Note: In this post, I discuss a vague similarity between some family trees and an archaeological dating technique, known as dendrochronology, that is, tree-ring dating.
Regular readers may recall me mentioning how my formal training as an archaeologist, which is what I did professionally, has been enormously useful in doing forensic genealogy. The inspiration for this story is drawn from archaeology, specifically, an archaeological dating technique known as dendrochronology, that’s to say, tree-ring dating. Admittedly, with slightly flippant intent, in this Blog post, I touch on a parallel between family trees and dendrochronology, and briefly explain the technique to provide the necessary context. Regardless of whether readers accept the notion of any connection between these matters, perhaps, they may come away with a better understanding of how this technique is used in archaeology.
For some time now, I have been researching one of my Uncle Dr. Fedor Bruck’s cousins, Elisabeth “Lisa” Pauly née Krüger, who will be the subject of the subsequent post. Lisa Pauly helped my Uncle Fedor survive during his 30 months “underground” in Berlin during WWII. I have a copy of a letter of recommendation she wrote on behalf of my uncle in 1947, along with a separate letter of reference written by a couple who also assisted my uncle during his years in hiding that mentions Lisa Pauly. Despite having these letters and having found Lisa Pauly listed in Berlin Phone Directories between 1966 and 1977 at an address she is known to have lived at in the Steglitz borough of Berlin, I had until recently been unable to learn anything more about her.
Faced with this hurdle, I turned to “Family Trees” in ancestry.com, and, finally, found her on a tree listed as “Lisa Krüger,” born in the year 1890. The title of the family tree in which I discovered her name is “Schlesische Jüdische Familien,” translated as “Silesian Jewish Families.” Because I utilize the free institutional version of ancestry at my local library, it is not possible for me as a non-member to contact family tree managers; only members can send messages to other ancestry affiliates. Consequently, I asked a friend of mine who volunteers at the Los Angeles Jewish Genealogical Society whether she could send an email on my behalf. She graciously agreed to do this, and within a day, the family tree manager responded and invited me as a “Guest” to the “Schlesische Jüdische Familien.” I was thrilled with this development.
I immediately opened the tree, and, to my amazement, discovered it includes 52,000 plus names!! To provide some context, my family tree has about 500 names. While seemingly faced with the daunting challenge of deciphering the connection between specific people in the larger tree and my own, I rationalized I might finally be able to discover the relationship between myself and people whose names I recognized if I could somehow find the names of one or more people on both trees. I naively assumed all the names on the Silesian family tree would be bound together like tango partners on a dance floor. I was sadly mistaken. Instead, I discovered that what I thought was one large tree with all people interrelated was instead branches of discrete Jewish families from Silesia. It was at this moment that a less-than-perfect archaeological analogy came to mind, namely, “dendrochronology.”
Dendrochronology, literally the study of tree time, is a multi-disciplinary science that provides accurate and precise dating information based on the analysis of patterns of tree rings, also known as growth rings. It burst into the national consciousness with the publication in December 1929 in National Geographic of an article by an astronomer from the University of Arizona, Andrew Ellicott Douglass, detailing his 15-year endeavor to date archaeological sites in the American Southwest. In the first half of the 20th Century, Douglass had established the Laboratory of Tree-Ring Research at the University of Arizona with the intent of better understanding cycles of sunspot activity; he had reasoned that changes in solar activity would affect climate patterns on earth, which would subsequently be recorded by tree-ring growth patterns.
Prior to publication of Douglass’ article, archaeologists had no idea, for example, how old Puebloan archaeological sites and cliff dwellings found in the Four Corners region of the United States were; archaeologists had estimated they were 2000 years old when tree-ring dates later confirmed they were only about 800 years old. When archaeologists realized sites were younger than previously thought, they were forced to change their interpretations about the rate of development of prehistoric societies in the American Southwest.
Tree rings or annual rings are the result of new growth in the vascular cambium, the layer of cells nearest the bark. Each year trees create a layer of new wood under the bark. In temperate climates, generally, one ring marks the passage of one year in the life of the tree. Critical to tree-ring dating, trees of the same species from the same region tend to develop the same patterns of ring width during any given period. Thus, researchers can compare and match these patterns ring-for-ring with patterns from trees of the identical species which have grown at the same time in the same locale (and therefore under similar climatic conditions). Chronologies can be built up when one can match tree-ring patterns of the same species from one tree to another in the same geographic area. It is this pattern that can be used for dating purposes whenever a piece of wood is preserved, such as in an archaeological site; matching wood from prehistoric and historic structures to known chronologies developed from tree-ring data is referred to as “cross-dating.” [NOTE: “Cross-dating” refers BOTH to “a method of establishing the age of archaeological finds or remains by comparing them with other finds or remains which sometimes have known dates” as well as to “a method of pattern matching a tree’s growth signals of unknown age (floating chronology) to that of a known pattern that is locked in time (master chronology).”]
Critical to the imperfect analogy I am drawing between family trees and tree-ring dating is this concept of a “floating chronology” versus a “fully anchored and cross-matched chronology.” A floating chronology is a tree-ring sequence whose beginning and end dates are not known. Thus, in the case of the Silesian family tree, the 52,000 plus individuals in it cannot directly be connected to one another in any linear sense, they’re “floating,” so to speak, branches of distinct Jewish families from Silesia. This contrasts with what’s dubbed a “fully anchored chronology,” where the beginning and end dates of a tree-ring sequence that has been established are known. In this instance, my own family tree where every person can linearly be connected to every other person in the tree would be so characterized.
In the case of trees and tree-ring sequences, a fully anchored chronology extends back 8500 years for the long-lived bristlecone pine in the western United States, and for the oak and pine in central Europe going back 12,460 years. Just as archaeologists are frustrated when they can’t cross-date a piece of wood from an archaeological site to a fully anchored chronology, genealogists are similarly disappointed when they are unable to connect branches of seemingly related families from the same general area with identical or familiar surnames. In the case of my own family, I know multiple living people with the Bruck surname whose linear connection to myself can’t be drawn. While, admittedly, not a perfect analogy, I argue there is some parallel between family trees where all individuals cannot be connected and floating chronologies that cannot be anchored in time.
In closing, I would emphasize one final point. Lisa Pauly, my uncle and father’s cousin who I began this post discussing, appears in both my family tree and the “Schlesische Jüdische Familien” family tree. However, because I can’t directly connect her on the Silesian tree to people with recognizable surnames, such as other Brucks, Berliners, Holländers, etc., I’m unable to determine how she is related to them, and, by extension, how I’m related to them. More forensic work is necessary.
I found this very interesting. I learned quite a bit.