Forestry exam

A woody perennial that is at least 5” dbh and 15’ tall at maturity

Definition of a tree

An ecosystem dominated by trees

Definition of a forest

over harvesting, soil erosion, degrade water quality

Impact of resource exploitation

Measured at 4.5’

DBH

Primary growth lengthens roots and shoots from apical meristems, while secondary growth thickens stems and roots through vascular and cork cambium activity.

Primary vs Secondary growth

Trees grow by lengthening through primary growth at root and shoot tips and by thickening through secondary growth that forms wood and bark.

How trees grow

61%

New York forests total land area

Harvesting System	Felling System	Extraction System

Conventional Logging

Chainsaw

Cable Skidder

Mechanized Logging

Feller-Buncher (wheeled/tracked)

Grapple Skidder

Cut-to-Length (CTL)

Processor (harvester head)

Forwarder (carries logs)

Felling and extraction systems for different harvesting systems

• Conventional Logging (Chainsaw + Cable Skidder)

• Small-Scale Mechanized Logging

• Cut-to-Length Systems (in some areas)

East Coast Harvesting Systems

• Mechanized Logging (Feller-Buncher + Grapple Skidder)

• Cable Logging (Skyline Systems for steep slopes)

• Helicopter Logging (for remote or sensitive areas)

• High-Production Clearcutting

West Coast Harvesting Systems

• Fast-growing

• Short-lived

• Need lots of light (shade-intolerant)

• Reproduce quickly (many small seeds)

• Colonize disturbed areas

• Examples: Aspen, Pin cherry

Pioneer Species

• Species Composition

• Age Distribution

• Density and size class distribution

• Forest Strata

4 components of describing forest structure

Even-Aged System

• One age class

• Trees are all about the same age

• Caused by big disturbances (like clearcuts or fires)

• Easier to manage and harvest

Multi-Aged System

• More than one age class

• Trees are different ages

• Created by cuttings or natural processes

• More natural and diverse

Even- vs multi-aged systems

1. Get the rotation age (how long trees take to mature)

2. Multiply it by 20%

3. Find the age difference between the oldest and youngest canopy trees

4. If the difference is less than 20% → Even-aged

5. If the difference is more than 20% → Multi-aged

How to determine age structure

Seeding- < 3 ft tall

Sapling- 3ft - 10ft tall and < 4” DBH

Pole Size- 4” - 12” DBH

Sawlog- > 12” DBH softwood, > 12” DBH hardwood pallet, > 14” DBH hardwood

Size classes

QSD or QMD

1. Overstory/ Structure

2. Understory

3. Shrub Layer

4. Herb layer

5. Forest Floor

Forest Strata layers

The art and science of controlling the establishment, growth, composition, health, and quality of forests and woodlands to meet the diverse needs and values of landowners and society on a sustainable basis.

Define: Silviculture

1. Forest Regeneration

2. Forest Tending

3. Harvesting and Stand Renewal

Three main parts of silviculture

• High Grading

• Diameter Limit cut

What is and is not silviculture

1. thinning

2. Sanitation

3. Salvage

4. timber stand improvement

Types of intermediate treatments

• Thinning from below

• thinning from above

• Selection thinning

• Geometric thinning

• Free thinning

Types of thinning

1. Thinning from Below

• Effect: Removes smaller, weaker trees.

• Result:

  • Increased growth for larger, healthier trees.

  • Better light for remaining trees.

  • Improved forest structure (fewer competition issues).

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2. Thinning from Above

• Effect: Removes larger, older trees to allow smaller ones more space.

• Result:

  • Increased growth for younger trees.

  • Promotes crown expansion for remaining trees.

  • Higher potential for regeneration of younger trees.

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3. Selection Thinning

• Effect: Selectively removes certain trees based on factors like size, health, or species.

• Result:

  • Improved stand composition (targeting specific trees for removal).

  • Balanced growth of selected trees.

  • More diverse forest structure.

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4. Geometric Thinning

• Effect: Removes trees in a systematic pattern (e.g., rows or spacing).

• Result:

  • More even spacing between trees.

  • Improved tree growth with less competition.

  • Simple, predictable forest layout.

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5. Free Thinning (Crop Tree Release)

• Effect: Focuses on removing trees around desired "crop" trees.

• Result:

  • Maximized growth of selected crop trees.

  • Better crown development for desired trees.

  • Increased profitability if done commercially.

Results of different thinning methods on residual forest

1. Clearcutting

2. Seed-Tree Method

3. Shelterwood Method

3 even aged regeneration methods

1. Establishment Cut

2. Removal Cut

2 phases of a seed tree

1. Preparatory Cut

2. Establishment Cut

3. Removal Cut

3 phases of a shelterwood

An even-aged regeneration method where a few trees are left to provide seed, and then removed after seedlings are established.

SSeed-Tree

• Owner Objectives

• Stand Capabilities

• Prescription Writing

• Marking Guidelines

What goes into a prescription?

A course of action to change a forest stand

What does a prescription describe?

1. owner objective

2. Stand capabilities

3. Forester/Logger Skills

4. Market demands

5. Trails/Special areas

Considerations for harvesting

To create regeneration

Why is uneven-aged silviculture not practiced?

The q-ratio is the ratio of the number of trees in one diameter class to the number in the next larger diameter class.

What is a q-ratio?

• Moderate growth rate

• Intermediate lifespan

• Some shade tolerance

• Begin to appear as pioneers die off

• Fill in gaps in the canopy

Mid-Successional Species

• Slow-growing

• Long-lived

• Shade-tolerant

• Reproduce less often, but with larger, fewer seeds

• Dominate stable, mature forests

• Examples: Sugar maple, Eastern hemlock

Climax Species

An even-aged regeneration method where trees are removed in phases, allowing new trees to grow under the partial shade of remaining trees

Shelterwood

A written plan that guides forest treatment based on the landowner’s goals, site conditions, and management needs.

Prescription

Concise instructions for the implementation of a prescription.

Marking Guide