Tree Rings:  Questions for Neil   Robert Leverett   May 05, 2004 05:16 PDT  Neil:        ENTS is as much about revering great tree age as tree size. When the two attributes go together, the result seems to fit our notion of what's supposed to happen with trees, but I for one, am also a fan of the bonzai forms.     For the benefit of our readers, would you be willing to take the time to answers a few questions that I suspect are in quite a few minds. When you are next up my way, I owe you a beer or an ice cream sunday. Take your pick. Now to the questions. 1. Which species are easiest to date in terms of ring visibility? 2. What's the story with missing rings, false rings, and multiple rings per year? 3. Which species give the best climate signals? 4. Which trees have provided the greatest surprises for you, Ed, etc.? 5. What is the oldest tree you have personally dated? 6. For the species you study, have you observed in north-south trends? East-west? High-low?     Oops, I think I may have exhausted my credit? Sorry to ask so many questions, but inquiring Ents just have to know. It will be interesting to see how your experience compares with that of Lee's, Dave's, Charlies, etc. Bob Re: Questions for Neil   Dee & Neil Pederson   May 05, 2004 19:10 PDT  OK, Bob. Here are a few answers. I'll try to keep 'em brief.   1. Which species are easiest to date in terms of ring visibility? It would probably conifers with well-developed latewood bands like red pine and most of the southern pines. Larch, when growing fast, isn't too bad. Ring porous species, especialy oaks, are not too bad, either. Diffuse porous species like black gum/tupelo, maple, birch can be a nightmare. There are dependencies; depends if they are suppressed, depends on growth rates, depends if you are looking at rings in the sapwood or heartwood. Rings of diffuse porous species are much easier to deal with in the heartwood. It doesn't make them easy, though [see #2].   2. What's the story with missing rings, false rings, and multiple rings per year? Missing rings are also called locally absent rings. This is a better term since they may be missing only at coring height on one side of the tree. If it were easier to core closer to the crown, there would likely be fewer missing rings. Locally absent rings are associated with stress: droughts, cold summers in treeline forests, defoliation events, etc. I've come across some spruce trees in the lower Hudson Valley with 10-15 missing rings over the last 30 years or so. Our lab has made collections from the northernmost trees on Earth, north of Siberia on the Taymir Peninsula. During an extremely cold period, a good proportion of larch essentially stopped growing or had very little radial growth. The tech that was working up those cores nearly went crazy. Crossdating such trees is like solving a complex riddle or puzzle. I've had the same experience recently with some suppressed red maple. Hopefully we'll have something written up about that later this year. For well-studied species [conifers, oaks], false or multiple rings are linked to a hiccup in seasonal climate. In conifers, a normally wet spring followed by a drought will cause the tree to begin forming cells that look like latewood. A resumption of normal to wet weather will cause formation or earlywood-like cells. The end of the growing season will stimulate the growth of normal latewood cells. This occurs a lot in southern pines. Larson's book on cambial growth has some amazing pictures of this. Dave Stahle's PhD was a study of false springs in the midwest. He used oaks and found false bands of growth related to spring frosts. I have to admit I haven't studied this work enough yet to discuss it further. Myvonwynn Hopton has worked up several chronologies of tulip-poplar, black birch and cucumbertree, trees not commonly studied via tree-ring analysis. From her experiences with these trees it appears that false rings are a significant problem. One cucumbertree had 25 false rings on one radii!! We figured this out because the other radii from that tree "only" had 5 false rings. The core with 25 false rings is not datable for much of its inner "80 years."   3. Which species give the best climate signals? For the eastern US, this question may cause an arm wrestling match between Dave Stahle and Ed Cook. Baldcypress [Dave] and eastern hemlock [Ed] are probably the best. Eastern white pine is among the least sensitive. We will be learning much more about eastern redcedar and northern white-cedar soon. Post, white and chestnut oak are fairly sensitive, especially for drought studies. Tulip-poplar and Atlantic -white-cedar are looking pretty good as new species under study. There is so000o much to discover!   4. Which trees have provided the greatest surprises for you, Ed, etc.? Hmm, this is a hard question. Can't speak for Ed. I'm not sure species have surprised me as much as situations, but that may be related to what I'm interested in right now. I get surprised at what trees can handle and what they are capable of: suppressed red maple growth [or the lack thereof] or persistence during suppression by chestnut oak. Things like that. The age of a black birch Ed cored 30 years ago [>350 years] was a surprise.   5. What is the oldest tree you have personally dated? I was lucky to be a tech during the beginning of our lab's Mongolia project. As a part of the project I dated [though it was more of a flirtation] a Siberian larch in western Mongolia that dated to the 1240s. It was likely a seedling around the time Ghengis Khaan ruled Asia and was pushing west into eastern Europe. Pretty neat to think about. In the eastern US the oldest living tree would be a black tupelo from Saratoga County, NY with an inner ring date of 1436 [not close to the oldest known tupelo].   6. For the species you study, have you observed in north-south trends? East-west? High-low?    I've just finished revisions on a paper to be published later this year describing higher January temperature sensitivity of white and chestnut oak [and to a lesser degree red oak and pignut hickory] in the southern Hudson Valley versus the same species in the Taconic and Adirondack mountains. It was exactly the opposite from what I expected. The best thing I can surmise is that the lack of consistent snow cover/pack in the southern HV versus the north plays an important role in root mortality and drives this temperature sensitivity. Needs testing though!        Oops, I think I may have exhausted my credit? Nope, not at all. I enjoy ENTS and I'm sorry I don't have the time to reply as much or as promptly as I would like. I learn so much from everyone else. I hope this wasn't too jargonny. Let me know if some things are not clear. A frosty barely pop would be nice. Neil   Home