Collect information on Little Wittenham wood

Building a GIS for forest management

In the following practicals you will learn how to integrate information on each stand of trees in a forest into a GIS. This will provide you with an invaluable forest management tool and a means to prepare accurate planning maps to include in your management plan. For example, you will be able to:

• Create a map showing the species composition of each compartment;
• Prepare an operations map for the year 2010 showing where management will be taking place;
• Make an accurate measurement of the area to be replanted in 2006.

You will do this by creating an Excel spreadsheet containing a list of compartments. You will record a number of attributes for each compartment and then import these data into MapInfo. You will be able to display the information contained in these records on a thematic map. Maps are an excellent way to show  the geographical occurrence and variation of a simple variable. Maps can often reveal patterns that are not obvious from a database. 

Creating  a vector compartment map

Although you have registered the scanned raster image of the Little Wittenham compartment map you cannot use this in a GIS as it does not contain any map objects - it is just a picture. In order to create a vector file in which each compartment is represented by a polygon you will need to trace over the outline of the compartments on the raster image using MapInfo's drawing tools and then save your newly drawn polygons to a fresh file. You will then import data in an Excel spreadsheet and attach the appropriate records for each compartment to the correct polygon in your new table.
 

First we need to collect some data on each compartment......

You will need:

1. A copy of the Little Wittenham compartment map (you can print a copy of compartment_map.TAB in MapInfo);
2. A 30m tape;
3. A notebook and pencil;
4. Warm waterproof clothing and boots;
5. A field first aid kit and mobile phone;

Before you start work, divide the class up into groups of three. Allocate an equal number of compartments to each group. You may want to make a master map showing which group is responsible for which compartments.

In the field:

1. Agree a rendezvous time and location with the fieldwork leader and the rest of the group. Do not start work if there is a risk of high wind or heavy rain. Make sure that the field first aid kit and mobile phone are kept in a place where they are accessible to all groups.
2. In each compartment you need to select five 0.02 ha (radius 8 m) sample plots, at random. Avoid sites that are within five metres of the edge of the plot.
3. In each sample plot count the number of trees > 2m tall of each species.
4. Pool your species composition data on the master map so that every member of the class can access the complete data set.