Total height is usually the most important cost factor. Likewise, the diameter of a tree's trunk is a factor in the cost of removal because of the time required to cut and remove it. Diameter also influences the price of grinding the stump.
The condition is also a factor, because if the tree is relatively healthy it's harder to cut. On the other hand, if a tree is dead or dying, then it should be easier to cut although perhaps more dangerous to work with because of its instability.
The cost of removing a tree is influenced by the species. That's because hardwood trees such as oak are very hard to saw, as well as heavy and often tall.
Location is also important. If a tree is located on a property in a remote area, then travel time to and from the job site may be a factor in tree removal prices.
At the same time, if a tree is located in a restricted space or close to buildings or other property that must be protected during the removal, then the work costs more because of the need for special equipment.