It still amazes me that it just happened. Over the years, I've had many ideas for research, but the one that resulted in the Hubbard Brook Study is the most important. Since it affected a lot of people at Yale and elsewhere, I thought it would be interesting to put its evolution in the Centennial News. Furthermore, it is a rather neat story.
For a long time, I have been interested in the response of whole systems. As Ph.D. students at Duke in the early fifties, we never made measurements of whole systems. Rather, we tried to develop concepts of whole systems from the bottom up. For example, we would measure the photosynthetic response of a single leaf and try to parlay that into a measurement of the photosynthesis of a whole forest. At that time, the idea of directly measuring a whole system was daunting.
Then Professor Ted Coile of Duke introduced me to forest hydrology studies at Coweeta where foresters were measuring the hydrology of whole forests by monitoring small watersheds. I latched onto this idea and used it in my teaching of ecology at Emory University. When I moved to Dartmouth in 1956, I linked up with the newly established U.S. Forest Service hydrology studies at Hubbard Brook and used them in my teaching. Direct measurement of whole systems was still very much on my mind, and then one day it all came together. I still remember the details.
With Hendrick Harries, a Ph.D. student from Rutgers, I was hiking beside a mountain stream in New Hampshire. We were talking about a new idea then current among European ecologists. It went something like this. Rain falling in mountainous areas sinks into the ground and becomes enriched with nutrients as it moves down the slope. As a consequence, the lower slopes become more fertile and productive. As Harries and I were walking and talking, my years of experience with forest hydrology kicked in — the stream must be collecting chemical debris from the whole watershed! By measuring the concentration of chemicals in the stream water and multiplying these concentrations by the volume of water leaving the watershed, you would have a measure of the rate at which the whole watershed ecosystem loses nutrients. The next step was easy. Take samples of rainwater, measure their chemical concentrations, and multiply by the volume of water entering the watershed, and presto, you've got a measure of chemicals entering the ecosystem. Comparing what enters with what leaves you have a budget whereby you can tell whether the whole system is losing or gaining nutrients.
It was immediately apparent that it was possible to measure critical ecosystem processes like primary mineral weathering. If it's known how rapidly a nutrient is leaving the system and the system is in a steady state, you know that the nutrient is being replaced. Since the amount that is being added through the air is known, you can ascribe what is left over to the breakdown of rock inside the system. Hence, you've got an estimate of weathering, one of the most fundamental processes in ecology.
Letter from Herb Bormann to Robert Pierce, then USFS Program Director for Hubbard Brook Experimental Forest, written in November 1960
The other day, while discussing the problem of mineral cycling through ecosystems, the thought came to me that your installation at Hubbard Brook represents a veritable research goldmine in regard to fundamental studies on mineral cycling. One of your small watersheds with a weir at the outlet represents a perfect area for controlled research. If one were to select one to several minerals, such as K+, it would be possible, by taking weekly water samples and analyzing them, to determine quantitatively the amount of K+ leaving the system. Weekly estimates of K+ per liter multiplied by the liters of water leaving the watershed would give the quantitative figure. Since the watershed is theoretically tight, all the water falling on the shed appears at the weir (excepting evaporation which would not remove any minerals), [thus,] the quantitative figure would represent total loss of K+ from the watershed (excepting leaf litter blown out, or presumably this would be counterbalanced by leaf litter blown in. The argument goes for other losses and additions due to animals, etc.).
Some minerals may be added by rain or snowfall, therefore both rain and snow would have to be analyzed for the mineral(s) in question. These analyses multiplied by the amount of rain or snow would give the total amount of mineral(s) added to the system.
By subtracting the total amount added from the total amount lost, it would be possible to estimate steady-state losses from the system. Theoretically the only place these minerals could come from is the underlying parent material and bedrock. Thus, the loss represents the rate at which bedrock is wasting away in terms of the mineral(s) under consideration. By knowing the chemical composition of the bedrock, it would be possible to determine the rate at which it is breaking down.
This figure would seem to be of considerable consequence because it would quantify the rate of erosion, it would shed considerable light on the rate of soil formation, and it would tell something about the rate at which minerals useful to plant growth are added and lost from the system. The latter might lead into further studies of how treatments affect mineral cycling patterns.
After our climb, I returned to my office and, in about an hour, I wrote a letter to Robert Pierce, project leader at Hubbard Brook, outlining the use of the small watershed technique for the study of biogeochemistry. [See text of letter at right.] This year, 2000, is the 4th anniversary of the letter and since that time the small watershed technique has been replicated throughout the world.
The Hubbard Brook Ecosystem Study started when I teamed up with Gene Likens, a fresh Ph.D. appointed assistant professor at Dartmouth in 1962. In 1963, with Bob Pierce's approval and encouragement, we got the first of what has been a continuous succession of National Science Foundation grants.
In 1966, François Mergen invited me to apply for a position in the School of Forestry. I did so because I liked the concept of basic research being affiliated with real life management problems. I had also had previous exchanges with George Furnival and Garth Voigt and felt like I would like to have them as colleagues, which proved to be true.
The School of Forestry, under Mergen's leadership, was undergoing vast changes. Within a couple of years, Rick Miller, Bill Smith and Bill Burch joined the School. Rick Miller, an animal ecologist who worked on a range of subjects from prairie blackbirds to African elephants, was responsible for pulling us into the wildlife field. Bill Smith came from Rutgers with a degree in forest pathology. He launched into significant work on pollutants and their effect on ecosystem function. He also did groundbreaking quantitative work on nutrient exudation through roots.
Burch came from Syracuse and was soon revolutionizing the U.S. Forest Service's view on forest recreation. Later, he directed the Tropical Resources Institute and established notable programs, particularly in Southeast Asia. He became a strong advocate for community forestry. Then he provided the brainpower and got urban ecology going. Bill is a truly innovative person and a good friend. Burch, Smith and Miller worked at Hubbard Brook, along with Tom Ledig and scores of masters and Ph.D. students.
Two colleagues I've reserved for last —that are far from last in my mind — are Garth Voigt and Tom Siccama. Garth, whose presence at Yale was influential in my coming, is a powerful soil scientist and a wonderful human being. We worked together on many projects, team-taught classes, and spent many hours trying to figure out what it was all about. He and I wrote a Ford Foundation grant. With five million dollars from the Ford Foundation in 1969, the School was on the environmental map. People began to flock to Yale F&ES to be trained in environmental science and policy.
Tom Siccama and I worked together on research and teaching and plain having fun. Tom really started the now world-famous JABOWA forest growth model, but after it was beginning to take off, dropped out because he had better things to do. He is the best field man I have ever known and has worked with scores of students, awaking their interests in an endless variety of topics, setting many of them on career courses.
Steve Kellert arrived several years later and brought concern about how people view and respond to nature. Ever since, he has been an innovative and productive leader in that field. About ten years ago, he and I put on a lecture series in Bowers on Ecology, Economics, and Ethics: The Broken Circle. There were so many people that we had to set up ancillary rooms with televisions to accommodate the crowd. The whole school was vibrating over those kinds of issues.
You've asked me about the structure and function of the School during my years. To me one of the great advantages of our School was that we were all one. There were no departments and no quibbling about departmental politics. We were all professors with allegiance to one place. We had one faculty meeting and when issues arose we all discussed them. We were by no means all of one mind, but in our discussions we learned first hand what we each thought and hoped for. That led to cooperation and integration and something we all desperately seek these days — systems thinking.
The greatest resource of our School is the students. They are intelligent, diverse and extremely interesting. I've been happy to see many arrive with a strong idealism. Some may think this idealism a kind of naiveté, but idealism is the hope for the future. As students go through our School, not only should we professors impart knowledge, but I think we also need to support their idealism. If we stamp out idealism and replace it with the notion that "we know the answers, this is the way to do it, and this is the way the system handles it," to me, that is devastatingly bad. In the long run, we never quite know the answers; there always needs to be room for questions and new ways of thinking and new goals.
Our students' level of intelligence and quality of thinking is very high. We don't get many students directly from undergraduate training. This made for an enormously interesting student body largely made up of people with real experience that made teaching a challenge and fun. You'd be lecturing when suddenly someone would say, "Hey, you know, down there at the EPA in Washington that isn't the way it works at all." So you would have to stop and put on your thinking cap and try to see how it all fits together. One of the things that I remember most strongly is that the students taught me a lot.
Life should not be all drudgery. I greatly valued sports and did my best to get everybody — students, faculty and even passers-by involved. We had classic bocce matches on the Greeley lawn. For about ten years, we played baseball in front of those big windows. Some of those guys — man they could hit a ball! Larry Forcier M.F.S. ’68, Ph.D. ’73, blasted a ball over Edwards Street.
Dan Pletscher For. ’79, Ph.D. ’82, was another long ball hitter. It's astounding that we never broke any windows. On rainy days, we used the Greeley hall as a soccer stadium. With two or three people at each end, the object was to try and kick a soccer ball beyond the other team. We made so much noise, we were lucky the president never walked in on us!
At Hubbard Brook, we had a sports program, too. We played softball and volleyball. I didn't have much affinity for volleyball; it wrecked my elbow. But I did try to keep it going by putting some gentle pressure on those who just wanted to sit in their rooms and read science.
The collegiality of F&ES and Hubbard Brook was just astounding. People in totally different fields forged long-term friendships and professional relationships. It was possible to work with all sorts of people. It was truly marvelous. I really feel very pleased to be part of it.