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TPO 64- Speaking Question 4

Listen to part of a talk in an environmental science class.

Professor: There’s one more method of forest conservation I want to talk about before we end today, and that’s forest fires.

It may come as a surprise to many of you, but fire is a key element of many ecosystems.

For example, it’s a natural, normal process that helps maintain a healthy forest.

For decades, we believe fire should be suppressed at all costs. So they were put out as quickly as possible to preserve the environment, but in the last twenty years or so, we’ve come to realize the advantages of regular, controlled fires to an ecosystem.

In fact, a lot of plant species depend on fire for survival. In a forest full of pine trees, for example, fire is necessary for reproduction. Pine trees in particular need fire in order to spread their seeds. Pine trees of course have pine cones, which contain their seeds. So what happens is that the heat from a fire melts the resin, you know that sticky stuff that holds the cone scales together. So the resin melts and the cone’s opened up, and the seeds inside the cone are released on the ground. And eventually, young pine trees grow from them. So thanks to the fire, we’ve got a new generation of pine trees.

Like I said earlier, fires can help grow better forests, which in turn creates a better habitat for wild life in the areas. For instance, they have an impact on the density of the forest, a fire that kills some trees but not others can open up a forest area previously thick with trees. This let’s in sunshine which encourages growth of new shrubs and grasses. The new plant life in turn brings in new animal species.