Ideas needed to figure out what happened to my orange tree. Sick? Frost? Bugs? What to look for. It produced all it's oranges for the winter and then in the past few weeks the leaves started curling and looks brown on top. I didn't harvest all of them and it is a mature tree in the garden so this is very strange. It rained really hard a few weeks back and the grass nearby was very soggy wet. So I thought it might have been water logged since most of the soil is clay around here. However tonight I checked and it seemed a bit dry at the base of the tree as it is in a raised box with potting soil. I stuck a wood chopstick to see if there was water further down but it didn't come back wet just cold loose potting soil under the base. I'm concerned even though the rain has made everything else wet this is raised enough it is not getting any? I am not sure on the root structures of these things. We had it getting water from the sprinklers but since the rain we haven't been running them for a month or so. Each year we turn off the sprinklers around this time. Maybe a water issue?? I wasn't sure if there should be something else to look for. We have had some cold weather between 35-40 degrees F at night for the past few weeks. Some frost in the mornings. The other citrus (small lemon tree, tangerine bush, small lime tree), don't seem affected although they are against a fence and much shorter. I attached photos of the tree I took in the evening and one during the day. The base is raised. This tree has been here for many years and I haven't seen it do this before. Any suggestions would be great. I checked the bark to see if it looked like one of the common virus but seems ok. Under the wood is still green. Leaves are curled up and a number are brown.