Tree is about ten feet tall.

Yes, looks like it indeed. They are actually more cold-tolerant than most think. Mine had a few terminal-bud problems first couple yrs, but none since. Both of mine have survived -8F w/no problem (and the last 2 quite cold winters), but the main issue has been ice & wet snow bending. Below is my 10 yr old over 20' tall in west MD:

Natural distributions reflect all circumstances occurring over all the time since plants from south of an area grew in that area (if they ever did). So these will often grow for some time without freezing out when brought north. Here the last true killer winter, that burned the leaves of long-planted coast redwoods, tan oaks and other trees and shrubs native south of here (primarily California) was in 1990. Before that the autumn freeze of 1955 was so bad the tops of some locally native trees died back. (In both instances the serious cold came in November - too early for woody plants not adapted to northern conditions).

Longleaf is not native here (midtenn) but is planted occasionally. I have two, the tallest ca 30'. Last winter's ice storms caused quite a bit of damage to the largest. They both have endured -21F with no damage, while loblolly had (cosmetic) foliage burn. The so called mountain form is native not all that far away in northern AL.