This video installation, “Years,” from artist Bartholomäus Traubeck, uses an optical… something… to “read” a thin cross section of a tree (the “record”) and translate it in to piano music. 

If you watch the video all the way through, you’ll notice that there are different types of records. The first is from a fir tree, and the second is from an ash with (notice the difference in texture between the two).

YEARS is from artist Bartholomäus Traubeck; watch it on Vimeo.

The specifications for most construction project are filled with seemingly endless phrases of precision such as “not less than 100 percent maximum density,”  “no variation greater then ¼,”  “shall be at least .005 in thickness,” “minimum strength of 3,000 psi,” etc. Why is this?

Buildings, bridges, roadways, utilities, and the like are all intended to last for 25 to 50 (or even 100) years. Engineers, architects and other design professionals know that phrases like the ones I’ve listed above and the standards that they are part of play a vital role in determining the life span of the finished product. 

For example, they know that the water : cement ratio is key to the performance of concrete, that the level of compaction of the sub grade is key to the performance of pavements, that proper surface preparation and thickness of the coat is key to the performance of paint, and so on and so forth.

What about trees?

There are standards that cover things such as quality of nursery stock, the dimensions of the planting hole, and the soil mix the tree is to be planted in — but what about the volume of soil available to the tree?  Just as the water : cement ratio is key to the lifespan of concrete, or compaction of the subgrade is key to the life span of pavement, the available volume of nutrient-rich soil is key to the sustained growth and performance of a tree.

To paraphrase our partner James Urban, most trees, when drawn on plans, are drawn with a canopy size representative of a 30 to 40 year old specimen — indicating that the trees are expected to live at least that long.  In most cases, however, the trees don’t stand a chance.  At DeepRoot we call these fantasy trees; they’re the product of magical thinking. Think about the average street tree or parking lot island tree planted in a typical 4’ x 4’ opening with maybe a yard or two of planting soil.  Without the ability to tap into some kind of adjacent soil source, such as a lawn or a large planter, that tree will be lucky to survive 10 to 15 years. Even with that, chances are good that it will spend most of that time in decline.

If we want trees to grow and to have a fighting chance to reach a mature age then we need to address soil volume requirements in project specifications. Just like with bridges and roadways, tree lifespan is dependent on certain construction factors. Project specs should include phrases such as “not less than” or “a minimum of” – and then a nice fat number, like 1,000 cubic feet — when it comes to soil volumes. See our earlier post about municipalities with impressive tree planting standards if you’re looking for some guidelines to start working with.

Image: Tim Dorr

Last August I went to one of Jim Urban’s Up By Roots seminars in Davis, CA, and it was one of the best days I’ve spent learning more about trees, soil biology, and urban forestry. Jim is back on the road again this year, and on March 21st he’ll be presenting the Up By Roots seminar in Ft. Lauderdale. 

The seminar is a full day and includes both lecture and hands-on instruction that addresses the principles of soil science and their use in facilitating the growth of healthy trees and developing water-efficient landscapes. Topics include:

• Soil Science and Tree Biology
• Ubran Soil Analysis
• Field Walk and Soil Assessment
• Practical Soil Applications

James Urban, Landscape Architect Fellow, FASLA and ISA member, is a landscape architect with more than 30 years of experience in the field of urban development. He is also a consulting advisor of ours. (And by the way, have you bought his book? It is fantastic).

Over the past three decades, Jim has routinely dealt with the challenge of planting trees in difficult urban sites. Since 1982, he has researched and tested various methods of tree installation in the urban environment. Jim has developed applications for practicing arborists and landscape architects that include the testing of new urban tree systems and planting concepts, developing new approaches to landscape architectural design, and detailing and specifications in the area of trees and urban soils.

Up By Roots Seminar
Wednesday March 21, 2012
Emma Lou Olson Civic Center
1801 NE 6th Street
Pompano Beach, FL 33060

I recommend signing up early, as spots do fill up (plus, it will save you money). Register at www.floridaisa.org!

Image: Jim Urban

Meet Almond the cat, demonstrating both the independent feline spirit and the importance of tending to the trees and/or cats in front of your house. 

Have a great weekend, everyone!

While I spend most of my days at a desk, arborists who work out in the field have a big impact on wildlife, whether they’re aware of it or not. I like to think that people who care about trees probably care about other living things too, yet many arborists may not be aware of some of the basic steps they can take to avoid harming wild animals as they work.

Fall is the best time to prune

Anyone who has watched a nature program knows that spring and summer are some of the most active times for most wildlife. Babies are being born and raised and going out in to the world. For this reason, if at all possible it’s best to avoid tree pruning and trimming in the spring. In the fall, there is much less animal activity.

Most routine pruning can be done at any time of year. If a tree is not a hazard, and your client (and you) and both willing, consider waiting it out until baby creatures have left the nest.

Do a pre-work wildlife survey

In some cases, waiting until the fall to do tree work is not a feasible option. If so, minimize your impact by conducting a pre-work wildlife survey. This doesn’t need to take long, and can be done at the same time that you complete your other prep work prior to beginning a job.

Here’s what David Lee, the former Program Director for the Wildlife Training Institute recommends:

• Learn about birds in your area – when they nest, where and what their nests look like.
• Be on the lookout for nesting birds all year-round, not just during the spring nesting season. Nesting birds can be found at any time of year, especially in warmer ‘sunbelt’ climates. Woodpeckers and owls often use nest cavities in dead limbs for shelter in winter.
• Inspect trees and other vegetation in the work area for bird activity before climbing or trimming. If possible, survey the work area at dawn or dusk when birds are more active, and glass the area with binoculars. Look at all sides of the tree, and make sure you can see the tallest branches. Look for any movement or shapes that do not fit the branch patterns.
• Listen for vocalizations or alarm calls of birds or other animals as you examine the tree. Talk to neighbors and tree owners to see if they have any additional information about resident animals.
• Look for signs of animal inhabitants at the base of the tree such as “whitewash” (bird droppings), bat guano, owl pellets, shelled nuts, paw prints, etc.

Your pre-work survey may not yield any clear conclusions, in which case you’ll need to consult a qualified biologist to determine the appropriate next steps. If the work is being done for a utility company, contact someone at the company (they may have their own in house wildlife biologists). Otherwise, call around for a reputable environmental consultant with experience conducting pre-work surveys.

What to do if you find a nest or baby animal

If you find an active nest while you’re working, stop and call a qualified biologist or a local wildlife agency. Do not touch or try to move the nest. Stay 50 feet away from active songbird nests, and 500 feet away from active hawk and owl nests.

If you find a nestling that you believe to be in danger, contact your local wildlife rehabilitation agency. According to the Hungry Owl Project, a volunteer-run group that tries to reduce the need for pesticides and rodenticides by introducing natural predators, removing a nestling from is an absolute last resort and should only be done if the bird is in serious danger. You may see nestlings on the ground during the fledging period, but they are still being cared for by their parents.  If you believe the nestling is in danger from ground predators, you can place a cardboard box over the bird until professional help arrives.

Conclusion

There are 836 different bird species that are currently protected by the Migratory Bird Treaty Act, including “common” birds like ducks, geese, woodpeckers, hawks, owls, herons, cormorants, crows, doves, and many songbirds.

Maybe you don’t care about wildlife (that’s a topic for a separate post). Protecting birds and other wildlife is also a legal issue. According to Lee, most birds “are protected by federal and state laws that can result in hefty fines for harassing or harming birds, their nests, or eggs.” In addition to birds, several species of bats, opossums, raccoons and squirrels also all use trees as their habitat.

If you work with trees, you will necessarily encounter wildlife. I think it stands to follow that working safely and respectfully with wildlife should be an important component of the arborist training program, but it’s entirely the responsibility of the arborist to educate themselves about these important issues. If you want to learn more about safety measures for working with wildlife, visit the Wildlife Training Institute website or consider enrolling in their Certified Wildlife Protector Program (1 CEU).

Images: Gardening in a Minute, Fran 53

My favorite industry website recently is Linda Chalker-Scott’s Horticultural Myths. Dr. Chalker-Scott is an Extension Urban Horticulturist at the Puyallup Research and Extension Center at Washington State University, and she takes great delight in debunking common and inaccurate beliefs about best practices for trees and other plants. Her one-page myth busters are informative, easy to read, and very entertaining.

I think my favorite is The Myth of Soil Amendments (“When transplanting trees or shrubs into landscapes, amend the backfill soil with organic matter”) but I also love The Myth of Fragile Roots (“You shouldn’t disturb the rootball when transplanting trees and shrubs”) and the Myth of Compost Tea (“Compost tea is an effective alternative to traditional pesticides”: Part 1, Part 2, Part 3 and Part 4).

So much to love!

Dr. Chalker-Scott also has an ongoing blog that she writes with four colleagues called The Garden Professors. And if you happen to be going to the ISA show this year, she’ll be debunking even more horticultural myths in an hour-long session there.

Image: SSTUDIO

Finding influential tree people in any one industry or organisation can be difficult. Finding influential tree people in various disciplines to get around a table at the same time can be like trying to find the Loch Ness Monster or a Sasquatch: we hear about these rare things, but finding them is elusive.

Since its first publication in 2008, however, Trees and Design Action Group (TDAG) has indeed achieved the seemingly impossible. In their “No Trees, No Future” report, TDAG has representation from central and local governments, landscape architects, arboriculturalists, water companies, insurance companies, developers, universities and NGO lobbyists. In 2011, they followed up with another report, “The Canopy,” which is a compendium of solutions to issues that affect tree establishment in the urban realm.

There are not many things that can bring such an array of different professions, disciplines and interests together, but trees do. Whether you hug ‘em, cut ‘em or work around ‘em, trees are either important to you or important enough to be aware of them and their related legislation.

Why a Trees and Design Action Group?

Trees are a critical tool to make our urban environments as healthy, livable, and valuable as possible. Still, studies have shown that in urban areas all over England trees are under threat, particularly from new building development. We can’t continue to develop the way we always have and simply expect that trees will successfully adapt.

TDAG’s work recognizes that trees should be a key part of infrastructure planning and need to be given equal weight and value to grey infrastructure elements. Their reports are comprehensive and persuasive, and their message is clear. With thoughtful planning, design, construction, and management of our urban infrastructure and spaces, trees can provide enormous benefits for generations.

What’s on the horizon?

2012 will be a very busy year for TDAG. Their next publication, “Trees in the Streetscape,” is being released shortly. They also plan to release a related publication, “Trees in the Hard Landscape,” before the end of the year.

The principles of TDAG are becoming established in London, and interest in the same ideas from other big cities in the UK such as Birmingham, Bristol, and Manchester has led to the establishment of smaller, regional TDAGs. In February, the first Southwest TDAG will meet. TDAG’s ideas are making international headway, too. Regions in India have also expressed an interest in the principals set out by TDAG, so the message is spreading worldwide!

If all of the people involved in tree design, construction and maintenance were to adopt TDAG’s recommendations about using trees as a green infrastructure solution, we would have a powerful  force indeed. We could make these principles relevant to what is happening at every street, car park, and development by pushing for quality trees that are fit for purpose and the long term integrated benefits we all know they are capable of.

Martin Weaver is a Product Manager with Geosynthetics.

In the day-to-day, we can become so focused on what isn’t working with the way we design and plant street trees that it can be difficult to focus on the people and places that are actually doing right by them. It’s just so much easier than trying to move the needle.

To that end, I want to recognize the envelope-pushers — those municipalities that are rethinking the vital role trees play in the health of our planet and population and creating rules and recommendations to support them. They take action every day by promoting policies and projects that set trees up for long-term success and environmentally meaningful contribution.

We’ve identified the following communities for their ambitious policies that are redefining requirements for green utilities, specifically for trees, soil and stormwater management:

• Toronto’s Green Development Standard – Perhaps the most ambitious initiative we’ve yet seen, the City of Toronto calls for street trees to get a minimum of 15 m3 (529 ft 3)of high quality soil per tree if in a shared planter, and a minimum volume of 30 m3 (1,059 ft3) of soil per tree if in a single planter.

• Baltimore Waterfront Healthy Harbor Initiative – This initiative sets an example for increasing the tree canopy as a way to preserve the environment and manage stormwater. Using permeable paving, landscaping, rain gardens, and green roofs, it asks for sites to filter more than 50 percent of stormwater runoff from areas and install at least 1,500 cubic feet of soil for tree pits using structural soils or suspended pavement for any new impervious surfaces or retrofit/redevelopment projects.

• University of Florida (IFAS Extension) – The project created an Urban Design for a Wind Resistant Urban Forest. Planners increased the soil and depth requirements to allow trees to mature and live longer using the following guidelines (soil area based on mature tree size, 3’ deep or greater):
  Small (shorter than 30’) = 10’x10’x3’ = 300 ft3
  Medium (Less than 50’ height or spread) = 20’x20’x3’ = 1,200 ft3
  Large (Greater than 50’ height or spread) = 30’x30’x3’ = 2,700 ft3

• West Virginia Department of Environmental Protection – The community created a municipal handbook to manage wet weather through specific green infrastructure and made the following soil recommendations:
  Large tree = 970 ft3
  Medium tree = 750 ft3
  Small tree = 500 ft3

• Athens-Clarke County, Georgia – The community created best management practices for community tree planting and soil volume minimums:
  Small Canopy: 100 square feet x 2’ deep = 200 ft3
  Medium Canopy: 225 square feet x 2’ deep = 450 ft3
  Large Canopy: 400 square feet x 2’ deep = 800 ft3

• State of Minnesota Sustainable Building Guidelines (MSBG) – Where trees are planted in hard surfaces, the community uses a structural soil media mix of minimum soil volume of 500 cubic feet (cf) per tree. If soil volumes cannot be met it is recommended that trees be planted in minimum 8′ wide by approximately 3′ deep trenches so that soil volumes are shared between trees.

• Charlotte, North Carolina & Mecklenburg County – Planners amended the planting area requirements and recommendations for commercial development to increase the absolute minimum soil volume and planting area to 274 square feet per tree. The minimum width of the planting area is 8’ at the trunk of the tree.

• British Columbia (Canada) 7^th Edition BC Landscape Standard - Recommended minimum soil volume per tree of 6m³ (212ft³), and more is better.

• Markham, Ontario “Trees for Tomorrow: Streetscape Manual”  – These design guidelines make the following soil volume recommendations:
  Large stature tree in boulevard = 30 cubic meters/1,059 cubic feet (if single) or 15 cubic meters/530 cubic feet (if shared) of root space
  Medium stature tree in boulevard = 23 cubic meters/812 cubic feet of root space
  Small stature tree = 15 cubic meters/530 cubic feet root space
  Minimum soil volume for tree planting in a parking lot island is 15 cubic meters/530 cubic feet.

• Aspen, Colorado & Pitkin County – The community amended its structural soils specifications so that soil area is now based on a targeted mature tree size, requiring 30 inches or more depth and a correcsponding increase in soil volume.
  Soil area based on mature tree size, 30” deep or greater
  Small (shorter than 30’) = 10’x10’x2.5’ = 250 ft3
  Medium (Less than 50’ height or spread) = 20’x20’x2.5’ = 1,000 ft3
  Large (Greater than 50’ height or spread) = 30’x30’x2.5’ = 2,250 ft3

• Chicago Landscape Ordinance – The city amended planting standards and now requires parkway trees to have a minimum depth of three feet of soil. Planting areas require a minimum of 24 square feet of surface area with no dimension less than three feet.

• Denver Parks and Recreation Forestry Department – The city’s “Street Tree Plan Review Checklist” sets a soil volume minimum of 750 cubic feet of soil per tree and states that, “5’ x 5’ pit areas shall no longer be accepted, must use trenches, root paths, break out zones, structural cells, or other un-compacted soil technology.”

• Emeryville, California - The community requires minimum rootable soil volumes for new trees planted in the public right of way by private developers. The minimum is based on the size of the tree at maturity: 600 cubic feet for a small tree, 900 for a medium tree and 1200 for a large tree.

• Alexandria, Virginia – The city’s Landscape Guidelines specify that street trees be provided with a minimum of 300 cubic feet of soil per tree and recommends that one tree be present for every ten spaces in parking areas.

Are any of these perfect? Probably not. Certainly there are things we would change about almost all of them. Still, setting soil volume minimums for street trees tacitly enforces the message that business as usual as far as tree planting is concerned isn’t good enough.

We need to rethink how we plan for our urban forests and the role of green infrastructure in the built environment. The new game in town is high performance urban forestry.

Are you involved with making soil volume recommendations for trees? Hopefully you can use some of this information to help persuade your co-workers and clients of this important effort.

Should your city or town be on this list, or do you know of any others that we missed? We want to hear about your goals for growing healthy trees in your community. Please email us at RethinkTrees@deeproot.com.

Earlier this year, Silva Cells were installed at the new Martin Luther King, Jr. memorial in Washington D.C. This site will commemorate the legacy of Dr. King but is not solely about the past; it is also about the future. 

Located on Independence Avenue, it utilizes Silva Cells to enable trees on the site to thrive long in to the future, helping to create an enduring reminder of Dr. King’s legacy.

Designed by Oehme van Sweden Landscape Architects, the Silva Cells were installed in February 2011 by Ruppert.

The original date for the grand opening was set for late August 2011. Unfortunately, it had to be postponed due to Hurricane Irene.

The trees, Kwanzan cherries and American elms, are doing great so far. We’re looking forward to checking in on them next season.

Last two photos courtesy of Oehme, van Sweden & Associates, Inc.
All other photos by DeepRoot Green Infrastructure, LLC.

2011 ended with a nice bit of publicity for the Silva Cell from The Globe and Mail (British Columbia edition only. Sad trombone). They filed it under the category “Things that work”!

Read the full article here.