GMAT: reading comprehension : GMAT 식 지문 분해

Chaparral ecosystems contain several species of plants that have evolved to take advantage of, or even require fires to stimulate flowing or seed dispersal. Certain pine species, for example, possess serotonin cones, characterized by a pitch seal surrounding seeds that does not allow for germination until it is broken by the intense heat of fire. This is complimented by the propensity of chaparral ecosystems to create dry-season conditions that allow fire to spread through the flammable shrubs. Animals in these environments have shown an adaptation to the frequency of fire, migrating to portions of the terrain that are safer during fire season. However, in areas such as southern California, the extensive chaparral poses a considerable fire threat to many residential settlements by playing an important role in the spread of wildfires, and there is an ongoing argument as to the best strategy in dealing with the incendiary nature of the surroundings.

The two schools of thought in mitigating fire damage to chaparral area homes are centered on either using fire to lower the flammability of the terrain, or attempting to suppress any fire. The discrepancy lies in the treatment of the inflammable fuel found around the area. Earlier studies theorized that chaparral naturally favored small fires, and the threat of massive wildfires could be traced to increased fuel buildup caused by efforts preventing these smaller fires from running their course. These studies have led to controlled burns being used to reduce the amount of flammable leaf litter in areas nearby houses, but homeowners have protested, due to the copious smoke produced. Control burns are difficult to execute safely, due to factors such as native chaparral plants producing pods that explode upon ignition as a way of plant species projecting seeds to a larger range.

Scientists from the USGS (United States Geological Survey) have called the efficacy of these practices into question, juxtaposing statistics of wildfire spreading in chaparral areas practicing control burns and those that do not. While there is yet to be a conclusive study, the USGS has issued statements that early findings do not point to control burns effectively lowering the spread of wildfires within chaparral areas, and have suggested focusing efforts on preventing fires altogether rather than wide-scale control burns. Advocates of current practices disagree, arguing that despite similar vegetation, the weather patterns in the areas compared are too different to make a direct comparison valid.