Not all composts are alike. Many are simply rotten mulch.
We use a "finished compost" - one that has cooled down and been professional produced by the organic folks here in Central Texas.
We've never had a problem with burning.
Holes are drilled down about 18 inches. Below that, you cant' find many roots in the heavy clays we sometimes drill into.
And in many sites around town, we can't drill down more than a few inches because of rock. In those areas, we drill until we hit rock.
By using a nicely finished compost and by putting in 4 to 10 times as many holes as my competitors, I get results they don't. When irrigated, the trees get a "compost tea."
Check out
Soil Foodweb, Inc. for more information about composts.