Due to the long-term planning horizons and the great variety of natural, economic, and operational hazards affecting forest ecosystems, uncertainty and multiple risk are typical aspects of forest management. Applications of risk analysis are surprisingly rare, in spite of the rich assortment of sophisticated forest planning tools that are available today. The objective of this particular volume within the book series Managing Forest Ecosystems is to present state-of-the-art research results, concepts, and techniques regarding the assessment and evaluation of natural hazards and the analysis of risk and uncertainty relating to forest management. Various aspects of risk analysis are covered, including examples of specific modelling tools. The book is divided into three sections covering ecological perspectives, applications in engineering and planning, and methods applicable to economics and policy.

The large-scale application of new silvicultural systems has become a political reality in many parts of the world. This involves a gradual transformation of traditional silvicultural practice towards Continuous Cover Forestry, also known as near-natural forest management, favouring mixed uneven-aged stands, site-adapted tree species and selective harvesting. Selective harvesting systems have a long tradition. Specific CCF-related resource assessment, forecasting and sustainable harvest control techniques have been developed, but details about their use are not widely known. The objective of this volume is to present state-of-the-art research results and techniques relating to CCF management with an emphasis on systems engineering and modelling. Using a very simple classification based on the development of timber volume over age or time we may distinguish two types of sustainable forest management systems. Rotation forest management (RFM) systems, characterized by standard silvicultural treatments and repetitive cycles of clearfelling followed by planting; and continuous cover forestry (CCF) systems which are characterized by selective harvesting and natural regeneration, resulting in uneven-aged structures and frequently also in multi-species forests. The distinction is usually the result of decisions relating to the cost of timber harvesting, simplicity of management, or various intangible benefits. The oldest and most perfect examples of CCF systems are the so called plenter selection forests found in France, Switzerland, Slowenia and Germany. Today, CCF systems are encountered in various regions of Europe, North America and in some tropical and sub-tropical forests of South Africa, Asia and South America.

Due to the long-term planning horizons and the great variety of natural, economic, and operational hazards affecting forest ecosystems, uncertainty and multiple risk are typical aspects of forest management. Applications of risk analysis are surprisingly rare, in spite of the rich assortment of sophisticated forest planning tools that are available today. The objective of this particular volume within the book series Managing Forest Ecosystems is to present state-of-the-art research results, concepts, and techniques regarding the assessment and evaluation of natural hazards and the analysis of risk and uncertainty relating to forest management. Various aspects of risk analysis are covered, including examples of specific modelling tools. The book is divided into three sections covering ecological perspectives, applications in engineering and planning, and methods applicable to economics and policy.

In an lUlffianaged woodland, forest development follows a succession of periods of undisturbed natural growth, interrupted by intermediate loss or damage of trees caused by fire or wind or other natural hazards. In a managed woodland, the most important periodic disturbances are the thinning operations, which are often carried out at regular intervals and which usually have a significant effect on the future evolution of the resource. Thus, a realistic model of forest development includes both natural growth and thinnings. The key to successful timber management is a proper understanding of growth processes, and one of the objectives of modelling forest development is to provide the tools that enable foresters to compare alternative silvicultural treatments. Foresters need to be able to anticipate the consequences of a particular thinning operation. In most cases, total timber volume is not a very appropriate measure for quantifying growth or yields, or changes caused by thinning operations. Yield in economic terms is defined by the dimensions and quality attributes of the harvestable logs, and estimating timber products is a central issue of production-oriented growth and yield research. Introduction 2 Growth modelling is also an essential prerequisite for evaluating the consequences of a particular management action on the future development of an important natural resource, such as a woodland ecosystem.