Spatial and Temporal Analysis of Fires in Nigeria

Software used: ArcGIS

I completed this research project in May 2012 for my graduate scholarly report.

Nigeria is the most populous country in Africa and will soon be one of the most populous countries in the world. Thus, Nigeria’s growing population could have a huge impact on future land use and human disturbance in the region. Fires, in particular, are a major cause of disturbance in Nigerian ecosystems. Most wildfires in Nigeria are caused by humans as an important aspect for many Nigerian cultures is burning land. Fire is an instrument used for many agricultural functions, such as land clearing, pasture management, hunting, and agricultural waste removal.

Research assessing the most recent fire occurrences in Nigeria is limited. Historically, Nigerian farmers with croplands within forests have provided accounts of forest and plantation fire destruction to the Nigerian Federal Department of Forestry as a way to keep an inventory of the damage that has been done.

Average Annual (2002-2010) Fire Points in Nigeria by State

To obtain a better understanding of the extent, distribution, frequency, and recent trends in fire occurrence, this project examined the spatial and temporal pattern of Nigeria for fire events that occurred from 2002 to 2010 using geospatial and remote sensing technology.

Using the FIRMS MODIS Fire Archive Download tool, I acquired vector active fire point data with a 1 km spatial resolution and daily temporal resolution from the Fire Information for Resource Management System (FIRMS) at the University of Maryland, College Park. After selecting Nigeria as the area of interest, I used the polygon tool to extract active fire points occurring from August 1, 2002 to July 31, 2010 in a shapefile (.shp) format to open up in ArcGIS.

Next, I downloaded the 2005 Nigeria land cover map provided by the Globcover regional dataset of Africa to obtain vegetation classifications such as croplands, forests, and savanna. In addition, I acquired reference data for Nigeria such as country and state boundaries. For the temporal pattern methodology, the fire counts were tabulated using spreadsheets in Microsoft Excel and used to plot a variety of graphs to examine the temporal patterns of fires in Nigeria. Each fire year was represented as a separate layer in ArcGIS.

For the spatial pattern methodology, the fire points shapefiles were spatially joined to the state boundaries and land cover shapefiles for each fire year in between 2002 to 2010 in ArcGIS. A table and graphs were created to showcase the counts of active fire points within each state boundary and land cover type. A choropleth map of the average annual counts of active fire points within each Nigerian state was made to additionally assess the fire spatial patterns.

FIRMS Active Fire Points in Nigeria for the 2006-2007 fire year

Temporal characterizations of Nigerian fire 2002- 2010
A total of 796912 active fire points were detected in Nigeria from the FIRMS dataset from 2002 to 2010. Nigeria fire seasons averaged 99614 detections a year. The most active Nigerian fire season year was 2006-2007 with 116224 detections, 16610 more detections than the average detections per year (16.67 % increase above the average).

Spatial characterization of Nigerian fire 2002 – 2010
Spatially, the 2002-2010 Nigeria fire events occurred throughout most of the interior region of the country, with fewer detections in Northern Nigeria and the Niger Delta region. The top three most fire active vegetation types for the 2002-2010 period were: closed to open shrubland (283375 points), open broadleaved deciduous forest (205935 points), and mosaic croplands/vegetation (24924 points). The fire activity in three most fire active vegetation types make up 81% of the fire activity occurring in the various vegetation types.