Question

ehy was forest affected by wars

Answer 1

it's why right. ????

Answer 2

Forests are affected by wars and this often leads to deforestation.  Forests  during wars are freely cut to meet the needs of war.
This blind destruction and cutting down of forests to fulfill national war requirements affects forests as they get depleted rapidly and are slow to grow back. Forests are as important resource and hence during wars they are destroyed by their own country under the 'a scorched earth policy'. This prevents the enemy from using this resource.