A key component of daily tree care operations is being able to lower large pieces and parts of woody debris with a fair amount of control and accuracy. Although all climbing arborists secretly dream of an endless stream of “freefall” jobs where the property owner will take care of the brush, the reality is that many removals, and even mildly significant pruning jobs, involve some obstacle or target that must be avoided. As gravity seems to be the law no matter where a tree crew works, and wood can generate a fair amount of damaging velocity from rather insignificant heights, rigging, and the control that should be a part of it, is part and parcel of the tree care industry’s daily existence. Knowledge of how to acquire, and the ability to build, systems that provide rigging control not only will assist in avoiding damage to property, but increase the safety and efficiency of the work site. After all, an energized conductor beneath a branch to be removed is not only an obstacle that has to be undamaged, but also a palpable threat to the climber and crew if not avoided safely and under control.
Additionally, a growing awareness through research and training has made many in the industry aware of the forces trees are exposed to during rigging operations. Some of which, if improperly handled/controlled, can have catastrophic physical results for both tree and crew. In years past, and on many work sites currently, the method for gaining control over a large piece of woody debris descending at a high rate of speed was to take wraps around the tree or an adjacent tree, thereby generating the required friction for some measure of control. This technique, though still useful at times, has a number of disadvantages, including friction generation that varies with species due to bark differences, ground personnel that must be experienced and knowledgeable enough to take an appropriate number of wraps, and the dizzying number of times a ground worker has to circle the tree to put on or take off wraps. One of the simplest, lightweight and most economical tools available to provide rigging control is the Port-a-Wrap, designed and developed by working climbing arborists Scott Prophett and Norm Hall. This safe and efficient lowering device not only provides consistent friction with attendant strength regardless of tree species, but also is simple enough for efficient use with a minor amount of instruction and training. However, as with anything new to the gear bag, it must be used correctly to reap its full benefits, while avoiding improper use and situations that could lead to its failure.
Attaching the Port-a-Wrap to the trunk of the desired tree is a simple and straightforward process requiring only an eye sling of proper length and knowledge of appropriate rigging sling attachment knots. The use of connecting links of any type to attach the sling to the Port-a-Wrap is not recommended in any rigging situation; and particularly not in a situation involving dynamic loading where the connecting link could become cross or side-loaded during movement and subsequently fail. Rather, the best and safest way to attach the sling to the device is by girth hitching the sling around the larger or longer of the U-shaped brackets beneath the barrel. Rigging slings with larger eyes that are large enough to pass all the way around the Port-a-Wrap will make this girth hitching process even easier, and avoid the possible weakness of a connecting link. A cow hitch with a better half is an excellent choice for securing the sling and device to the tree, although in the event the sling is too short, a timber hitch may be used. If additional eye slings are available, they can be tied to one another with a double sheet bend, creating a longer single sling, allowing for the use of the cow hitch. If the timber hitch is used, ground personnel should make sure it is loaded correctly after every load to ensure the timber hitch’s coils have not gotten too close together.
Setting the rigging line
In order to prepare the Port-a-Wrap to lower a load, a bight of the rigging line is fed through the smaller angled “U” on top of the barrel, around and under the forward end of the barrel itself, and beneath the protruding pin, between the pin and the “U,” thus securing the line in place. At this point, the operator should pull down on the part of the line leading up to the load and up on the part of line exiting the device. This will assist in removing slack from the line and rigging system, and though not eliminate the Port-a-Wrap sagging at the instant the piece or branch is cut free, will lessen the severity somewhat. The line is then passed completely around the barrel behind the “U” until the number of desired wraps and attendant friction is created. More wraps around the barrel obviously mean more friction, but personal experience has shown that the most common mistake among new users is too many wraps rather than too few. Two to three complete wraps will provide total control for all but the most extreme loads. The ground person can then stand out of the landing zone at almost any angle from the device as the two pins on the end of the barrel of the Port-a-Wrap direct the line into the barrel correctly. These pins also provide a place to “cleat” off the line, keeping the load from moving in the event of a static load or to enable ground personnel to cut some pieces off a large load while stable. The barrel should be filled with wraps in this application to provide enough friction to prevent the “cleat” to become overtightened to the point where the only option for removal is a knife.
The goal when lowering a load with the Port-a-Wrap, as with any rigging control device, is to lower the load smoothly and safely with a minimization of forces at the anchor point, which is typically quite near the climber aloft. This is not accomplished by snubbing the piece or load off and bringing it to an abrupt stop. In fact, that is the worst thing that can happen in regard to forces experienced by the anchor point and the climber. By using the proper amount of wraps on the Port-a-Wrap, the operator is able to gradually slow the piece, bringing it to a stop where required by obstacles and the level of the ground beneath the tree. This gradual deceleration will allow the elongation of the rope to absorb some of the generated forces, dissipating their severity at the anchor point. In cases where circumstances or obstacles dictate snubbing the piece off, all personnel involved should be aware of the possible forces that are going to be generated, examine the tree and gear for expected survival of such forces, and plan accordingly.
The Port-a-Wrap is most commonly used in rigging systems to control the descent of loads, but with a little imagination and common sense it has a wide variety of applications in other facets of rigging or tree care. The smaller version can be used as a personal descent device in place of a figure 8 on long descents, though gear used once for rigging should never be used for climbing after its rigging use. The device also works well in applications involving lifting, pulling and/or mechanical advantage to take up and hold the slack generated by the fiddle blocks or other system, or to create an adjustable “floating anchor” in tree pulling situations.
The Port-a-Wrap III, as well as earlier versions, are made by Buckingham Manufacturing, and are available in a number of sizes, materials (including steel and aluminum) and coatings from a variety of arborist retailers. Their safe working load (SWL) is dependent on model and material, but is generally in the 2,000-pound range for the larger models. A newer version has recently come on the market that is made overseas for SherrillTree. This is called the Port-a-Wrap IV, and is available in medium and large sizes in steel and stainless steel with a working load limit (WWL) of 2,000 pounds. This version also includes a cap at the end of the barrel intended to protect the bark and trunk of trees not being removed during rigging operations. The size of the device, regardless of manufacturer, will dictate what diameters of rigging line can be used with it, so operators should take that into consideration when selecting one. Personal experience has shown that the Buckingham Port-a-Wrap III and earlier versions are strong, durable and well-built. Hopefully the newly released Port-a-Wrap IV will live up to the legacy of its forefathers, and exhibit the same tendencies.
Rigging operations in tree care are, by their nature, dangerous undertakings, involving attempting to move large weights in a controlled fashion, while ropes, gear, trees and climbers are all possibly experiencing extreme forces. The Port-a-Wrap is an excellent tool in these undertakings, one that once understood and used correctly cannot help but increase the safety and efficiency of tree crews everywhere during rigging operations, and whose versatility will prove useful in a wide variety of applications. Simple, strong and easy to use, the Port-a-Wrap is definitely a tool that keeps on giving.
Editor’s note: This story was originally published in May 2010 and has been updated.
Characterized with high levels of biodiversity and endemism, the Atlantic Tropical Forest has been facing serious anthropogenic threats over the last several decades. Having put important ecosystem services at risk, such activities need to be closely studied as part of the forest dynamics. Thus, a Brazilian team of researchers spent a decade monitoring a semi-deciduous forest located in an ecological park in Southeast Brazil.
Read more: Technical Felling
An innovation providing key clues to how humans might manage forests and cities to cool the planet is taking flight. Researchers are using drone technology to more accurately measure surface reflectivity on the landscape, a technological advance that could offer a new way to manage climate change.
With changing environments, pond-breeding salamanders face increasingly hazardous treks as the space between breeding ponds and their non-breeding habitat widens or is degraded. A study now suggests that a salamander's success may depend more on when it breeds than on the landscape obstacles it might face. Scientists believe that knowing the patterns in which salamanders move back and forth could lead to better forest management and conservation strategies.
Tree care crews work in a variety of environments: urban, rural, suburban and sometimes isolated, but all of these work sites will typically have one very important, and dangerous, item in common: electricity.
As much as the beauty and wonders of electricity may evoke a sigh of contentment as a refrigerated adult beverage is cracked open and the flat screen responds readily to the buttons on the remote, that same force can stop a beating heart, cause horrific burns or even blow holes right through equipment and flesh. This almost always present, powerful and dangerous force requires that all crew members be well trained and educated on how to identify electrical hazards, avoid them and, if present, know the safest way to work around them.
Dr. John Ball’s accident and fatality statistics have shown year after year that electricity plays a major role in injuring, or, more sadly, removing permanently from the workforce, those tree care personnel who either don’t have a knowledge and understanding of electrical hazards, or use a little knowledge or misinformation to make very bad decisions. As with most topics discussed in this column, there is no substitute for hands-on field education and training in electrical hazards, and there are a wide variety of organizations that instruct in this vitally important topic, but the basic information discussed here provides a good introduction to what tree professionals should be looking out for as they go about their daily routine of caring for trees.
Minimum Approach Distances for Non-line Clearance Qualified Arborists
Kilovolts phase to phase Feet Meters
Table 1 illustrates the minimum approach distances for non-line clearance qualified arborists, and as such should be obeyed in all situations. In short, a non-qualified climber or crew member should never be closer than 10 feet from any energized conductor and should be much farther away in the case of greater voltages. As can be seen in the table, higher voltage means more distance. Crew members would do well to remember that while electricity typically will travel through any conductive material in the shortest and most direct path to the ground, it can certainly also arc right through the air to a conductive material, depending on weather conditions, and thus continue its journey to the ground through the climber, tree or aerial lift.
Electrical contact may be either direct or indirect, but the end result is typically the same, with the voltage continuing on its merry way to the ground leaving behind damaged, or even dead, material and personnel.
Personal protective equipment
As mentioned, non-line clearance qualified personnel should never be nearer than 10 feet from an energized conductor, and with higher voltage should be even farther away. However, there are aspects of PPE that even these personnel need to be aware of for safety reasons.
Any hard hat or helmet that is used in the vicinity of electrical hazards must have an E rating and consist of a solid body with no vents or holes that would permit electricity to directly enter the brain housing group. In general, all climbing equipment is conductive to some degree, but in the presence of electrical hazards tree crews should take care not to use gear that is extremely conductive, such as wire-core lanyards, and use less or nonconductive options, such as fiberglass ladders and foam-filled poles. A common misconception is that the material, if present, coating many electrical lines is insulation. This material is weatherproofing at best, providing minimal, if any, insulation and should never be considered to provide any protection against the electricity in the wire.
This term describes the contact of any part of the climber or operator’s body with an energized conductor. Direct contact is often a consequence of a climber or aerial lift operator not fully inspecting the work site or all aspects of the tree’s canopy for the existence of overhead energized conductors. In addition, storm situations in which lines have reached the ground, are entangled in brush, or have even settled and snaked into a tree’s canopy after detachment from the poles can lead to direct contact. There is no better preventative measure for direct contact than a full and complete hazard inspection of the tree and work site by all crew members prior to work. After all, if you don’t know it’s there, it’s pretty hard to avoid.
Indirect contact is contact with an energized conductor through something other than the pieces and parts of the climber’s or operator’s body. It can happen through trees, branches, ropes, trucks, uninsulated aerial lifts, conductive tools or anything else you care to name that can conduct electricity. Indirect contact can also happen, particularly during storm situations, when an energized conductor has come in contact with a typically “safe” conductor such as a metal fence, cable lines or even the metal stripping lining some street curbs. This type of indirect contact possibility can be particularly hard to identify due to the possible distance away from the downed line that has “electrified” the fence or curb. Once again, the primary preventative measure for avoiding indirect contact is inspecting and recognizing the existence of electrical hazards, but also being mindful of how actions within the work plan — climbing and rigging lines, aerial lift booms, pole pruners, falling branches, etc. — may come into or affect the minimum approach distance, allowing the electricity a path to the crew indirectly.
This term describes a situation in which the ground itself has become “juiced.” The area of ground energized will vary with voltage levels, soil type and the amount of moisture present, but is often caused by downed lines in storm scenarios or through the outriggers on an uninsulated or poorly maintained aerial lift that has come in contact with a line. In the case of the energized truck, it is yet another reason for ground personnel to avoid standing around leaning against the truck while the operator works aloft.
Particularly dangerous and unique to ground faults is the possibility of step potential. In all likelihood the areas of the ground that are energized are all at differing levels and anxious to “even” themselves out. A crew member walking through such an area, or fleeing a suddenly energized truck, provides the conductor the electricity needs, entering through one foot, moving up through the body and then out through the other foot to a piece of ground with a lower voltage. One option to deal with this step potential is for the crew member to take very small shuffling steps, keeping their feet close together, to get out of the area of ground fault, thereby minimizing the possible voltage differences between one foot and the other.
All crew members should have the knowledge and training to react quickly and efficiently in the event of an electrical hazard accident. This should include items such as operating a bucket with an electrically incapacitated operator from the ground, having the number of the responsible utility readily available, methods and techniques for safely breaking line contact from the ground, and how to avoid becoming a “second” victim.
Electricity is something that is present, both benevolently and hazardously, in almost every day of tree care work. While the hazardous nature of electricity can never be eliminated, knowledge, training and awareness can go a long way toward helping tree care professionals work safely and efficiently in its presence. Regardless of whether a crew member is line clearance qualified or not, they must always remember that electricity is completely and totally nondiscriminatory: it will take the shortest path to the ground, whether it be tree, tool or flesh, so it’s best to avoid being in its path.
Editor’s note: This article was originally published in August 2012 and has been updated.
Climate change is making Swiss forests warmer and drier. The trees would have to adapt genetically to the rapidly changing climate to continue flourishing at their current growth location. Yet, they are unlikely to do so in such a short period of time – a single tree generation already takes 100 years or longer. Therefore, the question on how well adapted the trees already are today to the future climate will be crucial for the forests' future.
More is better in some cases, and in others it’s not. When it comes to planting trees, more is almost always better. If your facility or customers could use a few more trees, think about one of the most commonly overlooked areas for siting sturdy trees: under other ones. Be especially mindful of the factors that make up the theme of right plant, right place when delving into the tree-under-tree endeavor.
Replicate Mother Nature
One of the main reasons for placing small trees under large ones is that Mother Nature does it. Small trees can serve the landscape well when placed under larger specimens. Again, this is the way that Mother Nature creates landscapes, with understory trees popping up in layers under larger trees. A healthy, sustainable landscape would normally contain large shade or framing trees; medium-sized trees well placed for color and interest; small trees under them for shape, color, texture and form appeal; and ground plane plants such as perennials, ground covers and turfgrasses. Once the layered landscape is developed, it provides beauty and function.
In addition to using small trees for layering, consider them to accent important features of the landscape. Because entrance areas are not always obvious in every setting, you may want to highlight building entrances, driveways and important paths by locating small trees nearby. This helps to focus attention on places where you want people to go or look.
Mother Nature is a good teacher in other tree care areas as well, such as mulching and planting trees from seed. The “stuff” that falls from trees — seeds, leaves, cones, needles, fruits, bud sheaths — creates an excellent natural mulch and should be allowed to accumulate to encourage root growth and expansion. Likewise, tree seeds that germinate develop healthier root systems than ones that are grown in nurseries for several years. Trees grown in nature develop root systems without pot-induced girdling roots and soil interface problems; in many ways, Mother Nature is a good teacher and role model.
Create depth in the golf course landscape
Golf courses, especially smaller facilities without an arborist on staff, can be a good customer and a significant income stream for qualified arborists. Because trees serve several functions on the golf course, care must be taken to identify and validate the purpose and placement of each one. First and foremost, trees serve to define the sides of the fairway. Any landscape space needs enclosure and enframement at some level, and the golf course is no exception. Depending on the level of maintenance of the course, the rough can be at various levels; normally from 2 to 6 inches. The lower the height of cut of the rough, the more trees and shrubs are needed to mark the fairway, providing a target for the golfer. In many cases, mature trees exist with no understory in place.
Tree placement that helps to define the fairway may have several approaches. The “layered” or “tiered” look can be effective, with small to medium-sized shrubs located in the first cut of rough, larger shrubs behind those, with trees of various sizes as a background to the shrubs. Alternatively, masses of small trees intermingled with larger ones can be planted in the deep rough to provide a sharp mass/void feature. This can be quite powerful, creating interest and functional appeal to the golfer.
Other good locations for trees under trees
Just about anywhere except where space is limited — home landscapes, corporate headquarters, city parks, recreation areas — is a good location for incorporating smaller trees under mature ones. The key phrase is “except where space is limited.” If room for adequate rootzone expansion exists, approaching clients with suggested plantings makes good sense.
On the other hand, shopping malls, parking lots, gas stations and along city streets are usually not the best locations for trees under trees and, actually, may not be prime locations for any trees. If space is limited, large and small shrubs, perennial flowers and ground covers are usually better choices than trees.
The best place to start with any planting project is with an accurate base map. The base map provides all necessary information regarding the permanent features of the area to be enhanced, including property lines, easements, building footprints, utility locations, contours and existing plants. A north arrow and graphic scale must be included to provide reference when communicating the eventual design to customers and to retain accurate space relationships if the finished plan is reduced or enlarged.
The overall design concept of incorporating smaller trees under mature ones will dictate the program. Program components quite simply are a listing of wants and desires of the stakeholders of a project. Early on in the design process, they tend to be general. A typical program statement for these types of enhancements would include such things as minimized turf areas, creation of ornamental beds containing fall color and spring blooms, screening, etc. Specific plants are chosen at the end of the design process, not the beginning.
The next step is a site inventory/analysis. This is best performed on site, gathering information, taking notes, and gaining a “sense of place” in the landscape space. The inventory is first, identification of problem areas as well as the assets of an area. Use a piece of tracing paper and lay it over the base map. This provides for accurate note taking and documentation of potential concerns or opportunities for features. You may want to photograph the area for future reference and comparison. If the finished design turns out well, you may want to use the before and after photos to sell a job to another customer. The analysis comes later, an evaluation of the importance of each specific condition. The soils, neighboring views and existing buildings may be only a slight concern, but the slope and prevailing winds may be major contentions.
A bubble diagram should be drawn after the program is in place and the site is analyzed. This will help put the written word into a visual format. Again, working on tracing paper over the base map, diagram the site according to function. Traffic flow, high-use areas, low-use areas, water features, etc., are all components that should be drawn in at this point. Exacting detail is not necessary in a bubble diagram; rather, circles and ovals with a light colored shade will suffice. Concept drawings are then developed, combining the program considerations with the site analysis information and the original design concept.
Site assessment/analysis creates business as well as prevents it. The opportunity to replace severe or moderately pest-susceptible specimens is a good one in that it creates voids that must be filled with better-adapted plant material. That’s one obvious source of income; another is the need for future inspections and analysis, which should not be gratis. Inspections are an important arboricultural and grounds maintenance function and should be profited from accordingly.
Tree selection criteria
After the site analysis is complete, consideration of general and specific issues related to the trees under trees concept can begin. Many issues should be considered and are not limited to the following:
Shade tolerance -- Because the new tree will be located under a taller one, it’s a given that partial to heavy shade will be present. Monitor the site at various times of the day to determine whether light shade, dappled shade or heavy shade characterizes the site.
Size -- In many landscapes, the lower branches of mature trees have been limbed up to create an unnatural openness. While plant selection for trees under trees is not akin to placing pieces of a jigsaw puzzle in place, there is a certain element of choosing based on eventual tree size for all specimens involved.
Rootzone allowance -- As mentioned before, adequate root zone allowance is crucial to the success of the enhanced landscape and should not be overlooked.
Disease resistance -- Due to the canopy effect of the mature trees and possibly the nearby smaller trees, wind speeds through the modified landscape are likely to be less than the previous condition. Be sure that the specimens chosen are resistant to periodic leaf wetness and a variety of foliar pathogens.
Fall color, bloom sequence -- One significant selling point to incorporating smaller trees under larger ones is the opportunity to infuse color and texture into a monochromatic or overly simplistic landscape.
Editor’s note: This article was originally published September 2011 and has been updated.
You see them in just about every part of the country — I know that I’ve seen them in each of the 40 states I’ve been to. Tree surrounds, or tree rings, are just an odd and head-scratching item in the arboricultural world. You see all types and varieties:
Why they’re used
Perhaps the most important consideration with tree surrounds is to gain an insight into why they’re there in the first place. After all, they cost money to install and need to be maintained. Four main reasons have been identified:
They hide ugly roots. Certain species such as maple, baldcypress and cherry tend to produce roots at or near the surface, in addition to ones deeper in the soil profile. Many clients consider them to be ugly and want them covered with soil or mulch. Others claim they’re a trip hazard, especially older folks. The “ugly” notion is up to the individual, however, there is a certain validity to the trip hazard rationale.
Grass won’t grow in the shade. Under trees with dense canopies, turfgrass struggles to thrive due to root competition and the shade itself. Turf is best thought of as a sun plant, with even the most shade tolerant species requiring four hours of sunlight. After several years of shade, bare soil usually results, and clients want a replacement plant, something/anything other than dirt or mud.
Tired of hitting their head on low branches. If turf is able to grow to some degree under a shade tree, the need to mow under lower scaffold limbs usually exists. And, naturally, as the focus of the mower operator is on the turf, sometimes they lose track of where they are and bonk their head on the branches that grow low to the ground. Ouch.
“Well, that’s what my parents did.” New, first time homeowners often report that they mimic their parents landscaping techniques, sometimes to a fault. For example, if mom and dad had a hedge, by golly, they want one too — until they realize that you have to shear the thing off several times a year and then gather up all the trimmings and do something with them. The same is true with a tree surround. They think, “If I have a tree in the front yard, then I need a tree ring to go with it.’
Why they’re bad
The previously-identified reasons are pretty strong in a compelling sense, so why is it important to discourage tree surrounds from being installed? Can’t we have both? Can’t we just all get along? Again, here are four reasons:
Soil on the trunk. In almost all tree-surround installations, a considerable amount of soil ends up in direct contact with the bark of the trunk — anywhere between 6 and 30 inches, or so. This usually results in the bark staying wetter than normal after a rainstorm and a reduction in the barks’ photosynthetic capacity. The loss of chlorophyll capacity isn’t that much of a problem, however, the bark being wet for long periods of time is, as it often leads to softening of the tissue and decay.
Cutting off soil oxygen. Fibrous roots need oxygen in order to expand and function well. If they’re covered with 2 feet of soil, that capacity is significantly reduced, much like people with asthma have trouble breathing under certain environmental conditions.
Encourages root girdling. Generally, when a tree ring is constructed, it’s filled with freshly-loosened soil to the top of the bricks/boulders/stones/timbers. In some cases, the property owner knows that shade-tolerant perennials or groundcovers grow best in amended soils, thus mixes compost with garden soil that exists on the site. When there’s a difference between the soil surrounding the tree and the amended soil (such as silty, compacted clay of new construction vs. compost or peat moss amended soil), the roots tend to preferentially stay in that, taking the course of least resistance as opposed to venturing out into the rest of the site. This causes circling roots, which eventually develop into stem girdling roots.
It’s just not natural! Maybe the best reason why tree surrounds are bad is that they’re not natural. When was the last time you were walking through a forest and found all those tree surrounds Mother Nature installed? My guess is never. If we’re supposed to follow her lead on tree care (yes, it’s best to follow it), we should avoid tree rings.
Now that we’ve examined why they’re used and why they shouldn’t be there, what should be done with tree surrounds when we have a client with one?
First, if you take on a client with an older tree (one that has been there for more than 10 years), there’s not much you can do. Hopefully, by now, the roots are out in the landscape. If possible, move the soil away from the trunk without injuring it. If they’ve been there for a short time, say two or three years, remove the boulders/bricks/railroad ties. Examine the roots if they’re visible and be ready with mulch to pile loosely over the mound. This allows for a gradual transition of the roots to a more natural and well-functioning state.
If you’re fortunate enough to spot one that has been recently installed, it’s best to convince the property owner of its negative effects, rip out the hardscape and topdress with mulch. Again, make sure the mulch isn’t piled on the trunk. As much as possible, return the tree ring tree planting to a proper one.
Prevent future injury
As a responsible tree care provider, it’s important to let your current and future clients know that a tree surround is bad landscaping and poor tree care. In any way possible, it’s up to you to communicate the information presented above. Get on Facebook, Twitter and your company newsletter or blog and explain why tree surrounds are bad for trees.
Additionally, contact your friends and colleagues that design and install landscapes and make sure they understand why this is a bad practice. Also, communicate the fact they’re a key player in preventing tree surround installations. If they take your advice, the trees they plant will be healthier, last longer, provide more benefits to their clients and be assets in the landscape, rather than detriments.
Alternatives to tree surrounds
The message shouldn’t simply be that “tree surrounds are bad.” Instead, it should be that “they’re bad, this is why and here are some alternatives.” To a certain extent, the alternatives are more of a landscape and planting design issue, but at a minimum, a couple of concepts are relatively easy to communicate and easy to understand:
Drought-caused tree deaths are produced by a combination of hydraulic failure and carbon starvation, shows new research. The finding, based on a meta-analysis by 62 scientists from across the world, will improve predictive models of how trees die in response to heat, drought, and other climate stresses.
Editor’s note: The fundamentals covered in this article are just some of the many things that climbers need to know to be efficient and proficient. It’s important for anyone new to climbing, or who has years of experience but never received formal training, to take a comprehensive class.
There are some pursuits in life, like scrapbooking or watercolor painting, where you can figure it out as you go. Climbing trees — safely and properly — is not one of those things. While there’s room for tweaks based on personal preference, there very definitely are right and wrong, safe and unsafe, efficient and inefficient ways of doing almost everything when it comes to climbing.
We asked a few climbing instructors about some of the most important fundamentals they cover when teaching students how to climb in order to work aloft:
Starting at ground level
Up in the tree
Room for improvement
Spar pole rigging is one of the most basic rigging systems, one that most, if not all, tree folk are familiar with. In this system, a trunk with few or no branches left is lowered down under control in manageable pieces to the ground. Although this technique is familiar to many, and seems quite basic in appearance, if not understood and carried out correctly it can lead to less-than-positive, if not catastrophic, outcomes.
While the written word and pictures can illustrate some of the forces involved, methods used and pros/cons of spar pole rigging, this should only be considered an introduction and not sufficient for Johnny B. O’Doughnuts to go scrambling up that white pine towering over the greenhouse ready to bring it down “chunky style.” The use of instructional videos through the “Interweb” or DVDs is highly recommended, hopefully followed up with hands-on field-based instruction in the step-by-step process by experienced climbers and riggers. Spar pole rigging is an excellent, safe and efficient technique to have in that mental toolbox, and an understanding of some of the ins and outs of it provided by this column will help Johnny along the path to rigging success.
When 500 pounds doesn’t mean 500 pounds
Forces in rigging is particularly important when the topic is spar pole rigging. Climbers and crews must always keep in mind that when using this technique the climber is attached to the spar, which also provides the rigging point. Thus, whatever forces are generated by the piece of wood are transmitted to the very thing that is keeping the climber aloft, not to mention the climber’s soft tissue and relatively fragile physiology. At a minimum, a 2-to-1 force factor will be present when spar pole rigging.
In simple terms, this means that if the piece weighs 500 pounds, then 500 pounds of force will be required to keep it aloft or control it, which in turn means the rigging point, typically immediately adjacent to the climber, will experience at least 1,000 pounds of force. Needless to say, this can lead to some interesting rapid movements, resulting in bruises, contusions and fractures, or even catastrophic failure of the entire spar itself.
The farther the piece falls prior to coming under the control of the rigging system, the greater the force is magnified, thus a block set well beneath the piece exponentially increases the forces experienced by the spar and the attached climber. This leads to the safest place for the placement of the rigging point on the spar being immediately below the piece, typically near the climber’s tie-in point, which adds its own complications. The reality of spar pole rigging is that reducing the forces experienced is the prime directive.
Energy flows and is absorbed, it doesn’t disappear
Most experienced spar pole riggers have spent years taking every branch off as they ascend the tree, taking the top out upon reaching it, and then working their way back down lowering pieces off the spar. However, field research/testing and personal experience have shown that leaving branches, where possible, attached to the trunk of the tree being removed significantly lessens the forces experienced at the anchor point high up the trunk. By leaving branches on the trunk during ascent, those branches actually absorb and dampen some of the forces experienced by the trunk during rigging, lessening the forces experienced at the anchor point and trunk movement.
This option won’t be possible on every tree and in every scenario, but when able climbers should attempt to create a “chute” that the pieces of the spar can be lowered down through, thus dramatically lessening the forces the spar and climber will experience during rigging.
When it’s not possible to leave branches to absorb energy, the climber and crew should be aware of the heightened forces that will be generated and either reduce the size of the pieces removed accordingly or take some of the other steps described to absorb the force generated.
Lowering is a required skill
One of the best ways to minimize the forces generated at the rigging point is in the hands of the oft maligned but highly influential branch manager. Two primary factors come into play in this force minimization: rope choice and lowering technique. Climbers and crews that get hung up on the strength of the rigging line without considering its elongation or elasticity are setting themselves up for a trip to the land of bad things.
A rope with extremely high strength but no elasticity does not have the ability to absorb any of the energy generated by the plummeting piece, thus all that force goes into the rigging point, spar and attached climber. Therefore, consider elongation of the rigging line along with strength. In addition, the gradual slowing or deceleration of the piece, as opposed to a sudden stop, will lessen the forces experienced at the rigging point.
Using any of the various lowering devices available, such as the Port-a-Wrap III, GRCS or Hobbs, will result in smoother and more controlled lowering than the traditional “tree wraps.” Experienced ground personnel can certainly accomplish smooth, controlled descents with tree wraps, but the use of lowering devices ensures that the friction level is the same regardless of tree species, and makes the operation more efficient by eliminating the tedious process of going around the tree with the rigging line again and again.
The best climber in the area will have an extremely bad day with a branch manager that is unfamiliar with smoothly slowing a piece during its descent to the ground; and climbers would do well to keep that in mind when verbally abusing ground personnel, as even an experienced branch manager can make a mistake after being yelled at one too many times. Situations will arise where a controlled “run-out” of the piece is not possible, perhaps due to hazards or obstacles beneath it, but the crew and climber must simply recognize this and prepare themselves as well as possible for the forces that will be generated and ensure the spar and climber can endure them.
Read more: 5 Tips for Spar Pole Rigging
When you gotta get away
If a crew is felling trees at ground level, a key component of the felling plan is their escape route, the ability to get away is just as important when aloft. After all, when one is 100 feet up in a Douglas fir spar, simply turning and running is not an option. Climbers must have a way to get quickly, safely and efficiently to the ground should it be required; and spur climbing down is not quick, safe or efficient, nor is it an escape route.
There’s a wide variety of systems, ranging from the simple to the complex, that allow a climber to be tied in to either a single or doubled-line system while on a spar. Climbers should choose the system that works best for them. Once that choice has been made, the system must be used when doing spar pole rigging – personal experience has shown that spur climbing down with an injury or while being attacked by insects is not a viable option, nor is it very pleasant.
Cuttin’ with no chuckin’
A climber aloft is required to be secured by two methods while operating a chain saw, and this requirement becomes even more vital when carrying out spar pole rigging. Typically, the cut being made is quite close to the climber’s system, which is preventing him from experiencing the inevitability, and attendant pain, of gravity. Being secured by two methods gives the climber a backup if something goes a little sideways with the cut and a rope or lanyard gets severed. In addition, the way in which the cut is made can affect forces at the anchor point and spar movement.
The use of a 45-degree notch while aloft will cause maximum pushback on the spar right at the moment of separation. Needless to say, this can lead to the climber performing some interesting “dance moves” high in the air. Climbers familiar and skilled with the open-face notch of 70 to 90 degrees will find it equally useful aloft, but should keep in mind that opening the notch too greatly will cause the piece to pull the spar with it prior to separation, once again leading to dance moves. In most cases, the best degree of opening is one that will allow the piece to separate when horizontal or slightly above horizontal with the ground below.
There is a great deal more involved with spar pole rigging than the basic methods, forces and techniques discussed here, but this discussion does provide an introduction to this useful technique, which can lead to safer and more efficient removals. The addition of spar pole rigging to a tree crews’ toolbox will not only help them get the job done, but make sure that when the top goes down, they’re ready.
Editor’s note: This article was originally published in August 2014 and has been updated.
Despite massive efforts at reforestation, China's native forests continue to be displaced by plantations. A new study argues that rural communities could help reverse this trend if they were given incentives to protect and restore native forests on their own land. A proposed new umbrella policy for environmental protection in China currently falls short of the measures needed, but if amended, could provide a unique opportunity to benefit rural communities and the environment.
The tree care industry has taken advantage of the capabilities of construction cranes and similar pieces of equipment for quite a few years, but the last 10 to 20 years have seen a large increase in their use throughout tree care, regardless of geographic location or market size.
There is no secret behind this expansion of crane use amongst climbing arborists, cranes are extremely useful, and in many hazard tree situations, vital pieces of equipment that can, if properly employed and operated, increase the safety and efficiency of many whole-tree removals, and even large pruning jobs in sensitive target-rich environments. Beyond these typical uses, tree companies with cranes in their inventory, or access to a rental unit with “tree work-friendly” operators, often find that these pieces of equipment have far more applications than they ever thought of. From simplifying and speeding the removal of large amounts of debris from “access troublesome” backyards to providing a safe tie-in point for a climber when working on a tree that is unsafe to climb, yet inaccessible to an aerial lift.
When any different or new piece of gear, method or technique is added to a tree crew’s physical and mental toolbox, knowledge, information and training must be part of the equation, lest inappropriate or unsafe use lead to a disaster. After all, larger things – and a crane, no matter how small and maneuverable, certainly qualifies as relatively larger – have larger, bigger and heavier consequences when things go wrong. There are a number of ongoing seminars, courses, demonstrations and hands-on field exercises pertaining to the safe use of cranes in tree care operations offered by different training companies and industry professional organizations, but as a minimum, an excellent place to start is the 2006 version of the Z133.1 (American National Standard for Arboricultural Operations: Safety Requirements), which has a section on crane use in tree care. Prospective arborist crane users should also keep in mind that their individual state or province might have additional rules/regulations/standards regulating tree care crane use and inform themselves accordingly.
Communication is a key element of all tree care activities, not only for the safety of those aloft and on the ground, but also for the efficient accomplishment of the task at hand. Throw a large motorized piece of equipment that towers over the work site into the mix, and communication becomes even more important. The frustrating experience of attempting to communicate effectively between the canopy and the ground is one that all tree crews are familiar with, adding the engine noise of the crane, a crane operator who may not be able to see the climber (and vice versa) and typically greater work heights all are factors that make communication during crane operations even more challenging.
There are a large number of communication systems available, ranging from simple hand/arm signals, such as illustrated in the appendix of the Z133.1, to voice-activated throat mikes and muff radio systems that can be fitted on existing helmets or hard hats. Regardless of which system is chosen, it is vital that all work participants know and understand the various signals or systems prior to the job beginning. Trying to remember what channel one is supposed to be on, or what the hand and arm signal for “boom up” is with a 5,000-pound piece of wood hanging free is not a good indicator that the job is going smoothly, let alone safely.
Additionally, situations that prevent the climber and crane operator from being in visual contact require that a spotter be used to not only carry out the important role of relaying signals, but, if necessary, inform the climber/crane operator what is occurring at the other end of the “stick.”
Crane and work site setup
Planning for crane and worksite setup should begin with the first person looking at, or estimating, the job. As much as is possible, everything that might affect crane operation and use should be considered and planned for, this includes traffic control requirements; size and capacity of the crane needed; suitability of ground and space available for crane use; power lines, septic tanks, overhead communication lines and other hazards; will additional cribbing or blocking be needed for the outriggers of the crane; is the tree safe to climb, or might a second crane be needed for a TIP; etc. Cranes are designed, constructed and intended to be operated in a uniformly level position on a firm surface that will adequately support not only their weight, but the additional weight they will be lifting and moving. In some situations, a great deal of time, energy and materials may be necessary to create an appropriate setup. Shortcuts or shoddy work in this area are an excellent way to end up purchasing a client’s newly crane bisected house, let alone the emotional cost of a possible death or injury to a crew member.
An additional part of this planning process should be the location of trucks and chippers in relation to the crane and tree for efficient removal of woody debris, saving time and energy by using a crane is not helpful if the branch managers have to hand carry every piece a great distance to the chipper.
How well or how poorly the crane is operated can often be the difference between a safe, efficient tree job and one that will give the company owner night sweats.
A tree company that owns or is interested in purchasing its own crane should be aware that some states and/or municipalities require licensing for crane operation; and given the amount of money typically spent on a crane, “on-the-job” training for the chosen operator may not be the best choice for long-term crane, crew and company financial survival. Crane operator training courses, though not always tree industry specific, are readily available in most states/provinces.
Should a tree care company prefer to rent a crane for individual jobs, they should request an operator from the company who is familiar with crane tree work, as it can be very different from construction crane use. Repeat business with a particular crane rental company can help both the tree and crane company know what they can expect from one another and grow more efficient in their tree crane operations.
Tie-in Points (TIPs)
Should a climber be using a crane as their TIP, there are a number of requirements of how they must secure themselves. Climbers can be lifted into the tree by a crane or use it as a tie-in point only when the person responsible for the work has decided a crane is the safest and most practical method available. TIPs should be secure, such as locking shackles, avoiding possible failures in the climbing system, should not interfere with any of the crane’s warning or operational devices, and should be designated anchor points on the boom or lift line.
Putting the work positioning lanyard through the hook, regardless of how it is attached to the climber’s harness, is not an appropriate or acceptable method. When the crane comes under load, the climber should be detached from the crane and attached to the tree itself, an adjacent tree, an aerial lift or even a second crane. If none of these options are available, or if they would create an unsafe situation, the climber may stay attached to a crane under load. When the climber is still attached to a crane under load, the operator must not exceed 50 percent of the crane’s load capacity at the existing boom angle and extension.
As strong and versatile as a crane might be, it is only designed for static lifting of loads, not for the dynamic forces of tree pieces/parts being “dropped” or felling into the load line or hook.
There is a wide variety of aerial chain saw cutting techniques that will assist climbing arborists in keeping loads as static as possible and avoiding unintended, and often catastrophic, dynamic loading of cranes. Excellent reference tools for crane operators and ground personnel are a green weight log chart or the Rigging Software 1.0 program loaded on a handheld device. Both of these will help the climber and operator be more confident about the weight of the intended lift and plan accordingly, particularly as it allows an operator with digital readout on the crane to put a roughly appropriate amount of lift on the piece prior to it being cut, helping prevent pinched saws or wild, sudden movements.
Obviously, the use of cranes in tree operations is a much more involved and complicated subject than the space available to discussed it here, but this introduction, in conjunction with additional knowledge and qualified field training, can help tree crews use this efficient piece of equipment not only to its full capacity, but also safely.
Editor’s note: This article was originally published in March 2011 and has been updated.
Mangrove trees, particularly their leaf litter, filter copper out of soil and water in Indonesia.
The past few decades have seen the rise of global incentive programs offering payments to landowners to help reduce tropical deforestation. In what might be a first of its kind study, researchers have integrated forest imaging with field-level inventories and landowner surveys to assess the impact of conservation payments in Ecuador's Amazon Basin forests. They found that conservation payment programs are making a difference in the diversity of tree species in protected spaces.
“Seeing is believing.”
“The proof is in the pudding.”
“Show me the money.”
“A picture is worth a thousand words.”
There’s a similar literary expression: “Show me, don’t tell me.” This refers to showing someone an example to help them understand what you’re saying.
Have you ever been frustrated that your employees, staff, co-workers, spouse, children or man on the street doesn’t understand what you’re trying to say, even after you’ve explained it for umpteenth time? If so, try taking a different tact.
Seeing is believing
I was recently attempting to describe to a crew leader over the phone how I wanted a client’s tree pruned, as I couldn’t be there to show him the job. Back at the office, phone in one hand, the other making sawing motions in the air, I was trying to describe the limb I wanted taken off. I also explained that there are a lot of suckers he should remove, as I was spreading my hands apart to demonstrate how far I want the tree pruned away from the eave.
When finished describing what I wanted, I waited for his confirmation that he understood.
All I heard is crickets.
After a long pause, he said, “Can you go over that again?”
So, I tried again – same results.
There’s no doubt in my mind he had no idea what I wanted, and not because this co-worker is dense; far from it. He’s led crews for 10 years, is an excellent tree pruner and warrants clearer directions than I was giving him in this example.
In one of my few flashes of brilliance, I asked if he could text me a photograph of the tree.
As an afterthought, I added, “and put a ribbon on the limb you think I’m telling you to take off.”
He said, “Sure.”
Ten seconds later, I had a picture of the tree on my phone. We were now looking at the same tree – and limb. We began to have an intelligent conversation about the job. With that being said, I couldn’t help but wonder after we ended the call how much clearer yet my instructions would have been if we were FaceTiming.
A few weeks ago, I was asked to provide a tree appraisal for a client who lives 400 miles away. The client told me, over the phone, that the trees were already removed but the stumps remained. The client also informed me that there were photographs of the former trees, courtesy of Google Earth Street View. These pictures provided me with enough information to identify the tree species and assess their general condition. But even with the photographs, and even with Google Street View, I still needed to measure the diameters of each stump so I could determine the trees’ sizes. Without this data, I couldn’t begin my calculations. Frankly, without them, I was … “stumped.”
Short of driving the full 400 miles to measure each stump or trusting that the client’s measurements were accurate, I asked the client if we could FaceTime so that I could watch him measure each one.
The client hesitated for a second, and then said, “Yes, I can.”
Two days later I was following him around the site on my iPad as he stretched a tape measure across the top of each stump. By taking this simple step I saved myself an 800-mile trip, not to mention I saved my client the expense of 14 additional hours of my consulting time.
A new way to estimate
I’ve recently been adding photographs to my tree care estimates, whether I’m estimating pruning, documenting a diagnosis or identifying a tree for removal. I’m not exaggerating when I say that the photographs have dramatically increased my sales close rates. There’s something about a picture that instantly implies to a client that I understand exactly what they want. Additionally, with the assistance of some software programs such as Sketch and Macaw, I can also circle or highlight their tree to clarify further what we propose to do.
We’re not using YouTube videos — yet. But I know of other tree care companies that are, and to great effect. I’m told that if we want to learn how, “just approach one of your youngest employees. They can create them in their sleep.”
I don’t doubt it.
Photos as tools
There are countless instances when taking photographs can improve your business. Given that everyone has a camera in their smartphones these days, it’s never been easier. Here’s a few applications where taking photos can help:
With a little imagination, you can probably think of several other applications.
A drawback to utilizing photographs has been that it’s slowed me down. Like learning any new skill, however, once I became more proficient at it, the little extra time it takes to photograph a project has been more than made up for in the time I save showing jobs, selling work or identifying issues. Instead of selling five jobs out of 10 in a day, I’m selling five out of seven. By the end of the day, I actually accomplish more in less time.
The crews also love having photos to guide them.
It’s not absolutely necessary, but I suggest acquiring some software to improve the quality of placing your photos into reports or estimates. You don’t have to buy publishing software, since most desktop computers, tablets and smartphones already have that ability. But typically, this software is clumsy to use, and it’s easy to become frustrated. Again, it takes some time to learn the newer programs, but once you’re proficient you won’t regret acquiring them.
The tree care business is such a visual business. Our work occurs in real life and in real time. There’s nothing virtual about it. What we do results in making tangible differences people can see. Yet, we so often try to describe what we do audibly, or in print.
Doesn’t it make sense to show people our work versus telling them?
The post Using Photography As A Tool For Your Tree Care Business appeared first on Tree Services.
A new study counters the view that tropical forests were pristine natural environments prior to modern agriculture and industrialization. Moreover, humans have in fact been having a dramatic impact on such forest ecologies for tens of thousands of years, through techniques ranging from controlled burning of sections of forest to plant and animal management to clear-cutting.
Determining what’s responsible for the demise or decline of your customer’s favorite tree can be difficult, especially when the causal agent is not readily visible. Fortunately, when dealing with leaf-feeding insects, there are usually visible clues to help with diagnosis.
Your best bet for success in controlling these insects is to follow an integrated pest management approach that includes accurate pest identification, assessing their damage potential, and selecting the least toxic control measures. Helping your clients manage their leaf insect populations provides a valuable service and offers the potential for profitability as well.
Consequences of leaf feeding
Not to downplay its importance, but just to make a distinction, leaf-feeding injury from chewing insects differs from damage to trees by wood-boring insects that tunnel in the cambium and sapwood, scale insects that extract plant sap through the bark, or gall insects that form unattractive or mysterious growths on tree leaves, but don’t generally cause any harm.
Leaf feeders typically cause defoliation and loss of photosynthetic capacity for one year; that’s a good thing and a bad thing. Good because if the tree is mature or at least more than a few years old, removal of one season’s growth usually won’t kill a tree. It’s bad because the defoliation robs the tree of the opportunity to produce adequate nutrients to defend itself against pests, expand the crown and root system and create shade for property owners.
Spotting leaf feeders
When leaf feeders damage a tree, the injury is often unique for individual insects. For example, Japanese beetles produce a characteristic honeycomb pattern in the damaged leaf. In other cases, the injury can consist of nondescript removal of leaf tissue, even though the outward appearance of the responsible parties can be quite different. When inspecting trees for leaf feeders, the main symptom to look for is the presence of leaves with parts missing. All leaf feeders create some sort of “leaf minus a piece” condition. Naturally, because various tree tissues vary from species to species, the damage can appear differently upon first glance. However, after a closer look, the signature characteristic of the missing leaf parts will remain constant. For example, Austrian pine and Caddo maple appear quite different in phenotype or outward physical appearance. When infested with leaf feeders, even though the pine needles are narrow and rounded and maple leaves are wide, thin and flat, noticing that parts are missing will guide you toward the culprit. Comparison of the affected leaves and uneaten portions of leaves can be helpful in spotting leaf-feeder damage. Of course, the presence of actual insects on the leaves or needles helps immensely with diagnosis.
Common leaf feeders
Caterpillars -- Caterpillars are the larvae of butterflies and moths. There are scores of species that infest ornamental trees and shrubs. All caterpillars have chewing mouthparts; six small, true legs behind the head; and several false or prolegs on the abdomen. Most feeding damage by caterpillars is not serious, but a few species can damage the vigor of trees by continued defoliation over a period of years. Life cycles vary with each species.
Cankerworms -- Cankerworms feed on most species of deciduous trees and some shrubs, but elm, oak and hackberry are their favorites. Spring cankerworms overwinter in the soil. Wingless adults emerge in the spring, mate, and then climb a nearby tree to deposit eggs under flakes of bark on the trunk and branches. Adults may emerge as early as late February and early March during warm periods. Upon hatching, the caterpillars or “measuring worms” feed voraciously on the leaves, at times completely stripping the tree. Severe defoliation over a number of consecutive years may weaken the tree, but most likely won’t kill it. After completion of feeding, larvae spin down from the canopy on a silken thread and enter the soil to overwinter. There is only one generation per year.
Tent caterpillars -- Tent caterpillars are voracious feeders on numerous deciduous trees including ash, oak, boxelder and cottonwood, but wild plum and cherry are their favorite hosts. In late summer, female moths lay eggs in shiny, brown, frothy masses that encircle twigs. These eggs overwinter and hatch in the spring, when leaves are beginning to expand. Eastern tent caterpillars construct a “tent” in the crotches of branches. These caterpillars are hairy, almost black with a white stripe down the back and a row of blue spots on each side. They can reach 2 inches in length when fully grown. Infested trees are often completely defoliated, and their growth and vigor are reduced. There is only a single generation each year.
Bagworms -- Bagworms are common pests of evergreens, junipers, and occasionally deciduous trees and shrubs. The case, or bag, which provides a home for the bagworm caterpillar and gives the insect its name, is constructed of silk and fragments of needles or leaves. Bagworms overwinter as eggs within the bags. In the spring, larvae hatch from eggs and immediately begin construction of small protective bags. Caterpillars feed from within their bags and move along the branch in search of food. If food is depleted in one area, they simply move to another area.
Fall webworms -- Fall webworms feed on nearly all deciduous trees and shrub species. Larvae construct silken webs around branches, feeding on leaves and living within these shelters. Webs are enlarged as the caterpillars grow. Fall webworms are covered with long hairs and vary in color from white to yellow, orange to gray. All color phases, however, have a series of distinct black dots along the body. Fall webworms typically appear in late summer and fall. While fall webworms can cause significant defoliation of trees and shrubs, damage is generally minimal, since defoliation occurs late in the season.
Mimosa webworm -- Mimosa webworms are prevalent anywhere that honey locust trees are planted. Mimosa webworms overwinter as pupae in cracks or crevices of infested trees or in protected areas nearby. Adult females emerge in the spring and deposit their eggs. The larvae are gray to brown with five white longitudinal stripes. Larvae web leaflets together, feeding inside the webs and skeletonizing leaflets. The webs are unsightly and may cover entire trees.
Sawflies -- Sawfly larvae resemble caterpillars, but are actually the immatures of primitive stingless wasps. Sawflies feed on a wide variety of evergreens and broadleaf trees, and are therefore quite variable as a group in behaviors, feeding habits and life cycles. Pine sawfly larvae vary in color from grayish to yellowish green. Some species have one or more lengthwise stripes. Larvae typically reach .75 to 1 inch in length and rear up in a characteristic defensive “S” profile when disturbed. Most species overwinter as pupae, but a few spend the winter as eggs inserted in the needles. In the spring, sawfly larvae feed in groups on needles, starting at the needle tip. Feeding habits among species vary, but those that feed only on old or young needles weaken trees or slow their growth, while species that feed on both young and old needles may severely injure or kill trees. After feeding for several weeks, the larvae of most species drop to the ground, spin cocoons and pupate in the soil.
Beetles -- A second important group of leaf-feeder insects are the beetles. Most beetles overwinter as adults in leaf litter layers under trees. They emerge in spring and begin feeding on new leaves of trees and shrubs. Some species have several generations each year. Beetles are characterized by thick, hardened hind wings that form a protective shield over the body of the insect.
Elm leaf beetles -- A good example of a leaf-feeding beetle is the elm leaf beetle. These insects feed on the foliage of American and Siberian elms. Adults are .25 inch long, yellowish green and have a black stripe on the outside of each wing cover. Larvae reach about 3/8 inch in length and are yellow with black spots and stripes. Elm leaf beetles overwinter as adults in sheltered areas, especially in and around buildings and in litter and bark crevices. In the early spring, they emerge from overwintering sites as leaves are beginning to expand. After feeding on leaves, adults lay clusters of yellow eggs on the foliage. Eggs hatch in late spring, and the first signs of larval feeding are skeletonized areas between veins, giving leaves a lacy appearance. As damage accumulates, leaves take on a ragged appearance and turn brown. Heavily infested trees often prematurely lose their leaves. There are two generations per year. Interestingly, a parasitoid wasp, Tetrastichus gallerucae, which attacks elm leaf beetle eggs has significantly reduced elm leaf beetle numbers over the past decade.
Cottonwood leaf beetles -- Cottonwood leaf beetle adults are about .25 inch long. They are yellow with black stripes, and the head area is black. Larvae reach 1 inch in length and have dark bodies with two white spots on each side. These spots are scent glands that give off a disagreeable odor when larvae are molested. Larvae feed in groups, skeletonizing leaves. As they grow, they feed individually and consume entire leaves. These leaf beetles overwinter as adults under bark or debris on the ground. There may be several generations each year. In addition to cottonwood, these beetles will also feed on willow and other poplar species.
Controlling leaf feeders — timing is everything
Applying a foliar insecticide to mature, fully grown leaf feeders is problematic on two fronts:
1. It’s not all that effective – large insects are more tolerant of insecticide applications than newly hatched ones.
2. The opportunity to prevent damage has been lost – by the time they are fully grown, chances are that they’ve already eaten most of what they are going to eat, and application does little more than provide revenge for the property owner.
Injections offer potential for “rescue” treatments, however, because of the potential for injury to the tree cambium, it’s best to consider this approach only when spray applications would cause injury to surrounding elements such as cars, buildings and other personal property.
The importance of timing cannot be underestimated, this is why regular inspections are a hallmark of integrated pest management and plant health care. If an infestation is identified early in the insect’s life cycle, and an appropriate application is made, arborists win on two accounts. First, the applications tend to be more effective, and second, a greater amount of foliage loss is prevented, providing the customer with a better value for their investment.
Incorporating regular inspections into your tree program involves a paradigm shift. Traditionally, arborists and tree workers have been paid based on how much product they could spray on a tree. The change in thinking that must take place is that timely inspections are as (or more) important than pesticide applications. As such, it’s crucial that arborists make money from inspections by charging a reasonable hourly rate based on the experience and training of the inspector. Our advice: don’t give your inspections away, after all, you get what you pay for in life, and good tree care is no different than buying clothes, cars or carpet.
Editor’s note: This article was originally published May 2011 and has been updated.
Oftentimes, advances in science and technology are progressing at a faster rate than they are in the field. “By applying what we know to what we do,” Mark Roberts explained on Tuesday, August 1 at the International Society of Arboriculture’s Annual International Conference & Trade Show, “better decision making, more efficient tree work and improved tree care can be achieved.”
Roberts, of Roberts Consulting, is an arborist with over 25 years of experience and has worked in all facets of the industry, from “dragging brush through the streets of London” to being a former president of the ISA. He holds qualifications from Otago University, Massey University and The Otago Polytechnic. He’s also an ISA-certified arborist and TRAQ.
During his presentation, Roberts discussed how the use of science can defend actions, support decisions and, in many cases, do less to achieve more. These concepts especially apply to older, mature trees, Roberts explained. He presented a quote from The Ancient Tree Forum that reads “Ancient trees are found in an extremely wide range of situations. Therefore, it’s not possible to present a simple, easy to follow set of guidelines which will work for every tree in evert situation.”
In managing trees as a general concept, Roberts encouraged attendees to not fear “doing something different and owning and managing what you’ve done. If you mange a tree, make sure you’re managing it for the long haul.”
TRADE NAME: Blue ash
GENERAL DISTRIBUTION: Commonly found in the Midwest from Oklahoma to Michigan, as well as the Bluegrass region of Kentucky and the Nashville Basin region of Tennessee. Isolated populations exist in Alabama, Southern Ontario (Canada) and small sections of the Appalachian Mountains. Is typically found over calcareous substrates such as limestone, growing on limestone slopes and in moist valley soils.
WOOD VALUE: Is used to make flooring, baseball bats, furniture, tool handles, crates and barrels. Has also been traditionally used to build houses and can be harvested for firewood.
EMERALD ASH BORER CONSIDERATIONS: Blue ash appears to be least threatened in comparison to other North American ash by the infestation of the emerald ash borer. First detected in North America in 2002, this invasive beetle has since spread throughout much of this tree’s range. Approximately 60 to 70 percent of blue ash trees survive the emerald ash borer. (This is in comparison to other ash, such as black and green, where up to 99 percent fall victim to the emerald ash borer.)
SEASONAL DEVELOPMENT: Flowering dates are March to April, while seed dispersal dates are September to October.
General Botanical Characteristics:
Sources: Oklahoma Biological Survey; Iowa State University Forestry Extension; University of Kentucky Dept. of Horticulture; Ohio Dept. of Natural Resources
The Amazon rainforest emits three times more isoprene than was previously estimated, airborne measurements show. Isoprene is one of the main precursors of ozone and indirectly influences the balance of greenhouse gases in the atmosphere.
How does your company handle pest management?
That was one of the many topics of conversation on Monday, July 31 at the International Society of Arboriculture’s Annual International Conference & Trade Show, held at the Gaylord National Resort & Convention Center in Oxon Hill, Maryland on the National Harbor.
In his presentation titled “Your Pest Management Strategies: Which Pests Matter?” Joe Boggs, assistant professor with the Ohio State University extension and department of entomology, explained how every tree care company needs to carefully categorize where to put their pest management emphasis.
“Share your philosophies with your customers,” Boggs explained to the attendees. “There’s a whole lot of pest management decisions that stop with saying, ‘This pest causes no harm to that tree.’ That’s a rough position to be in, when you’re looking at a tree covered in fall webworms and you’re saying they’re causing no appreciable harm.”
Boggs explained that proper pest management practices support good tree health, identify the problem (subsequently making a diagnosis) and separate “serious from not-so-serious” pests. He also explained to the attendees that, “tree death without a correct diagnosis is malpractice.”
In terms of how individual tree care companies evaluate pest impacts, Boggs said that a common dilemma faced is “How do I make money if I’m not treating, and I’m just telling my customers that those fall webworms aren’t hurting the tree?” Boggs went on to say that, “On one hand we have clients that have zero tolerance with a tree looking bad; we can’t convince them to plant a plastic tree. On the other hand, all of us in this room know that there are very few tree pests that require treatments — if we measure strictly based on tree health.”
The problem, Boggs said, is that “not all pests are equal. We can’t say all defoliated caterpillars act the same. We can’t say all scales act the same.”
Boggs recommended sorting out pests into three categories:
Determining which category each tree pests fits into is a creative exercise all tree care companies should engage in each year, to “be the most productive and profitable this coming season,” Boggs said.
Urban food demand in the Amazon could be hitting wildlife up to 1,000 km away from the city, according to new research.
Three more frog species have been discovered in the Peruvian Andes, raising to five the total number of new frog species the group has found in a remote protected forest since 2012.