Simple tree demographics
Simple demographic spreadsheet
Linked below is a simple demographic spreadsheet in excel format. The spreadsheet is intended to enable a practicing arborist or urban tree manager to track their tree population over time.
Instructions are included in the top row of the spreadsheet. Start by entering the parameters - starting population, estimated yearly mortality rate, and yearly actual plantings or a "planting goal" - in the brightly colored boxes (row 2). The rows below will update automatically, and provide output for 100 years into the future.
Note that you can also enter data for individual years, e.g., in case of a mass tree mortality (or a mass planting event). Simply enter the negative number of dead/removed trees (or the positive number of mass-planted trees) in the row for the year in question. Calculations will update, but parameters entered in the top row will remain unaffected and will continue to apply to preceding and to subsequent years.
The "complex example" is an attempt to provide additional specificity for the higher mortality of newly planted trees; please follow the directions in the top row. Note that this example uses a fairly crude calculation for that "excess mortality of newly planted trees." Its main advantage will be in cases where periodic mass-planting events are held. If you do not have those (i.e., if your planting numbers are relatively stable from year to year), then it is simpler/easier to use the "simple example" spreadsheet and adjust upwards your -overall- mortality rate if you wish to account for the excess mortality in newly planted trees.
If you discover any errors, please let Igor know!
Click here to download the spreadsheet