Posted: Tue Apr 18, 2017 11:03 am
by gnmcmartin
Bob, and others interested in Norway spruce:

I left out a couple of important things related to poor performing Norway spruce. One problem for landscape/ornamental plantings is its high sensitivity to weed control lawn chemicals. I don't have any data on specific chemicals and the application rates that can cause NS problems, but damage to Norway spruce is quite common, usually leading to the thin scraggly appearance, and/or death. Colorado spruce I believe is sensitive also, and perhaps other spruces. But the problem seems to be worse for NS than any other tree.

Next, Norway spruce has a habit of "hanging on to life" in very harsh conditions rather than dying quickly as do many other trees. I had a discussion about this with Charles Maynard of SUNY Syracuse, and he explained by saying that Norway spruce is a robust species. I can't now remember exactly how he defined "robust" in this context, but the gist is that the tree is very strong in the face of various kinds of "adversity," and "chooses" to reduce its foliage and adjust to the harsh conditions, whatever they are, rather than dying, as some other trees would do. Hence, we see more poor specimens than would otherwise be the case. My own observations of certain individual trees suggests that NS can often recover from severe stresses, and sometimes return to full health, but that takes time.

And, while I have your attention: I mentioned that a study was done at SUNY Syracuse of growth curves. What was found in their extremely meticulous study is that after a NS tree reaches 4.5 feet in height (trees can be slow starters), for the next 50 years the growth rate is absolutely steady, with no decline, even at the 50-year mark. Virtually all other trees grown in the NE quadrant of the US show a decline during the first fifty years, so the line on the graph bends over, so to speak. For NS the line on the graph is absolutely straight. Not long after age 50, or 60, the growth rate of NS does decline significantly. On the best sites in central NY, in the 50 years after achieving 4.5 feet, NS grows to a height of about 114 feet. On my timberland, they seem to be doing slightly better than that.

Eastern white pine shows a radically different growth curve, quickly accelerating to a very fast growth rate, and then very substantially declining between the ages of something like 30 to 50 or so, so that at that point, NS is growing faster. On my timberland, if the NS is not overtopped by white pine early, the height of the two species is essentially equal at age 50. After age 50 or 60, I believe that white pine may take the lead in growth rate again, but I have no data to back that up.

The site factors study done at SUNY has one or two somewhat surprising results, perhaps the most unusual is that position on a slope, and aspect, have no impact, at least in Central NY, where the study was done. Of course, position on a slope usually affects soil depth and texture, but in isolation from other factors, whether a tree is growing high or low on a SW facing slope, or a NE facing slope, makes no difference.

Also, In a study that as far as I know, remains unpublished, SUNY did a thorough study of NS root growth, at least on one or two soils. Edwin White summed this up by saying that NS roots grow extremely aggressively, and that they "very efficiently fill up the available soil." If anyone ever visits my timberland, I can show one very special aspect of NS root growth. One thing that I have observed is that the roots of NS that often grow very near the surface, do so even in somewhat dry climates like that here in Winchester, VA, and even where the soil is well drained and deep. These roots also can extend far from the tree. What???

Well, I won't say that NS is my favorite species of tree, or that it is superior to eastern white pine, or whatever, but in the face of all the negative stuff that has been published about the species, I have taken on the job of "setting the record straight." And, in addition to its beauty, NS has some especially interesting and remarkable characteristics. I was wonderfully pleased when I found that many NTS members share my appreciation of Norway spruce.

--Gaines