Laboratory Deforestation Rates and Cross Analysis Land Use / Cover Change Exercise © prepared by Dr. Arturo Sanchez-Azofeifa Earth and Atmospheric Sciences Dept. University of Alberta, Canada Introduction In this lab you will identify tropical deforestation trends and analyze species distribution as a function of landscape characteristics (soils, life zone etc.). Materials Data sets for the Puerto Viejo de Sarapiqui region, Costa Rica: Satellite interpreted forest cover maps (sampled in 1976, 1986, 1996; 1=forest, 2=non-forest, 3=clouds, normalized for all 3 years), soils, life zones, and sampled spatial distribution of the following trees: Carapa guianensis and Phitecellobium elegans. These are highly valued hardwoods; the points represent sampled sites, not the total population. Units are in meters and the projection is UTM. Assignment Conservation International (CI), a Non-governmental Organization from Washington D.C., has asked you, to prepare a study of spatial distribution of Carapa guianensis and Phitecellobium elegans for in-situ conservation activities. From the provided materials, estimate the following: Deforestation rates (use both tabular and spatial analyses). Spatial distribution of Carapa guianensis and Phitecellobium elegans as function of different biophysical characteristics, specifically: soils types, Holdridge Life Zones. Processing steps Data - Create a Lab_LUCC sub-directory in your personal directory and retrieve the data into your new sub-directory. You should have 3 images (polygons) and 3 shape files. - New View, Add Theme, Data Source, choose the three images, press OK. - Active one image at a time and go to Theme, Convert to Shape File. Select the same folder that you are working on, give the same name to the shape file than the image. Press YES when the program asks Add shape file as theme to the view. - Now you should have 6 images in the View screen. Select the image files and delete them (Edit, Delete Theme, YES). - Make active the 1976 shape file (i.e. Selva76) and double click on it in order to open the Legend Editor. In Legend type choose Unique Value and in Values Field select Gridcode. Click in Apply in close the Legend Editor. - Open the Table for the 1976 shape file, go to Query and put type ( [Grid-code] = 1 ), Add To Set. Then go to File and Export the Query as a dbf. Open the dbf in Excel and calculate the forest area for 1976. - Do the same for the 1986 and 1996 coverages and get the Deforestation rates. Deforestation Rates For the three forest cover coverages calculate the total area forest cover and estimate average annual deforestation. Remember that annual deforestation rates are calculated as follows: annual deforestation rate = 1 - (yearx / year0)**1/n, where n is the number of years between yearx and year0 (base year). Has deforestation decreased or accelerated during the last decade? Look at the different coverages that you produced and give a qualitative analysis of deforestation. Where does deforestation occur? Is it along a 'front', or are there 'wedges' or other 'paths' penetrating deep into the forest? Is deforestation 'massive' or 'patchy'? Spatial distribution of Carapa and Phitecellobium - Open a new view; go to File, Extensions and click in the Geoprocesing box. - Add the trees coverage, the soils coverage, and the lifezone coverage to the view. - Make active the view screen the trees coverage and the soils coverage. - Open the Legend Editor for both coverages, choose Unique Value, and for the trees coverage choose Type and for the soils coverage select Clase. - Now, go to View, Geoprocesing, Assign data by location, Next. The theme to assign data to is Treespro and the theme to assign data from is Soilspro. - Press Finish. - Now open the Table for the Trees coverage and export it as a dbf. Open the Table in Excel and leave only the columns Type and Clase. You can use the autofilter option in Excel to have the final results. - Repeat the same procedure for Trees and LifeZones. Questions On which soils are the tree species growing? In what life zone do they grow? Are they restricted to certain soil types and life zones? Visually analyze the tree distribution with respect to the deforestation trends. Do you think that the trees suffered during the deforestation over the years? Do you think that the Carapa and Phitecellobium species are under a threat of being lost due to uncontrolled deforestation? Please explain in detail. Reporting Prepare a report presenting a detailed analysis of your findings. Use graphics to illustrate your analysis. Be as explicit as you can with your statistical analysis and use tables to present outputs from your analysis. The size limit of the report is approximately five pages.