You're only supposed to ask one question at a time. This thing is two questions.
There's no answer to the first question because the significant thing about the Time War is that it was a time war. It involved two sides that both had time travel.
To the second question: Skaro does (or did) have forests of trees. It also has caves. Both a forest -- in which the trees had by then become petrified -- and caves featured in the first Dalek story, "The Daleks", which was set on Skaro.