical that trees are planted with healthy growth and mature establishment in mind. 

 

So let's get down to business! Below are some of the principle benefits that trees bring to our cities:

 

Aesthetics

Few things can compare with the visual impact and seasonal interest that trees bring. They offer immense visual appeal to any area and will enhance the design of any streetscape. 

 

Air Quality

For every 10% increase in urban tree canopy, ozone is reduced by between 3-7%. 

Trees are proven to absorb carbon. After removing it from the air, it is stored as cellulose in their trunks, branches, and leaves (a process called sequestration). Planting trees remains one of the cheapest, most cost effective means of drawing excess carbon dioxide from the atmosphere (Tina Prow, "The Power of Trees"). A single mature tree can absorb carbon dioxide at a rate of 21.6 KG/year and release enough oxygen back into the atmosphere to support 2 human beings. 

Research has also shown a 60% reduction in particulates from exhaust fumes in tree lined streets. 

 

Health & Well-Being

Trees have a positive impact on the incidences of skin cancer, asthma, hypertension, and stress related illness by filtering out polluted air, reducing smog formation, providing shade from solar radiation, and giving an attractive, calming setting for recreation. 

Pollutant Removal - sulphur dioxide, nitrogen oxides and particulates, carbon monoxide, cadmium, nickel, and lead are all substances that a tree works 24 hours a day, 7 days a week to remove and store. 

Noise Reduction - trees form an effective sound absorbing barrier. 

Biodiversity - the benefits of providing natural habitats for birds, squirrels, and other fauna are incalculable. 

 

Cost Savings

According to the U.S. Forest Service, every $1 invested in trees brings a return of $2.70 in benefits. A similar study performed in the United Kingdom by 'Natural England' calculated that every £1 spent on tree planting would yield £7 savings, which if taken nationally would amount to potential annual savings of £2.1 billion. 

 

Managing Stormwater

For every 5% of tree cover in a community, stormwater runoff is reduced by 2%. Trees prevent rainwater runoff from reaching water courses with the harmful chemicals it collects from urban roadways and sidewalks, while also reducing topsoil erosion. 

 

Property Values

Trees can increase real estate values. Independent studies have shown a consistent 5-15% increase in property values on tree lined streets. 

 

Community Improvement

Crime reduction - researchers have discovered reductions in both violent and petty crime, including domestic violence through the therapeutic, calming influence of mature tree planting. 

 

Cooling Effects

Trees reduce temperatures by shade and transpiring water. This helps reduce air conditioning bills and energy use. One mature tree can produce the same cooling effect as 10 room-sized air conditioners. This becomes an effective tool in reducing urban heat islands and hot spots in cities. 

Trees can also save up to 10% of local energy consumption through their moderation of local climate. 

 

Wind Speed Reduction

Buildings increase wind speed as wind is forced to travel further around them. Trees significantly reduce wind speed up to a distance of 10 times their height. 

 

Helping New Urban Trees Thrive

Trees in urban spaces face a difficult environment. Hard paved surrounds limit access to rainfall irrigation and the engineered requirements of hardscapes are the complete opposite of what the tree needs to grow into. GreenBlue systems help provide optimal conditions to give trees a chance to reach mature. Soil support cells allow for plenteous root growth while still providing the structural stability required for paved areas. 

 

The ArborSystem brings together the key elements of successful tree pit design and simplifies the design and installation process for specifiers and contractors. 

 

With all these benefits outlined, it's important to understand that a large portion of urban trees that are planted do not reach maturity, therefore not providing the extent of the benefits that they could. 

 

To learn more about the benefits of urban trees, download the FREE eBook. Please also considering sharing this article with your colleagues and friends. 

 

Infographic  

What Trees Bring to Our Cities  

 

Download the"Benefits of Urban Trees"eBook

Written by Shane Carpani

Shane Carpani is the Creative Director and Manager of Content Strategy at GreenBlue Infrastructure Solutions. Connect with Shane on LinkedIn or follow @ThinkGreenBlue on Twitter.

 

http://blog.greenblue.com/9-reasons-our-cities-need-mature-urban-trees?utm_content=20547849&utm_medium=social&utm_source=linkedin

 

 

 

 

 

National NeighborWoods® Month is an annual campaign to plant and care for community trees during the month of October

 

National NeighborWoods® Month is an annual campaign to plant and care for community trees during the month of October. Each year, tens of thousands of volunteers take action to make their communities greener and healthier by planting trees—turning their neighborhoods into vibrant, livable communities! Join the celebration!

 

 

National NeighborWoods Month began in 2005. During the month of October, local organizations nationwide engage tens of thousands of volunteers to green up their neighborhoods. Together, Alliance for Community Trees organizations have planted and cared for more than 15 million trees with help from more than 5 million volunteers. Trees have a remarkable economic, environmental, and health benefits for our communities including decreasing utility bills, increasing property values, and reducing carbon emissions.

 

Learn more about National NeigbhorWoods Month at www.NeighborWoodsMonth.org and follow us on Twitter @NeighborWoods.

 

http://neighborwoodsmonth.org/

 

 

 

 

 

The Melbourne treemail phenomenon

 

Leaf letters: fan email for Melbourne's trees pours in from around the world

Monica Tan     @m_onicatan

Wednesday 15 July 2015

 

Emails from overseas as part of Melbourne’s Urban Forest Visual project have urged English elms to savour the Ashes and warned a Chinese elm to ‘keep away from fire’

Trees in Melbourne have been receiving fan mail from around the world since the city council’s project to assign an email address to each one received worldwide publicity.

A recent article in the Atlantic Monthly is the latest to fuel the global response to the scheme, with some letter writers expressing their admiration, intense homesickness and making suggestions such as to “keep away from fire”.

The 70,000 trees are mapped in a project called Urban Forest Visual, with each tree assigned an identification number.

City of Melbourne councillor Arron Wood said their original intention was to help residents report tree vandalism or branches dropping – instead “people began sending emails professing their love for trees”.

Since launching in May 2013, the website has received more than 3,000 emails to individual trees. The emails have come from as far afield as Russia, Germany, the US, Britain, Hungary, Moldova, Singapore, Brazil, Denmark and Hong Kong.

Some of the trees’ fans have never set foot in the city:

Brush Box (ID 1039919) 14 July 2015

Hello, dear Tree.

I read about this wonderful project and suppose to write you from another side of Earth - Russia. I hope you have a good care and don’t sick. One day we will meet, may be.

Other writers have attempted to make contact with compatriots:

English Elm (ID 1032245) 14 July 2015

Are you and your fellow English Elms enjoying the Ashes series as much as we in England are, and are you giving the native Aussie trees some stick over their team’s performance?

And some have provided sage advice for their tree:

Chinese Elm (ID 1289990) 19 February 2015

Hi tree,

My Name is Tina I’m from Germany. I like trees all over the world, you know. Let me tell you something about German trees. They live in huge woods and because it rains often in Germany they almost never suffer from draught. This might sound heavenly to you but believe me Germany is not heavenly in winter - it’s freezing cold and quite dark. I wish I could come and tell you more about them but Australia is damn far away from here.

Keep away from fire!

Sending you best wishes from Germany

The most popular tree is a 13m-tall golden wych elm (ID 1028612) on Punt Road estimated to be about 70 years old.

The tree has received seven emails to date, including this one on 30 January:

Hi tree on the corner of Punt Road and Alexandra Avenue and that little street that goes up the side,

How are you? How old are you?

I’ve always wondered about you ever since my slightly strange driving instructor (who always smelled like cat food and peppermints) told me you were his favourite tree.

I hope they don’t knock you down.

The project is part of a wider push to revitalise Melbourne’s greenery, with aims to double canopy cover from 20 to 40% by 2040. Wood believes this will cool the city’s summertime temperatures by 4C.

More than four in 10 of Melbourne’s trees will be lost over the next 20 years due to old age. Having planted 12,000 new trees in the past four years, the city is on track to replace those trees and increase canopy cover.

Wood is pleased with the project’s success. “We know that Melburnians are passionate about their trees, parks and gardens. We were surprised and delighted to find that many people all over the world feel the same way.”

http://www.theguardian.com/australia-news/2015/jul/15/leaf-letters-fan-mail-melbourne-trees-pours-in-around-the-world

 

To listen to a related story, go to: http://www.npr.org/2015/07/16/423434833/to-melbourneelm22-subject-my-dog-peed-on-you-today-body?sc=17&f

 

 

 

 

 

Don’t trim your palms!

Don't trim your palms!  Or at least don't trim until the fronds are brown.

A question that we are frequently asked is whether or not palms in the landscape should be trimmed. The answer in almost all cases is NO! There are several reasons why this is not a good practice.

1.   Your palms have stored energy inside their fronds. Unless the frond is completely brown, there are stored carbohydrates (sugars) that the palm is expecting to utilize. As each frond changes from green to yellow to brown, the palm is withdrawing the stored nutrition inside the frond. The palm then uses those sugars to produce new growth. Removing even a few green fronds from a healthy palm will induce a nutrient deficiency and in some cases can be fatal. Similarly, removing chlorotic (yellow) fronds will create a vicious cycle and force the palm into a continually malnourished state, even if the deficiency has been corrected by proper fertilizer application. Removal of green fronds is an unnatural act and forces a palm to use its stored nutrition before it normally would. Think of each frond as a dinner plate with food on it. Removing plates of food will cause the palm to become hungry.

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2.   The palm frond is the palm's sole source of energy. Palms, like nearly every plant, rely on photosynthesis to survive. Photosynthesis is the process of converting light into sugars, which are then stored in the fronds. Removing fronds prematurely reduces the photosynthetic capacity of the palm and therefore slows its growth. Unlike hardwood trees that can grow multiple leaves from multiple branches, palms can only create one frond at a time.

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3.   Trimming can spread diseases.  When living fronds are removed from a palm, living tissue is cut.  Palms have a circulatory system and sugars and water are constantly moving throughout the palm.  If the pruning equipment has been exposed to disease from an infected palm, it is highly likely to be transmitted to a healthy palm when living fronds are removed.

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Removing healthy fronds makes palms LESS storm tolerant.  Many people have their palms trimmed near the start of hurricane season.  This is not a good practice as stated previously, as palms store energy in their healthy fronds.  Over pruning leaves the fewer remaining fronds more susceptible to wind damage.  Healthy palms with full canopies are much more tolerant of hurricane force winds and are able to recover more quickly.  After a hurricane, leaving cracked, hanging green fronds on the palm is a good practice as well.  In the months after Hurricane Wilma in 2005, we observed a quicker recovery and less death on palms that were left alone rather than heavily pruned.

Palms that are fertilized properly at consistent intervals will remain green from top to bottom and will not prematurely yellow. Palms with a crownhsaft are self-cleaning and will drop their fronds naturally when they are finished using the energy stored inside. Palms that do not drop their fronds naturally are finished using the stored energy when each frond browns completely.

In conclusion, with regards to removing fronds from palms, the less you do, the better.

 

 

 

http://palmtreedr.com/blog/dont-trim-your-palms/

 

 

 

 

 

Are You A Tree “Volcano Mulcher”? Hope Not

Yes, unfortunately, we have this problem in Fort Lauderdale and throughout South Florida.  With all the moisture we have in the area, "Volcano mulched" trees are very susceptible to decay and the unwanted roots mentioned below.  –Gene

 

By Paul Cappiello

Crestwood, KY (May 29, 2015) — Thanks to tree friend Paul Cappiello at Yew Dell Botanical Gardens for calling out the practice of "volcano mulching" and demanding an end to it. His article created a firestorm on social media this week. Find out what Cappiello has to say about the practice and why it's so bad for urban trees.

Photo Courtesy of Yew Dell Botanical Gardens

 

According to Cappiello, "Now to be clear right of the bat, let's get this out of the way. Volcano mulching is bad for trees.… Let us count the ways." And he does — four of them to be exact. Here they are:

Smothered Roots — Volcano mulching essentially plants a tree too deeply. Even if you plant at the right height, the mounds and mounds of mulch will act like additional soil volume, seriously limiting the tree's chance to flourish.

 

Unwanted Roots — What? Aren't all roots good for the tree? Not really. Volcano mulching tends to encourage the tree to produce roots out into the mulch pile rather than in the soil. The result is that later in the summer, when that loose mulch dries out, those roots will be the first to die off.

 

Fungus and Rodents … and Bears, oh my! — Deep piles of mulch around the trunk form the perfect place for decaying fungus to thrive. Crown rots, root rots, you name it … they are all encouraged by mulch volcanoes. The fluffy mounds are also the perfect place for mice, moles and voles to burrow. And guess what … all those little rodents love to snack on tree bark.

 

Think of your wallet — If you are doing the mulching yourself, you're buying mulch you don't need. You're hauling mulch you don't need. You're spreading mulch you don't need. If you're paying someone to do the work it's even worse. They're buying the mulch and marking up the price.

 

Cappiello concludes: "Bottom line … mulch is good … volcanoes are bad. Keep the mulch at 2" deep and remember, more of a good thing ain't always such a good habit." Read his full — and very lively — article, "Volcano mulching is a no-no," The Courier-Journal

 

http://actrees.org/news/trees-in-the-news/newsroom/are-you-a-tree-volcano-mulcher-hope-not/