Answer: Well... it seems as both you and your Norfolk Island Pine have been through quite an experience together! I don't think it's a lost cause, but I do think it will take some time for the tree to recover. If it is really badly damaged, you may want to replace it with a healthy new specimen and then treat it like the King or Queen it wants to be in your home.
Norfolk Island Pines may be grown in most temperature ranges which are suitable for people. However, they will do better when grown in cooler temperatures of about 65 degrees f., with slightly cooler night temperatures (never below 50 degrees). Extremes in temperature, either hot or cold should be avoided.
Norfolk Pines need bright light (but never full sun), preferably a spot within four feet of a large window. These plants can survive, with only household incandescent or fluorescent lighting if they receive a minimum of 16 hours of light each day. Although this will be effective in keeping the plant alive for a year or two, there is no substitute for bright, natural light. Turn the plant frequently to keep it symmetrical.
They should be thoroughly watered (preferably with rainwater or water which has set for 24 hours or longer to allow chemicals to evaporate) weekly in the summer to keep it slightly moist, never soggy. (Water more often if the plant is drying out earlier). In the winter, allow the soil to dry completely before watering again.
Feed monthly in the summer with a diluted (half strength), soluble house plant food.
Humidity is very important. Lack of sufficient moisture in the air will cause tip browning, needle drop, and eventually, the lower branches to die off. Misting is the best thing you could do for your tree, followed by any other method which would add humidity to the room (humidifier or aquarium?) Norfolk Pines are one of the very few plants who enjoy being misted with COOL water, rather than room temperature water.
The only pruning that should be done is snipping off brown tips and dead branches. Brown tips will never turn back to green, and unfortunately, once they have turned brown, growth will stop from that point. Any other pruning you may decide to do will have the same effect... no new growth from that point.
Norfolks resent replanting, so they should only be repotted every 3-4 years, in the spring. Use a fast-draining, sterile, commercial potting soil mix.
Should you decide to decorate and use your Norfolk as a Christmas tree, be sure that the soil is kept sufficiently moist during that time when it is decorated.
Lights have a severe drying effect on plants. Be sure to mist your tree daily, or provide other sources of ADDITIONAL humidity. And, don't leave the decorations in place any longer than necessary!
Best wishes with your Norfolk Island Pine!
Q&A Library Searching Tips