I have two large jacarandas growing in my front yard. They were pretty much the same size when we moved in back in 1976. Between five and ten years ago tree roots began to push up the sandstone blocks in front of the house. Three years ago I pulled up some of the blocks and chopped back the thick roots beneath. This was when I discovered I had a heart condition and had to stop. The roots have now pushed up more blocks and damaged the front step. I have always blamed the jacaranda, but it has just occurred to me that the pine growing next to one of the jacarandas might be to blame. We had no root problems for the first 30+ years we were in the house and the pine, planted as a small bush, has grown dramatically in the last 6 to 10 years. Which tree's roots are causing the problem?

Below are four images of the two trees and the root damage. note, in the second image the pine is directly in front of the jacaranda.