This big branch was dead and it needed to be removed. You can do this yourself if it’s not too big or high. This is the 3-cut method. Essential here is not to cut into what is called the “collar” of the tree, where it joins up with the trunk. This could damage the tree and make it hard for it to heal after the cut. But you also don’t want to leave a big stub because that could look bad and (I believe it is also harder for the tree to heal.)Also important is not to take too much off a tree at one