Entering tree data interactively
Creating a stand from external data is fairly easy once you have the data in an Excel worksheet. Excel has powerful facilities for importing data from other programs. You can also enter data manually in a variety of ways using the Auto-filter and Form facility in the Excel Data menu. Where large volumes of stand data have to be handled, automatic methods can usually be developed using Visual Basic techniques. Once the data is in a spreadsheet, all you need do is rearrange the table of trees to conform to the MGM Stand sheet format and enter a few parameters such as the name of the stand, the number of trees and the stand age.
The typical source of data for creating your own stand is plot data (either fixed or variable area plots) or stand table summaries of tree data.
The procedure for creating a stand using your own data begins with the MGM Tools menu item "New Stand Wizard". The process follows:
1. You are prompted for the general information about the stand. This includes stand identification name, site vector, and stand age--time since disturbance or "origin", other items are not currently used. A site value must be included for each species present in the tree list. For the Alberta Variant, species are grouped as[Sw, Pl, Aw, Sb] = [Sw Se Fd, Pl Pj Pf Pw, Aw Pb Bw, Sb Fb Lt Lw La Fa]. If a species is not present, the site vector may include an .NA. entry. There may be some variation for different regional Variants.
2. A new "Stand" worksheet is created in the MGM Stands workbook using the name you provided in step 1.
3. You are prompted to enter tree data. You may enter data using the form provided; click the Enter button to enter additional trees. Alternatively, you may click "Close" immediately if you don't want to enter data using this form. This may be helpful if you want to create data using copy/paste.
Notes for data entry:
- Enter NA for missing data
- Species is a required entry based on the applicable regional codes
- Dbh . if dbh is NA, then height may not be NA
- Trees/ha . required, the number of trees/ha represented by the tree
- Height . if height is NA, then Dbh may not be NA
- Total age . if total age is NA, then breast height age may not be NA
- Breast height age . if breast height age is NA, then total age may not be NA.
- Other fields are optional and may be left empty if values are not available.
4. When you click on "Close", you are asked if you want to leave the worksheet open for additional editing. If you click Yes, the Stands workbook is left open and you may do additional editing or entering of tree data , otherwise the Stands workbook is saved and closed.
5. To use the newly created stand in a Crop Plan, you must edit the Establish event in a new or existing crop plan. Click on the "Read Trees (XLS)" tab. A list of stands will appear (stands found in the MGM Stands.xls workbook). Select the name of the stand you have just created and click OK. When the Crop Plan is executed, the stand will be retrieved from the MGM Stands.xls workbook and then the growth simulation will proceed.
6. To edit the stand data after it has been created in the Stands workbook:
- Retrieve the stand by executing the Establish event.
- Edit the stand data that is now located in the Stands worksheet.
- Save the stand using the Save button on the MGM Toolbar.
- Instead of using the previous three steps to edit the stand data, you may also open the Stands workbook and edit the worksheet for any stand.
7. Save changes and close the Stands workbook before continuing to work with the MGM workbook.
- If you change the stand age, you must edit the Establish event (in the Crop Plan), select the appropriate stand name, and click OK. This is necessary to update the stand ages in the Crop Plan. If desired, the Crop Plan should be saved to reflect the changes.
8. Other possibilities
- To create stands composed of both simulated and real tree data, first create the simulated tree data by executing up to the Establish event. Then add the additional trees. Then save the stand using the MGM Toolbar Save button and edit the Establish event in the Crop Plan to establish the stand by reading it from the Stands workbook.