Green tree pythons require a bit more care in order to thrive. They are not as tolerant of husbandry errors as colubrids and some other pythons and boas. However, if you have reasonable experience in keeping snakes and do your homework, they are not overly difficult to keep.
General Information:
Green tree pythons are found in Indonesia and parts of Papua New Guinea. Temperatures range from the 90's down to the 70's. Humidity is relatively high as it rains most every day there. They are almost entirely arboreal althought they do spend some time on the ground and in the evenings in Indonesia can be found crawling by roads.

Housing:
Young snakes up to a year old can be housed in a Rubbermaid tub. Rack systems are fine for very small hatchlings and will maintain them easily and more cheaply than getting an arboreal cage.
Adults can also be housed in large plastic tubs if desired, but most people enjoy viewing their colorful snakes and so usually purchase a more expensive arboreal cage made from plastic or plexiglass. You can also make your own. Adults require a minimum cage size of 24" X 24" X 24" (61cmX 61cmX 61cm) I prefer to house my adults in something larger. 30-36" X 24" X 24" (76-91cm X 61cm X 61cm). Any cage you purchase must be heat and moisture resistant. Glass terrariums/reptile cages usually do not hold temperatures well or the humidity. They are cheaper but much more difficult to maintain.

Heat:
Since GTP's are arboreal, they require overhead heat rather than floor heat. Babies housed in racks can use heat tape on the sides, but regular tubs can be heated using heat lamps or heat panels. Rubbermaid tubs can have a hole cut in the lid, and the holde covered with wire mesh. The heat lamp can be placed on this to provide overhead heat. With tubs, I usually put some fiberglass screen inside the tub so that the snake is unable to touch the hot wire mesh.
Arboreal cages can easily be fitted with heat panels which provide safe radiant heat. They cannot burn the snake when touched and since they are fitted on the roof, they cannot lie on them and get burned. Temperatures should be kept around 85 F (30C) on the warm side and 78-80F (26-27C) on the cool. Some people are finding that keeping the temps at around 82F (28C) will ensure the animal's body temperature is around 85 F. A good thermostat is needed to keep temperatures stable. I use a proportional thermostat and it keeps the temperature within +- 1 degree.

Humidity:
Babies should be kept at approximately 80% humidity all the time. Adults can be cycled with a high humidity of 90% or greater after you spray and then allowed to dry out to about 50-60% by the next spraying. If using tubs, holes that are drilled in the sides can be covered or opened to adjust the humidity levels until they are where you want them. A hydrometer can help you better gauge the actual humidity.

Substrate:
It can be as simple as paper towels, cotton towels or the rubberized shelf liners. I use shredded cypress for most of my cages as it holds humidity well without molding. Forest Floor is a general name brand reptile bedding that can be purchased, or check your local gardening store. Cedar and pine should not be used as the aromatic oils can cause respiratory and neurological problems.

Feeding:
Babies should be fed every 5 days or so on pinkies. Most will readily take frozen thawed.
Adults will eat an appropriately sized mouse/rat every week or two. GTP's digest slowly and have slow metabolisms so it's important not to overfeed, which can cause prolapse. You will probably end up feeding 2-3 times before your animal deficates. Babies will go more of course, but adults will probably deficate every month to 6 weeks.

Health Problems:
The most prevalent problems are Respiratory infections and intestinal prolapse.
Keeping temperatures and humidity at proper levels are very important. Lung linings on GTP's are quite thin and they will succumb to R.I's fairly rapidly if untreated...and sometimes even if they are.
Rectal prolapse can occur for a number of reasons:
Parasites, improper humidity, overfeeding and sometimes an unknown reason. Usually it occurs during defication but not always.
Most health problems can be avoided if you purchase a captive born and bred animal from a breeder and stay away from farmed imports. Most (not all) animals that are imported are full of parasites and some can be in very poor condition. The money you spent on the purchase will now go towards the vet! Better to stay with a reputable breeder. You'll be better off in the long run.

These animals are addictive and beautiful! Their diverse colors and well as the amazing color change as they mature make them hard to resist. They are relatively costly however and I can't stress enough....if you can't afford to take care of them (and that means all aspects including veterinary care) don't get one! If you don't have a vet in the area or any that you can trust, it might be best to wait. These are not animals you want to try to treat yourself if they become ill.

cheers babe

A very nice care sheet for GTP.
I used to keep them. He was quite temper. haha
Green tree pythons are fab animal. I like their attitude and the pose!

I've been very lucky. Out of my collection, I only have one that is nasty...and boy is she nasty!! the rest are very nice and my one Sorong type is as gentle as a kitten. They are horribly addicting though! I don't know how you could bear to give them up!

Kitten is gentle??? haha they are so naughty and playful! But as you said Morelia sp look like Cats. They are so sexy animal. I like the born stracture of the head.
Enjoy with your GTP!

Well, a sleeping kitten then. She will literally sleep with her head on your chest while you pet her. She's really cool. I do enjoy them alot!

i think they are stunning snakes to have you must be very lucky

I do feel very lucky! I've had such wonderful experiences with all my snakes and it seems that each time I get a new species, I happen upon the perfect one! Of course the down side is that I end up getting more....hmmm, not that bad a downside...

nope not at all i would love one but im looking to get a pie-bald nxt year my fella doesnt like snakes so im kinda lucky that i can get one more snake so ive decided on a pie. Well its a toss up between a pie a blood or a gtp and a friend is breeding pies nxt year and im getting one for a great price so i cant refuse. I can always work on my fella after i get this one so who knows

Luckily for me, my hubby likes the snakes. He's just not as obsessed about it as I am. I'm going to be getting another Aru male at the Daytona show in Aug. Gotta sell a bunch of my cornsnake babies!