Application Series 6

SEEING THE WOOD FOR THE TREES

SIR profiles Jerold Hahn, Principal Mensurationist at the North Central Forest Experiment Station(NCFES) to find out how SIR can be used to help forests.

Background

My job is to find out better ways to measure trees within forests, forests within states and in general forests within a region. That's where database technology comes in because a database is a way of handling measurements. We maintain an inventory of the status of current volumes of trees by various classes and the rates at which they're growing and harvested within each region. Out group is responsible for the North Central region.

There are six Forest Inventory and Analysis Units in the US, each responsible for the forests in their region and continually interacting with each other. Just recently we had a meeting here with representatives from each of the other five units. We want to find ways of doing similar things in similar ways so that the data we all collect will be consistent across all the units.

What to Measure

Right now we have a large staff of about 40 people measuring trees in Michigan, based on statistical designs that I developed. It is a sample-based system - we don't measure every tree. The sampling methodologies tell our field crews where to go and which trees to measure and which measurements to take.

The chief measurement is the diameter of the tree. That's the thing that almost all foresters work with. Technically it's called diameter at breast height (dbh) - the diameter of the tree 4.5 feet above ground. That's a standard measurement known to everyone in forestry. The other important things are the species, the height, and the condition of the tree. We also take measurements on the entire stand of trees - how many of them there are, the location, the owner etc. This information is what ends up in our database. There are 150 different measurements or variables in our database.

Field Recording

We record the data on Husky Field Data Recorders. They are little portable computers with about 640K in each one. They run a data gathering program that prompts the worker for the proper things to input and checks that input as it is entered. If we are remeasuring a location, the Husky can also carry the previous measurements. This lets the field workers know they're in the right place and allows them to verify the previous worker's data.

The data is transferred from the Husky to a diskette and then mailed to us. The information on the floppies is then processed into SIR generally using batch data input statements.

What SIR provides

Our databases are basically two logical databases. However we maintain them in multiple physical structures because we're into the millions of records and they'd be too large to conveniently manipulate otherwise. So we break them down, generally by state.

Essentially we break the data down into various forms for generating reports. Hundreds of tables are generated, broken down by volume and number of trees, by species and tree size, area by various conditions such as forest types, site quality, owner, etc.

There are two basic 'products' that we furnish - the tables I just referred to and the subsets of our databases to interested users for direct entry into SIR or as flat files. Every state east of the Mississippi and many states to the west have all of their data in this format.

How It is used

Forestry and paper companies commit millions of dollars to various forest-related projects based on studies provided by our unit's research. Environmental groups use the data to determine where to put their efforts in developing environmental programs - what areas are threatened, which species need protection, what sorts of problems are the trees having, and what programs need to be undertaken.

This data is "public domain" and any citizen has the right to it: because it was collected at the government's expense. Individual states use the data for making policy decisions on where to commit funds for planting problems. On the national level, the federal government uses it to decide whether and how much to commit for forestry programs, to get farmers to plant more trees or manage their land better for wood.

The enabling legislation that governs all our work is called the Resources Planning Act and the product of Forest Inventory is the Resource Assessment that this act requires us to produce every ten years. This document is used to support the Forest Service's program recommendations to Congress.

For further information on how NCFES uses SIR, please contact:

Jerold Hahn
North Central Forest Experimental Station
1992 Folwell Ave
St Paul MN 55108
USA

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