Mixed Deck — All ISA Topics Flashcards

What is the primary purpose of establishing a drop zone during tree removal operations?

Answer: To create a clear area where cut material can safely fall without striking people or property

A drop zone is a designated clear area below the work where cut branches and sections can fall safely, protecting ground workers and bystanders from being struck by falling material.

Nitrogen deficiency in trees typically presents as:

Answer: Uniform yellowing of older leaves first

Nitrogen is mobile in the plant, so deficiency symptoms appear first on older leaves as nitrogen is redirected to new growth.

What is the proper timing for fertilizing deciduous trees in most temperate climates?

Answer: Late fall after leaf drop or early spring before bud break, when roots can absorb nutrients without supporting active shoot growth

Fertilization is most effective in late fall (after leaf drop, while soil is still warm) or early spring (before bud break). Late fall applications allow root absorption and storage; spring applications support the flush of new growth.

What is the proper hand signal for 'stop' during crane-assisted tree removal?

Answer: One arm extended with a closed fist

The standard hand signal for 'stop' in crane operations is extending one arm with a closed fist. This is part of the universally recognized crane hand signal system used across industries.

Which of these processes is essential for converting stored sugars into usable energy for a tree's growth, maintenance, and defense, and requires oxygen to occur?

Answer: Respiration

Respiration is the metabolic process where trees break down sugars (produced during photosynthesis) to release energy for various life processes. This process requires oxygen, which is why soil aeration is critical for root health, as roots must also respire. Photosynthesis creates sugars, while respiration consumes them to produce energy.

What is the recommended depth for applying organic mulch around trees?

Answer: 2–4 inches

A 2–4 inch mulch layer conserves moisture and moderates temperature without creating anaerobic conditions at the root flare.

Why is the concept of the 'critical root zone' important during construction near trees?

Answer: It defines the minimum area around a tree that must be protected from soil compaction, grade changes, and root severance to maintain tree health and stability

The critical root zone (CRZ) represents the minimum root area necessary for tree survival and structural stability. Damage within the CRZ from compaction, root cutting, or grade changes frequently leads to post-construction tree decline and potential failure.

A 'target' in tree risk assessment refers to:

Answer: People, property, or activities that could be harmed by tree failure

A target is any person, property, or activity in the vicinity of the tree that could be injured or damaged if the tree or a part of it fails.

What is 'etiolation' in trees or seedlings grown under insufficient light?

Answer: Abnormal elongation of stems and pale coloration due to low light

Etiolation is the elongated, pale, and weak growth that occurs when plants are grown in insufficient light, as they stretch toward the light source while producing less chlorophyll.

An arborist is setting their climbing line using a moving rope system (MRS) with a friction hitch. Before leaving the ground, what is the most critical safety check that must be performed on the climbing system?

Answer: Testing the hitch to confirm it grips the rope securely and releases when intended.

Before an arborist's weight is committed to the climbing system, the friction hitch must be tested to ensure it functions correctly. This involves making sure it will grab the rope to hold the climber's weight, but also release smoothly for controlled movement. This function check is paramount to preventing an uncontrolled ascent or descent.

In which direction does the phloem primarily transport photosynthates (sugars) within a tree?

Answer: From leaves and other sources to roots and other sinks

Phloem transport follows the source-to-sink model: sugars produced by photosynthesis in leaves (sources) are loaded into the phloem and transported to areas of active growth or storage such as roots, developing fruit, and cambium (sinks). This pressure-flow mechanism moves photosynthates bidirectionally along the phloem but always from high-pressure sources to low-pressure sinks.

What biosecurity measures should arborists take when pruning trees affected by or at risk for certain transmissible diseases?

Answer: Disinfect cutting tools between trees using 70% isopropyl alcohol, 10% bleach solution, or other approved disinfectants; clean equipment; and properly dispose of infected material

When pruning trees with transmissible diseases (fire blight, Dutch elm disease, oak wilt), tools must be disinfected between cuts or between trees. Infected material should be disposed of properly (not chipped on site), and equipment should be cleaned to prevent spreading pathogens.

A landscape design specifies planting several trees in an area with sandy soil. To improve the site for better tree establishment, an arborist should primarily focus on amending the soil to:

Answer: Increase the water and nutrient-holding capacity.

Sandy soils are characterized by large particles and large pore spaces, leading to rapid drainage and low nutrient retention. The primary goal of amending sandy soil for tree health is to increase its ability to hold water and essential nutrients, typically by incorporating organic matter.

An arborist is tasked with reducing the length of a major limb on a mature maple tree to provide clearance for a nearby structure. To maintain structural integrity and promote proper wound closure, which type of pruning cut is most appropriate for this task?

Answer: A reduction cut (drop-crotching)

A reduction cut, also known as drop-crotching, is the correct technique for reducing the length of a large branch. This cut shortens a limb back to a lateral branch that is large enough (at least one-third the diameter of the removed portion) to assume the terminal role, which helps maintain a natural form and promotes compartmentalization. Heading cuts on large branches are a form of topping that leads to decay and weakly attached sprouts. A flush cut removes the branch collar, damaging trunk tissue and inhibiting wound closure. A removal cut is used to take off an entire branch at its point of origin, not to shorten it.

A soil test report for a park's London plane trees indicates a pH of 8.0. This alkaline condition is most likely to cause a deficiency in which of the following micronutrients?

Answer: Iron and Manganese

Soil pH significantly affects the availability of nutrients to tree roots. In highly alkaline soils (pH above 7.5), micronutrients such as iron and manganese become chemically locked and less available for plant uptake, often leading to deficiencies.

An arborist observes a tree with a tall, dominant central leader and suppressed lateral branch growth. This growth pattern is a classic example of:

Answer: Apical dominance

Apical dominance is the phenomenon where the central, terminal bud (apical bud) produces hormones, primarily auxin, that inhibit the growth of the lateral buds below it. This results in the tree prioritizing vertical growth over lateral branching, leading to a strong central leader.

What is the effect of over-watering trees?

Answer: Leads to root rot

Over-watering trees deprives their roots of essential oxygen by saturating the soil, creating an anaerobic environment. This lack of oxygen, combined with excessive moisture, promotes the growth of harmful fungi and bacteria, which leads to root rot. Root rot severely impairs the tree's ability to absorb water and nutrients, ultimately causing decline and death.

Which nutrient deficiency is most commonly associated with interveinal chlorosis on young (new) leaves?

Answer: Iron

Iron deficiency causes interveinal chlorosis on young leaves because iron is immobile in the phloem and cannot be reallocated from older tissues to new growth.

Why is deep root fertilization often preferred over surface application for established trees in maintained landscapes?

Answer: Deep injection places nutrients below the turfgrass root zone, reduces nutrient competition, and can help alleviate mild soil compaction

Deep root fertilization injects liquid nutrients below the competing turfgrass root zone (8-12 inches deep), delivering nutrition directly to the tree's absorptive root zone while the injection pressure provides minor soil aeration benefits.

A TRAQ-qualified arborist is assessing a tree with a significant cavity at its base. The tree is located in a remote, rarely visited section of a large forest preserve with no trails or structures nearby. How does the absence of a target affect the overall risk rating?

Answer: It significantly lowers the risk rating, as risk requires a combination of a failing tree part and a target to be impacted.

For a significant risk to exist, there must be both a tree with the potential for failure and a target (people, property, or activity) that could be affected. If there is no target, even a tree with a high likelihood of failure will have a very low overall risk rating because the 'consequences' component of the risk equation is negligible.