Pattern and Process in a Forested Ecosystem

The advent of ecosystem ecology has created great difficulties for ecologists primarily trained as biologists, since inevitably as the field grew, it absorbed components of other disciplines relatively foreign to most ecologists yet vital to the understanding of the structure and function of ecosystems. From the point of view of the biological ecologist struggling to understand the enormous complexity of the biological functions within an ecosystem, the added necessity of integrating biology with geochemis try, hydrology, micrometeorology, geomorphology, pedology, and applied sciences (like silviculture and land use management) often has appeared as an impossible requirement. Ecologists have frequently responded by limiting their perspective to biology with the result that the modeling of species interactions is sometimes considered as modeling ecosystems, or modeling the living fraction of the ecosystems is considered as modeling whole ecosystems. Such of course is not the case, since understanding the structure and function of ecosystems requires sound understanding of inanimate as well as animate processes and often neither can be under stood without the other. About 15 years ago, a view of ecology somewhat different from most then prevailing, coupled with a strong dose of naivete and a sense of exploration, lead us to believe that consideration of the inanimate side of ecosystem function rather than being just one more annoying complexity might provide exceptional advantages in the study of ecosystems. To examine this possibility, we took two steps which occurred more or less simultaneously.

This volume draws on the Hubbard Brook Experiment to present an integrated picture of the structure, function, and development over time of the northern hardwood ecosystem in northern New England.

1 The Northern Hardwood Forest: A Model for Ecosystem Development.- Objectives.- Limits for Our Theoretical Model of Ecosystem Development.- Biomass Accumulation After Clear-Cutting.- The Hubbard Brook Ecosystem Study.- Summary.- 2 Energetics, Biomass, Hydrology, and Biogeochemistry of the Aggrading Ecosystem.- Solar Energy Flow.- Biomass: Development of Regulation and Inertia.- Detrital-Grazing Cycles.- Biotic Regulation of Biogeochemical Flux.- Nutrient Reservoirs Within the Aggrading Ecosystem.- Sources of Nutrients for the Aggrading Ecosystem.- Circulation and Retention of Nutrients.- Summary.- 3 Reorganization: Loss of Biotic Regulation.- A Deforestation Experiment.- Relationship of the Deforestation Experiment to Commercial Clear-Cutting.- Summary.- 4 Development of Vegetation After Clear-Cutting: Species Strategies and Plant Community Dynamics.- What is Secondary Succession?.- Reproductive and Growth Strategies Responsive to Perturbations That Open the Forest Canopy.- The Buried-Seed Strategy.- Floristic Response to Removal of the Forest Canopy by Clear-Cutting.- Differentiation of the Vegetation Established Immediately After Clear-Cutting.- Growth Strategies Underlying Initial Canopy Differentiation.- Morphogenesis and Growth Strategy.- Endogenous Disturbance.- Interactions Between Reproductive Strategies and Degree of Canopy Disturbance.- Composition of the Dominant Layer During Ecosystem Development After Clear-Cutting.- Species Richness.- Summary.- 5 Reorganization: Recovery of Biotic Regulation.- Primary Productivity.- Recovery of Biotic Regulation Over Ecosystem Export.- Coupling of Mineralization and Storage Processes.- Replacement of Lost Nutrient Capital.- Ecosystem Regulation.- Summary.- 6 Ecosystem Development and the Steady State.- Evidence for a Steady State.- Steady-State Models.- Living Biomass Accumulation.- Total Biomass Accumulation.- The Plot as a Unit of Study.- Trends Associated With Ecosystem Development.- Summary.- 7 The Steady State as a Component of the Landscape.- Exogenous Disturbance Defined.- Comparative Effects of Major Perturbations.- Disturbance in Presettlement Northern Hardwood Forests.- Postsettlement Disturbance.- Increased Regularity of Whole-System Biomass Oscillation.- Summary.- 8 Forest Harvest and Landscape Management.- Air Pollution.- Forest Harvesting Practices.- Landscape Management.- References.