Class Paragraph assignment: The consequences of deforestation (about 200 words)

I'm a new member here and I'm doubted whether this thread could be put in this Category. I'm sorry if I've done wrong.

Recently, some environmentalists have warned that the number of forests chopped down or burnt worldwide is increasing sharply. This fact could lead to various unexpected problems. In the first place, deforestation could be a culprit of causing serious soil erosion. Trees play an important role in protecting land from heavy rain, strong wind and such natural disasters as hurricane or flood. The soil which suffers from deforestation will lose its nutrition as well as mineral whenever there is rain. Gradually, it becomes waste land where no tree could grow. In additionl, destroying the forests also exerts a negative influence on the natural habitats of differen animals. Once tree are cut down, they lack shelters, food, and are on the verge of becoming extinct. Another problem is that deforestation could result in a huge loss in the amount of oxygen on Earth. Forests are regarded as "the green lungs" of our planet. When these "lungs" are destroyed, most creatures would disappear, including human beings. Overall, not only does deforestation destroy the natural environment but it also harm our life. People should be aware of the value and importance of protecting "the green lungs" of the Earth.

I think it is good.

those belows would have been like this.
1.
In additionl , destroying the forests also exerts a negative influence on the natural habitats of differen animals.
In addition
2.
Once tree are cut down, they lack shelters, food, and are on the verge of becoming extinct
shelters and food and are

Thank you. Could you tell me why it must be "Once tree are cut down, they lack shelters and food and are on the verge of becoming extinct"?