and warehouses needed as temporary housing for the slaves. In addition, other vendors provided clothes, food and supplies for slaves. As the trek advanced, some slaves were sold and new ones purchased. Berlin concluded, "In all, the slave trade, with its hubs and regional centers, its spurs and circuits, reached into every cranny of southern society. Few southerners, black or white, were untouched." Once the trip ended, slaves faced a life on the frontier significantly different from most labor in the Upper South. Clearing trees and starting crops on virgin fields was harsh and backbreaking work. A combination of inadequate nutrition, bad water and exhaustion from both the journey and the work weakened the newly arrived slaves and produced casualties. New plantations were located at rivers' edges for ease of transportation and travel. Mosquitoes and other environmental challenges spread disease, which took the lives of many slaves. They had acquired only limited immunities to lowland diseases in their previous homes. The death rate was so high that, in the first few years of hewing a plantation out of the wilderness, some planters preferred whenever possible to use rented slaves rather than their own. The harsh conditions on the frontier increased slave resistance and led owners and overseers to rely on violence for control. Many of the slaves were new to cotton fields and unaccustomed to the "sunrise-to-sunset gang labor" required by their new life. Slaves were driven much harder than when they had been in growing tobacco or wheat back East. Slaves had less time and opportunity to improve the quality of their lives by raising their own livestock or tending vegetable gardens, for either their own consumption or trade, as they could in the East. In Louisiana, French colonists had established sugar cane plantations and exported sugar as the chief commodity crop. After the Louisiana Purchase in 1803, Americans entered the state and joined the sugar cultivation. Between 1810 and 1830, planters bought slaves from the North and the number of slaves increased from fewer than 10,000 to more than 42,000. Planters preferred young males, who represented two-thirds of the slave purchases. Dealing with sugar cane was even more physically demanding than growing cotton. The largely young, unmarried male slave force made the reliance on violence by the owners "especially savage". New Orleans became nationally important as a slave market and port, as slaves were shipped from there upriver