Philippine Forester Licensure Examination (PFLE) — Questions and Answers

Question 1: The edge effect in forest ecology typically results in which of the following?

Lower ambient temperatures along forest edges
Reduced invasive plant establishment
Increased nest predation rates for forest interior birds (Correct answer)
Decreased species diversity at habitat boundaries

Correct answer: Increased nest predation rates for forest interior birds

Forest edges expose bird nests to higher predation pressure from edge-adapted predators like raccoons and crows that penetrate into adjacent interior habitat.

Question 2: In forest economics, 'stumpage value' refers to:

The value of wood after milling
The standing timber value at the stump before harvest (Correct answer)
The cost of removing stumps after logging
The market price of finished lumber

Correct answer: The standing timber value at the stump before harvest

Stumpage value is the price paid for standing timber, representing what remains after subtracting harvesting and transport costs from log market value.

Question 3: Which defect causes the most significant reduction in structural lumber strength according to US grading rules?

Large knots crossing the grain at critical locations (Correct answer)
Slight discoloration (stain)
Surface checks on wide faces
Minor pitch pockets in the heartwood

Correct answer: Large knots crossing the grain at critical locations

Knots interrupt the continuity of wood fibers and create stress concentrations, dramatically reducing tensile and bending strength, especially when located in high-stress zones.

Question 4: Which soil property most directly controls the rate of infiltration?

Soil color
Organic matter color
Bulk density and porosity (Correct answer)
Cation exchange capacity

Correct answer: Bulk density and porosity

Bulk density and porosity determine pore space available for water entry; compacted soils have low porosity and reduced infiltration rates.

Question 5: After a disaster, the first step is for the soil to form.

Primary succession (Correct answer)
Secondary succession
Tertiary succession
Ecological succession

Correct answer: Primary succession

Primary succession is the ecological process that occurs in an area where no soil or life previously existed, such as after a volcanic eruption or glacial retreat. The very first step in this process is the formation of soil from bare rock, typically initiated by pioneer species like lichens and mosses. These organisms break down rock and contribute organic matter, gradually creating a substrate for more complex plant life.

Question 6: The Janka hardness test for wood measures:

Resistance to splitting when a nail is driven
Tensile strength parallel to the grain
Modulus of elasticity under bending loads
The force required to embed a 0.444-inch steel ball halfway into the wood surface (Correct answer)

Correct answer: The force required to embed a 0.444-inch steel ball halfway into the wood surface

The Janka test presses a standardized steel ball halfway into a wood surface and records the load required, providing a relative measure of hardness and wear resistance.

Question 7: In forest soils of the southeastern US, Phytophthora cinnamomi causes a root rot disease that is most severe under which soil condition?

Highly acidic peat soils
Calcareous limestone soils
Poorly drained, waterlogged soils (Correct answer)
Well-drained sandy soils

Correct answer: Poorly drained, waterlogged soils

Phytophthora cinnamomi thrives and spreads its zoospores most effectively in poorly drained, saturated soils where anaerobic conditions develop.

Question 8: Which forest mensuration approach uses fixed-radius plots to estimate stand density and species composition?

Line-intercept transects
Fixed-area plot sampling (Correct answer)
Point sampling (prism cruising)
Bitterlich method

Correct answer: Fixed-area plot sampling

Fixed-area plot sampling enumerates all trees within a defined radius, allowing direct calculation of density, basal area, and species composition per unit area.

Question 9: The 'fire rotation' concept refers to the average time required for fire to:

Consume all available fine fuels
Burn an area equivalent to the entire landscape once (Correct answer)
Complete one full seasonal cycle
Return to the same stand twice

Correct answer: Burn an area equivalent to the entire landscape once

Fire rotation (or fire cycle) is the estimated time needed for fire to burn across an area equal to the total landscape under study.

Question 10: In the calculation of a rangeland's carrying capacity, which one of the following factors is excluded from the computation?

Area of the rangeland (Correct answer)
Forage production
Forage consumption
Proper use factor

Correct answer: Area of the rangeland

The calculation of a rangeland's carrying capacity primarily involves factors like total forage production, the proper use factor (percentage of forage that can be safely consumed), and the forage consumption rate per animal unit. While the total area of the rangeland is essential for determining the *total* forage production, it is often considered an input to derive total production rather than a separate factor *excluded* from the core calculation of how much forage is available and consumable per animal unit.

Question 11: Capability to rapidly revert to pre-disturbance conditions

Adaptation
Resilience (Correct answer)
Sustainability
Stability

Correct answer: Resilience

Resilience, in an ecological context, is the capacity of an ecosystem to absorb disturbance and reorganize while undergoing change, so as to retain essentially the same function, structure, identity, and feedbacks. Specifically, it refers to the speed and extent to which an ecosystem can recover and return to its pre-disturbance state after being disrupted. This ability to bounce back is crucial for ecosystem health and persistence.

Question 12: The International 1/4-inch log rule, Scribner rule, and Doyle rule are all examples of:

Silvicultural treatment prescriptions
Log volume estimation methods (Correct answer)
Stem taper equations
Site index tables

Correct answer: Log volume estimation methods

These are standard log rules used in the US to estimate the board-foot volume of sawlogs based on log diameter and length.

Question 13: What is the initial stage of the selective logging process called?

Road construction
Residual inventory
PCT inventory
Tree marking (Correct answer)

Correct answer: Tree marking

Tree marking is the initial and critical stage in the selective logging process. During this phase, foresters identify and mark individual trees to be harvested and those to be retained as residuals, based on specific silvicultural guidelines and management objectives. This careful selection ensures that the desired stand structure, species composition, and future productivity are maintained after logging.

Question 14: The CODIT (Compartmentalization of Decay in Trees) model, developed by Alex Shigo, explains how trees respond to wounding by:

Shedding infected branches through abscission to prevent decay from entering the trunk
Forming four walls of chemical and anatomical barriers to limit decay spread in existing and new wood (Correct answer)
Producing systemic antifungal compounds that kill pathogens throughout the tree
Rapidly replacing infected sapwood with heartwood to physically block pathogen advance

Correct answer: Forming four walls of chemical and anatomical barriers to limit decay spread in existing and new wood

CODIT describes four compartmentalization walls that trees form—blocking vertical, radial, and tangential spread in existing wood, plus a barrier zone in new wood—to limit decay following wounding.

Question 15: Which statistical measure is most commonly used to express the precision of a timber cruise estimate?

Sampling error (expressed as a percentage of the mean at a specified confidence level) (Correct answer)
Range of plot volumes
Mode of the volume distribution
Median absolute deviation

Correct answer: Sampling error (expressed as a percentage of the mean at a specified confidence level)

Timber cruises report sampling error as a percentage of the mean volume at a specified confidence level (usually 95%), indicating how close the estimate is likely to be to the true value.

Question 16: Which fire ecology term describes a landscape pattern where patches of high-, moderate-, and low-severity fire create a mosaic of habitat types?

Pyroclastic heterogeneity
Fire patchwork syndrome
Burn severity gradient
Pyrodiversity (Correct answer)

Correct answer: Pyrodiversity

Pyrodiversity refers to the variety of fire effects across a landscape, which promotes biodiversity by creating diverse habitat structures simultaneously.

Question 17: An exemplary instance of a surface fire is...

fires that occur along newly exposed edges of forest after fragmentation has occurred
fire that allows dead wood, leaves, and other flammable ground litter to accumulate
fire that is deliberately set, frequently in the tropical rainforest, after the trees have been cut down
the type of fire that burns seedlings, small trees, and leaf litter, but not mature trees and most animals (Correct answer)

Correct answer: the type of fire that burns seedlings, small trees, and leaf litter, but not mature trees and most animals

A surface fire is characterized by burning low-intensity fuels on the forest floor, such as leaf litter, dead wood, and small plants. It typically moves quickly and does not reach the crowns of mature trees, allowing them to survive. While it can kill seedlings and small trees, many animals can escape, making it distinct from more destructive crown or ground fires.

Question 18: Which abiotic factor most commonly predisposes western conifers to infection by Cytospora canker pathogens in managed forest stands?

Drought stress that reduces resin pressure and carbohydrate-based defense capacity (Correct answer)
Excessively wet soils that promote root asphyxiation
Elevated soil nitrogen from fertilizer applications
High light intensity causing photoinhibition of the outer crown

Correct answer: Drought stress that reduces resin pressure and carbohydrate-based defense capacity

Drought reduces the constitutive and induced resin-based defenses that otherwise repel Cytospora and other opportunistic bark pathogens, making moisture stress a key predisposing factor.

Question 19: In wood chemistry, cellulose makes up approximately what percentage of wood by dry weight?

60–70%
40–50% (Correct answer)
15–20%
80–90%

Correct answer: 40–50%

Cellulose typically comprises about 40–50% of wood's dry weight, making it the most abundant polymer in wood and the primary raw material for paper.

Question 20: Necessitates obtaining permits for the excavation or filling of wetlands and mandates compensatory measures for such actions.

Wilderness Act 1964
National Environmental Policy Act
Endangered Species Act
Clean Water Act 1972 (Correct answer)

Correct answer: Clean Water Act 1972

Section 404 of the Clean Water Act (CWA) of 1972 grants the U.S. Army Corps of Engineers authority to regulate the discharge of dredged or fill material into 'waters of the United States,' which includes wetlands. This regulation necessitates obtaining permits for activities like excavation or filling in wetlands. Furthermore, the CWA often mandates compensatory mitigation, requiring the creation or restoration of wetlands to offset any unavoidable losses, thereby protecting these vital ecosystems.

Question 21: Which term describes the tree layer that provides most of the photosynthetic canopy in a forest stand?

Shrub layer
Understory
Duff layer
Overstory (Correct answer)

Correct answer: Overstory

The overstory (main canopy) layer captures the majority of incoming light and drives stand-level productivity.

Question 22: Which soil horizon is characterized by the accumulation of leached minerals and organic matter from upper horizons?

C horizon
B horizon (Correct answer)
O horizon
A horizon

Correct answer: B horizon

The B horizon (subsoil) is the zone of illuviation where clays, iron oxides, and organic compounds leached from upper horizons accumulate.

Question 23: The hedonic pricing method is used in forest valuation to estimate:

How proximity to forested areas affects nearby residential property values (Correct answer)
The replacement cost of destroyed old-growth timber
The shadow price of carbon stored in biomass
Willingness to pay for hunting permits

Correct answer: How proximity to forested areas affects nearby residential property values

Hedonic pricing isolates the implicit value of forest amenities by comparing sale prices of properties with and without nearby forest access.

Question 24: In the US wood products industry, 'kiln drying' lumber is done primarily to:

Kill insects and pathogens and reduce moisture content for dimensional stability and strength (Correct answer)
Add preservative chemicals under heat and pressure
Increase wood density for high-value markets
Straighten warped boards before grading

Correct answer: Kill insects and pathogens and reduce moisture content for dimensional stability and strength

Kiln drying removes excess moisture from green lumber, preventing warping and shrinkage in service, increasing strength, and sterilizing the wood.

Question 25: The concept of 'habitat heterogeneity' suggests that landscapes with diverse habitat types tend to support higher wildlife diversity because:

Uniform forests are easier to manage for maximum timber yield
Single habitat types reduce competition between species
Different species require different resources found in varied habitat conditions (Correct answer)
Homogeneous habitats are more productive per unit area

Correct answer: Different species require different resources found in varied habitat conditions

Habitat heterogeneity provides varied resources, microclimates, and structural conditions that meet the diverse needs of many species, supporting greater overall biodiversity.

Question 26: Which wood product uses small wood particles mixed with resin and pressed into panels?

Particleboard (Correct answer)
Glulam
Cross-laminated timber (CLT)
Laminated veneer lumber (LVL)

Correct answer: Particleboard

Particleboard (chipboard) is manufactured by binding small wood particles or chips with resin under heat and pressure, often used for furniture and cabinetry cores.

Question 27: What is the primary function of 'spot fires' in relation to overall wildfire behavior?

They cool the fire perimeter by creating backfires
They serve as indicator fires for predicting fire weather changes
They extend the fire perimeter beyond the main fire front via windborne firebrands (Correct answer)
They signal the transition from surface to crown fire

Correct answer: They extend the fire perimeter beyond the main fire front via windborne firebrands

Spot fires ignite ahead of the main fire front when firebrands (burning embers) are lofted by convective columns and deposited by wind on receptive fuels.

Question 28: Chestnut blight, caused by Cryphonectria parasitica, kills American chestnut by producing which mechanism?

Oxalic acid that lowers canker pH, killing cambial tissue while sparing roots (Correct answer)
Producing enzymes that digest the heartwood, causing structural failure
Systemic toxins that move through the xylem and kill the root system
Blocking phloem transport by forming dense mats of mycelium throughout the bole

Correct answer: Oxalic acid that lowers canker pH, killing cambial tissue while sparing roots

Cryphonectria parasitica produces oxalic acid within cankers, creating a low-pH environment that kills cambial tissue but cannot penetrate below the soil line, allowing root sprouting.

Question 29: Which phenomenon describes the situation where fire suppression in dry mixed-conifer forests has led to dramatically increased tree densities and fuel loads compared to historical conditions?

Stand homogenization
Forest densification syndrome
Mesophication (Correct answer)
Overstory recruitment pulse

Correct answer: Mesophication

Mesophication refers to the transition of fire-adapted open forest ecosystems toward denser, more mesic conditions as shade-tolerant species recruit in the absence of regular fire.

Question 30: Which regeneration method relies on vegetative sprouting from stumps or roots?

Selection system
Seed-tree method
Coppice system (Correct answer)
High forest system

Correct answer: Coppice system

The coppice system regenerates forests through stump sprouts (epicormic shoots) rather than seeds.

Question 31: Why is proper valuation of goods and services provided by forests and nature areas essential?

To increase market demand for forest products
To understand the extent of costs and benefits associated with forest use (Correct answer)
To create financial resources for forest management
To raise public awareness about ecological impacts

Correct answer: To understand the extent of costs and benefits associated with forest use

Proper valuation of goods and services provided by forests and nature areas is essential to understand the full extent of costs and benefits associated with their use or conservation. By assigning economic values to these services, decision-makers can make more informed choices that consider both economic development and environmental sustainability. This helps to justify conservation efforts and integrate natural capital into economic planning.

Philippine Forester Licensure Examination (PFLE)

The Philippine Forester Licensure Examination (PFLE) tests BSF/BScF graduates on forest ecosystem science, forest production and management, forest utilization engineering, and forest governance and social forestry, administered by the Professional Regulation Commission (PRC).

Questions

35 min

Time Limit

70%

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