me wrote:
Thank you all for sharing valuable hints and links. I am also sharing
some photos as David asked earlier. The quality is not that great,
hopefully it will still be useful for seeing/analyzing the problems
further.

https://docs.google.com/file/d/0B5qz...it?usp=sharing
https://docs.google.com/file/d/0B5qz...it?usp=sharing
https://docs.google.com/file/d/0B5qz...it?usp=sharing
https://docs.google.com/file/d/0B5qz...it?usp=sharing

1) The tree has been planted too shallow or the earth around it has been
eroded, those are the roots you can see at the base. Add good soil around
it to about halfway up to the graft or a little more out about 3ft from the
stem, you want to encourage new roots to grow and spread out, citrus is
shallow rooted.

2) No mulch, it needs it on top of the soil. This will help it get through
dry summers. Put it on thickly but not touching the stem, something that
will break down (straw etc) not that long-lasting pink bark. You will need
to replace it from time to time.

3) What direction is the fence from the tree? This is what I meant by
aspect. If that fence is sunwards (south in your case) the tree will hardly
ever (maybe never) see sun and will not thrive.

4) Note various comments about your watering practices.

5) What is the wrapping about the stem? How tight is it?

6) Next winter prune off the dead twigs.

7) Have you dug any holes yet? What depth of soil do you have?

8) Keep the ivy away as it will compete for nutrients.

D