I've worked in rural areas...very rural, in fact. It's all about how you run the biz. Some people let the customers run the biz, only doing what the customers say and only working when they call. These people will not be working the winter months. People in general spend more time outdoors in the warmer months. Also, they are more likely to have their trees worked on when they are spending more time with their trees.
Those that can educate their customers on the countless advantages of doing treework in the winter (Gopher, for example) will have work throughout the winter, though it does slow down.
Also point out that in summer months, you can barely keep up with the work, and there are more hours in the day in which you can work. There fore you can make enough to live off, PLUS save some to get you through the winter, which manage through careful budgetting. While other people are slaving away 40 hrs/week, winter time for you is a cake-walk...a vacation.
Let them chew on that for a while. And don't spend all your money on the summer or else you will be applying for unemployment benefits in the winter.
love
nick