Global economic conditions are still pretty turbulent atm. We could see a break in the pattern.

In Europe, where most of the Christmas traditions originated, most of the trees lose their leaves in the winter. The few trees (and plants) that stayed green year-round were celebrated and even brought inside the house; not just pine trees but also things like holly, ivy, and mistletoe. Because who wants to decorate his house with bare twigs? This tradition probably even goes back before Christmas was celebrated in that part of the world.

As for red, the connection is not as old. Holly berries are red and also apples and other fruit that might be used to decorate around Christmas-time. Another connection with red is the red robes of the bishops. Since the historical St. Nicolas was a bishop, he was often portrayed using a red robe, and the character of Santa Claus (which is ultimately based on St. Nicolas) likewise tends to wear red. (Some say it's because of a Coca-Cola advertising campaign, but that's not correct. Santa Claus was commonly depicted wearing red long before Coca-Cola was using him to advertise their products.) Maybe it's just due to the fact that green & red are complementary colors, like purple & yellow or blue & orange.