I have a Japanese Maple tree that we planted 6 years back. It is on the east side of the lot and gets morning and afternoon sunlight. I have not done much to care for it and it has not grown in size at all in 6 years. What do I need to do so it grows in size? I am in Northern California.
It has grown, and about as much as I'd expect in six years for a healthy Acer palmatum variety, if you include the dead twigs at the top. It's simply showing signs of dieback, which is usually caused by verticillium wilt, and is very common in Acer palmatum (japanese maple) varieties. Prune back all the dead shoots showing at the top and throughout to live wood now. You may find the dieback is worse next year, or it may improve, there's not a great deal you can do once it's set in except keep your fingers crossed.
Information on dieback here http://homeguides.sfgate.com/prevent-twig-dieback-japanese-maples-22287.html though it's a little late for preventative treatment now.