Tree inventories

trees gps

Tree inventories are powerful management and planning tools. There are three types commonly carried out:

  • Sample: a random selection used to estimate properties of the whole forest
  • Partial: a non-random selection, such as all declining trees
  • Full: all trees, and often planting sites as well

It is possible to calculate the economic benefits of the trees recorded by any of these approaches.

Sample

A sample tree inventory examines a random sample of a community's urban trees instead of every single tree. Details below.

Partial

Partial tree inventories provide information about a portion of the tree population (an older area, a particular species, etc.) that is perceived as critical. As with a Sample Inventory, such an approach can provide an effective and affordable management tool when budgets are limited. Unlike the Sample Inventory, however, a Partial Inventory usually provides little information about the urban forest as a whole. On the positive side, this method can be used to spread out the work of a full inventory over several years by doing one part each year.

Tree-lined street

Full

A full tree inventory includes all the trees (and empty planting sites) in some sort of urban forest. Typically, in a municipal environment, that means all the street trees in the public right-of-way and, in many cases, the municipal parks and other municipally owned land; the tree population to be inventoried could also be defined by geographic limits. If planting sites are included in the inventory, it allows the stocking rate to be calculated, i.e., what percentage of the available sites are currently filled, providing very useful planning information.

How much does all this cost?

Since different communities have different needs and resources, we offer a cafeteria-style approach to this service that allows communities to pay only for what they need and can not supply themselves. Options include:

  • Random sampling procedures
  • Field data collection
  • On-site training for community data collection
  • Setup, data input, results generation
  • Storm damage estimate setup and establishment
  • Survey Report or Management Plan for distribution
  • Management software
  • Location options (e.g., GPS)

Please contact us about tailoring this service to your needs and obtaining the current price structure.

Population and sample

Sample

Sample inventories are a cost-effective way to obtain a large-scale picture of an urban forest and its needs, from which a strategic plan to address management issues or enhance tree benefits can then be developed. Note that a sample inventory is not a day-to-day management tool, though the data can be used later in a full inventory program.

Method

By using public software known as i-Tree, it has become much easier in recent years to carry out a statistically valid sample inventory. The basic steps are these:

  • create a random sample of the tree population using blocksides or small areas
  • collect data on all the trees in the random sample
  • import the data into the appropriate i-Tree software
  • export the results for use

The combination of a statistically valid sampling procedure and scientifically-based data processing gives the results a credibility that proves very useful in the everyday world of urban forestry.

Results

A sample inventory permits answering some critical questions at reasonable expense:

  • How many trees do I have?
  • What condition are my trees in?
  • What are the significant management issues?
  • What return are we getting for our money?

These answers provide the foundation for responsible urban forest planning that aims for clear and well-defined community goals. Please contact us if you are considering a sample inventory, we would love to help.

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