Concept of Forest Development Phases: Identification and Classification Issues

Abstract

The decision making in forestry and choosing the appropriate silvicultural practices are based on the knowledge about forest development. Usually, forest development is described as a cycle or sequence of phases similar to the development cycles of organisms. The information about the development cycle of unmanaged forest ecosystems is applied and adapted to managed stands to refine the managerial approaches and decision making. Moreover, natural forests are more stable and resist pests and diseases better. Thus, knowing the mechanisms that lie behind this self-sustainability could help in forest management. Assigning a patch of a stand a specific development phase makes it possible to evaluate its productivity and make decisions about necessary silvicultural operations. Yet there is no single opinion among scientists about how many phases the forest’s life cycle has, not to mention that different classifications offer different and sometimes even contradictory criteria to define the current forest development phase for a given subplot. The confusion in terminology for stand structures and stand development phases is also an issue to be considered. Additionally, the most popular approaches to assigning forest development phases are compared. A short overview of the algorithms used to define the forest development phases is given. There is a lack of a complex approach in the offered algorithms of assigning a subplot to a certain development phase. In particular, soil properties, as well as belowground biomass, are entirely ignored. It is necessary to develop a more comprehensive and detailed approach to defining forest development phases and arranging the diagnostic criteria in a clear and easy-to-use system that could enhance decision making in forestry. Only a few studies are currently focused on soil properties and belowground biomass in temperate deciduous forests under different development phases. Although there is still little information on this issue, the data are insufficient and/or controversial. Our study offers several possible directions to make the classifications of forest development phases more elaborate by considering the soil and belowground parameters. They include, but are not limited to, the quantity, density, humidity, and acidity of the forest floor, soil respiration, and content of water-extractable organic matter in the soil.

New ways for (in)validating the forest carbon neutrality hypothesis

“…Provided no stand replacing disturbances occur in earlier successional stages, the development of unmanaged forests ends decades to centuries later due to stand replacing disturbances, such as fires, storms, avalanches, mud slides, droughts, and insect outbreaks. Although several classifications of the developmental stages of forests have already been proposed (Krotiuk & Bedernichek, 2021), this opinion distinguishes an early (⁓0–100 years), mid (⁓100–200 years)‐, and late (>⁓200 years) developmental stage with the late developmental stage starting after the net ecosystem carbon balance plateaus (Curtis & Gough, 2018) and ending with a stand replacing disturbance. The original neutrality hypothesis assumed a closed nutrient cycle and acknowledged that open systems may not experience a decline in productivity at maturity (Odum, 1969). Nutrient cycles in forests are characterized by continuous gains and losses and are thus open systems (Galloway et al., 2004).…”