MODULE THREE

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Cruising Timber & Determining Volume

Part 2 Topics Covered

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Land Measurement

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Boundary Marking & Maintenance

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Tree Measurements

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Log Volume & Weight

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Aerial Photography & GPS

Land Measurements and Boundary Marking/Maintenance

Land Measurement

Boundary Marking & Maintenance

A legal description defines the property’s boundaries. The actual boundaries on the ground must be marked or delineated to maintain ownership and guard against trespass or encroachment. 

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• Property Corners 
• Usually included in the legal description of the property and may be marked by monuments, steel rods or pins, rock piles, fence corners or other means. 
• Corners may be further marked with witness trees which “point” to the location of the corner. 
• Boundary Lines 
• Historically marked by stone or wire fences, especially in areas where livestock were grazed. 
• Today, property lines most often marked by “blazing” trees along the boundary. 
• Blazing entails using a draw knife to scrape bark off trees and painting blazes with a long-lasting boundary paint. 

Boundary Marking & Maintenance

• Boundary Line Maintenance 
• Maintenance is necessary to ensure it remains visible. 
• Boundary paint is designed to be long lasting but will fade over time. 
• Where boundaries are delineated by natural features, those features may change over time so lines should be marked. 
• Relocating Boundary Lines 
• Where boundary line maintenance has been neglected, it may become necessary to re-establish those boundaries. 
• If the boundary was established along a surveyed line, the boundary may be re-established by a surveyor. 
• If identified by natural features, fences, or painted boundaries, it may be necessary to research original legal descriptions and re-trace the line to find evidence of the line to remark it. 

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Boundary Marking & Maintenance

• Conflicts With Surveyed Lines 
• Many boundary lines were established and mutually agreed upon by neighboring landowners using natural features, fences, or painted lines were used to delineate those boundaries.  
• Legal descriptions may call for straight lines between property corners, these mutually agreed upon lines may vary from these
• Corners accepted by mutual agreement may not match the location of the surveyed corner. 
• Current property owners or heirs retain the property, the historically used lines and corners are often accepted. 
• Conflicts may arise, however, when one owner sells the property, and the new owner has the property surveyed and finds that the lines or corners on the ground do not match the legal description. 
• These conflicts are resolved on a case-by-case basis, but the surveyed line may not prevail. 

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Tree Measurements

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• Diameter
• Height
• Age
• Site Index
• Basal Area

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Tree Measurements

Diameter

• Diameter is the most important measure observed on a tree.
• Diameter characterizes stand structure and estimation of the trees volume or weight
• The most common method of measuring diameter is diameter at breast height (DBH), which is 4.5 feet above ground level on the uphill side of the tree
• A Biltmore Stick and Diameter Tape (D-Tape) are the most popular instrument for measuring DBH.

Tree Measurements:

Height

14”

• Instruments
• Clinometer
• Hypsometer
• Key Measurements
• Total Height
• Bole Height or Height to Live Crown Base
• Crown Length
• Stump Height
• Merchantable Height
• Merchantable Length

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Tree Height

Crown Height

Bole Height

Crown Diameter

Merchantable Length

Merchantable Height

• An Increment Borer is used to extract a small cylindrical core of wood from a tree, log, or pole usually taken at DBH
• Growth rings are then used to determine age and past tree growth.
• Trees produce one growth ring per growing season
• Earlywood growth in spring and latewood growth in summer.

• Measure of actual or potential forest productivity
• Used as indicator of site quality; can be used to estimate tree volume production
• Site index is species specific and based on average height of dominant and co-dominant trees at specified index or base age
• The higher the site index, the better the trees will grow and thrive.

Tree Measurements:

Site Index

Crown Class

D = Dominant

C = Codominant

I = Intermediate

S = Suppressed

Tree Measurements:

Site Index

14”

Tree Measurements:

Basal Area

• Basal area is derived from tree diameter
• Defined as the cross-sectional area (usually in square feet) of a tree at breast height (DBH = 4.5 ft.).
• Basal area is directly related to the volume and growth of forest stands.
• Basal area per acre is the measure of the sum of the basal area of each tree growing on that acre.
• This measurement shows crowding or density in a stand and is frequently used to determine how many trees to remove in a thinning operation.

Table of Basal Areas

Aerial View

Present Stand

Thinned Stand (Residual)

Gingrich Stocking Guide

• Cord
• Board Feet
• Tons

Volume and Weight

Cord = a stack of pulpwood (or fuel wood) that measures 4 x 4 x 8 ft., or 128 ft3 including wood, bark, and empty space within the stack. The wood content is less than 128 ft3.

Volume Measurements

Board Foot = the amount of wood contained in an unfinished board

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Ex. 1"x12"x12"= 1 Board Foot

Volume Measurements

What’s the Girard Form Class 78?

Ratio between diameter inside the bark at the top of the first log (16’), divided by DBH, multiplied by 100.

22”

17”

16’

Timber Inventory

What is an “inventory?”

A detailed list of the current goods, or materials, or property; An assessment of what you have.

Timber Inventory

Detailed list of timber in a forest stand.

Purpose of a Timber Inventory

Timber inventories are conducted for a variety of reasons:

• Value of timber assets
• Purchasing/selling timber or forest land
• Establishing tax basis for depletion allowance, estate planning or litigation
• Forest management planning
• Evaluate damage to the stand

Systematic Samples

Random Sample

Random Sample

Measure a Plot (Fixed Radius)

• 1/10 acre plot
• 37 feet 3 inch radius
• I decide plot center
• Measure all trees greater than 2 inches
• Division of duties
• Recorder
• Height Measurer
• Species/DBHer

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Variable Radius/Prism Plot

• Wedge Prism

Tally “In” Tree

Borderline Tree

Out

Limiting Distance Formula for Borderline Trees

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DBH” x PRF = Limiting Distance

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Example (PRF is 2.75 for 10BA Prism and DBH is 20”

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2.75x 20 = 55 feet (tape distance to tree is 55 feet or less than is “In”)

Simple Ecosystem

Monoculture, even-aged, plantation, pine Mixed, uneven-aged, natural, hardwoods

Complex Ecosystem

Aerial Photography & GPS

• Aerial photographs provide useful information and details on forested property.
• The relative size, location, and shape of forest stands, streams, roads, and other features can be seen in aerial photographs.
• Global Positioning System (GPS) is a satellite-based navigational device.
• 3 basic types (grades) of GPS:
• Navigational or Recreation
• Mapping
• Surveying
• A Geographic Information System (GIS) is a method for capturing, manipulating, and displaying forms of geographically or spatially referenced information that can be used on personal computers.

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Unmanned Aircraft Systems in Forestry

• Unmanned Aircraft Systems (UAS)
• Commonly called Drone Systems
• Used in emergency response situations, such as wildland firefighting where UAS can detect spot fires occurring outside a contained fire perimeter.
• Can be used to monitor forest stand conditions, to pinpoint sources of water quality issues, and to map the spread of forest health.

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