GEOG306 Lecture 17: Bio Hazard Notes
13 Jul 2016
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Most damage in poor countries insects destroy 20% of crops worldwide rodents destroy 10% on average, some more. Specific infestations: locust (africa), pine bark beetle (bc) Theory: fire suppression + climatic warming = tasty mature pine-dominated ecosystem . Greatest risk in late spring: fragile growth, weather extremes, incentives to plant as early as possible. Risk and damage increasing: agricultural in marginal areas, citrus crop at greater risk, florida: 7 devastating frosts in 100 years. Damage reduction: warning shelters, sprinklers, heaters, artificial winds, hazard avoidance (choice of site) Forest fire (canada), brushfire (california), or bushfire (australia. Often triggers secondary hazards (erosion, debris flow) Wildfire as a secondary hazard (drought/lightning wildfire) Australia is the most fire-prone country in world. Recipe: high wind, low humidity, prior drought, fire suppression, steep slopes, ignition source. Influential factors: forest: age, density, tree types, pattern. Trees blow down: moisture content of soil, detritus. Ignition: anthropogenic (main reason, lightning, other reasons:
