
Additionally looking at the grassland area on the USDA Web Soil Survey website it appears that much of the area is made up of Diablo-Olivenhain complex (clay and cobbly loam) with 9 to 30 percent slope; the adjacent hillsides are largely fine sandy loam with 30 to 70 percent slope. In this picture the oval on the left encircles an area of sage and chaparral above the grassland which is largely contained in the oval on the right. The broad difference in soils can be seen. Both soils have good drainage. I don't know exactly how the soil type might affect the vegetation in this instance but the grassland may also be in the flood plain of the San Diego River which I would think might affect the mineral composition of the soil.
	The photo on the left shows the Mission Trails Park grassland shortly after a fire in 2003 from a very similar perspective to my recent picture on the right. This was the most recent major disruption in the area and it affected both grassland and shrubland in the park. Much of the chaparral vegetation is fire-adapted and some like Ceaonothus actually requires heat for the seed to germinate. According to the park website all areas have recovered well from the fire. 
	 Historical records indicate that aside from fire human disturbances have been frequent in the area. The native Kumeyaay people lived in villages along the river and would burn underbrush in the oak woodland to stimulate growth and attract deer. Later the Spanish built a dam across the river here. There was also a World War II-era training camp north of the river which later became a bombing range. Because the higher elevations are more rugged and inaccessible it seems probable that more human activity was concentrated around the river and the grassland area but I can't know that for sure. If this is a fact then it would make sense that more frequent disturbances would have introduced more foreign grass seeds and provided more opportunity for them to establish themselves.
As mentioned above the grassland occurs in an area with significantly less slope than the sage scrub and chaparral at slightly higher elevations.

	Although most people don't think about it very often, vegetation and the factors that influence its distribution affect almost every aspect of our lives, from the food we eat to the wood that builds our houses and the paper we write on. In the future climate change, biofuels, and the dietary demands of a growing population will make these effects even more obvious. Creating more experts in this field is in Colorado's interest to help keep our state and nation competitive and successful in a changing world.
	I will examine two major areas in which knowledge of global vegetation types and distribution would benefit us: conservation of wildlife, and dealing with climate change.
