Pam:

I would dig down a foot or so where you think there could have been a spill--maybe in 3 or four different places--and sniff the soil for evidence of gasoline or oil or something. For those who may think that soil compaction from the vehicles may have killed the tree, I know I need not to be too cocksure of anything, but let me say anyway, "no way!" Norway spruce are very, very tolerant of having soil compacted around them by vehicles, etc. I don't say it is good, and I don't say it won't eventually kill a Norway spruce--it can--but if it is extreme, the tree will slowly deteriorate and linger on for years before dying.

There is one place in Burlington, WV where I have observed this for about 30 years. All kinds of industrial vehicles were driven and parked around these two NS trees, which I observed carefully because they were beautiful. Well, eventually, these trees began to look pathetic. About 5 years ago they began stacking old tires around these trees, so the vehicular traffic stopped. You should see the trees now. The tops are still thin and sick looking, but the lower 2/3rds of the trees are filling out and looking quite nice. I will see if the trees continue to recover. There are a few other instances I could site, but I do, I know, go on and on too much. Anyway, NS trees are really tough old buzzards.

Yeah, something poisonous got into the soil.

--Spruce

SPruceman has summed up the situation with regards to soil compaction well-bad for trees, but not likely to have caused such rapid demise.

So yes, something could have been spilled into the soil, and your test digging may reveal this. Another thought-could the sudden change in site exposure with the clearing of the adjacent forest cause the decline of the tree? Still, it doesn't seem even this would cause so sudden a decline. Most environmentally caused tree decline takes a course like Spruceman described, with the tree hanging on miserably, sometimes for years, not a rapid decline like your tree has experienced.

So I agree. Check especially the soil in the dead spot. The dying from the top down is characteristic of root damage.

+oM