Some Giants of Forest Mensuration

by Albert R. Stage
Rocky Mountain Research Station

How does scientific knowledge grow? I think this picture of Sir Ronald. A. Fisher and some 30 members of Forest Service Research tells a fascinating story about the propagation of science. Major advances in science are triggered by new capabilities to “see” objects and processes in action that had been heretofore unobservable. Along with the invention of telescopes, microscopes and spectrometers, I include development of statistical methods for estimating effects not directly evident by plotting data. Sir R. A. Fisher was a prolific source of such statistical methods, but disciples also are important to the advance of knowledge.

In 1936, Fisher, Fellow of the Royal Society and Professor at London University, was a Visiting Professor at Iowa State University. While he was in the United States, the U.S. Forest Service engaged Fisher to participate in their yearly series of statistical seminars. His impact on the group was evident when one reviews the careers and productivity of those pictured with Fisher during the seminars. Dr. F. X. Schumacher (to right of Fisher in the photo) was the moderator of the seminars, and probably was responsible for Fisher’s invitation. Unfortunately, the contents of Fisher’s lectures were not recorded. However, Dr. Roger Chapman, whose father attended the seminars, shared with me verbatim notes of their afternoon discussions.

My review of these notes suggests that “Schu” had a much larger role as a proponent of Fisher’s methods than would first appear. One of Fisher’s contributions, a method for inferring relations not directly observable except in the aggregate, was published by Fisher in his 1924 “The influence of rainfall on the yield of wheat at Rothamsted.” Within a few years after the Fisher seminars, at least five papers based on Fisher’s methodology were published by four of the people pictured with Fisher: Schumacher, Chisman, Day, and Lexen. Schumacher was a co-author on four of those papers! Later, in 1971, Bob Curtis used newly available computer power to extend the method to a more sophisticated conceptualization of the problem of estimating the area utilized by trees and I used the method to allocate effects of daily moisture stress to yearly increments of dbh. (Curtis 1971, Zahner and Stage 1966).

Schumacher’s propagation of Fisher’s new methods through leadership from the Forest Service Washington Office also can be inferred from the near simultaneous installation of Latin-square thinning trials in the southeast by Bull, and at Deception Creek Experimental Forest in Idaho by Kenneth P. Davis. Their study plans, dated in 1933, following publication in 1925 of Fisher’s book: “Statistical method for research workers” and two years before his “The design of experiments” attributed the design to suggestions by V. L. Harper and J. G. Osborne, who also were participants in the seminar.

Contributions of other attendees come immediately to mind: Bickford, Hasel, and Osborne were influential in forest inventory. Reineke’s Stand Density index, Keen’s ponderosa pine vigor classes, Coile’s soil/site relations, Haig’s yield tables for western white pine, Meyer’s yield tables for Douglas-fir, Gevorkiantz’ growth predictions for uneven-aged stands, and Hepting’s contributions to forest pathology were all of lasting significance. Publications of research are not the only measure of influence on posterity: fathers of Larry Davis (University of California), Roger Chapman (Washington State University) and Kent Connaughton (Pacific Northwest Research Station) are prominent in the picture.

Papers applying Fisher’s method of statistical disaggregation:

Chisman, H.H. and F.X. Schumacher 1940. On the tree-area ratio and related stand density measures for Douglas-fir. Jour. of Forestry 38(4)311-317.

Curtis, R.O. 1971. A tree area power function and related stand density measures for Douglas-fir. Forest Science 17(2):146-159.

Fisher, R.A. 1925. The influence of rainfall on the yield of wheat at Rothamsted. Royal Society London Phil. Trans., Series B. 213:89-142.

Labyak, L.F. and F.X. Schumacher 1954. The contribution of its branches to the main-stem growth of loblolly pine. Jour. of Forestry 52 (5):333-337.

Lexen, B. 1939. Space requirement of ponderosa pine by tree diameter. Res. Note 63. U.S.D.A. Forest Service, Southwestern Forest and Range Experiment Station. 4p.

Schumacher, F.X. and B.B. Day 1939. The influence of precipitation upon the width of annual rings of certain timber trees. Ecological Monographs 9:387-429.

Schumacher, F.X. and W.C. Jones Jr. 1940. Empirical log rules and the allocation of sawing time to log size. Jour. of Forestry 38:889-896.