Yes. For example, if you have a 10-acre parcel that has an area of forestland and an area that you farm, you can put 5ac into the timber exemption and 5 acres into the agricultural exemption.
You cannot, however, have both exemptions on the same piece of ground. For example, if you have 10 treed acres, and you graze cattle throughout the trees, you will have to choose either the grazing or the timber exemption. Keep in mind that in an instance such as this, if you choose to go into the grazing exemption and at some point decide to harvest some of your trees, you will have to pay a 3% yield tax on whatever you make from the mill.