While cut Christmas trees are much "greener" than they used to be, from the growing to the composting - post holiday, a live tree provides more long-term green benefits. Such trees are intended to be planted out, instead of tossed out, after the Holiday. So, you get more bang for your buck as your Yule tree doubles as a landscape addition - that increases in value each year, and it serves as a living reminder of that special time of year.
Live trees are typically sold at heights from 2-4' so you won't need to rearrange all the furniture to accommodate one. You will, however, need to plan ahead more than you would for a cut tree. Go tree shopping a few weeks before you actually plan to bring the tree into your home for the best selection. Shopping early also allows time for the necessary acclimation from outdoor to indoor temperatures and time to get the hole dug for later planting.
When choosing a live tree for holiday décor, keep in mind its future as a landscape addition. Get information on the tree's ultimate size and its cultural requirements, so you can make the best choice for your landscape. After that, look for a well shaped tree with a good amount of healthy roots and good needle retention. You may want to purchase an anti-desiccant spray as well, to help reduce loss of moisture through the needles when the tree is placed indoors.
Once you get your evergreen home, spend some time preparing for its planting, before you begin the acclimation process. If you live in a climate where the soil is likely to be frozen, or the air temps just too dang chilly after the holiday, then dig the planting hole ahead of time! The hole should be dug twice as wide as the tree's container and to a depth that will allow the top of the root ball to be flush with the ground. Covering the hole, and the soil removed from it, with a tarp can be very helpful in keeping it workable until planting time.
In cooler climates, immediately introducing the tree to the warmer temperature of the house is strongly discouraged as it can trigger new growth that will be too tender to survive when the tree is moved outside. So, unless you live in a very temperate zone, the tree will need to be acclimated. This is easily done by placing the tree in an unheated garage or enclosed porch for three to four days prior to moving it into the house. The tree should be kept watered and the anti-desiccant applied, if one is being used, during this transition time. This is also a good time to clean off dust, cobwebs and other debris. After acclimation, display the tree in a cooler area of your home; avoiding heat vents, fireplaces and bright, sunny windows. Keep the soil moist, but not soaking wet and turn off tree lights overnight to decrease moisture lose through the needles. Limit the tree's stay indoors to 10-14 days, again to avoid triggering new growth.
After its stay indoors, the tree will need to be acclimated back to outdoor temperatures before planting. Move it again to the unheated porch or garage, but this time give it a two week stay to be sure it "goes back to sleep". After two weeks, plant the tree in its pre-dug hole; being sure to loosen the roots a bit then covering them with the reserved soil, tamping it down and watering well. Do not fertilize until new growth appears in the spring.