Oaks can grow 20-40m in height, with a spread of 20m or more. A mature holm oak can reach 25m by 20m, and Turkey oaks can grow to around 30m. When grown as a hedge, oak can be clipped to an appropriate size.
Oak trees are one of the longest-lived trees, with a potential lifespan of over 1,000 years. They reach maturity at around 40 years old, by which time many will be producing acorns. When trees reach 150-300 years old, they are usually classed as veteran trees. From 400 years old, they are known as ancient oaks. Even when an oak tree dies, the deadwood continues to provide habitats for wildlife including beetles, birds and many species of fungi.
A mature oak can produce around 100,000 liters of oxygen in a year. If you divide that by 365 days, it's about 274 liters per day.