Planning tools and decision-making processes to support sustainable forestry are an integral part of practicing good forest stewardship in British Columbia. The challenges when applying stewardship principles are often at their greatest when resource extraction activities and habitats of forest-dependent species overlap. Tools to represent and integrate information about both ecological processes and predicted consequences of forest management activities, and approaches for comparing costs and benefits of both economic and environmental values, are evolving to meet this challenge. In this document we present a spatial modelling framework designed to assist those confronting these challenges to sustainable forestry. Users can use this framework as a tool to evaluate hypotheses about the ecological and economic consequences of management strategies. Of particular interest is the capability of the framework to assist in the search for acceptable trade-offs between social and ecological values¡Xa necessary but challenging requirement of meeting good stewardship objectives in natural resource management.
We illustrate application of the framework using an endangered species in British Columbia, the Northern Spotted Owl (Strix occidentalis caurina; SPOW). Our approach was designed to help decision-makers understand the probable roles of currently hypothesized threats to the population in modelled experiments conducted within the framework. We developed indicators representing the condition of the landscape, volumes of merchantable timber harvested from the landscape, and several types of indicators representing population-level status of Spotted Owls. The main questions we examined during the evolution of the framework were:
- What is a reasonable recovery goal for the study species (Spotted Owl) expressed as the number of breeding pairs?
- Is habitat loss a continuing threat, and if so, how?
- Is habitat recovery possible, and if so, when and where?
- Can potential outcomes for both the case study species and socioeconomic values using a suite of potential management policies be demonstrated?
- Is some suitable habitat of better quality than others? Does the definition of suitable habitat need to account for spatial locations of current and potential populations, a concept related to the idea of 'critical habitat'?
- Where should we place our species-specific management areas to capitalize on habitat?
- Can we better understand the relationship between the recovery goal, the current population size, and current habitat amount and configuration?
- Could Barred Owls (Strix varia varia; BDOW) be a significant threat?
To help answer these questions, we developed models for spatial landscape projection, ecological classification, cross-scale habitat assessment, population dynamics, and reserve selection. The modelling framework used to represent these components is necessarily a simplistic representation of a very complex reality (Walters Æ̀986). Sufficient empirical data needed to define functional relationships were not always available. Estimates of parameters, even where data are available, required care in their use and interpretation. These, combined with informed expert judgements about many key hypotheses and relationships, formed the basis of model building and testing. The following chapters outline the data and assumptions used to model the Spotted Owl, the development of the suite of tools for the framework, and the findings on both the model framework and the Spotted Owl as synthesized through the framework.
Section 1 presents an overview of the modelling framework, and describes the six integrated, spatially explicit model components. These are:
1. a landscape dynamics model for projecting forest growth and stand-replacing natural disturbances that is capable of fully spatial timber supply analyses;
2. a habitat supply model that can be tailored for particular species;
3. a spatial model for calculating locat
Sutherland, Glenn D., O'Brien, Daniel T.; Fall, S. Andrew; Waterhouse, F. Louise; Harestad, Alton S.; Buchanan, Joseph B.. 2006. A framework to support landscape analyses of habitat supply and effects on populations of forest-dwelling species. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report