PHOTO BY JEFFREY HEYDEN-KAYE/THINKSTOCK.

Fertilization programs are utilized to maintain the vigorous and healthy growth of trees and to increase their resistance to damage from insects and diseases. When applied judiciously they can be a valuable part of a plant health care program.

The foundational tenet of tree fertilization is that it should be an as necessary procedure, not a standard, one-size-fits-all program.

Fall versus spring

When needed, there are two general time frames to fertilize trees: early to mid-spring and late fall when plants are dormant. In spring, applied nutrients are converted to essential plant compounds – sugars, carbohydrates and amino acids – that bolster stem, trunk and root growth. In late fall, some nutrients are used in root growth, with the remainder stored in other plant tissues ready to be used when the roots resume absorption and expansion in the spring.

Early fall applications aren’t recommended because the resulting encouragement of growth that often occurs may not have adequate time to harden off before the onset of winter. If not winter-ready, the stems have a greater potential to suffer winter injury because of their soft and supple nature. Depending on where you live, root function can continue into December.

The amount of fertilizer applied in fall versus spring should also be considered. A good rule of thumb for fall applications is to apply about a third of the amount normally used for spring applications – enough to encourage root and future shoot growth, but not more than will be absorbed. Judicious applications don’t facilitate ground or surface water pollution. Slow-release nutrient formulations decrease the odds of leaching and runoff, but always use caution when fertilizing trees.

Undersized or pale leaves are good indicators of the need for fertilization.
(PHOTO BY JOHN C. FECH, UNL.)

Determining need

When determining whether to fertilize and how much, lean on factors such as soil testing, appearance, growth rate and the surrounding plant material in the landscape.

Soil testing – The critical indicators provided by a soil test report are nitrogen, phosphorous, potassium, pH, secondary nutrients and the micronutrients. Cation exchange capacity, salt index, sodium absorption ratio and organic matter content should also be considered when determining need.

Before submitting a sample for soil testing, ask the testing lab how to best obtain a representative sample for the appropriate testing procedure and follow their instructions carefully. Once the report is back, consider the tree and its specific needs. For example, if the tree in question is a red maple or pin oak in northern Illinois, the soil test report is likely to indicate a high pH and a suggestion to lower it to make the iron in the soil more available. As such, it’s important to match up the specific needs of the tree species with the test results.

Species aside, nitrogen is generally the nutrient required in the greatest quantity. However, because it is a mobile nutrient, test reports tend to be transitory and reliable only for a short time. As a result, it’s common for soil tests to indicate a need for low to moderate amounts of nitrogen and that an adequate amount of phosphorous and potassium, which are more stable and required in lesser quantities, already exist. Again, good communication with the soil-testing lab is essential.

Appearance – The color of foliage, condition of the branch tips, size of leaves, thickness of crown, and comparison with other specimens of the same species are good indicators of the need for added nutrients. If foliage is pale green, the tree has undersized leaves, a thin canopy is present, or stems have dieback, fertilization may be beneficial.

Trees with root damage from construction or trenching should not be fertilized.
(PHOTOS BY JOHN C. FECH, UNL.)

Surrounding plant material – If the tree is in the middle of a lawn that receives periodic nutrient applications, the need for tree fertilization is reduced, as small amounts of the applied materials will move downward in the soil profile and be absorbed by the tree roots. If grass clippings are returned to the lawn during mowing operation, then small amounts of the nutrients present in the grass blades are recycled to the soil, where both grass and tree roots can grab them.

The situation is different for a tree growing in a mulch bed or in a parking lot. Neither of these landscape spaces offer the benefit of applied nutrients to turf; however, depending on the amount of leaf debris that’s recycled back to the tree roots, the need will change. In mulch beds, the decomposition of debris that falls on the mulch layer is helpful in maintaining the fertility level of the soil, thereby decreasing the need for added nutrients. Parking lots, on the other hand, offer little potential for turf fertilizer or tree debris to encourage healthy tree growth. Fertilization may be helpful in landscapes that offer minimal inputs. In addition, fertilizer injections may be best in these scenarios, as they are generally not conducive to water lance or surface applications.

A thin crown can indicate a need for fertilizer if other factors are not limiting.

Regardless of the application method, the rate should be based on the area occupied by the roots. Unless severely restricted because of planter boxes or tree pits, roots typically spread well beyond the branches on established trees and shrubs. Therefore, the target area for fertilization should be two to three times beyond the diameter of the branch spread.

Growth rate over time – A tree that grows at a rate typical for its species for several years followed by a decline in growth rate over successive years should be considered a candidate for fertilization. If a slowed growth rate is observed in conjunction with an indicated need in a soil test report for a tree in an area that is well aerated but not routinely fertilized (such as an ornamental bed), then a low to moderate application of nitrogen and other elements may be useful in improving the tree’s health.

On the other hand, if a tree has been receiving nutrients from lawn applications, has received adequate rainfall, and there are no visible pests, then added nutrients are generally not recommended. Also, if a tree has produced growth that is healthy and typical of its species over time, the need for fertilization is not justified.

Trees located in good growing conditions but producing a poor growth rate over time may benefit from fertilization.
(PHOTO COURTESY OF JOHN C. FECH AND STEVEN N. RODIE, UNL.)

Other caveats

Fertilizing trees under stress isn’t generally recommended. It’s better if the tree’s resources are used to defend it against insects and diseases and for root regrowth, rather than using up stored sugars to produce new leaves. Other trees and shrubs that should not be fertilized include newly planted specimens and those with root damage from recent trenching or construction. The root systems need time to re-establish before fertilizers are applied.

For mid-spring and late fall applications, there’s a fine line when it comes to fertilizing specimens under stress. Yes, applied nutrients can increase resistance to stressors; however, if the stressors are causing the tree to decline, it’s best to avoid fertilization until the tree recovers.

Also, a specimen may not need fertilizer if an application has been made and the tree still looks thin or produces inadequate growth. In other words, if your fertilizer application doesn’t produce the results you were looking for, investigate to determine the factors that are affecting the tree’s health.

Expanded mulch areas provide enhanced growing areas for tree roots.

Alternative treatments

There are some other treatments that can produce a similar effect on tree health as fertilization.

Aeration – This opens up compacted soils, increasing the movement of oxygen into the pore spaces and facilitating greater water infiltration. Many specimens struggle because the roots cannot expand laterally to support the needs of the tree.

Expanded mulch area – Mulch, placed in a manner that simulates Mother Nature, could be the ticket to improved tree health. Expanded mulch areas offer the additional benefits of moisture retention and weed suppression.

Compost application – Depending on the landscape situation, thin applications of compost will provide a dose of slow-release nutrients. The key is thin, not more than 1/3 inch deep. Compost applications are best following lawn aeration in landscapes where a tree is in the midst of a sward of turfgrass.

John C. Fech, an ISA certified arborist and certified tree risk assessor at the University of Nebraska-Lincoln, is a contributing writer to Tree Services.

(Article courtesy of Tree Services Magazine: http://www.treeservicesmagazine.com)

Summer is often the busiest season for production tree workers. Dormant season’s end, summer storms and active insect and pathogen populations all add to the pace of tree care operations. Many tree care companies depend on the summer months to sustain them through the rest of the year. For most it is a make-it-or-break-it time. Therefore, a successful summer season is important.

Just as any tree job has specific concerns, so too does the summer tree season. Never is safety and efficiency more important than when workloads increase and the difference between a good year and a bad one may boil down to the activities of a few short months.

Photos courtesy of Tony Tresselt .

Safe work practices are always necessary and cost-effective. However, each season brings its own challenges. Tree workers can do many things to stay safe and productive this summer; we’ll look at three. By avoiding heat injuries, watching out for summertime pests, and ensuring proper equipment maintenance, this summer can be safe and successful.

How about this heat?

For many parts of the country, summer months mean increased temperatures and/or humidity. Heat injury, from mild dehydration to outright heat stroke, is a constant worry. Review the additional hazards of working in high heat and humidity during site safety briefings. Be sure the job plan includes breaks and that plenty of cool, clean water is available.

Focus a longer safety meeting on recognizing heat injuries in yourself and other crew members. Look at abatement strategies and proper treatment. If caught early, heat injuries can often be lessened or entirely avoided. Should a crew member become incapacitated by the heat, be sure he receives proper medical care promptly.

Heat injuries are serious and must be acted on accordingly. Just because there is no blood and gore does not mean a crew member may not need quick, thorough medical care. Just as with so many things, an ounce of prevention is worth a pound of cure.

Pests

Warmer weather also means that many other forms of life are more active. Bees, wasps and other stinging insects can be hidden in thick tree canopies or trunk cavities. In early summer, wildlife may be breeding or already have young broods. Beware of animals that may be more aggressive because of these cycles. Animals and birds are also more likely to be in nests and dens and may not appreciate your daytime visit to their lofty perches.

Be thorough in your risk assessments and inspect for evidence of wildlife before starting work. If crew members have any allergies, be sure the entire crew is aware and knows what to do should an incident occur. Make ready any necessary medications or other forms of treatment, and be trained and ready to use them when needed.

Not all pests are four-legged. Be aware of and able to identify poisonous plants. Even a mild allergic reaction to plants can cause discomfort and add to fatigue and frustration at the end of a long day. Be sure crew members can identify the major reaction-causing plants in your area, and develop a plan to avoid the risk or minimize the exposure.

Equipment woes

Production tree care is dusty, dirty work any time of year. Add high temperatures and longer hours and summer work takes its toll on workers and equipment alike. Be sure all motorized equipment is serviced and running well. The frustration of malfunctioning equipment and long, hot days can be hazardous, if not fatal.

Sharpen saws and brush chippers regularly. Dull tools are no fun and can be dangerous. Be sure to clean radiators and cooling fins often. A clogged radiator might not make a difference when the temps are below freezing, but it can ruin efficiency on a warm day, not to mention the time lost and repair cost of a cracked block or other damage.

Mechanics will tell you they get more service calls on days with extreme temperatures. Make sure tires are at the correct pressure and in good shape. Tighten lug nuts and check brakes regularly. Top off fluids as necessary. Machinery without proper fluid levels has to work harder to do the same job. Low fluid levels usually mean higher working temps, and greater and quicker wear. What you may squeak by with on a mild day will catch up with you as time and temperature increase.

Be sure to store fuel and oils in shaded or cooler areas, as direct sunlight can cause unvented cans and/or storage bins to become pressurized and/or explosive. Saws and other gas equipment are slower to cool, so extra care when refueling is wise. Clean up spills promptly and use good judgment when filling hot equipment on hot days.

The summer season can be a great time to get a lot of work completed. However, increased workloads and temperatures, active hazardous pests and plants, as well as more demanding equipment usage can all add to the stress of a busy season. Make sure that safety briefings reflect these added concerns. Prepare workers and equipment alike with the tools and knowledge necessary to deal with the summer heat. Plan your work and work your plan. This becomes especially important as the summer months settle upon us.

There are many critical issues in the tree care industry, from invasive pests to the implementation of pest monitoring, from training new workers to marketing to new customers, and from tree risk assessment to tree establishment. Human nature being what it is, our interests are not equal amongst them. Unfortunately, although it’s of central importance to tree care workers and arborists, pesticide safety is one area where there is a low level of interest. As such, it is easily overlooked, and in some cases downright ignored. There are several facets of pesticide safety, and they should be considered in the daily course of operations.

Safety during selection

When choosing amongst all the available products, consider those that require less exposure during application, mixing and storage. Straightforward discussions with product distributors and university extension faculty as well as a thorough reading of the label will provide information about which products are associated with the various types of protective gear and equipment. When the decision is being made, selecting product x, which requires less exposure, over product y is a type of preemptive action that can prevent potential problems before the product is put in the spray tank.

In addition to exposure, consider the toxicity level of the product. The three signal words are good clues for this factor. Products with the signal word “caution” are lower in toxicity; those with the signal word “warning” are moderately toxic; and those marked “danger” are highly toxic. For example, soaps and oils are generally safer than other pesticides since they are lower in toxicity and as such are marked with the signal word “caution.” The LD₅₀, (lethal dose to kill 50 percent of the test population) is another indicator of potential risk from the product.

Safety during mixing

Your eyes, hands, face and, dare I say, the organs below the belt need to be protected. When in doubt, focus on the protective gear needed when mixing the product with water, as this is when you’re dealing with the product in its most concentrated form and therefore poses the most risk. At a minimum, a face shield, rubber apron, nitrile gloves and rubber boots should be worn.

Typically, eye and skin exposure is the most common when applying or handling (loading, reorganizing, reading labels, etc.) pesticides. It’s also the easiest route of entry to prevent. Chemical-resistant gloves that cover the hand and forearm provide very good protection. Unlined gloves made of nitrile, neoprene or butyl rubber are excellent choices. Fortunately, quality gloves are not expensive. Depending on the frequency of use, manufacturer and product choice, gloves may last from a day to a week to a month.

Safety during application

Whether the application is a spray, injection or basal drench, appropriate footwear is commonly overlooked when applying or handling pesticides. Boots can either prevent or promote pesticide poisoning. Leather boots, such as work boots or cowboy boots, can easily absorb pesticide products. The harm can be initial and long term. If a liquid product is spilled on leather boots, it’s possible for the pesticide to be absorbed as it soaks through the boot. If this occurs, immediately consult the pesticide label for information on how to reduce harm to your body. Better yet, read the label before mixing or applying the pesticide so you know this information beforehand and can act immediately.

Chronic or long-term pesticide poisoning can result from small amounts of product that are absorbed with each application. The product is likely to be retained in the leather, creating an unacceptable risk to the applicator. Chemical-resistant boots or shoe coverings should be worn. Use the pesticide label as a guide when choosing footwear. Generally, rubber is considered to be a better material for preventing pesticide absorption than leather.

For eye protection, consider the wide array of goggles on the market. Most are designed to fit over eyeglasses. Some have shielded vents that allow for reduced fogging and heat buildup. All are designed to prevent splash and particle drift during application. The bottom line: eyewear is important. In many application scenarios, the product mist is quite fine and may be unnoticeable to the applicator.

In addition, for specifics on rates, water pH, reentry time, need for surfactants and compatibility with other pest control agents, as well as what personal protective equipment (PPE) may be required, read the pesticide label thoroughly before use. That’s where you’ll find this and other valuable information.

Safety after application

Quick, think of three things that you don’t use your hands to do … kind of hard to think of any, let alone three. Even after applying a pesticide with nitrile rubber gloves, get into the routine of washing your hands. The rule is to do so three times using hot water, followed by a good rinsing. Of course, this is to be done before using the restroom, smoking, eating or any other activity where you might touch an unprotected part of the body or material that might absorb or hold pesticide residue, such as a ball cap or steering wheel.

Proper laundering of pesticide-contaminated clothing is essential for applicator safety. The first consideration is to deem any clothing worn while at work as contaminated and in need of washing. It’s important to always wash pesticide-contaminated clothing immediately after use (don’t let it lay in a heap for a week or leave it in your hamper, and be sure to separate it from other laundry) and start by prerinsing. Research at several land-grant universities has indicated that using hot water, heavy-duty liquid detergents and the maximum water level for the washing machine are most effective at removing pesticide residues from clothing.

Just as with rinsing spray tanks and backpack sprayers, removing possible residues from the washing machine is important. When the wash cycle is completed, run the empty washer through a complete cycle with detergent and hot water to clean the machine.

Storage of unused pesticides is another facet of pesticide safety. Certain products may require unique conditions, so storage location/facilities may vary, but all should be well lit so it’s easy to read the label and distinguish similarly looking products from each other.

Generally, favorable environments for pesticide storage maintain a temperature of 60 to 65 degrees Fahrenheit, have a low relative humidity, are out of direct sunlight, and are arranged in such a way that access is easy and open and allows for quick observation to see if products are missing, bags are torn or put away incorrectly. A good storage unit will be able to be securely locked and posted as a pesticide storage area, will keep pesticide products dry, is fire resistant, and contains a well-functioning exhaust fan for ventilation. It’s wise to design the facility to make it adaptable and allow room for expansion. To create good storage conditions, follow these rules: the area must be stable, easy to use, and accommodate the products you use.

The author is a horticulturist and certified arborist located in Omaha, Neb.

(Article courtesy of Tree Services Magazine: http://www.treeservicesmagazine.com)

The history of the site is telling; imagine inspecting this tree 10 years in the future and not knowing that the roots were cut early on in the tree’s life.
Photos by John C. Fech, UNL, unless otherwise noted.

Fighting Fungus … a daunting magazine article title and overall endeavor indeed. However, it’s a battle worth waging, regardless of the difficulty factor. Though a bit on the trite side, the phrase attributed to Theodore Roosevelt, “Nothing in the world is worth having or worth doing unless it means effort, pain, difficulty,” is often shortened and modified to “nothing worth having is easy” and certainly applies in this case.

Though it’s sometimes a difficult task, the challenge of keeping trees healthy and fungus-free is best accomplished through a multifaceted approach. Identification, monitoring, evaluation of methodologies, preventative measures and conducive growing conditions are some of the more important considerations.

Regular inspection

Whether you call it monitoring, scouting or inspection, a regular close-up look at trees on a customer’s property is a tried and true part of integrated pest management and integral to fighting fungus. If the goal is to keep fungi at bay, you need to know when and where they are attacking, or at least present. If you don’t look, there is no real way to know.

So, what is “regular?” In terms of tree inspection, regular means frequent and thorough. Since many fungi that cause problems for trees are active in the spring, regular inspection should be more frequent in the spring than in the summer or fall. As a result, symptoms are noticed sooner and there is more time left in the year to treat. When maladies are noted in the fall, the action is more a matter of notation and recommendation for follow-up applications in spring, especially if the treatment threshold has been surpassed.

The often underutilized part of inspection is profit. In short, do it, do it often and make money from it. When one considers the investment of time, training and effort that a qualified tree worker puts into their career, it needs to pay off in one way or another. If certification through the International Society of Arboriculture (ISA) or a state arborists association has been achieved, the knowledge, skill and experience must be factored into the equation. After all, the ISA doesn’t hand out certification to just anyone.

A good way to be sure that inspections are an integral part of the income stream is to explain to customers that inspections are just as important as spray applications. Depending on where your customers live, it may be wise to equate monitoring for insects with a fall furnace checkup or a spring air conditioning service. No one wants to suffer through a cold winter or hot summer without relief. If the temperature outside is the same as it is inside in summer or winter, then the equipment is broken or it’s an anomaly.

In terms of the number of site inspections, it’s dependent on the disease susceptibility of the species on the property and the localized conditions. For example, if a given customer has a ginkgo, a red oak and an Osage orange tree, they would need fewer inspections per season than one with a crabapple, an Austrian pine and a cottonwood; the former are generally considered to be disease-resistant trees, while the latter are more likely to develop fungal problems from time to time. Likewise, since many fungal pathogens require high moisture content on foliage to develop and infect a tree, properties with low air flow across leaves are more likely to be conducive to ongoing problems than ones with good air circulation. These factors should be made clear to a customer when pitching the service of regular inspections.

Determination

Determination in the endeavor of fighting fungus on landscape trees is important from two perspectives: determination in the sense of persistence, and determination in the sense of identification.

First, identification. Even after years and years of diagnosing unknown maladies, determining which exact causal agent is responsible for the symptoms that have been produced on a tree can be challenging. How can you fight something if you don’t know what it is?

Determination, or diagnosis, can start in many ways. My preference is to begin with known maladies of the tree species. For example, crabapple has a long history of susceptibility to powdery mildew, apple scab, fire blight and cedar apple rust. If the customer has a crabapple, your first step is to get to know the symptoms of these diseases and compare the current presentation of the leaves, stems and trunk to those established characteristics.

A good second step is to consider the micro and macroclimates of the property. When I was starting out in horticulture and arboriculture, a wise arborist did me the favor of teaching me how to walk the entire property, as well as the adjacent lots and neighboring areas, looking for clues as to what might be influencing the current situation. He taught me to carry a clipboard and use it to make notes on wind patterns, sunlight penetration, coverage of the root system with impervious surfaces, and competition from other species.

Knowing the history of a site is useful as well. Interviewing the owner and possibly the neighbors about recent herbicide applications to the turf, soil modifications, utility work, and the performance of other woody species can be helpful in determining what’s causing the tree’s health to decline.

It’s not all about fungus. To eliminate possible nonliving/abiotic organisms as causal agents, items important to learn to distinguish between fungus and non-fungus. In fact, one of the little known secrets of determination is that less than half of the causes of tree problems are related to fungal or bacterial organisms. Overwatering, lack of separation of turf and trees, planting errors and mower blight are just some of the non-fungal inputs that can cause trees to suffer.

Next, persistence. Because it’s not easy, sometimes it just takes time to get it right. After a good first look, take the time to check the resources on your bookshelf. Go online and type in phrases such as “maple diseases in the Northwest” or “ash problems” into Google Images or Yahoo Image Search. You’ll be amazed at what you find. Talk to other service technicians in your company and university extension faculty about possible causes.

As you move through the process, stay in communication with the client. They’ll appreciate your thoroughness and your persistence.

Timing

Whether you’re delivering a joke at a dinner party or buying an airline ticket, timing is undeniably crucial. The same is true when fighting fungus on broadleaf and evergreen trees. Too early or too late with inspection, determination or treatment is not going to cut it. Correct timing is important for each of these factors. The timing needs to be right for inspection in order to be ahead of the curve, to read and react in relation to the clues given by the plant. The determination of the causal agent needs to be on track, and needs to be done in advance of the treatment application if one is necessary. Treatments applied before or after the vulnerable stage of the fungus or plant part are simply not effective and should be viewed as a disservice to the customer.

Each is important on its own, but the correct timing of all three needs to occur in order to conquer fungus. With time, training and experience, as well as due consideration of the key elements presented in this article – regular inspection, species vulnerability and characteristics, the history of the site, differentiation between abiotic and biotic causes, persistence and timing – the fight can be won.

John C. Fech is an ISA Certified Arborist, PNW ISA Certified Tree Risk Assessor at the University of Nebraska-Lincoln and a frequent contributor.

(Article courtesy of Tree Services Magazine: http://www.treeservicesmagazine.com)