Sylvan Stand Structure Models
Overview - Equipment - Getting Started - Mapping - Crown - Heights - Other Data - Data Review

Sylvan Datalogger


The Sylvan Stand Structure Model uses complex spatial data from stands to predict the growth of trees. To make it easier to collect this type of data, we have developed a data entry program called Datalogger. The purpose of the program is to directly collect from electronic measurement instruments the necessary information and store that data in a SQL database real-time. This allow the field crews to see a map of the plot and editing tools to assure data quality. The SQL database can be used in the Sylvan Stand Structure Model or the data can be export to a comma delimited file format, R statistics package format, or ESRI ShapeFile format.

As with all Sylvan software, it will run on Windows (XP, Windows 7), Linux (Ubuntu), and MacOS (Snow Lepoard). We have the serial port communication working on Windows, MacOS, and Linux though both wired and bluetooth.

Sylvan-Datalogger screen on opening

Figure 1. Datalogger software on open on a Windows 7 operating system. This data is a square plot with a SW corner reference point. This screenshot show both the map and profile views.

Sylvan-Datalogger screen on opening

Figure 2. Datalogger software on open on a Windows 7 operating system. This data is a square plot with a SW corner reference point. This shot shows the missing data window and the server window. The server window shows the connected datalogger-lite clients.

Work-flow and Tasks

The Sylvan datalogger program can be used to measure one time plots or repeat measurement plots. To measure a data on a plot with the Sylvan datalogger you must complete the following tasks:

Map reference points and trees

Reference point are used as a the basis for mapping trees. All plot have one default reference point (0,0) either in the Southwest corner for square plots or in the center for round plots. All trees are mapped in x, y, z dimensions with polar coordinates relative to the default reference point. The software converts the coordinate into Cartesian coordinates for storage in the database. This mapping also creates a tree number for each tree. This task must be done first as all other tasks depend on the availability of tree numbers. One repeat measurement plots this task only need to be done once for each tree. In re-measurements only, new trees need to be mapped and the existing trees are assumed not to move.

Once the trees are mapped and each tree has a tree number the following steps can be done in any order.

Species, Diameters and Crown Polygons

The tree species are entered by picking from a menu list the current species list is is a composite of the US Forest Service, Forest Inventory and Analysis list and the USDA Plant database. Trees are codes by four methods, English common name, Scientific name, the USFS 3 number codes or the USDA 4 letter + codes. Many species not native to the US are include in the list as they have been planted in the US. There is an mechanism to add species or amend the base species list. The species list is in alphabetic order with frequently used species moved to the top of the list.

Diameter is the one variable that does not have a current electronic input method. The value is measured and enter in a text box.

Crown polygons are measured by the use of crown radii, the measurer stand under the tree crown edge and shoot the laser back to the tree stem, this distance plus the stem radius and the azimuth of the vector are recorded. The measurer can record as many crown radii as are need to describe the crown polygon, one radii is required. We have tested up to 72 although most measurers would find this very tedious.

Tree Heights

We have defined the three most common measured tree heights, two of these heights are required to draw the trees in the map and profile. The measure follows the common procedure of stand at a location where the height points are visible. They determine the distance from the measuring point to the tree with the ranging laser. Then determine the angle to the base of the tree, the merchantable tree top, the crown base and the top of the tree. Only the merchantable height is optional, but in may cases this is need to correct tree volume for tree damage or forking. The height calculations are performed in the software from the basic laser data.

Data Review

The most expensive trees to measure are those that were missed causing the crew to return as second day. Because of this the Sylvan datalogger has many tools to help ensure that all data is collected and it appears to be correct. The program provides a missing data list so that the crew can correct those entries before leaving the plot. Also the data are plotted in map and profile views as they are measured, allowing graphical per tree inspection of the data.

All these topics will be explained in more detail in the other special topic webpages list at the top of this page.

Overview and Purpose



Input and Output

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial 3.0 United States License.

Author: Dr. David R. Larsen
Created: January 31, 2013
Last Updated: February 19, 2013