Other Disease & Stunt Disease finale, + Climbing Intro.

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Other diseases, such as ringspot and yellowing, and some stunt diseases, are caused by viruses and phytoplasmas (PLOs). Viruses are frequently spread by the feeding activity of insects and require a wound to enter the tree. 

Viruses seldom completely kill their hosts, although plants may show decline over time. Some highly prized plant traits, such as unusual leaf coloring and blossom patterns, are the result of viruses. 

Management of plant diseases may be considered an exercise in prevention. Planting species or cultivars that are resistant to prevalent diseases is the best start. Most fungicides are best used to prevent the establishment of disease rather than to eliminate existing disease problems. Steps taken to maintain tree health and improve cultural conditions are often the best disease prevention measures.

In diagnosing tree health problems, it may be helpful to get laboratory assistance. In some cases, testing may be the only way to confirm a diagnosis. A new or unusual pest or plant may be difficult for anyone to identify, and diagnostic laboratories can assist arborists by providing diagnoses of trees and shrubs. 

Some laboratories can also recommend management strategies for insects and disease-causing organisms, such as fungi, bacteria, and viruses, in addition to isolating pathogens, identifying pests, and keeping arborists informed of potential problems of the season. 

Many countries and most states in the United States have diagnostic facilities available to the public through universities, the local extension service, or the USDA. If practical, it is better to bring plant samples to the lab and describe the problem to the laboratory technician. Alternatively, include written descriptions with color photographs of the problem. 

If the sample must be mailed, it should be freshly cut and sealed in a paper bag. Wet or moist plant samples mailed in plastic bags arrive at the laboratory mildewed or rotted. Minimize sample damage by proper packing and by shipping early in the week using the fastest shipping method available. Samples should be taken from representative portions of the plant. If a disease organism is to be isolated, the sample should contain the interface between diseased and healthy tissue. 

Most important of all, a detailed description of the problem, the host plant, and the surrounding conditions should accompany the sample to the lab. Rarely is the real problem a simple matter of isolating a fungus or identifying a pest. 

Climbing Introduction

A tree climber's safety depends on the reliability of the safety gear. A worker's safety gear is called personal protective equipment (PPE). This equipment includes a hard hat, safety glasses or goggles, hearing protection, and personal protective clothing. Approved head and eye protection are to be worn at all times by workers engaged in tree care operations.

All equipment used by tree workers, including climbing gear and tools, must conform to applicable safety standards and should not be altered.

Equipment should be inspected according to manufacturers' guidelines. Climbing saddles should be checked for excessive wear and to see that stitching and rivets are strong and intact.

Snaps used in securing the climbing line or lanyard must be self-closing and double-locking. Carabiners for climbing arborists must meet two requirements. First, carabiners used in tree climbing must be positive-locking, which means a climber must perform two separate actions prior to opening the gate. Second, carabiners must meet the minimum tensile strength for traditional steel rope snaps [22.24 kN].

Snaps and carabiners should be checked before and during use to see that they are functioning properly. If carabiners are used, they must be loaded only along their major axis.

A carabiner is strongest when loaded on the major axis, with the gate closed and the sleeve locked. Loading a carabiner in any other way can be dangerous.  This means load on the ends near the curves in the frame and never on the gate or spine.

Climbing lines must be identified by the manufacturer as suitable for tree climbing with adequate strength, wear, and stretch characteristics. Climbing lines are constructed of synthetic materials, and have a minimum tensile strength, when new, of at least 24.02 kN.

Climbing lines should be inspected before each use. Check for cuts, puffs, abrasions, changes in diameter, discoloration, or glazing of the fibers. Be sure that rope ends are sealed by taping or whipping. Snaps should be routinely moved to the opposite end of the line so that the line wears evenly. If one end of the climbing line shows signs of excessive wear, it should be cut off. Old, worn, or cut ropes must be retired from use.

Work-positioning lanyards must also be inspected carefully before each climb. They must meet strength requirements for ropes and snaps. Look for abrasions, excessive wear, or faulty snaps.

Prusik loops and split-tails used in a climbing system must meet the minimum strength standards for climbing lines.

All tree workers should be familiar with the knots and hitches used in tree work. A climber should know how to tie and untie the proper knot or hitch for each application.

A rope has a working end and a running end, or the ends in use and not in use, respectively. Anything not in use in between is the standing part.

Part of knowing how to tie a knot is knowing how to "dress" and "set" the knot properly. To tie a knot, one must first correctly form the knot in the rope. The dressing of the knot is the aligning of the parts; setting it tightens the knot in place. A climber must know how each of the common knots is used, and the advantages and disadvantages of each.

"Knot" is the general term given for all knots, hitches, and bends. A hitch is a type of knot used to secure a rope to an object, another rope, or the standing part of the same rope. A bend joins two rope ends together. There are several categories of knots, hitches, and bends. Tree climbers use endline knots, hitches, and bends to secure the climbing line to carabiners or rope snaps. Endline knots are also used to tie off branches being rigged. 

A type of knot important in tree climbing is the climbing hitch.  Climbing hitches are the "climbing knots" used by climbers to tie in.

For years, the primary climbing hitch used by climbers in the United States has been the tautline hitch.

Characteristics include:

• Used as a climbing (friction) hitch

• Requires a stopper knot (figure 8)

• Has a tendency to roll out

• Must be adjusted (tended) frequently

The Blake’s hitch is growing in popularity because it maintains more uniform friction and does not roll out.

Characteristics include:

• Climbing (friction) hitch, often preferred over the tautline

• Stays dressed and set; no need to tend

• Doesn’t roll out (although a stopper knot is still recommended)

• Higher tendency to glaze on a long or rapid descent

Figure 8:

Characteristics include:

• Used as a stopper knot

• Fast and easy-to-tie endline knot

Bowline:

Characteristics include:

• Strong knot for forming a loop

• Easy to untie, even after loading

• The basis for other knots in the “bowline family” (running bowline, bowline on a bight, sheet bend, double bowline)

Midline Clove hitch:

Characteristics include:   

• Used to send equipment up to the climber

• Quick to tie in the “bight” of a line

Slipknot:

Almost any knot can be “slipped.”  Typically this means the final tuck of the working end is replaced by tucking a bight, instead, so that the knot can be rapidly untied by pulling on the working end. The knot known as the slip knot is a slipped overhand knot.  The bow with which we tie our shoes is a doubly slipped square knot.

Characteristics include:

• Easy to tie, even with one hand

• Experienced climbers find many uses for this knot

• This is a directional knot—it tightens when loaded one way but spills when pulled from the other side.

Sheet bend:

Characteristics include:

• Used to join two ropes of different diameters; often used to send a line up to the climber

• The smaller line should be the one tucked under its own standing part

Double Fisherman's knot

Characteristics include:

• Primary arborist purpose is to form a Prusik loop

• May be difficult to untie after it has been loaded

Prussik hitch:

Characteristics include:

• Friction hitch used in both climbing and rigging applications

• Bi-directional in some applications

• When used as a Prusik loop (as in the secured-footlocking technique), a smaller-diameter rope is used to attach the Prusik to a working line.  The type of rope affects how the knot will work.

Cow hitch with half hitch:

Characteristics include:

• Tied with a sling and used for securing hardware to a tree

• Variation on a simple girth hitch but formed with a line instead of a loop

Timber hitch:

Characteristics include:

• Tied with a sling and used for securing hardware to a tree (especially on large trees when the rope sling is not long enough to tie a cow hitch)

• Always make at least five wraps, spread around the stem

• This hitch is most secure when tied on larger pieces and when the pull is always against the bight, such that it tightens the hitch on the stem. The sling should never be loaded away from the bight because doing so could loosen it.

Half hitch to running bowline:

Characteristics include:

• Used to tie off a section when butt-hitching or when there is no secure point for a running bowline alone

• The half hitch shares the load with the running bowline and reduces the chances of the knot slipping off the piece, once cut.

Tree Inspections and Briefings

Every job must begin with a job briefing that covers the work plan, potential hazards, and all required gear and procedures. Before climbing a tree, a climber must always look carefully and locate any electrical conductors or utility lines.

Check for hazards such as dead or broken limbs, cracks, insects or other animals, weak branch unions, or signs of decay such as conks or fruiting bodies.

Always check the root crown (trunk flare) of a tree as well. Soil, bark, or vines may hide signs or symptoms of decay. Severe crown rot may result in the tree falling over.

The pre-climb inspection should also be used to plan how the tree will be climbed. It is usually a good idea to plan the climbing route while still on the ground and to choose a safe tie-in point from which the tree can be accessed. An experienced climber will also become familiar with the characteristics of various trees. It is essential to know how strong or brittle a tree's wood is. 

Once the tree, site, and climbing gear have been inspected and determined to be acceptable to climb, the climber can plan a climbing strategy. There are many ways of getting into and ascending a tree.

The climber can use the climbing line, a ladder, or climbing spurs (if the tree is to be removed) or a combination of tools. Each method has advantages and limitations. A climber must be tied in or otherwise secured while entering or working in a tree. A safe, acceptable technique is the use of a 2-in-1 lanyard to allow safe movement in the tree while always being secured. This personal lanyard type allows a part of the system to be attached while moving to another limb.  

To set a rope in the tree, a climber may choose to use a throwline. A shot pouch attached to the throwline can be thrown with amazing accuracy through crotches 60 ft (18 m) or higher. Shot pouches are available in various weights, and selection is mostly a matter of preference.

Arborists have developed a number of techniques for throwing, launching, and manipulating throwlines to put them in the specific tree crotch desired. After the throwline passes through the crotch, it falls to the ground. Sometimes the climber must manipulate the cord to encourage the weight to come down. The climber's line can then be attached to the cord of the throw weight (shot pouch) and pulled through the crotch. 

Sometimes a climber may throw the climbing line directly into the tree. On short, open throws, it may be easiest to simply loop the rope over a low limb. For trickier throws, the climber may use a throwing knot. A throwing knot is simply a series of wraps that hold the rope together and provide end weight to facilitate throwing. The throwing knot can be used in an open or closed form; the closed version will not come undone when the rope is thrown.

Once a rope has been set in the tree, there are several methods of ascending. One method is the body-thrust technique in which the climber uses a dynamic rope system or double rope system to climb the tree. Another method is the secured footlock technique in which the climber climbs the rope itself. Other alternatives are variations of the two or techniques that employ mechanical ascending devices. 

In body thrusting, the climber attaches one end of the climbing line to the center D-ring or rings of the saddle. This can be accomplished using a locking snap or double-locking carabiner. After attaching the rope to the hardware, a tail piece of rope is left (or a separate piece is left) to form the climbing hitch around the standing part of the climbing line. 

Technique is important in the body thrust. The climber should place his or her feet high on the trunk of the tree. The hips are thrust upward, creating slack in the line, and simultaneously the other side of the line is pulled down, taking up the slack and keeping the line taut. The climber who relies solely on upper body strength to body thrust can be exhausted after reaching the top. The addition of a micropulley  below the climbing hitch allows a ground worker to advance the knot and pull slack out of the climber's line while the climber ascends. 

Footlocking is another method of ascending a tree once a rope has been set. When footlocking, the climber actually climbs the rope and might not contact the tree until the top. If the footlocking method is used, the climber must use the secured footlock technique. In the secured footlock technique, the use of a Prusik loop makes footlocking much safer. The Prusik loop is tied to the climber's line using a Prusik hitch (or a mechanical device) and attached to the front D-rings of the saddle, using an approved double-locking carabiner or snap. This serves as a means of securing the climber to the line. 

Standing with hands high on the climbing line and with the Prusik hitch above the hands, the climber grabs the rope, raises one foot, and aligns the rope on the inside of his or her knee and across the top of the instep. Then with knees apart, the feet are raised high and the second foot pulls the rope from below and over the first foot. The rope is locked off by standing on top of the section of rope that is wrapped around the foot. The climber then stands up, grabbing with the hands, and the process is repeated.  Once at the top of the rope, the climber must transfer into the tree.

The climber's hands must always stay below the Prusik hitch. Putting the hands on or above the hitch could cause it to slide down the climbing line creating a fall. After ascending, the climber must transfer into the tree. This is a potentially dangerous transfer, so the climber must either tie in or use a work-positioning lanyard before removing the Prusik. If the footlocking rope has been set above a lower limb, the climber will be able to enter the tree onto the lower limb, and transfer will be facilitated. 

Another method of ascending a tree is the use of climbing spurs. Because spurs can damage a tree, they are approved for use only on trees to be removed or for aerial rescues. A climber should never spur up a tree without using a work-positioning lanyard and being tied in with a climbing line. Lanyards are available in a number of lengths and styles. Some have a wire core that makes the line more rigid. This type should never be used around electrical conductors. It should also not be assumed to provide protection from cutting with a chain saw. 

-Information cited from ISA study material.

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