Q: I have a saguaro that has developed, over the past couple of years, a marked tilt in the top reach of the main stem (trunk?). It has started to crack at the point of inflection. Should I be concerned that the entire top might come off? If it does, might it bring down the whole saguaro? If this is likely to happen, should I have the saguaro topped?
A: Yes, you should be concerned, especially if there is anything nearby that could be damaged. From the photos you sent, it looks like it is near enough to your driveway to be dangerous. Saguaro cacti are very heavy and could easily harm you or your property. I recommend you employ a certified arborist to visit your property and give you an estimate on the potential hazards, the options you have, and the cost to remedy the situation. You might get more than one estimate to be sure you get a second and third opinion, not to mention the best price.