銀行◆英文題庫下載題庫

Forest fires can be beneficial for trees, soil, and animals. First, trees are the major beneficiaries. Many naturally occurring forest fires, often caused by lightning strikes, are surface fires that burn the understory – the shrubs and herbs from the forest – without damaging the trees in the overstory. In this way, the fire eliminates competition from the smaller trees,

allowing the larger trees to flourish. Once the understory has been burned away, the forest is less likely to burn from high-temperature fires – the combined crown, surface, and ground fires that can do real damage to the tall trees. Burns are also a natural form of control for tree disease and insect pests.

Furthermore, forest fires can improve soil quality by converting the “litter” – dead leaves, twigs, and branches on the forest floor – to nutrient-rich soil. Normally, litter decomposes very slowly. However, fire releases the nutrients in the litter immediately. This creates an increase in the amount of phosphorus and potassium which are key elements that promote tree

growth. The resulting rich soil encourages seed growth.

Additionally, forest fires can ‘thin out’ the forest so larger animals can live in the forest. Animals like deer and moose, which need some open space to live, benefit from the thinning of the understory. As the enriched soil allows new herbs and shrubs to grow, there is new food for these animals as well.