Across the United States, people looking to buy real Christmas trees are either finding reduced choices, higher prices, or both.The worldwide supply problem has also affected the number of artificial trees, like those made from plastic.A combination of severe weather and difficulties getting trees from factories overseas caused what one industry expert called "a double whammy."This means that the situation is bad in two different ways.Jami Warner is executive director of the American Christmas Tree Association.She said, "Growers have been hard hit by floods, fires, smoke, drought, extreme weather conditions."Heat and fires in the northwest U.S. in June hurt Christmas tree farms in Oregon and Washington.Those are the states where most of the trees come from.It takes 10 years for most trees to grow.So, losing trees to fires and bad weather creates problems that may last for many years.Even for the trees that do get cut down for sale, there are not enough truck drivers to bring them into city markets.