This concluding chapter is a synthesis of everything said earlier in the book. Here I examine stability of age structure and species composition over time and the different types of dynamics that forests may exhibit as a result of their level of stability. Some of the most important linkages among neighborhood, stand and landscape spatial scales will be made here. The real reason we are interested in the material from all of the previous chapters is to generalize about stability of forests. Under what conditions will they change or stay the same? We need to answer those questions now because we are purposely changing the disturbance regime in forests from one dominated by natural disturbance to one dominated by harvesting. Global climate change will also change the disturbance regime, even in forests reserved from logging, in ways that are difficult to understand.

Sometimes investigators have found that their study site was just big enough for a certain disturbance process to operate in stable fashion, according to the study results (e.g. Lorimer 1980, Lorimer and Frelich 1984, Frelich and Lorimer 1991a; Frelich and Graumlich 1994, Frelich and Reich 1995b). This is because there is a continuum of disturbance processes at overlapping temporal and spatial scales and researchers mostly detect the ones operating at the scale of their study area. Some studies examine a large-scale process in a small study area and conclude that forests are unstable.