Fertilization

Fertilization

Fertilization Timing and Frequency for Different Tree Species

Fertilizing trees can feel a bit like a guessing game sometimes. Unlike our annual flowers and veggies that give us clear signs they need a boost, trees are a bit more stoic. Knowing when and how often to fertilize them is crucial for their health and vigor, and this timing and frequency varies greatly depending on the species.


Young trees, regardless of species, generally benefit from more frequent fertilization, especially during their first few years of establishment. Think of it like giving a growing child regular meals. These young trees are putting a lot of energy into developing their root systems and top growth, so a light feeding in spring or early summer can give them the extra nutrients they need. A balanced, slow-release fertilizer is usually recommended, avoiding anything too high in nitrogen which can encourage rapid, but weak, growth.


Mature trees, on the other hand, are often more self-sufficient. They've established extensive root systems and are generally better at scavenging for nutrients. While they may not need fertilization every year, a periodic boost can still be beneficial, especially if they're showing signs of nutrient deficiency, like pale leaves or stunted growth. For example, a mature oak might benefit from fertilization every 2-3 years, whereas a fast-growing birch might appreciate a yearly application.


The specific timing also depends on the tree species. Some trees, like maples and dogwoods, prefer fertilization in early spring as they're breaking dormancy. Others, like evergreens, may benefit from a late summer or early fall feeding to help them prepare for winter. It's always best to research the specific needs of your tree species. Local arborists or cooperative extension offices are excellent resources for tailored advice.


Over-fertilization can be just as harmful as under-fertilization, leading to root burn, environmental pollution, and even tree decline. So, while it might be tempting to give your trees a big dose of fertilizer, remember that less is often more. A soil test can be a valuable tool to understand the existing nutrient levels in your soil and guide your fertilization decisions. By understanding the specific needs of your trees and practicing responsible fertilization techniques, you can help ensure they thrive for years to come.

Recognizing nutrient deficiencies in trees is a crucial skill for anyone interested in maintaining healthy, vibrant trees. While a lush green canopy is often seen as a sign of good health, a closer look can reveal subtle clues that a tree is struggling to get the nutrients it needs from the soil. Just like us, trees require a balanced diet, and a deficiency in even one essential nutrient can have a significant impact on their growth, vigor, and ability to withstand stress from pests, diseases, and environmental factors.


One of the first steps in diagnosing a nutrient deficiency is understanding the role of essential nutrients. Nitrogen, for example, is vital for leaf development and overall growth, so a nitrogen deficiency often manifests as stunted growth and pale, yellowish leaves. Phosphorus is key for root development and flowering, and a deficiency can lead to poor root growth and reduced flowering. Potassium plays a role in water regulation and disease resistance, so a potassium deficiency can make a tree more susceptible to drought stress and various diseases. Other essential nutrients, such as iron, magnesium, and manganese, each have specific roles and corresponding deficiency symptoms.


Learning to recognize these symptoms is like learning a new language spoken by the trees. Yellowing between the veins of older leaves can indicate a magnesium deficiency, while yellowing of younger leaves might point to an iron deficiency. Premature leaf drop, scorched leaf margins, or unusual discoloration can all be signs of different nutrient deficiencies. It's important to note that these symptoms can sometimes mimic other problems, like pest infestations or disease, so careful observation and, if necessary, professional consultation are essential.


Soil testing can provide valuable information about nutrient levels and help confirm a suspected deficiency. However, visual diagnosis is often the first step, allowing for a quick assessment and potential early intervention. By learning to recognize the subtle signs of nutrient deficiencies, we can take proactive steps to correct the imbalances and ensure our trees thrive for years to come. This might involve applying appropriate fertilizers, amending the soil, or addressing underlying issues that might be hindering nutrient uptake. Ultimately, recognizing nutrient deficiencies is an important part of responsible tree care, allowing us to nurture these majestic plants and enjoy their beauty and benefits for generations to come.

Citations and other links

Methods of Tree Fertilization: Soil Application, Foliar Spraying, and Trunk Injection

Keeping trees healthy and vibrant often involves fertilization, and there are several ways to deliver those essential nutrients. Let's explore three common methods: soil application, foliar spraying, and trunk injection.


Soil application is probably the most familiar method. It involves spreading granular or liquid fertilizer around the base of the tree, within its root zone. This allows the roots to absorb nutrients as they take up water. It's a relatively simple and cost-effective method, good for providing a slow-release supply of nutrients. However, it's not always the most efficient. Factors like soil compaction, pH levels, and competing vegetation can affect how well the tree actually absorbs the fertilizer.


Foliar spraying, on the other hand, delivers nutrients directly to the leaves. A diluted fertilizer solution is sprayed onto the foliage, allowing for rapid absorption. This method is particularly useful for addressing specific nutrient deficiencies quickly, as the tree can access the nutrients immediately. It's also a good option when soil conditions hinder nutrient uptake. However, foliar sprays have limitations. The effects are relatively short-lived, requiring more frequent applications. Plus, application needs to be timed carefully to avoid leaf burn and ensure optimal absorption.


Finally, trunk injection delivers fertilizer directly into the tree's vascular system. Small holes are drilled into the trunk, and fertilizer is injected under pressure. This method is highly effective, bypassing soil issues and providing a targeted dose of nutrients. It's especially useful for treating severe deficiencies or when rapid response is critical. While very effective, trunk injection is more invasive than other methods and should be performed by trained professionals to minimize the risk of harm to the tree.


Each of these methods – soil application, foliar spraying, and trunk injection – has its own advantages and disadvantages. Choosing the right method depends on the specific needs of the tree, the type of fertilizer being used, and the overall site conditions. A certified arborist can help assess your trees and recommend the most appropriate fertilization strategy for optimal health and growth.

Methods of Tree Fertilization: Soil Application, Foliar Spraying, and Trunk Injection
Potential Risks of Over-Fertilization and Best Practices for Sustainable Tree Care

Potential Risks of Over-Fertilization and Best Practices for Sustainable Tree Care

Over-fertilizing trees, while seemingly beneficial, carries a surprising number of risks. Think of it like overfeeding a pet – too much of a good thing can lead to problems. With trees, excessive fertilizer, especially nitrogen-rich types, can cause a flush of rapid, weak growth that's susceptible to pests and diseases. These tender new shoots are like an all-you-can-eat buffet for insects and fungi. Over-fertilizing also disrupts the natural balance of nutrients in the soil, potentially leading to nutrient deficiencies, even though you're adding more. It's like giving a child only candy – they might be full, but they're not getting the balanced nutrition they need. Another serious consequence is fertilizer burn, where high salt concentrations damage delicate root systems, hindering water and nutrient uptake – essentially dehydrating the tree from the inside out. Runoff from over-fertilized areas can also pollute waterways, contributing to algal blooms and harming aquatic life.


Sustainable tree care takes a more nuanced approach. Instead of relying on frequent, heavy doses of fertilizer, the focus shifts to building healthy soil. This involves practices like mulching, which suppresses weeds, conserves moisture, and gradually releases nutrients as it decomposes. Composting adds beneficial organic matter, improving soil structure and providing a slow-release source of nutrients. Soil testing is crucial to understand existing nutrient levels and tailor fertilization accordingly. Choosing the right fertilizer, if needed, is essential. Slow-release fertilizers provide a steady supply of nutrients, minimizing the risk of burn and runoff. Mycorrhizal fungi, beneficial organisms that form a symbiotic relationship with tree roots, can also be introduced to enhance nutrient uptake. Proper watering practices are equally important, ensuring that trees can access and utilize available nutrients effectively. By focusing on these sustainable practices, we can nurture healthy, resilient trees without harming the surrounding environment. It's about working with nature, not against it, to create a thriving ecosystem for generations to come.

 
Tree trimmer on tracked treads
(Click for video)

Tree care is the application of arboricultural methods like pruning, trimming, and felling/thinning[1] in built environments. Road verge, greenways, backyard and park woody vegetation are at the center of attention for the tree care industry. Landscape architecture and urban forestry[2][3] also set high demands on professional tree care. High safety standards against the dangers of tree care have helped the industry evolve. Especially felling in space-limited environments poses significant risks: the vicinity of power or telephone lines, insufficient protective gear (against falling dead wood, chainsaw wounds, etc.) and narrow felling zones with endangered nearby buildings, parking cars, etc.. The required equipment and experience usually transcends private means and is often considered too costly as a permanent part of the public infrastructure. In singular cases, traditional tools like handsaws may suffice, but large-scale tree care usually calls for heavy machinery like cranes, bucket trucks, harvesters, and woodchippers.

Road side trees are especially prone to abiotic stress by exhaust fumes, toxic road debris, soil compaction, and drought which makes them susceptible to fungal infections and various plant pests[4] like the spotted lantern fly.[5] When tree removal is not an option, because of road ecology considerations, the main challenge is to achieve road safety (visibility of road signs, blockage-free lanes, etc.) while maintaining tree health.

Tree removal

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While the perceived risk of death by falling trees (a part of the "tree risk" complex) is influenced by media and often hyped (the objective risk has been reported to be close to 1 : 10.000.000, almost as low as death by lightning),[6] singular events have encouraged a "proactive" stance so that even lightly damaged trees are likely to be removed in urban and public traffic surroundings.[3] As a tree ages and nears the end of its safe useful life expectancy (SULE),[7] its perceived amenity value is decreased greatly. A risk assessment normally carried out by local council's arborist to determine the best course of action.[8][9] As with all public green spaces, trees in green urban spaces and their careful conservation is sometimes in conflict with aggressive urban development even though it is often understood how urban trees contribute to liveability of suburbs and cities both objectively (reduction of urban heat island effect, etc.) and subjectively.[10][11][12][13] Tree planting programs implemented by a growing number of cities, local councils and organizations is mitigating the losses and in most cases increasing the number of trees in suburbia.[14] Programs include the planting of 2 trees for every 1 tree removed, while some councils are paying land owners to keep trees instead of removing them for farming or construction.[15]

Standards

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United States

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The voluntary industry consensus standards developed by TCIA, resulted in the ANSI A300 standard, the generally accepted industry standard for tree care practices including trees, shrubs, and other woody plants.[16] It includes the following parts:

  1. Pruning
  2. Soil management
  3. Supplemental support systems
  4. Lightning protection systems
  5. Management
  6. Planting and transplanting
  7. Integrated vegetation management
  8. Root management standard
  9. Tree risk assessment
  10. Integrated pest management

Professional associations

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See also

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References

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  1. ^ Council, Cornwall. "Practical Guidelines for Young Tree Care - Cornwall Council". www.cornwall.gov.uk. Retrieved 2018-04-06.
  2. ^ "Urban Forestry Management in Denver Colorado - Denver Tree Service - Tree Removal - Snow Removal". environmentaltreecarellc.com. Retrieved 2018-06-11.
  3. ^ a b "Urban Forestry Operations". City of Toronto. Urban Forestry maintains 4.1 million trees on public property, which includes an estimated 3.5 million trees within Toronto's parks and ravines, and approximately 600,000 trees on City streets. ... The focus of our maintenance service is shifting progressively from reactive maintenance to proactive maintenance.
  4. ^ Frankfurt, Umweltamt. "Tree protection in Frankfurt : Stadt Frankfurt am Main | Dezernat Umwelt und Gesundheit | Umweltamt". frankfurt-greencity.de (in German). Retrieved 2018-04-06.
  5. ^ "spotted lantern fly".
  6. ^ "EPA – Home" (PDF).
  7. ^ "NOTES ON SAFE USEFUL LIFE EXPECTANCY (SULE RATING) AS USED IN TREE DESCRIPTION" (PDF). strathfield.nsw.gov.au.
  8. ^ Northrop, Andrew K. Koeser, Gitta Hasing, Drew McLean, and Rob (2016-12-20). "Tree Risk Assessment Methods: A Comparison of Three Common Evaluation Forms". edis.ifas.ufl.edu. Retrieved 2018-04-06.cite web: CS1 maint: multiple names: authors list (link)
  9. ^ "Tree Removal Australia – Stay Smart, Save Money". GoTreeQuotes. Retrieved 2018-04-06.
  10. ^ "Greening Our Streets Street Tree Management Plan" (PDF). City of Whittlesea, Australia. 2016.
  11. ^ Peter Mitham (2015). "Redevelopment, urban tree removal raise city residents' concerns". Business Vancouver.
  12. ^ eugenie stockmann (2016). "Are developers to blame for loss of tree cover in urban areas?". The Green Swing.
  13. ^ Dinh Muoi, Thanh Nien News (2016). "Ho Chi Minh City announces massive tree removal plan for metro station". Archived from the original on April 14, 2016. Ho Chi Minh City has announced a plan to move and cut down 300 trees on Ton Duc Thang Street in District 1 to make space for a bridge connecting to District 2 and a metro station.
  14. ^ "Buy Trees and Learn About Trees - Visit our Online Nursery". www.arborday.org. Retrieved 2018-04-06.
  15. ^ "NVIM Quick Reference Guide. Obligations under the Biodiversity Conservation Strategy" (PDF). environment.vic.gov.au.
  16. ^ Advanced Solutions International Inc. "TCIA | A300 Standards". www.tcia.org. Retrieved 2018-04-06.
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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

The best fertilizer depends on the species of tree, its age, soil conditions, and existing nutrient deficiencies. We can perform a soil test to determine the optimal fertilizer blend.
Typically, the best time to fertilize is in the spring, before new growth begins. However, some trees may benefit from fall fertilization. We can advise you on the ideal timing based on your specific trees.
We use various methods depending on the tree and its needs, including surface application, deep root feeding, and foliar spraying. We’ll choose the most effective method for your situation.