There are a few things you can do to make the hump look less intrusive::

• Some of the preset tree shapes have less of a hump than others - try them until you find the best one.
• Increase the trunk thickness and adjust the distribution dials to make the branches break from a poinr as close to the hump as possible - this makes it look more natural
• Adjust the distribution and gravity dials to get some foliage hanging down to break the outline of the hump
• Stick a tiny tree with big leaves roots-first into the hump to look like a branch - again that makes the hump look more like a natural growth bulge
• Put two trees together then adjust their height and rotation until each one's branches are disguising the other tree's hump
• If all else fails use some small trees as suckers or shrubs around the base to hide the hump