In most years, your one off situation happens many times over in our area. Most deciduous trees are fine though some develop witch's brooms over many years. Conifers are variable...Hemlock, White Pine, White Spruce, and Thuja have little/no tolerance. Austrian Pine, Scot's Pine, Blue Spruce and strangely, Douglas Fir have quite a bit of tolerance.

Happens here every year with little to no impact. It just depends on species.

It they aren't tolerant, it can cause quite a bit of damage.

Here is a link that might be useful: Salt Spray

My two Ilex whatevers down by the road look pretty tan. Maybe the cold, maybe the salt. The small one sheltered up by the house looks ok though

Yeah, what smivies said. White pine especially seems to get hammered, here in the salt capitol of the nation.

+oM

Our native conifers (what I've seen along the highways) are mostly Juniperus virginiana and Pinus virginiana. I see trees that resemble P. taeda, but I think we're outside their native range. I suppose they could have been planted, but they don't "look" planted.

Hair, pinus taeda easily escapes cultivation where it is otherwise hardy but not native. It isn't native to my area but it is everywhere! Every bit as common along the roadsides as shortleaf pine (ok, that's a slight exaggeration), the most commonly encountered native pine. So I wouldn't rule it out just because it isn't native. I'd think your zone 7 would be every bit as appealing to that species my zone 7 appears to be =)

Makes me wonder why it isn't native to my area as easily as it spreads. They certainly fair worse from ice storms compared to shortleaf pines. I also wonder if they are more susceptible to some disease but there are many large old loblolly's around. They don't appear to die off any faster than shortleaf pines either.

This post was edited by j0nd03 on Fri, Jan 24, 14 at 10:19

Good point - I guess I don't think of most conifers as being weedy/invasive except for Norway Spruce in some areas (not much here, but it does grow well & occasionally seeds itself).

Most conifers in the east are not climax forest species. For introduced species like Norway spruce, they will almost always yield to more shade tolerant tree species (usually deciduous tree species in the east). Though they can be 'common', they are not really 'invasive'.
Major exceptions for conifers...
1. Regions vulnerable to fire - Shortleaf and/or Pitch Pine in drought prone areas. Virginia and/or Loblolly in wetter environments. Cold & ice storms are probably Loblolly's greatest handicap when competing against other pine species in the north. They will all get crowded out in the absence of fire.
2. High altitude environments where winter cold, summer cool, lower soil fertility, and higher precipitation give Fir, Spruce, and White Pine a competitive edge over many deciduous species.
3. Mesic environments without ANY fire - Hemlock.

I expect the areas where Norway spruce is most likely to be 'invasive' would be where Red spruce currently dominates....both are fairly similar in climate/soil requirements and fire frequency tolerance where both would have a competitive edge over other species.

Does all of that salt ever contaminate the soil around the roots? Seems like the roadsides up there should be barren.

"Does all of that salt ever contaminate the soil around the roots? Seems like the roadsides up there should be barren."

The total seasonal airborne salt deposition is actually quite low compared to precipitation (snow & rain) available to wash it off. Road surface run-off is more of a concern immediately adjacent to the pavement and in nearby ditches and streams. Overall though, spring rainfall & snow melt is great enough that the winter salt is leached out pretty quickly.

Unlike spray at a seaside location, the salt is only applied between December and March when it's required (1 to 10+ times a week, depending on the weather).

On the whole, not as bad as it seems.

This post was edited by smivies on Sat, Jan 25, 14 at 19:09

I did read somewhere that plants that grow on beaches have been spreading along highways. The edge of a highway may be salty, there is clear sun on one side, and (depending on how it is constructed) there is often sand on the side of highways. As far as plants are concerned, it's a beach.

Here is a link that might be useful: More Salt Please!