Over the past 30 years, my
students, colleagues and I have worked on a wide range of projects, from natural
forest and soil dynamics in northern
My current work focuses on the production ecology of forests, and on forest restoration ecology in the Rocky Mountains. I'm also working on a variety of synthesis projects, including Biology of Temperate Forests for Oxford University Press.
The latest in Production Ecology of Forests
The growth of a tree or a forest depends on the supply of resources (light, water, nutrients) available in the environment, the proportion of available resources obtained, the efficiency of harnessing resources to drive photosynthesis, and the partitioning of photosynthates into various tree parts (including stemwood). This production ecology approach allows for quantitative tests of ideas. For example, if a tree or forest has a higher capture of sunlight, will it use the sunlight more efficiently or less efficiently in producing wood? It might seem to intuitively obvious that a tree or a forest capturing very little light would need to be especially frugal and efficient at using the light, yet we hypothesized in various studies that trees and forests capturing more light (or water, or nutrients) actually use the resources more efficiently.
This graph summarizes the pattern of growth, light use, and efficiency of light use for Eucalyptus trees. Not surprisingly, larger trees (to the right on the X axis) grew faster than smaller trees. An 80th percentile tree grew at a rate of about 150 g of stemwood per day, compared to 65 g of stemwood growth for a 40th percentile tree. The same trees used 170 and 90 MJ of sunlight to produce the wood; this difference in light use is smaller than the difference in growth, so the larger tree not only used more light, they used it more efficiently (producing 0.9 g of wood per MJ of light) than the smaller tree (0.4 g of wood/MJ of light): (Binkley, D., J.L. Stape, W.L. Bauerle, and M.G. Ryan. 2010. Explaining growth of individual trees: Light interception and efficiency of light use by Eucalyptus at four sites in Brazil. Forest Ecology and Management 259:1704-1713.)
The same pattern tends to apply at the level of forests; forests that intercept more light tend to use the light more efficiently in producing wood. We still don't know how much of this efficiency difference relates to total photosynthesis (Gross Primary Production) and how much depends on partitioning carbohyrates to wood versus other tissue. The forest may grow faster than another forest, because of landscape location (bottom of a hill versus a ridge), species composition, or silvicultural treatments. Does faster growth of a forest typically result from increased resource use, or from higher efficiency of resource use? The answer is "yes"; both factors in the production ecology equation commonly are higher for faster growing forests. Intriguingly, it's rare (or non-existent) for the efficiency of resource use to decline as the rate of use goes up: (Binkley, D. 2010. Understanding the role resource use efficiency in determining the growth of trees and forests. In: Forests in Development: A vital balance. In press.)
These patterns of growth and use and efficiency of resources lead to fasicnating patterns of dominance within forests. We've developed a quantitative approach to mesuring dominance in forests, and some hypotheses about patterns through stand development. Fascinatingly, some forests have lined up nicely with the hypothesis, and others have not (for reasons we can't (yet) explain).
Recent publications on these and related topics:
The Latest in Forest restoration in the Rocky Mountains
Forests have two rates of change: so slow that it takes decades for us to notice, and so rapidly that it must be someone's fault! A century of heavy grazing and fire suppression have dramatically changed the structure and composition of some forests in the Rocky Mountains, but these driving factors and responses vary greatly among forests. We've done a variety of research projects to determine how much forests changed in the past two centuries, providing an intellegent starting point for discussions about forests of the future.
Was Aldo Leopold right about the Kaibab deer herd? A central paradigm in wildlife ecology is that predation is a good thing for prey species: predation limits the population of the prey, and keeps the prey from overpopulating and devastating the habitat. This appealing idea was advocated by Aldo Leopold, and he used the classic story of the Kaibab deer herd as an illustration. The wolves, lions, and coyotes on the Kaibab Plateau were decimated by government hunters after the plateau was established as a game preserve -- and Leopold tells the story that the deer population exploded, the range was degraded, and the deer population crashed below the level that could have been sustained with a healthy amount of sustained predation. We challenged this idea by determining the cohort structure of aspen across the Plateau. High populations of starving deer should have prevented the establishment of aspen during the 1920s; if we found a sizable cohort from that period, Leopold’s story would have to be wrong. Our descriptive and experimental investigations supported the idea of a major deer explosion in the 1920s – but also a much fuller story of long-term changes on the Plateau:
Mountainside Stewardship on the Uncompahgre Plateau: The UP is one of the Colorado's most beautiful areas, with conifer forests changing across landscapes, mixed with abundant aspen trees and occassional meadows. These forests have probably changed substantially in the past century, but by how much, and where? We're working with a place-based collaborative group, the Uncompahgre Plateau Project (http://www.upproject.org) to understand forest dynamics of the past as way to inform our choices about forests of the future. The idea of mountainside stewardship developed as a way to facilitate (and fund) restoration activities at lower elevations, while generating wood products, revenue, and patches of younger forests at higher elevations. We've worked with volunteers to conduct "forensic ecology" assessments on the Plateau, and on-going projects will characterize the history and current condition of aspen across the Plateau.Recent publications on these and related topics: