how to do an inventory of your trees

March 2004 Potts Tree Farm 1

HOW TO DO AN INVENTORY HOW TO DO AN INVENTORY OF YOUR TREESOF YOUR TREES

Dick Potts

Potts Tree Farm

Holmes County, Ohio


Reasons for InventoryReasons for Inventory

Basic Business Process:What’s in stockWhat’s its valueWhat’s for sale

Tree Farming:Timber management

Timber sale

Timber value

Timber basis


How to InventoryHow to Inventory

Count them ALL - 100% inventory!


What Information is Needed?What Information is Needed?SiteSoil, Slope, Orientation, Aspect, Elevation, Watershed, Site Index

TreesSpecies, DBH, Height, Logs (16’), Quality, Acceptable Growing Stock (AGS), Unacceptable Growing Stock (UGS), Sawtimber, Pole, Sapling, Cull, Understory, Regeneration, Number of Trees

ResultsStocking (Chart or %), Basal Area, Board Feet (BdFt) Sawtimber, Sawtimber Value, Tons or Cords Pulp, Rings per Inch


Which Trees Are Yours?Which Trees Are Yours?Where are your boundaries?Survey, Corners, Line Markers, Acreage


PropertyPropertyMapMap

Very Very UsefulUseful


Inventory MethodsInventory Methods

100% inventory High accuracy but requires time and effort

1/10th Acre Plots 66’ square, multiply by 10 for per acre approximation

1/5th Acre Plots 53’ radius, multiply by 5 for per acre approximation

Variable Radius Plots Most widely used for speed and sufficient accuracy


SamplingSampling

Approximate Methods Require Statistical Random Sampling

Location of PlotsRandom with no overlapping

Stay away from edges and unusual areas

Number of Sample PlotsDepends on total area size

~10 or greater is desirableReference:

Avery and Burkhart 1994, Forest Measurements, 4th ed., McGraw Hill, Inc., New York.

Ashley 1991, Simplified Point-Sample Cruising, USDA FS, NA-UP-01-91.


Variable Radius PlotVariable Radius Plot

Instruments Biltmore Stick – Angle Gauge

Glass Prism

Penney – Angle Gauge

Basal Area Factor (BAF) Most common BAF = 10

Results Basal Area = BAF X “trees IN”

Stand Density Measure

Reference: McEvoy, How Point Sampling Works, Forest Products EQUIPMENT, Vol. 11, No. 7, March 2003, pp. 24….


Number of Tree per AcreNumber of Tree per AcreCount in 1/10th or 1/5th Acre Plots then convert to one acre

Use Variable Radius Plot Data then calculate Expansion Factor for each tree and sum for number

Calculation of Expansion Factor (EF)

EF = BAF/(.005454 x N x D x D) for individual tree

BAF = 10 N = # sample points D = DBH

Example: EF = 10/(.005454 x 10 x 11 x 11) = 1.5 trees/acre

Sum EF for all trees in Plot for number of trees per acre.


Stocking ChartStocking ChartPlot of Basal Area vs Trees per Acre


Data Analysis by ComputerData Analysis by Computer

Create your own spreadsheet for data entry and calculations

Use available software


Commercial SoftwareCommercial Software


Freeware - USFSFreeware - USFS



Northeast, Central States, Lake States Versions


Example TWIGS ResultsExample TWIGS Results

2004 Harvest – Clearcut1986 Inventory Projected to 2001 10,832 BdFt/acre

1997 Inventory Projected to 2002 12,629 BdFt/acre

2002 Sale Inventory 14,167 BdFt/acre

1989 Harvest – Clearcut1987 Inventory 12,755 BdFt/acre

1989 Inventory Koral’s data (TWIGS) 10,692 BdFt/acre

1989 Inventory Koral’s data (SILVA) 10,175 BdFt/acre


TWIGS Information and DataTWIGS Information and Data


Data CollectionData Collection


TWIGS DataTWIGS Data


TWIGS Data FileTWIGS Data File

Generate TWIGS data file with the program TREEGEN

Switch to TREEGEN and TWIGS

how to do an inventory of your trees

Economy & Finance

inventory korals data

sale inventory

inventory methods

baf x trees

twigs data file

inventory korals data

data entry

data analysis