I have a small space in front of my townhouse that I would like to put a paver patio.. There is a great tree that I would like to keep there. I would like to fill the whole area with pavers, but dont know if i need to keep a certain distance from the tree, or if there will be enough water and oxygen getting through the base rock and leveling sand. Can I still do this project without killing the tree?
The base rock and leveling sand should not be a problem. The photo below shows crape myrtles (which is what I believe is pictured in your photo) planted in a compacted bed of small crushed gravel and natural fines (rough sand) soon after planting.
These trees have been in place for almost 4 years now, and they are thriving.
With a structural base like that in place, compaction should not be an issue. However if too much of the surface area is covered with slabs of stone, oxygen exchange and water infiltration could be an issue. Leaving open spaces (un grouted) between the stones will reduce the negative effects of cutting off so much soil surface from the elements, but it will still be important to leave some space around the tree as shown below to provide contact with the atmosphere and leave room for growth.