Oak is a very useful and beautiful tree. Oak wood is very resistant to insect and fungal attack because of its high tannin content, that's why it is used in making furniture, houses, cognac and wine barrels and costs a lot. The highest oak is about 29 meters high. Usually oaks grow in 20 maeters high, but it depends on their species. Oaks have green leaves, they are always thik and massive. Oaks grow in middle Russia. Oaks are often compared to old and wise people.