Of course you can buy them here.
Artificial trees are available in many stores. I believe in they have them at Lulu, Carrefour, and Dream something on Airport road where they have been advertising for Xmas decorations.
Fresh trees will be available too but later on towards Xmas. If you would buy one now it would be dead by Xmas. But Al Hollandi flowershop opposite Carrefour in Villagio imports them each year. Ask them and find out when they will be here.
But if you want my recommendation, get an artificial one. Will last much longer and less hassle.