Deforestation Puzzle

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Across
  1. 5. The action of clearing a wide area of trees
  2. 6. The presence in or introduction into the environment of a substance or thing that has harmful or poisonous effects.
Down
  1. 1. the condition of being populated with excessively large numbers.
  2. 2. A natural fuel such as coal or gas, formed in the geological past from the remains of living organisms.
  3. 3. Operations associated with the production of oil or gas from reservoir access holes drilled from underground shafts or tunnels.
  4. 4. The activity or business of felling trees and cutting and preparing the timber.