Lab 8

The Station Fire which started on August 26, 2009, was the largest fire in the recorded history of Angeles National Forest (est. 1892) and the 10^th largest fire in California since 1933 (“Station Fire,” 2009).  The Station Fire caused massive damage to the ecology and public property of the communities in Los Angeles County. For example, a 40-mile stretch of the Angeles Crest Highway was closed until 2010 due to guardrail and sign damage, although the pavement remained largely intact (Weikel, 2009). So how did the Station Fire spread? What were the possible conditions that favor fire spread? For this lab, I chose to analyze the effects of slope and land cover on the spread of the Station Fire.

An investigation of the location of the Station Fire is necessary before we do the analysis of those effects on the spread of the Station Fire. From the reference map of California, it is clear to see that the 2009 Station Fire occurred almost at the center of LA County in Southern California. From the location map of Los Angeles County, we can see more clearly about the growth of the fire at a certain time recorded. Fortunately, the fire was not in the zone of urban areas. Only one or two major highways were present in the fire zone and no cities or hospitals were there. However, there were several cities quite near the burning area.

Terrain slope can be a primary influence on wildland fire behavior (Weise, 1993). When compared to flat terrain, heading fire spread rates will increase by two times on 10 degree slopes and four times on 20 degree slopes (McArthur, 1968). Thus, we should expect that the Station Fire also generally spread in the terrain with steep slopes such as in the mountain areas. By the tool of spatial analysis in GIS, I created a map of elevation contour and a map of slope. From the contour map, we can see that the fire grew in the area with dense contour lines which indicate severe steepness of the area. Also, the slope map shows that the fire generally grew in the area with high-degree slopes.

Fire spread is also thought to be impacted by land covers which include grass, trees, water and so on. Fire is easily ignited and spread in forests where wood can be easily burned. From the map of land cover, we can see that the fire was generally spread in forests. One of the remarkable species in the area is Montane Hardwood-Conifer. Research shows that Burned locations in Montane Hardwood-Conifer vegetation were significantly more likely to burn at moderate/high severity than locations in other species (Bond, Lee, Bradley and Hanson, 2009).

In conclusion, I examined the effects of slope and land cover on the spread of the 2009 Station Fire. Maps show that the fire generally spread in areas with high-degree slopes as well as in forests. Understanding those kinds of effects can help us predict where a fire hazard severity zone is. The last map shows the very high fire hazard severity zones. The data were downloaded from California Department of Forestry and Fire Protection. The 2009 Station Fire actually started with some overlap in one of the zones.

References

Bond, M. L., Lee, D. E., Bradley, C. M., & Hanson, C. T. (2009). Influence of pre-fire tree

mortality on fire severity in conifer forests of the San Bernardino Mountains, California. The Open Forest Science Journal, 2, pp. 41-47. Retrieved from www.biologicaldiversity.org

Incident Information System. (2009). Station Fire. Retrieved December 12, 2012,

from http://inciweb.org/incident/1856/

McArthur, A. G. (1968). Fire behavior in Eucalypt forests. Leaflet No.107. Ninth

Commonwealth Forestry Conference, India.

Weikel, D. (2009, September 4). Angeles Crest Highway closed indefinitely

because of fire. Los Angeles Times. Retrieved December 12, 2012, from http://latimesblogs.latimes.com/lanow/2009/09/angeles-crest-highway-closed-indefinitely-because-of-fire.html

Weise, D. R. (1993). Modeling wind and slope-induced wildland fire behavior. Ph.D

Dissertion. Berkeley: University of California at Berkeley. 130 p.

Lab 7

The population density of Asian Americans is relatively low across the continental United States. Most Asians reside on West Coast and East Coast, with the highest density 30.8% in San Francisco County, California. In the Midwest and other parts of the continental US, Asian population spreads out randomly with densities generally below 2.28%. The pattern of the population is formed due to geographical locations between Asia and North America. Since Asia is to the west of the US, the first place immigrants from Asia arrived at is West Coast. Thus, the population density is high in counties on West Coast. Since New York and surrounding cities are always attractive places to immigrants because of abundant job opportunities and modernization in those cities, a lot of Asian immigrants also reside in those areas.

From the map, we can see that the population density of African Americans is highest in the southeastern part of the US, with the highest density 86.5% in Jefferson County, Mississippi. The population densities of many counties in Mississippi and Alabama are above 50%, while in northwestern part of the US, the population densities of most counties are below 10%. In the history of the United States, black slavery were brought from Africa to the southeastern part of the US and most of their descendants still stayed there.

The population densities of other minorities are highest in counties in California, New Mexico and Texas, with densities generally above 10%. The highest density is 39.1% in Imperial County, California. However, the densities are quite low in Midwest and other parts of the US. They are generally below 5%. From the map, we can see that the places with highest densities of other minorities are on border with Mexico. Thus, we can imagine that the dominant ethnic in this category is Hispanic. Due to the proximity to Mexico, most immigrants decided to settle down in South and Southwest US.

In general, I find that the population densities of Asians and other minorities are highest in the southwestern part of the US, while the density of African Americans is highest in the southeastern part of the US. Across the continental US, there is no county with a population density of Asians or other minorities over 50%. The census experience I had with GIS is quite interesting and useful. I not only know more about the geographical distribution of population densities of different races, but also developed my GIS manipulation skills of integrating data from external sources into the software. The series of census maps allows me to analyze real-world problems in population distribution. Overall, GIS is quite useful and powerful in map-making and geographical data processing. We can generally utilize it with ease once we know the basic methods of manipulation.