- What is CODIT?
- Compartmentalization Of Decay In Trees — how trees wall off decay behind four protective boundaries (Shigo).
- What is the branch collar?
- The swollen base of a branch where it joins the stem; pruning cuts must be made just outside it, never flush.
- What is a flush cut?
- An improper cut that removes the branch collar, damaging the stem and preventing proper compartmentalization.
- What is a stub cut?
- Leaving too long a branch stub; it dies back, decays, and delays wound closure — improper pruning.
- What is the 3-cut method?
- A pruning technique for heavy branches: undercut, top cut to remove weight, then a final cut at the collar to avoid bark tearing.
- What is the branch bark ridge?
- The raised line of bark in a branch union that, with the branch collar, marks where a proper pruning cut is made.
- What is crown cleaning?
- A pruning type that removes dead, dying, diseased, broken, and weakly attached branches from the crown.
- What is crown thinning?
- Selective removal of live branches to reduce density, improving light and air movement while keeping the natural form.
- What is crown raising?
- Removing lower branches to provide clearance for traffic, pedestrians, buildings, or sightlines.
- What is crown reduction?
- Decreasing the height or spread of a crown using reduction cuts back to a live lateral large enough to assume the terminal role.
- What is a reduction cut?
- Removing a larger branch back to a living lateral at least one-third its diameter (the 1/3 rule), able to assume apical dominance.
- What is a removal (thinning) cut?
- Cutting a branch back to its point of origin at the parent stem or trunk, just outside the branch collar.
- What is a heading cut?
- Cutting between buds or nodes (or to a too-small lateral); causes weak, dense regrowth — generally avoided.
- What is topping?
- An unacceptable practice of cutting branches to stubs or small laterals; causes decay, weak sprouts, and stress.
- What is lion-tailing?
- Over-thinning that strips inner foliage and leaves growth at branch ends; increases breakage risk — avoid it.
- Why prune in the dormant season?
- Less stress and disease spread, clearer structure to see, and vigorous spring growth; ideal for most structural pruning.
- When should oaks NOT be pruned?
- During the growing season in oak-wilt regions; prune in dormancy to avoid attracting beetles that spread oak wilt.
- What is structural (subordination) pruning?
- Reducing competing leaders and co-dominant stems early to develop one dominant trunk and strong scaffold branches.
- What is a co-dominant stem?
- Two or more similarly sized upright stems competing for dominance; often weakly attached and a structural concern.
- What is included bark?
- Bark trapped between a branch and stem (or two stems); creates a weak union prone to splitting.
- How much live crown should be removed at once?
- Generally no more than about 25% in a single pruning, and less for mature or stressed trees.
- Should pruning wounds be painted?
- No — wound dressings are not recommended; they do not prevent decay and can interfere with compartmentalization.
- What is directional (drop-crotch) pruning?
- Reduction cuts to a lateral that redirect growth away from a target like a utility line.
- What is apical dominance?
- The terminal bud's suppression of lateral buds; pruning the leader releases laterals to grow.
- What is a water sprout?
- A vigorous, upright epicormic shoot arising on a branch or trunk, often after heavy pruning or stress.
- What is a sucker?
- An epicormic shoot arising from the root system or below the graft union; usually removed.
- Why disinfect pruning tools?
- To prevent spreading pathogens (e.g., fire blight) between cuts and between trees.
- What is espalier?
- Training a tree to grow flat against a support in a pattern through selective pruning and tying.
- What does the ANSI A300 standard cover?
- U.S. industry standards for tree care operations — pruning, and other practices — that define proper techniques.
- What is photosynthesis?
- The process where leaves use light energy, water, and CO₂ to make sugars (food) and release oxygen.
- What is respiration in trees?
- The process that breaks down sugars to release energy for growth and maintenance, using oxygen and releasing CO₂.
- What is transpiration?
- Water loss as vapor, mostly through leaf stomata; it drives water movement up from the roots.
- What is the function of xylem?
- Conducts water and minerals upward from roots to leaves; older xylem becomes the structural wood.
- What is the function of phloem?
- Transports sugars (food) made in the leaves down and throughout the tree; it lies just inside the bark.
- What is the cambium?
- A thin layer of dividing cells between xylem and phloem that produces new wood and bark, increasing trunk diameter.
- What are stomata?
- Tiny pores, mostly on leaf undersides, that open and close to exchange gases and release water vapor.
- What is heartwood?
- The older, central, non-conducting wood that provides structural support; often darker than sapwood.
- What is sapwood?
- The younger, outer, living wood that actively conducts water and minerals (functional xylem).
- What is meristem tissue?
- Undifferentiated tissue where cell division occurs, allowing growth (apical and lateral meristems).
- What is an apical meristem?
- Growing tip tissue at shoot and root ends responsible for primary (length) growth.
- What is a lateral (root) hair's role?
- Root hairs greatly increase surface area for the absorption of water and nutrients.
- What are mycorrhizae?
- Beneficial fungi that form a symbiosis with roots, extending their reach for water and nutrients.
- What is chlorophyll?
- The green pigment in leaves that captures light energy for photosynthesis.
- What is girdling and why is it fatal?
- Severing bark/phloem around the trunk; it stops downward sugar flow and eventually kills the tree.
- What is the dripline?
- The ground area beneath the outer edge of the crown; a rough guide to root spread, though roots extend beyond it.
- Where are most absorbing roots located?
- In the top 6–18 inches (about 15–45 cm) of soil, often extending well past the dripline.
- What is a deciduous tree?
- A tree that sheds its leaves seasonally, typically in autumn.
- What is a coniferous (evergreen) tree?
- A tree, usually cone-bearing with needles, that keeps foliage year-round.
- What are annual growth rings?
- Yearly layers of xylem; earlywood and latewood form one ring, allowing age and growth-rate estimation.
- What is photosynthate?
- The sugars produced by photosynthesis, transported by phloem to fuel growth and stored as starch.
- What is dormancy?
- A period of suspended growth (often winter) that lets trees survive cold or drought.
- What is alternate leaf arrangement?
- One leaf per node, staggered along the stem — a key ID feature distinguishing many genera.
- What is opposite leaf arrangement?
- Two leaves per node directly across from each other (e.g., maple, ash, dogwood — 'MAD' families).
- What is a simple leaf?
- A leaf with a single, undivided blade attached to the petiole.
- What is a compound leaf?
- A leaf blade divided into multiple leaflets along a common stalk (rachis).
- How do you tell a leaflet from a leaf?
- A bud is found at the base of a true leaf (petiole), but not at the base of a leaflet.
- What is the genus and species format?
- Scientific (binomial) name: capitalized Genus + lowercase species, both italicized (e.g., Quercus rubra).
- Why use scientific names?
- They are precise and universal, avoiding the confusion of multiple common names for one tree.
- What is 'right tree, right place'?
- Matching a species' mature size, form, and site needs to the planting location to reduce future conflicts.
- What is a tree's mature size used for?
- Selecting species that fit the space (above and below ground) to avoid utility, structure, and root conflicts.
- What is hardiness zone selection?
- Choosing species adapted to the site's climate (cold/heat tolerance) for long-term survival.
- What does monoculture risk mean?
- Over-planting one species makes the urban forest vulnerable to a single pest or disease (e.g., elm, ash).
- What is species diversity guidance (10-20-30)?
- Aim for no more than 10% one species, 20% one genus, 30% one family in the urban forest.
- What is a native species?
- A species that occurs naturally in a region; often well-adapted and supportive of local wildlife.
- What is an invasive species?
- A non-native species that spreads aggressively and harms ecosystems, economy, or health.
- What is a cultivar?
- A cultivated variety selected for desirable traits (form, flower, disease resistance); named in 'single quotes'.
- What is deciduous vs evergreen selection?
- Deciduous gives summer shade and winter sun; evergreens give year-round screening and windbreaks.
- What is a tree's form/habit?
- Its characteristic shape (columnar, round, vase, pyramidal) — a key selection and ID trait.
- What is leaf margin?
- The edge of a leaf (entire, toothed/serrate, lobed) used as an identification feature.
- What is bark texture used for?
- An ID feature, especially in winter — smooth, furrowed, plated, or peeling bark distinguishes species.
- What is a dichotomous key?
- An ID tool of paired either/or choices that narrows down to a species step by step.
- What is loam?
- A balanced soil of sand, silt, and clay — good drainage, aeration, and water/nutrient holding for trees.
- What is soil texture?
- The proportion of sand, silt, and clay particles in soil, which affects drainage, aeration, and nutrients.
- What is soil structure?
- How soil particles clump into aggregates, creating pore space for air, water, and roots.
- What is soil compaction's effect?
- It reduces pore space, limiting oxygen and water to roots — a leading cause of urban tree decline.
- What soil pH do most trees prefer?
- Slightly acidic to neutral, roughly 6.0–7.0, where most nutrients are available.
- What is chlorosis?
- Yellowing of leaves (often between veins) from nutrient deficiency, frequently iron or manganese at high pH.
- Which nutrient is most often limiting for trees?
- Nitrogen — needed in the largest amounts and the most common deficiency in landscapes.
- What do N, P, and K stand for?
- Nitrogen (leaf/shoot growth), Phosphorus (roots/energy), Potassium (overall vigor/stress) — the three macronutrients.
- Why is a soil test recommended before fertilizing?
- It identifies pH and actual nutrient needs so you apply only what's deficient, avoiding waste and harm.
- What is mulch and its benefits?
- Organic material over the root zone that conserves moisture, moderates temperature, reduces weeds, and adds organic matter.
- What is a 'mulch volcano' and why avoid it?
- Mulch piled against the trunk; it traps moisture, invites decay and pests, and can girdle the tree.
- What is the correct mulch depth?
- About 2–4 inches (5–10 cm), kept a few inches away from the trunk flare.
- What is cation exchange capacity (CEC)?
- A soil's ability to hold and supply nutrient cations; clays and organic matter raise CEC.
- What is soil aeration (vertical mulching/radial trenching)?
- Techniques that loosen compacted soil and add air/organic matter to improve root health.
- What is field capacity?
- The amount of water soil holds after drainage by gravity — the ideal moisture range for roots.
- What is the permanent wilting point?
- The soil moisture level below which a plant cannot extract water and wilts irreversibly.
- Why is soil organic matter important?
- It improves structure, water holding, nutrient supply, and feeds beneficial soil organisms.
- What is salinity stress?
- High soil salts (e.g., de-icing salt) that draw water from roots and cause leaf scorch and decline.
- What is a soil amendment for the planting hole?
- Generally, backfill with native soil; broad amendment of the hole is not recommended for landscape trees.
- How wide should a planting hole be?
- 2–3 times the width of the root ball, with sloping sides; only as deep as the root ball.
- At what depth should a tree be planted?
- With the trunk flare (root flare) at or slightly above grade — never buried too deep.
- What is the trunk (root) flare?
- The widening at the base where the trunk meets the roots; it must be visible at the soil line.
- Why not plant too deep?
- Deep planting suffocates roots and promotes stem-girdling roots and decline.
- What should be done with burlap and wire baskets?
- Remove/fold down the top of the basket and burlap after setting the ball to free the roots.
- How should circling roots be handled at planting?
- Tease apart, straighten, or cut circling/girdling roots so they grow outward.
- When is staking necessary?
- Only when needed for stability or vandalism; stake low and loosely, and remove after about one year.
- Why remove stakes after one year?
- Trees develop stronger trunk taper and roots when allowed to flex; long-term staking weakens them.
- What is the watering need for a new tree?
- Deep, regular watering during establishment (often the first 1–3 years) to keep the root ball moist, not soggy.
- What is transplant shock?
- Stress and reduced growth after planting from root loss; minimized by proper handling, planting, and watering.
- What is B&B stock?
- Balled-and-burlapped: field-grown trees dug with a soil ball wrapped in burlap.
- What is bare-root stock?
- Trees sold with soil removed from roots; lightweight, best planted dormant with roots kept moist.
- What is container stock?
- Trees grown in pots; check for and correct circling roots before planting.
- How long does establishment take?
- Roughly one year per inch of trunk diameter before a tree is fully established.
- Should you fertilize at planting?
- Generally no nitrogen at planting; focus on proper depth, mulch, and water for root establishment.
- What is the best season to plant most trees?
- Dormant season — fall or early spring — to reduce stress and allow root growth before heat.
- What is a stem-girdling root?
- A root that grows around and compresses the trunk, restricting flow and slowly killing the tree.
- Why keep the root ball intact for B&B?
- Disturbing the ball breaks remaining roots and worsens transplant shock.
- What is Plant Health Care (PHC)?
- A holistic program of monitoring and maintaining tree health using cultural, preventive, and least-toxic methods.
- What is Integrated Pest Management (IPM)?
- A strategy that prioritizes monitoring, prevention, and cultural/biological controls, using pesticides only as a last resort.
- What is the first step in IPM?
- Correctly identify the pest/problem and monitor; intervention follows only when thresholds are exceeded.
- What is an action (treatment) threshold?
- The pest level at which control action is justified to prevent unacceptable damage.
- What is a biotic disorder?
- A problem caused by a living agent — insect, fungus, bacterium, virus, or nematode.
- What is an abiotic disorder?
- A non-living cause of stress — drought, compaction, salt, mechanical injury, or improper planting.
- How do biotic vs abiotic damage patterns differ?
- Biotic spreads progressively and is often species-specific; abiotic is usually uniform and non-spreading.
- What is the disease triangle?
- Disease requires a susceptible host, a virulent pathogen, and a favorable environment together.
- What is a fungal pathogen example?
- Anthracnose, powdery mildew, or root rots (e.g., Armillaria) caused by fungi.
- What is a signs vs symptoms distinction?
- Signs are the pathogen itself (fungal fruiting bodies); symptoms are the host's response (wilting, cankers).
- What is a borer?
- An insect whose larvae tunnel under bark or in wood (e.g., emerald ash borer), disrupting transport.
- What is the emerald ash borer (EAB)?
- An invasive beetle whose larvae kill ash trees by tunneling and girdling the cambium.
- What is leaf scorch?
- Browning of leaf margins from water stress, heat, salt, or root problems — often abiotic.
- What is a canker?
- A localized dead area of bark and cambium, often from fungal or bacterial infection at a wound.
- What is the role of biological control?
- Using natural enemies (predators, parasitoids, pathogens) to suppress pest populations.
- What is a sucking insect?
- Pests like aphids and scale that feed on sap, causing distortion, honeydew, and sooty mold.
- What is honeydew and sooty mold?
- Sugary excretion from sap-feeders (honeydew) that grows black sooty mold fungus on leaves.
- What is a defoliator?
- An insect that eats leaves (e.g., caterpillars); repeated defoliation stresses and can kill trees.
- Why is proper diagnosis essential before treatment?
- Treating the wrong cause wastes resources and can harm the tree; identify the agent first.
- What is the tree (root) protection zone (TPZ)?
- A fenced area around a tree, often based on trunk size or dripline, that excludes construction impacts.
- What is the critical root zone (CRZ)?
- The soil/root area essential to a tree's survival, commonly estimated from trunk diameter (e.g., ~1 ft radius per inch DBH).
- What is the biggest construction threat to trees?
- Soil compaction and root severance in the root zone — often unseen until decline appears later.
- Why install protective fencing before construction?
- To keep equipment, materials, and traffic out of the root zone and prevent compaction and damage.
- What is grade change and why is it harmful?
- Adding or removing soil over roots; fill suffocates roots and cuts reduce them, both causing decline.
- What is DBH?
- Diameter at Breast Height — trunk diameter measured at 4.5 ft (1.4 m), used for sizing CRZ/TPZ and risk work.
- What is trenching damage?
- Cutting through roots for utilities; severs major roots, reducing stability and water uptake.
- What is a tunneling (boring) alternative?
- Boring under the root zone instead of trenching to install utilities with minimal root loss.
- Why involve an arborist before construction starts?
- Early planning protects trees through design, fencing, and specifications rather than reacting to damage.
- What is a tree inventory/assessment for a site?
- Documenting species, condition, and value of trees to decide which to preserve and how.
- What is the effect of paving over roots?
- Reduces oxygen and water infiltration to roots; use permeable surfaces or suspended pavement where possible.
- What can mitigate root-zone soil compaction?
- Mulch, plywood/ground protection mats over root zones, and limiting equipment access.
- What is structural soil?
- An engineered load-bearing soil that supports pavement while allowing root growth in urban sites.
- What is a tree well?
- A retaining structure around a trunk when grade is raised, intended to keep soil off the root flare.
- Why does damage from construction often appear years later?
- Root loss and compaction cause a slow decline; symptoms can lag the injury by several years.
- What is air spading near construction?
- Using compressed air to excavate soil without cutting roots, exposing them for inspection or utility work.
- What are the components of tree risk?
- Likelihood of failure × likelihood of impacting a target × consequences of that impact.
- What is a 'target' in risk assessment?
- People, property, or activities that could be struck if a tree or part fails.
- What are the three levels of tree risk assessment?
- Level 1 (limited visual), Level 2 (basic walk-around), and Level 3 (advanced, with tools).
- What is a Level 2 (basic) assessment?
- A 360° ground inspection of the whole tree and site — the standard arborist assessment.
- What is a codominant stem with included bark (risk)?
- A weak union prone to splitting; a common structural defect raising failure likelihood.
- What is a cavity/decay defect?
- Internal or open decay that reduces sound wood and load-bearing capacity, raising failure risk.
- What is a hanger?
- A broken, detached branch lodged in the crown that can fall — an immediate risk.
- What is lean as a risk indicator?
- A recent or progressive lean (especially with soil heaving/cracking) suggests possible root or stability failure.
- What is girdling/root decay as a risk factor?
- Loss of structural roots reduces anchorage and increases whole-tree (uprooting) failure likelihood.
- What is a risk rating matrix?
- A tool combining likelihood of failure-and-impact with consequences to assign Low/Moderate/High/Extreme risk.
- What is a mitigation option for tree risk?
- Pruning, cabling/bracing, moving the target, reducing use, or removing the tree.
- What is cabling and bracing?
- Hardware that supplements weak unions/limbs to reduce failure risk; cables (flexible) and rods/braces (rigid).
- What is the difference between hazard and risk?
- A hazard is a defect with potential to cause harm; risk also considers the likelihood and the consequences.
- What is a 'qualitative' risk assessment?
- A categorical (Low–Extreme) judgment of risk, the most common method in ISA's TRAQ approach.
- What does TRAQ stand for?
- Tree Risk Assessment Qualification — ISA's standardized methodology for assessing tree risk.
- What is a residual risk?
- The risk that remains after mitigation actions are taken.
- What is the response time for an imminent risk?
- Action is recommended urgently — the failure is likely and a target is present.
- What is a likelihood of failure scale?
- Improbable, Possible, Probable, or Imminent — describing how likely a part is to fail.
- What is a basal/root crown inspection?
- Checking the trunk base and root flare for decay, cavities, fungi, and girdling roots affecting stability.
- What do fungal fruiting bodies (conks) on a trunk indicate?
- Possible internal wood decay; a sign to investigate structural soundness.
- What is the 'occupancy rate' of a target?
- How often a target is present in the strike zone; it affects the likelihood-of-impact rating.
- What PPE is required for chain saw work?
- Head, eye, and hearing protection, cut-resistant leg protection (chaps), gloves, and proper boots.
- What is the minimum approach distance (MAD)?
- The closest a worker may get to energized power lines; only qualified line-clearance arborists may work near them.
- Who may work near energized conductors?
- Only qualified line-clearance arborists, trained and authorized — never untrained ground workers.
- What standard governs U.S. arborist safety?
- ANSI Z133 — the safety standard for arboricultural operations.
- What is the drop zone?
- The area where cut limbs or debris may fall; it must be kept clear of people and verbally controlled.
- What is the role of a second worker (ground person)?
- To monitor the climber, manage the drop zone, handle ropes, and respond to emergencies — never work alone aloft.
- What is an aerial rescue?
- A planned procedure to bring down an injured climber; ground crew must be trained to perform it.
- What is kickback on a chain saw?
- A sudden upward/backward thrust when the upper bar nose contacts wood; a major cause of saw injuries.
- How is chain saw kickback reduced?
- Chain brake, reduced-kickback chain, avoiding the bar-nose 'kickback zone', and proper technique.
- What is a climbing system requirement?
- A climber must be tied in with a proper climbing line/saddle; ANSI Z133 requires being secured while aloft.
- What is two-rope (work-positioning + lifeline) practice?
- Using a separate secondary attachment so a climber is never reliant on a single point during certain operations.
- What is a chipper safety rule?
- Never reach into the feed; feed butt-first, stand to the side, and keep loose clothing away.
- What is traffic/work-zone control?
- Cones, signs, and flaggers to protect workers and the public around roadside tree work.
- What is electrical hazard recognition?
- Identifying nearby conductors and assuming all lines are energized until verified otherwise.
- What is a pre-work job briefing?
- A crew discussion of hazards, the work plan, the drop zone, communication, and emergency procedures.
- What is lowering (rigging) used for?
- Controlling the descent of cut limbs with ropes/blocks to protect targets and workers below.
- What is the danger of working a chain saw above shoulder height?
- Reduced control and higher kickback injury risk; use a pole saw or reposition instead.
- What is fall protection while aloft?
- Continuous tie-in with a climbing system; never disconnect from all attachment points while in the tree.
- What is a 'qualified arborist' under Z133?
- One trained and knowledgeable in tree work and associated hazards to perform the task safely.
- What is the first action at an electrical contact incident?
- Stay clear, keep others back, call for help/utility; do not touch the victim or equipment in contact.
- What is GFCI / equipment inspection?
- Inspecting saws, ropes, saddles, and lanyards before use and removing damaged gear from service.
- Why is hydration and fatigue management a safety issue?
- Fatigue and heat impair judgment and reaction time, raising the chance of serious tree-work accidents.
- What is urban forestry?
- The management of trees and forests in cities for environmental, social, and economic benefits.
- What is the urban heat island effect?
- Cities are hotter than surrounding areas; tree canopy cools them through shade and transpiration.
- What are ecosystem services of urban trees?
- Stormwater interception, air-quality improvement, cooling, carbon storage, wildlife habitat, and property value.
- What is canopy cover?
- The percentage of ground shaded by tree crowns; a key metric of urban forest extent and benefit.
- How do trees manage stormwater?
- Canopies intercept rain and roots increase infiltration, reducing runoff and flooding.
- How do urban trees improve air quality?
- They capture particulates and absorb some gaseous pollutants, while shade reduces ozone-forming heat.
- What is a tree inventory?
- A record of a community's trees (species, size, location, condition) used to plan and manage the urban forest.
- What is an urban forest management plan?
- A long-term strategy for planting, maintenance, diversity, and budgeting of community trees.
- Why is species diversity important in cities?
- It limits catastrophic loss from a single pest/disease and stabilizes the urban canopy over time.
- What is the role of community engagement?
- Public support and stewardship (e.g., volunteer planting, care) sustain the urban forest.
- What is a 'right-of-way' tree concern?
- Trees near utilities and roads requiring clearance pruning and careful species selection.
- What is carbon sequestration by trees?
- Trees absorb and store atmospheric carbon in wood and soil, offsetting some emissions.
- What is the value of mature canopy vs young trees?
- Large, healthy mature trees provide far greater benefits than many small ones, so preserving them is high priority.
- What is a pollard?
- A pruning system that repeatedly cuts back to the same points (pollard heads) to maintain a small, formal crown.
- What is restoration pruning?
- Selective pruning over several years to improve the structure of a topped, vandalized, or storm-damaged tree.
- What is vista pruning?
- Selective branch removal to open a view through a tree without harming its health or form.
- When is the best time to remove dead wood?
- Dead, diseased, and hazardous branches can be removed at any time of year.
- What is the natural target pruning concept?
- Cutting just outside the branch collar/bark ridge so the tree's natural defenses close the wound (Shigo).
- Why avoid pruning a newly planted tree heavily?
- It needs its full leaf area to make food and establish roots; limit early pruning to defects only.
- What is utility (line-clearance) pruning?
- Specialized pruning to keep trees a safe distance from power lines, using directional reduction cuts.
- What is the parent branch?
- The larger stem or limb from which a smaller branch arises; removal cuts return to it at the collar.
- What is turgor pressure?
- Water pressure inside plant cells that keeps tissues firm; its loss causes wilting.
- What is the role of leaves' palisade layer?
- The upper leaf cells packed with chloroplasts where most photosynthesis occurs.
- What is starch storage in trees?
- Excess photosynthate is stored as starch in roots, stems, and branches for use during dormancy and flush.
- What is the difference between primary and secondary growth?
- Primary growth lengthens shoots/roots (apical meristems); secondary growth thickens them (cambium).
- What are lenticels?
- Pores in bark and stems that allow gas exchange between internal tissues and the air.
- What is a node and an internode?
- A node is where leaves/buds attach; the internode is the stem segment between nodes.
- What is photoperiodism?
- Plant responses to day length, triggering events like dormancy, flowering, and leaf drop.
- What is the cohesion-tension theory?
- Transpiration pulls a continuous water column up the xylem, held together by water's cohesion.
- What is a vascular cambium product toward the inside vs outside?
- It produces xylem (wood) toward the inside and phloem (inner bark) toward the outside.
- What is a whorled leaf arrangement?
- Three or more leaves arising at a single node.
- What is a pinnately compound leaf?
- Leaflets arranged along both sides of a central rachis, like a feather (e.g., ash, walnut).
- What is a palmately compound leaf?
- Leaflets radiating from a single point, like fingers from a palm (e.g., buckeye, horsechestnut).
- What is venation?
- The pattern of veins in a leaf (pinnate, palmate, parallel) used in identification.
- What is a samara?
- A winged dry fruit (e.g., maple 'helicopter', ash) — an ID clue.
- Why match a tree to soil and drainage?
- Selecting species tolerant of the site's soil, pH, and moisture greatly improves survival.
- What is salt tolerance in selection?
- Choosing species that withstand de-icing or coastal salt for roadside and seaside sites.
- What is a tree's growth rate trade-off?
- Fast-growing trees establish quickly but often have weaker wood and shorter lives than slow growers.
- What is fertilizer 'slow-release' nitrogen?
- Nitrogen that releases gradually, reducing burn risk and leaching and feeding over a longer period.
- What does a high clay content cause?
- Poor drainage and aeration but high nutrient/water holding; prone to compaction.
- What does a high sand content cause?
- Excellent drainage and aeration but low water and nutrient retention.
- What is the rhizosphere?
- The zone of soil around roots influenced by root activity and rich in microbial life.
- What is leaf tissue analysis?
- Lab testing of foliage to diagnose nutrient deficiencies more precisely than soil tests alone.
- What is the role of beneficial soil microbes?
- They cycle nutrients, improve structure, and protect roots — supported by organic matter and mulch.
- What is poor drainage's effect on roots?
- Waterlogged, low-oxygen soil suffocates roots and promotes root-rot pathogens.
- What is a percolation test?
- Measuring how fast water drains from a hole to assess soil drainage before planting.
- What is the correct way to carry a B&B tree?
- By the root ball, never by the trunk, to avoid breaking roots and loosening the ball.
- Why water deeply and infrequently after establishment?
- It encourages deep, drought-resistant roots rather than shallow ones from frequent light watering.
- What is anti-desiccant use?
- A spray sometimes used on evergreens to reduce winter water loss after transplanting.
- What is the danger of synthetic burlap?
- Treated/synthetic burlap does not decompose and can girdle roots; remove it at planting.
- What is hardening off?
- Gradually acclimating nursery stock to outdoor conditions before or after planting to reduce shock.
- Should turf grow right up to a young tree?
- No — grass competes for water/nutrients; a mulch ring reduces competition and mower/trimmer damage.
- What is trunk protection for young trees?
- Guards or wraps that prevent sunscald, rodent damage, and string-trimmer wounds.
- What is a systematic diagnostic process?
- Identify the plant, define normal, examine symptoms/signs, consider history and site, then diagnose.
- What is a soil-borne pathogen example?
- Phytophthora and Armillaria root rots that attack roots and the root collar.
- What is a vascular wilt disease?
- A pathogen (e.g., Dutch elm disease, oak wilt, Verticillium) that plugs the water-conducting xylem.
- What is Dutch elm disease?
- A fungal vascular wilt spread by elm bark beetles and root grafts that kills American elms.
- What is oak wilt?
- A lethal fungal vascular disease of oaks spread by beetles and root grafts; avoid wounding oaks in season.
- What is a host-specific pest clue?
- Damage limited to one species or genus often points to a biotic (living) cause.
- What is the least-toxic control principle?
- Choose cultural, mechanical, and biological controls first; use targeted pesticides only when justified.
- What is a trunk-injection treatment?
- Delivering a pesticide or nutrient directly into the vascular system for certain pests/diseases.
- What is monitoring (scouting)?
- Regularly inspecting trees to detect pests/problems early before they exceed action thresholds.
- What is a tree appraisal?
- Estimating a tree's monetary value (e.g., trunk-formula method) for loss, insurance, or planning.
- Why is a single trunk-wound rarely fatal alone?
- Healthy trees compartmentalize a wound; repeated or large wounds plus root loss cause decline.
- What is the impact of soil fill over the root zone?
- Even a few inches of fill can reduce oxygen to roots and cause gradual decline.
- What is a preservation specification?
- Written requirements (fencing, no-storage, pruning, monitoring) protecting trees during a project.
- What is the order of CRZ priority?
- Protect the root zone first; root and soil damage is harder to fix than canopy pruning.
- What is the effect of equipment fluids/spills near trees?
- Fuel, oil, and concrete washout are toxic to roots and soil — keep them out of the root zone.
- What is the difference between sound and decayed wood strength?
- Decayed wood loses load-bearing strength; the amount and location of remaining sound wood matter for stability.
- What is the 't/R' or wall-thickness guideline?
- A rough rule that risk rises when sound shell thickness is small relative to trunk radius (interpret with judgment).
- What is a crack as a defect?
- A separation in wood (e.g., from included bark or stress) that can indicate impending failure.
- What is a target rating?
- An evaluation of how exposed people/property are to a potential failure (occupancy and value).
- What is a risk assessment report's purpose?
- To document findings, risk rating, and recommended mitigation so the owner can make informed decisions.
- What is an advanced (Level 3) tool example?
- Resistance drills, sonic tomography, or pull tests to assess internal decay or root anchorage.
- What is the role of tree history in risk?
- Past failures, weather events, and recent site changes inform the likelihood of future failure.
- What is the ANSI Z133 electrical rule of thumb for non-qualified workers?
- Maintain a safe minimum distance from energized lines; treat all conductors as energized.
- What is a friction-saving device in rigging?
- Hardware (blocks, friction devices) that controls rope load when lowering heavy limbs.
- What is the proper way to start a chain saw?
- On the ground or firmly braced with the chain brake engaged — never 'drop starting'.
- What is a safe ground-worker position when limbs drop?
- Out of the drop zone, in clear view of the climber, with planned escape routes.
- What is the danger of a lone climber?
- No one can perform aerial rescue or manage hazards; a trained ground person is required.
- What is high-visibility clothing for?
- To make workers visible to traffic and equipment operators in and near roadways.
- What is the inspection rule for climbing rope?
- Inspect before each use for cuts, glazing, and wear; retire any rope that fails inspection.
- What is i-Tree?
- A suite of tools that quantifies the benefits and value of trees (canopy, stormwater, air, carbon).
- What is structural diversity in the urban forest?
- A mix of tree ages and sizes so the canopy is sustained as old trees decline.
- What is a planting plan's site assessment?
- Evaluating space, soil, utilities, and use to choose the right tree for each location.
- Why do urban trees often have short lifespans?
- Compacted, limited soil, heat, drought, salt, and damage shorten city tree life versus forest trees.
- What is the economic benefit of street trees?
- Higher property values, business district appeal, and reduced energy costs from shade.
