Glen W. Armstrong

Sustained Yield Forestry in Sweden and Russia: How Does it Correspond to Sustainable Forest Management Policy?

This paper analyzes how sustained yield (SY) forestry is defined and implemented in Sweden and Russia, two countries with different forest-industrial regimes. We first compare definitions of SY forestry in national legislation and policies. Then we study forest management planning in two large forest management units with respect to: delivered forest products and values, how the harvest level of timber is defined, where the harvest takes place, and what treatments are used to sustain desired forest products and values. In Sweden SY forestry is maximum yield based on high-input forest management, and in Russia it is forestry based on natural regeneration with minimum investments in silviculture. We conclude that how SY forestry contributes to SFM depends on the context. Finally, we discuss the consequences of SY forestry as performed in Sweden and Russia related to its ability to support diverse forest functions, as envisioned in sustainable forest management policy.

Joint production of timber, carbon, and wildlife habitat in the Canadian boreal plains

This study investigates the relationships and trade-offs between forest carbon management, sustained timber yield, and the production of wildlife habitat to provide a more complete picture of the costs and challenges faced by forest managers for a particular case study in Canada’s boreal mixedwood region. The work presented is an extension of a previously published model that analysed the joint production of timber supply and wildlife habitat using a natural disturbance model approach to ecosystem management. The primary contribution of the present study is the detailed incorporation of a carbon budget model into the framework developed previously. Using the Carbon Budget Model of the Canadian Forest Sector, dynamics specific to separate biomass and dead organic matter carbon pools are represented for individual forest cover types. Results indicate the potential for cost thresholds in the joint production of timber supply and carbon sequestration. These thresholds are linked to switch points in the decisi...

An analysis of alternative cropping decision rules

Abstract The research reported here measures the effects on the probability distribution of the present value of after-tax income of several different cropping decision systems in Alberta. Dynamic flex-cropping decision rules generate higher levels of returns and less downside risk than all other alternatives considered here. Dynamic decision models which ignore taxes and the stochastic dynamic nature of prices produce suboptimal results relative to models which consider these factors and relative to a fixed rotation decision rule. This suggests that careful attention must be paid to the factors included in these models if they are to generate rules which will improve the risk-return trade-off for farm managers.

Shadow prices as estimates of the cost of forest fires

Linear programming based timber harvest scheduling models produce shadow prices of constraints as a standard output. We present a method whereby the shadow prices of starting inventory constraints can be used to approximate the costs of potential res, expressed in terms of the units of measure for the objective function in the timber supply model. The approximation worked remarkably well over a large range of re sizes, and alternative model formulations, for a study area in northeastern Alberta.

Environmental and Financial Sustainability of Forest Management Practices

One of the guiding themes for forest management policy throughout much of North America is sustained yield. The basic premise behind this theme is that a constant or non-declining flow of services from the forest is socially desireable. Unfortunately, the act of capturing the benefits of this service (timber harvesting) often has detrimental effects on the timber-productive capacity of a forest site. This paper presents a dynamic program that is used to determine the optimal harvest system choice for a timber stand described by average piece size, stand density, a measure of site quality, and stumpage value. The harvest systems are defined by logging costs, reforesation and rehabilitation costs, and the impact of the system on the productivity of the site. An application of the model is presented for lodgepole pine in Alberta. We conclude that at high discount rates, soil conservation is not economically rational. At lower discount rates, some degree of soil conservation is desirable on the more productive sites. At lower discount rates, there also appears to be an incentive for mroe intensive forest management. Limitations on acceptable harvest practices can have a large impact on optimal rotation age and the volume harvested. There is a large opportunity cost resulting from a requirement for sustainable volume production because of the impact of harvsting on soil productivity.

An Economic Analysis of Alternative Cropping Decisions Under Uncertainty

This project has examined after tax gross margin net present values accruing to Albertawheatf armers under three fertilizer and crop rotation systems; a fixed rotation traditional fertilizer system, a static economic fertilizer decision system within a fixed rotation, and a static economic fertilizer decision system within a dynamic flex-cropping framework. Decision rules appropriate to each system were developed for case farms in three Alberta agro-climatic regions; Medicine Hat, Lethbridge and Olds. The flex-cropping issue is expressed in a dynamic programming framework and incorporates elements not fully explored in previous studies; income taxation, variable input level decisions and stochastically determined moisture conditions and crop prices. Decisions are compared by simulating net present values of after tax gross margins for each system. The traditional system generatedthe lowest net present value, approximately 5 to 17 per cent below the static economic system. Greater improvements, on the order of 14 to 31 per cent above the static economic system, were observed by following dynamic flex-cropping decision rules. Not only did the dynamic flex-cropping decision rules generate superior decision rules regarding mean net present values, the rules were also risk efficient. The probability of low gross margins was minimized in all cases by following the dynamic flex-cropping decision rules. The results of this and related studies indicate that dynamic flex-cropping models are viable for solving crop scheduling problems. The prescriptive power of the model is limited by available data, limitations which reside primarily in the agronomic components. The relationship between spring soil moisture, soil nutrients, and yield must be more clearly defined. This may be accomplished through extensive and long term field trials or through use of emerging biophysical models. Standardization of soil moisture classifications, including method of sampling and depth of measurement, would make field data more adaptable for making fertilizer and recropping decisions. The production functions defining the relationship between spring soil moisture levels and yields are particularly important. These require continued empirical attention. The model developed lends itself readily to extensions such as additional crops,fertilizer inputs, erosion costs and soil degradation issues, financial structure of the farm, and evaluating the influence of government programs. Modern computers with large computational and storage capabilities make the implementation of stochastic dynamic programming methodology a viable farm management tool.