Hiring a Professional eg certified arborist

Hiring a Professional eg certified arborist

Understanding Arborist Certifications and Credentials

Hiring a professional arborist is a smart move for the health and safety of your trees, but the world of tree care can feel like a jungle of its own. One of the first things you'll encounter is a bunch of acronyms after an arborist's name – ISA Certified Arborist, TRAQ, CTSP, BCMA – what does it all mean? Understanding these certifications and credentials is key to finding the right person for the job.


The most common and important certification is "ISA Certified Arborist." ISA stands for the International Society of Arboriculture, the gold standard for tree care professionals. This certification means the arborist has demonstrated a certain level of knowledge and experience, passing a comprehensive exam covering everything from tree biology and identification to pruning techniques and safety practices. It also means they adhere to a code of ethics, giving you peace of mind that they'll prioritize the well-being of your trees.


Beyond the basic ISA Certified Arborist credential, there are specializations. For example, a "TRAQ" qualified arborist specializes in Tree Risk Assessment Qualification, meaning they're trained to identify and evaluate potential hazards posed by trees. This is crucial if you're concerned about a tree's stability or its proximity to your home. A "CTSP" or Certified Treecare Safety Professional has advanced training in safety practices and procedures, essential for complex tree work. If you're dealing with municipal trees or large-scale projects, you might encounter a "BCMA" or Board Certified Master Arborist, the highest level of certification offered by the ISA, representing extensive experience and expertise.


Don't be afraid to ask potential arborists about their credentials and what they mean. A true professional will be happy to explain their qualifications and how they apply to your specific needs. Checking for ISA certification in particular is a simple way to ensure you're hiring someone with a solid foundation in tree care. It's like checking for a licensed plumber or electrician – it's a basic assurance of competence and professionalism. Taking the time to understand these certifications is an investment in the health and longevity of your trees, and ultimately, the safety and beauty of your property.

So, you've decided to call in a professional arborist. Smart move! Trees are complex organisms and a certified arborist brings the knowledge and experience to keep them healthy and safe. But what exactly should you expect during their initial assessment? It's kind of like a doctor's visit for your trees.


First, expect a conversation. A good arborist will want to hear your concerns and goals. Do you have a specific problem like dead branches or leaning? Are you looking for preventative care? Do you just want advice on pruning for better fruit production? Be ready to share your observations and any history you know about the tree(s) in question.


Next, prepare for a thorough examination. The arborist will visually inspect the tree from top to bottom, looking for signs of disease, pest infestation, structural weaknesses, or other issues. They might use tools like a magnifying glass to get a closer look at suspicious areas. They'll likely check the surrounding environment too, noting things like soil conditions, nearby construction, or power lines, as these can impact tree health.


Depending on the situation, the arborist might go beyond a visual assessment. They could use specialized equipment like a resistograph to measure the internal density of the wood and detect decay that isn't visible from the outside. For more complex situations, they might recommend a soil test to analyze nutrient levels.


Finally, expect a clear explanation and recommendations. A professional arborist won't just tell you what's wrong; they'll explain it in a way you can understand. They'll outline their recommended course of action, whether it's pruning, cabling, fertilization, pest control, or even removal in extreme cases. They should also provide you with a written estimate for any proposed work.


Don't be afraid to ask questions. This is your chance to learn about your trees and make informed decisions about their care. A good arborist will welcome your curiosity and be happy to explain their findings and recommendations in detail. After all, you're both working towards the same goal: healthy, thriving trees.

Citations and other links

Obtaining and Comparing Quotes from Different Arborists

Hiring a certified arborist is a smart move for significant tree work, but it's not a decision to take lightly. Just like any other professional service, getting multiple quotes is crucial for both your wallet and your peace of mind. Think of it like shopping for a car – you wouldn't buy the first one you see without checking out a few others, right?


Obtaining quotes from different arborists allows you to compare not just the price, but also their approach to your specific needs. One arborist might suggest a drastic pruning, while another might recommend a more conservative approach. These differing opinions highlight the importance of understanding their reasoning and choosing the plan that best suits your tree's health and your long-term goals. A cheaper quote doesn't always mean a better deal; it could indicate they're cutting corners or lack the necessary experience.


When requesting quotes, be as detailed as possible about the work you need done. Are you looking for pruning, removal, cabling, or something else entirely? Provide clear access to the trees and be prepared to answer questions about their history, any known problems, and your desired outcome. This allows each arborist to give you an accurate and tailored quote, minimizing surprises down the line.


Once you have a few quotes in hand, take the time to compare them carefully. Don't just focus on the bottom line. Look at what each quote includes. Does it cover debris removal? Are there any extra charges for permits or specialized equipment? A comprehensive quote will outline all the costs involved, preventing misunderstandings and unexpected expenses.


Beyond the numbers, consider the arborist's credentials and experience. Are they ISA certified? Do they have insurance and liability coverage? A reputable arborist will be happy to provide proof of these qualifications. You can also ask for references or check online reviews to get a sense of their reputation and customer service.


Finally, trust your gut. Choose the arborist who you feel most comfortable with and who you believe has your trees' best interests at heart. Getting multiple quotes empowers you to make an informed decision, ensuring you get the right service at a fair price. It's an investment in the health and longevity of your trees, and ultimately, the beauty of your property.

Obtaining and Comparing Quotes from Different Arborists

Ensuring Safety and Liability Coverage

Hiring a professional for any job, especially one involving potential risks like tree work, requires careful consideration of safety and liability. When you bring a certified arborist onto your property, you're entrusting them with the health of your trees and the safety of your surroundings. That's why ensuring they have adequate safety measures and insurance coverage is paramount.


A reputable arborist prioritizes safety. Before any work begins, they should conduct a thorough assessment of the tree and its surroundings, identifying potential hazards like power lines, weak branches, or unstable ground. They should also clearly explain the work process, including safety precautions they'll take. Ask about their equipment maintenance practices – regularly inspected and well-maintained tools are crucial for preventing accidents. A good arborist will be happy to discuss these matters openly.


Liability coverage is equally essential. Accidents can happen, even with the most skilled professionals. If a tree falls on your house or a worker gets injured on your property, you want to be protected from financial ruin. Ask the arborist for proof of insurance, including both general liability and workers' compensation. General liability covers property damage or injuries to third parties, while workers' compensation protects the arborist and their crew in case of a work-related injury. Don't hesitate to verify the validity and coverage amounts of these policies. It's a small step that can save you a lot of trouble down the line.


Ultimately, hiring a certified arborist with a strong safety record and comprehensive insurance coverage provides peace of mind. It allows you to enjoy the benefits of professional tree care without the worry of potential accidents and liabilities. It's an investment in the health of your trees and the safety of your property.

An arborist using a chainsaw to cut a eucalyptus tree in a public park
Arborists in Ontario
Two arborists climbing and dismantling a Norway Maple in Ontario, Canada

An arborist, or (less commonly) arboriculturist, is a professional in the practice of arboriculture, which is the cultivation, management, and study of individual trees, shrubs, vines, and other perennial woody plants in dendrology and horticulture.[citation needed]

Arborists generally focus on the health and safety of individual plants and trees, rather than managing forests or harvesting wood (silviculture or forestry). An arborist's scope of work is therefore distinct from that of either a forester or a logger.[citation needed]

Scope of work

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An ISA Certified municipal arborist examining a Japanese Hemlock at Hoyt Arboretum in Portland, Oregon

In order for arborists to work near power wires, either additional training is required or they need to be certified as a Qualified Line Clearance Arborist or Utility Arborist (there may be different terminology for various countries). There is a variety of minimum distances that must be kept from power wires depending on voltage, however the common distance for low voltage lines in urban settings is 10 feet (about 3 metres).[1]

Arborists who climb (as not all do) can use a variety of techniques to ascend into the tree. The least invasive, and most popular technique used is to ascend on rope. There are two common methods of climbing, Single Rope System (SRS) and Moving Rope System (MRS). When personal safety is an issue, or the tree is being removed, arborists may use 'spikes', (also known as 'gaffs' or 'spurs') attached to their chainsaw boots with straps to ascend and work. Spikes wound the tree, leaving small holes where each step has been.[citation needed]

An arborist's work may involve very large and complex trees, or ecological communities and their abiotic components in the context of the landscape ecosystem. These may require monitoring and treatment to ensure they are healthy, safe, and suitable to property owners or community standards. This work may include some or all of the following: planting; transplanting; pruning; structural support; preventing, or diagnosing and treating phytopathology or parasitism; preventing or interrupting grazing or predation; installing lightning protection; and removing vegetation deemed as hazardous, an invasive species, a disease vector, or a weed.[citation needed]

Arborists may also plan, consult, write reports and give legal testimony. While some aspects of this work are done on the ground or in an office, much of it is done by arborists who perform tree services and who climb the trees with ropes, harnesses and other equipment. Lifts and cranes may be used too. The work of all arborists is not the same. Some may just provide a consulting service; others may perform climbing, pruning and planting: whilst others may provide a combination of all of these services.[2]

Qualifications

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An arborist disassembling a tree using a crane and bucket

Arborists gain qualifications to practice arboriculture in a variety of ways and some arborists are more qualified than others. Experience working safely and effectively in and around trees is essential. Arborists tend to specialize in one or more disciplines of arboriculture, such as diagnosis and treatment of pests, diseases and nutritional deficiencies in trees, climbing and pruning, cabling and lightning protection, or consultation and report writing. All these disciplines are related to one another and some arborists are very well experienced in all areas of tree work, however not all arborists have the training or experience to properly practice every discipline.[citation needed]

Arborists choose to pursue formal certification, which is available in some countries and varies somewhat by location. An arborist who holds certification in one or more disciplines may be expected to participate in rigorous continuing education requirements to ensure constant improvement of skills and techniques.[citation needed]

In Australia, arboricultural education and training are streamlined countrywide through a multi-disciplinary vocational education, training, and qualification authority called the Australian Qualifications Framework, which offers varying levels of professional qualification. Government institutions including Technical and Further Education TAFE offer Certificate III or a diploma in arboriculture as well as some universities.[3][4] There are also many private institutions covering similar educational framework in each state. Recognition of prior learning is also an option for practicing arborists with 10 or more years of experience with no prior formal training. It allows them to be assessed and fast track their certification.[citation needed]

In France, a qualified arborist must hold a Management of Ornamental Trees certificate, and a qualified arborist climber must hold a Pruning and Care of Trees certificate; both delivered by the French Ministry of Agriculture.[5][6]

In the UK, an arborist can gain qualifications up to and including a master's degree. College-based courses include further education qualifications, such as national certificate, national diploma, while higher education courses in arboriculture include foundation degree, bachelor's degree and master's degree.[citation needed]

In the US, a Certified Arborist (CA) is a professional who has over three years of documented and verified experience and has passed a rigorous written test from the International Society of Arboriculture. Other designations include Municipal Specialist, Utility Specialist and Board Certified Master Arborist (BCMA). The USA and Canada additionally have college-based training which, if passed, will give the certificate of Qualified Arborist. The Qualified Arborist can then be used to offset partial experience towards the Certified Arborist.

Tree Risk Assessment Qualified credential (TRAQ), designed by the International Society of Arboriculture, was launched in 2013. At that time people holding the TRACE credential were transferred over to the TRAQ credential.[citation needed]

In Canada, there are provincially governed apprenticeship programs that allow arborists' to work near power lines upon completion. These apprenticeship programs must meet the provincial reregulations (For example, in B.C. they must meet WorkSafeBC G19.30), and individuals must ensure they meet the requirements of the owner of the power system.[citation needed]

Cultural practices

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Arborists may use specialised vehicles to gain access to trees, such as this Unimog equipped with a power take-off driven woodchipper

Trees in urban landscape settings are often subject to disturbances, whether human or natural, both above and below ground. They may require care to improve their chances of survival following damage from either biotic or abiotic causes. Arborists can provide appropriate solutions, such as pruning trees for health and good structure, for aesthetic reasons, and to permit people to walk under them (a technique often referred to as "crown raising"), or to keep them away from wires, fences and buildings (a technique referred to as "crown reduction").[7] Timing and methods of treatment depend on the species of tree and the purpose of the work. To determine the best practices, a thorough knowledge of local species and environments is essential.[citation needed]

There can be a vast difference between the techniques and practices of professional arborists and those of inadequately trained tree workers. Some commonly offered "services" are considered unacceptable by modern arboricultural standards and may seriously damage, disfigure, weaken, or even kill trees. One such example is tree topping, lopping, or "hat-racking", where entire tops of trees or main stems are removed, generally by cross-cutting the main stem(s) or leaders, leaving large unsightly stubs. Trees that manage to survive such treatment are left prone to a spectrum of detrimental effects, including vigorous but weakly attached regrowth, pest susceptibility, pathogen intrusion, and internal decay.[8]

Pruning should only be done with a specific purpose in mind. Every cut is a wound, and every leaf lost is removal of photosynthetic potential. Proper pruning can be helpful in many ways, but should always be done with the minimum amount of live tissue removed.[9]

In recent years, research has proven that wound dressings such as paint, tar or other coverings are unnecessary and may harm trees. The coverings may encourage growth of decay-causing fungi. Proper pruning, by cutting through branches at the right location, can do more to limit decay than wound dressing [10]

Chemicals can be applied to trees for insect or disease control through soil application, stem injections or spraying. Compacted or disturbed soils can be improved in various ways.[citation needed]

Arborists can also assess trees to determine the health, structure, safety or feasibility within a landscape and in proximity to humans. Modern arboriculture has progressed in technology and sophistication from practices of the past. Many current practices are based on knowledge gained through recent research, including that of Alex Shigo, considered one "father" of modern arboriculture.[11]

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Depending on the jurisdiction, there may be a number of legal issues surrounding the practices of arborists, including boundary issues, public safety issues, "heritage" trees of community value, and "neighbour" issues such as ownership, obstruction of views, impacts of roots crossing boundaries, nuisance problems, disease or insect quarantines, and safety of nearby trees or plants that may be affected.[citation needed]

Arborists are frequently consulted to establish the factual basis of disputes involving trees, or by private property owners seeking to avoid legal liability through the duty of care.[12] Arborists may be asked to assess the value of a tree[13] in the process of an insurance claim for trees damaged or destroyed,[14] or to recover damages resulting from tree theft or vandalism.[15] In cities with tree preservation orders an arborist's evaluation of tree hazard may be required before a property owner may remove a tree, or to assure the protection of trees in development plans and during construction operations. Carrying out work on protected trees and hedges is illegal without express permission from local authorities,[16] and can result in legal action including fines.[17] Homeowners who have entered into contracts with a Homeowner's association (see also Restrictive covenants) may need an arborists' professional opinion of a hazardous condition prior to removing a tree, or may be obligated to assure the protection of the views of neighboring properties prior to planting a tree or in the course of pruning.[18] Arborists may be consulted in forensic investigations where the evidence of a crime can be determined within the growth rings of a tree, for example. Arborists may be engaged by one member of a dispute in order to identify factual information about trees useful to that member of the dispute, or they can be engaged as an expert witness providing unbiased scientific knowledge in a court case. Homeowners associations seeking to write restrictive covenants, or legislative bodies seeking to write laws involving trees, may seek the counsel of arborists in order to avoid future difficulties.[19]

Before undertaking works in the UK, arborists have a legal responsibility to survey trees for wildlife, especially bats, which are given particular legal protection. In addition, any tree in the UK can be covered by a tree preservation order and it is illegal to conduct any work on a tree, including deadwooding or pruning, before permission has been sought from the local council.[citation needed]

Organizations

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  • Australia Limited, a non-profit organisation, is a national organisation promoting and representing tree workers, arborists, professional tree management and urban forestry throughout Australia and the Asia-Pacific region.[20]
  • The Tree Care Industry Association (formerly the National Arborist Association) is a public and professional non-profit organization for the arboriculture field. It has more than 2,000 member companies representing over a dozen countries. TCIA's Accreditation program certifies that tree care companies that have been inspected and accredited based on adherence to industry standards for performance and safety; maintenance of trained, professional staff; and dedication to ethics and quality in business practices. In addition, they provide safety and educational programs, guidelines for tree service operations, ANSI A300 tree pruning standards, and consumer resources.[citation needed]
  • The International Society of Arboriculture, a non-profit organization, maintains a list of ISA Certified Arborists who have passed a written exam and demonstrated a basic level of knowledge in arboriculture.[21] There are also additional classifications of certified arborists with Certified Arborist/Utility Specialist for those who work near power lines, and Certified Arborist/Municipal Specialist for those who deal mostly with community trees. Other certifications exist for Certified Tree Workers, and the highest level of certification, the Board Certified Master Arborist.[citation needed]
  • The American Society of Consulting Arborists is an organization whose membership is exclusive to those with a certain level of industry experience, plus higher educational experience or continuing education; some members may achieve a higher status by fulfilling the requirements to become a Registered Consulting Arborist.[22] Consulting arborists generally specialize in the areas of ethics, law, land planning and development, and tree valuation, among others. Consulting arborists are often called on for legal testimony and report writing in various instances where a particular authority on trees is necessary for consequent actions.
  • In the UK, the professional body representing the sector is the Institute of Chartered Foresters. The trade body representing arborists is the Arboricultural Association. The association maintains a register of consultants who have demonstrated a high level of technical arboricultural knowledge, and operate an Approved Contractor scheme. This scheme assesses both the technical competence and business practices of arboricultural contractors.
  • The European Arboricultural Council is a European group of multiple arboriculture organizations from various countries.
  • Plant Amnesty is a public education and advocacy group, based in Seattle, dedicated to promoting proper pruning methods. Founded in 1987, Plant Amnesty became an international resource for arborists and their clients in the mid-1990s.[23][24]

In literature

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The protagonist in Italo Calvino's novel The Baron in the Trees lives life on the ground as a boy and spends the rest of his life swinging from tree to tree in the Italian countryside. As a young man he helps the local fruit farmers by pruning their trees.[citation needed]

Notable arborists

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Some noteworthy arborists include:

  • Francis A. Bartlett – founded The Bartlett Tree Experts Co., the world's leading scientific tree and shrub care company in 1907.
  • John Chapman – pioneering U.S. frontier nurseryman and orchardist, commonly known as Johnny Appleseed.
  • Canopy Cat Rescue[25] – rescues domestic cats from tall trees; appears on Treetop Cat Rescue.
  • Sebastian Junger – author of Perfect Storm and War. Previous to becoming a journalist, Sebastian was an arborist in Massachusetts.
  • Chuck Leavell – two-time recipient of the Georgia Tree Farmer of the Year award, and author of the children's book, The Tree Farmer. In 2006 Leavell was appointed by Governor Sonny Perdue to the Georgia Land Conservation Council. He is also an accomplished jazz pianist and keyboardist for the Rolling Stones.[26]
  • Alex Shigo – considered the father of modern arboriculture.
  • David Mitchell - Devon born tree inspector and veteran tree expert
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See also

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References

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  1. ^ American National Standards Institute Z.133- and International Brotherhood of Electrical Workers.
  2. ^ Harris, Richard W., James R. Clark, and Nelda P. Matheny: Arboriculture Integrated Management of Landscape Trees, Shrubs, and Vines, third edition; Prentice-Hall, Inc. 1999.
  3. ^ "Becoming an Arborist". Victorian Skills Gateway. Archived from the original on 2018-03-16. Retrieved 2018-03-15.
  4. ^ "Graduate Certificate in Arboriculture". University of Melbourne. Retrieved 2018-03-15.
  5. ^ "Les formations qualifiantes des arboristes : certificat de spécialisation CS " taille et soin des arbres "". Copalme (in French). Retrieved 2018-03-15.
  6. ^ "Le CFPPA à l'action sur le domaine Paul-Riquet - Enseignement et formation - Un vrai chantier pour les lycéens". La Dépêche (in French). February 23, 2017. Retrieved 2018-03-15.
  7. ^ "Pruning Standards to Maintain Landscape Trees (3)". E. Thomas Smiley, Ph. D., Plant Pathologist and Bruce R. Fraedrich, Ph. D., Plant Pathologist; Bartlett Tree Research Laboratory.
  8. ^ "Follow Proper Pruning Techniques | Earth-Kind® Landscaping". aggie-horticulture.tamu.edu.
  9. ^ "Access Trees Home". treesaccess.com. Archived from the original on 2022-03-22. Retrieved 2022-03-30.
  10. ^ https://joa.isa-arbor.com/request.asp?JournalID=1&ArticleID=1923&Type=2, Wound dressings results of studies over 13 years
  11. ^ Alex Shigo pioneered tree-friendly pruning by Ron Sullivan; San Francisco Chronicle November 15, 2006.
  12. ^ Common Law Branches Off Into New Directions; by Victor D. Merullo; Journal of Arboriculture 20(6): November 1994.
  13. ^ Landscape Tree Appraisal by David P. Mooter, et al.; University of Nebraska–Lincoln Extension; March 2004.
  14. ^ Guide for Plant Appraisal, 9th ed; by the Council of Tree and Landscape Appraisers; International Society of Arboriculture; 2000.
  15. ^ See also specific legal provisions for "tree theft" such as, for example, the Revised Code of Washington title 64.12.030 for Washington (State, USA) or similar state, provincial, or local statutes.
  16. ^ "A Guide To The Laws Of Arboriculture & Tree Legislations". Surrey Tree Surgery. Archived from the original on 4 April 2014. Retrieved 4 April 2014.
  17. ^ "Businessman fined £28,000 for felling protected yew tree". The Daily Telegraph. London. 3 June 2013. Archived from the original on 6 June 2013. Retrieved 4 April 2014.
  18. ^ Arboriculture and the Law in Canada by Julian Dunster and Susan Murray; International Society of Arboriculture; 1997.
  19. ^ Arboriculture and the Law by Victor D. Merrullo; International Society of Arboriculture; 1992.
  20. ^ "About Us". arboriculture.org.au. Archived from the original on 2016-08-08. Retrieved 2016-07-22.
  21. ^ "Verify an ISA Certification / Find a Tree Care Service". International Society of Arboriculture. Archived from the original on 27 March 2014. Retrieved 4 April 2014.
  22. ^ "American Society of Consulting Arborists – Registered Consulting Arborist". Archived from the original on 2003-02-28. Retrieved 2008-04-29.
  23. ^ "The Seattle Times: Pacific Northwest Magazine". The Seattle Times.
  24. ^ Young, Paul. "Bakersfield CA Local Online Stock Brokerage Firms | Berkeley Daily". Archived from the original on 2020-08-09. Retrieved 2019-11-08.
  25. ^ "Cat stuck in a tree in Washington". Canopy Cat Rescue. Archived from the original on 2019-11-08. Retrieved 2019-11-08.
  26. ^ "Chuck Leavell - Trees". chuckleavell.com. Archived from the original on 2007-07-03. Retrieved 2007-07-21.
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An arborist practicing tree care: using a chainsaw to fell a eucalyptus tree in a park at Kallista, Victoria.

Arboriculture (/ˈɑːrbərɪˌkʌltʃər, ɑːrˈbɔːr-/)[1] is the cultivation, management, and study of individual trees, shrubs, vines, and other perennial woody plants. The science of arboriculture studies how these plants grow and respond to cultural practices and to their environment. The practice of arboriculture includes cultural techniques such as selection, planting, training, fertilization, pest and pathogen control, pruning, shaping, and removal.

Overview

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A person who practices or studies arboriculture can be termed an arborist or an arboriculturist. A tree surgeon is more typically someone who is trained in the physical maintenance and manipulation of trees and therefore more a part of the arboriculture process rather than an arborist. Risk management, legal issues, and aesthetic considerations have come to play prominent roles in the practice of arboriculture. Businesses often need to hire arboriculturists to complete "tree hazard surveys" and generally manage the trees on-site to fulfill occupational safety and health obligations.[citation needed]

Arboriculture is primarily focused on individual woody plants and trees maintained for permanent landscape and amenity purposes, usually in gardens, parks or other populated settings, by arborists, for the enjoyment, protection, and benefit of people.[citation needed]

Arboricultural matters are also considered to be within the practice of urban forestry yet the clear and separate divisions are not distinct or discreet.[citation needed]

Tree Benefits

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Tree benefits are the economic, ecological, social and aesthetic use, function purpose, or services of a tree (or group of trees), in its situational context in the landscape.

Environmental Benefits

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  • Erosion control and soil retention
  • Improved water infiltration and percolation
  • Protection from exposure: windbreak, shade, impact from hail/rainfall
  • Air humidification
  • Modulates environmental conditions in a given microclimate: shields wind, humidifies, provides shade
  • Carbon sequestration and oxygen production

Ecological Benefits

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  • Attracting pollinators
  • Increased biodiversity
  • Food for decomposers, consumers, and pollinators
  • Soil health: organic matter accumulation from leaf litter and root exudates (symbiotic microbes)
  • Ecological habitat

Socioeconomic Benefits

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  • Increases employment: forestry, education, tourism
  • Run-off and flood control (e.g. bioswales, plantings on slopes)
  • Aesthetic beauty: parks, gatherings, social events, tourism, senses (fragrance, visual), focal point
  • Adds character and prestige to the landscape, creating a "natural" feel
  • Climate control (e.g shade): can reduce energy consumption of buildings
  • Privacy and protection: from noise, wind
  • Cultural benefits: eg. memorials for a loved one
  • Medical benefits: eg. Taxus chemotherapy
  • Materials: wood for building, paper pulp
  • Fodder for livestock
  • Property value: trees can increase by 10–20%[citation needed]
  • Increases the amount of time customers will spend in a mall, strip mall, shopping district[citation needed]

Tree Defects

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A tree defect is any feature, condition, or deformity of a tree that indicates weak structure or instability that could contribute to tree failure.

Common types of tree defects:

Codominant stems: two or more stems that grow upward from a single point of origin and compete with one another.

  • common with decurrent growth habits
  • occurs in excurrent trees only after the leader is killed and multiple leaders compete for dominance

Included bark: bark is incorporated in the joint between two limbs, creating a weak attachment

  • occurs in branch unions with a high attachment angle (i.e. v-shaped unions)
  • common in many columnar/fastigiate growing deciduous trees

Dead, diseased, or broken branches:

  • woundwood cannot grow over stubs or dead branches to seal off decay
  • symptoms/signs of disease: e.g. oozing through the bark, sunken areas in the bark, and bark with abnormal patterns or colours, stunted new growth, discolouration of the foliage

Cracks

  • longitudinal cracks result from interior decay, bark rips/tears, or torsion from wind load
  • transverse cracks result from buckled wood, often caused by unnatural loading on branches, such as lion's tailing.
  • Seams: bark edges meet at a crack or wound
  • Ribs: bulges, indicating interior cracks

Cavity and hollows: sunken or open areas wherein a tree has suffered injury followed by decay. Further indications include: fungal fruiting structures, insect or animal nests.

Lean: a lean of more than 40% from vertical presents a risk of tree failure

Taper: change in diameter over the length of trunks branches and roots

Epicormic branches (water sprouts in canopy or suckers from root system): often grow in response to major damage or excessive pruning

Roots:

  • girdling roots compress the trunk, leading to poor trunk taper, and restrict vascular flow
  • kinked roots provide poor structural support; the kink is a site of potential root failure
  • circling roots occurs when roots encounter obstructions/limitations such as a small tree well or being grown too long in a nursery pot; these cannot provide adequate structural support and are limited in accessing nutrients and water
  • healthy soil texture and depth, drainage, water availability, makes for healthy roots

Tree Installation

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Proper tree installation ensures the long-term viability of the tree and reduces the risk of tree failure.

Quality nursery stock must be used. There must be no visible damage or sign of disease. Ideally the tree should have good crown structure. A healthy root ball should not have circling roots and new fibrous roots should be present at the soil perimeter. Girdling or circling roots should be pruned out. Excess soil above the root flare should be removed immediately, since it presents a risk of disease ingress into the trunk.

Appropriate time of year to plant: generally fall or early spring in temperate regions of the northern hemisphere.

Planting hole: the planting hole should be 3 times the width of the root ball. The hole should be dug deep enough that when the root ball is placed on the substrate, the root flare is 3–5cm above the surrounding soil grade. If soil is left against the trunk, it may lead to bark, cambium and wood decay. Angular sides to the planting hole will encourage roots to grow radially from the trunk, rather than circling the planting hole. In urban settings, soil preparation may include the use of:

  • Silva cells: suspended pavement over modular cells containing soil for root development
  • Structural soils: growing medium composed of 80% crushed rock and 20% loam, which supports surface load without it leading to soil compaction

Tree wells: a zone of mulch can be installed around the tree trunk to: limit root zone competition (from turf or weeds), reduce soil compaction, improve soil structure, conserve moisture, and keep lawn equipment at a distance. No more than 5–10cm of mulch should be used to avoid suffocating the roots. Mulch must be kept approximately 20cm from the trunk to avoid burying the root flare. With city trees additional tree well preparation includes:

Tree grates/grill and frames: limit compaction on root zone and mechanical damage to roots and trunk

Root barriers: forces roots to grow down under surface asphalt/concrete/pavers to limit infrastructure damage from roots

Staking: newly planted, immature trees should be staked for one growing season to allow for the root system to establish. Staking for longer than one season should only be considered in situations where the root system has failed to establish sufficient structural support. Guy wires can be used for larger, newly planted trees. Care must be used to avoid stem girdling from the support system ties.

Irrigation: irrigation infrastructure may be installed to ensure a regular water supply throughout the lifetime of the tree. Wicking beds are an underground reservoir from which water is wicked into soil. Watering bags may be temporarily installed around tree stakes to provide water until the root system becomes established. Permeable paving allows for water infiltration in paved urban settings, such as parks and walkways.

UK

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Within the United Kingdom trees are considered as a material consideration within the town planning system and may be conserved as amenity landscape[2] features.

The role of the Arborist or Local Government Arboricultural Officer is likely to have a great effect on such matters. Identification of trees of high quality which may have extensive longevity is a key element in the preservation of trees.

Urban and rural trees may benefit from statutory protection under the Town and Country Planning[3] system. Such protection can result in the conservation and improvement of the urban forest as well as rural settlements.

Historically the profession divides into the operational and professional areas. These might be further subdivided into the private and public sectors. The profession is broadly considered as having one trade body known as the Arboricultural Association, although the Institute of Chartered Foresters offers a route for professional recognition and chartered arboriculturist status.

The qualifications associated with the industry range from vocational to Doctorate. Arboriculture is a comparatively young industry.

See also

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References

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  1. ^ "arboriculture". Dictionary.com Unabridged (Online). n.d.
  2. ^ "Amenity landscapes • Environment Guide". www.environmentguide.org.nz. Retrieved 2020-04-28.
  3. ^ "Town and Country Planning Association". Town and Country Planning Association. Retrieved 2020-04-28.
  • Harris, Richard W. (1983). Arboriculture: Care of Trees, Shrubs, and Vines in the Landscape. Englewood Cliffs, New Jersey: Prentice-Hall, Inc. pp. 2–3. ISBN 0-13-043935-5.
  • "arboriculture". Merriam-Webster's Collegiate Dictionary, Eleventh Edition. Merriam-Webster.
  • "arboriculture". Encyclopædia Britannica Online. 2007.
  • "arboriculture". The American Heritage Dictionary of the English Language, Fourth Edition Online. Houghton Mifflin Company. 2000.
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Frequently Asked Questions

Hiring a certified arborist is especially important for complex tree removals, large trees near structures, diseased or hazardous trees, or when you need expert advice on tree health and preservation. Simple pruning of small, healthy trees might not necessitate an arborist.
Look for ISA Certification, proof of insurance (liability and workers compensation), and check for local licenses or permits required in your area. Ask for references and examples of their previous work.
Search the International Society of Arboriculture (ISA) website, ask for recommendations from neighbors, friends, or local nurseries, and get multiple quotes from different arborists.
Ask about their experience with similar projects, their approach to the specific tree work you need, how they handle cleanup and debris removal, and for a detailed written estimate outlining all costs.