Here is a site I found with some information on it........
http://www.pickyourownchristmastree.org/caring4atree.php
Important Tips on Caring for Your Christmas
Selecting a tree
1. Get a healthy tree - Dont buy a tree that is losing green needles, or has dry, brittle twigs or a sour, musty smell. Excessive needle loss can be detected by vigorously shaking the tree, or dropping it onto the end of the trunk several times from a height of about 1 ft (30 cm). The loss of old dead needles from the inside of the tree does not indicate that there is a problem with the tree. Mechanical shakers can remove these needles, and reduce the potential for a mess inside the home.
2. Size of the tree - Do not buy a tree that is too large for the area where it will be displayed. Aside from paying more than necessary, up to $10 per ft (30 cm) of height, you will have to cut off a large section of the lower trunk, and possibly the lower whorl of branches. This might ruin the appearance of the lower part of the tree.
3. Bottom of the tree - Note the location of large branches at the bottom of the tree. Be sure that the handle is long enough to allow display of the tree without cutting off the lower whorl of large branches. USDA grading rules specify trees should have a handle 1 to 12 in (2.5 to 3.8 cm) long per ft (30 cm) of height. However, some species are routinely sold without pruned handles, eg, Fraser fir.
3. Shaking the tree - When purchasing a tree from a choose-n-cut farm, have the producer mechanically shake the tree, if possible. This will eliminate dead, loose needles, especially in species such as Virginia pine, white pine, Scotch pine and red cedar. There is less potential mess to reach the home.
Transporting the tree
4. Wrap the tree - If the transport time from the retail lot or farm to the final destination is more than 15 min, it is best to wrap the tree in a tarp, or carry it in an enclosed camper or the back of a pick-up. Strong wind of 60 mph (100 km h-1) on the highway, especially during warm weather, can damage a tree in a short time.
5. Orientation on the car - Put the bottom of the tree aiming forward to protect the needles from being blown off.
6. Tie it securely! - If the tree is carried on the outside of a vehicle, tie it securely.
Storing the tree before bring it in the house
7. Keep out of the sunlight - Do not leave a cut Christmas tree lying in the sunshine for long periods of time, especially if air temperatures are warm. Fresh trees dry rapidly in those circumstances.
8. Keep it in water - If a tree cannot be immediately displayed in water, make a fresh cut on the base of the trunk, and stand it in a bucket of water in a cool, shaded location, either indoors or outdoors. When the tree is displayed in a water holding stand, a second fresh cut is probably unnecessary, but might enhance water uptake.
Setting up the tree in your stand
9. Cut off a disk of wood about 0.5 to 1 inch (1.25 to 2.5 cm) thick from the base of the trunk immediately before putting the tree in the stand. Make the cut perpendicular to the stem axis. Do not cut at an angle, or into a v-shape, which makes it far more difficult to hold the tree plumb in the stand, and reduces the amount of water available to the tree. Do not cut off too much trunk, resulting in a handle too short for the stand. This would lead to the situation described in (2) and (3) above.
If no saw is available, get the retailer to make a fresh cut on the base of the trunk before departing for home. Assuming that the trip home is relatively short, put the tree in water as soon as possible. Species like Douglas-fir and Fraser fir can go 6 to 8 h after cutting, and still take up water. Do not bruise the end of the trunk or get it dirty.
10. Drilling a hole in the base of the trunk does not affect water uptake. The use of I-V type devices to supply water directly to holes drilled in the tree is not as effective as displaying the tree in a more traditional type of stand.
11. Use a stand that fits your tree. Some stands have circular rings at the top, so the ring must be large enough so the trunk goes through the hole. Other stands are open, which allows more range in trunk size. Avoid whittling the sides of the trunk down to fit a stand. The outer layers of wood are most efficient in taking up water and should not be removed. Use a stand with an adequate water holding capacity for the tree. Using stands that are too small is a very common mistake. Fresh trees use about 1 qt (about 1 L) of water per day per in (about 2.5 cm) of trunk diameter. The stand should hold enough water to last 24 h. If the stand goes dry and is subsequently refilled, water uptake may stop or be severely limited, leading to premature drying. Contraptions are available that maintain constant water level in the stand, working on the principle of a commode float.
12. Cold water - Do not use hot water in the stand; it is of no benefit.
13. No chemicals - Do not use chemicals in the stand to prevent evaporation. Water moves into the trunk at the lower cut end, and eventually evaporates (transpires) from the foliage. Evaporation from the surface of water in the stand is negligible, compared to the loss from transpiration. Do not use additives in water, including floral preservatives, molasses, sugar, bleach, soft drinks, aspirin, honey, or other concoctions. Do not apply film-forming anti-transpirants. The products supposedly block the evaporation of water from the surface of foliage, but in reality have little benefit. Do not use water holding gels in the stand. They reduce the amount of water available to trees. Clean water is the only requirement to maintain freshness.
Decorating your tree
14. Keep away from heat - Keep displayed trees away from point sources of heat (fireplaces, heaters, heat vents, direct sunlight). Lowering the room temperature will slow drying, resulting in less water consumption.
15. Lights - Use only UL approved lights and electrical cords and devices on trees. Check electrical cords and lights for damage prior to placement on the tree.
16. Placement of ornaments - Hang all ornaments that are breakable, have small, detachable parts or metal hooks, or that look like food or candy on higher branches where small children can't reach them. Green floral wire, which can be twisted firmly around branches, is a great way to hang fragile ornaments.
17. Pets - Keep pets out of the room in which the tree is placed, especially if you can't be there to supervise. Cats are known for leaping onto Christmas trees, especially when pursued by another pet. Use a ceiling hook to keep the tree from toppling. Both cats and dogs can knock down and break glass ornaments, then cut themselves on the pieces. Pets may also gnaw on electrical cords for Christmas tree lights. So hide them when possible, or help prevent injury by purchasing a pet-proof cover for the wiring.
18. Avoid using artificial snow sprays, to which some people are allergic and may cause lung irritation if inhaled.
19. Turn off tree lights when you go to bed or leave the house. Use only UL-approved electrical decorations and extension cords, and check to be sure no cords have frayed since you last used the lights.
Watering your tree
20. Always keep the tree stand filled with water. Dried sap will form a seal over the cut stump within several hours if the water level falls below the base of the tree. If this occurs, make another fresh cut in the butt-end and promptly fill the stand with water. Use hot tap water which will soften sap and facilitate absorption.
21. How much water - A tree will absorb as much as a gallon of water or more in the 24 hours after it is cut, and one or more quarts everyday after. Maintaining a steady water level prevents the needles from drying out and dropping off and the boughs from drooping. Water will also keep the tree fragrant. Do not allow the water pan to empty or go below the tree base
Taking down the tree
22. Monitor the tree for dryness. If the tree is dry, remove it from the house.
23. Disconnect all electrical devices prior to removing them from the tree.
24. Never burn a tree in a fire place or wood stove. Pine trees have a lot of sap which can flash and also create a chimney fire.
I think it depends on the tree itself on how long it will last.
We just love Christmas!
