Finland's diverse and abundant forest resources form the foundation for their sustainable utilization. As the operating environment for the forest sector changes, the objectives for forest management are becoming more varied, and the available options are increasing. Forests are expected to produce more wood for industrial raw materials, sequester and store carbon, provide habitats for diverse species, and offer recreational opportunities for people. To meet these goals, forest growth must be enhanced.

Beyond timber production, most forest owners have other objectives for managing their forests. According to the "Forest Owner 2020" study, forest owners can be categorized into five groups based on their goals: multiobjective (38%), economy and security-focused (24%), hands-on foresters (18%), recreation users (13%), and uncertain (7%). Often, non-economic values influence stand harvesting and management activities. These can relate to, for example, nature values, game management, landscape, or emotional values.

An infographic showing how increasing or decreasing thinning intensity affects eight different forest properties, such as carbon sequestration and damage risks.

Figure 1. Forests face multiple demands. Forests serve as habitats, carbon sinks, and providers of numerous ecosystem services. Growing, adaptable, and damage-resistant forests make all of this possible. The growth and adaptability of forests can be enhanced through measures such as species diversity, good forest management practices, and forest breeding.

Continuous cover forestry

Continuous cover forestry (CCF) is a forest management approach that avoids clear-cutting, relying instead on natural regeneration and the utilization of existing undergrowth (Figure 2). CCF methods include selection cutting, small-gap cutting, and shelterwood cutting. In selection cutting, the largest trees are removed, creating space for new seedlings and undergrowth to develop. Small-gap cutting involves creating small openings in the forest that regenerate from the surrounding trees. Shelterwood cutting aims to transform even-aged stands into uneven-aged structures, promoting the establishment of new seedlings and undergrowth.

A significant portion of the trees left to grow in CCF have developed under the shade of larger trees. These shade-grown trees need years to strengthen their root systems and develop their crowns before they can fully utilize the growth space freed up by harvesting. In the long term, successful natural regeneration is one of the key prerequisites for the sustainability of CCF. The shading, large trees must be kept sparse to ensure regeneration and undergrowth development. Among native tree species, only spruce tolerates heavy shading, which poses a risk of spruce dominance in the stand. Light-demanding pine requires either a seed-tree stand or small gaps for regeneration.

In spruce stands managed with selection cutting, both tree volume and growth are, on average, lower than in even-aged, thinned spruce stands. The basal area growth in selection-cut spruce stands is approximately 20% lower than in even-aged spruce stands during the thinning phase. The greater the intensity of the harvest, the larger the difference in tree growth response between CCF and periodic forestry.

However, empirical data based on long-term measurements regarding the effects of CCF on forest growth and yield is scarce. Experimental studies on the effects of shelterwood and small-gap cutting have only begun in recent years.

A diagram comparing continuous cover forestry and periodic (rotation) forestry, showing different development stages and their impacts on long-term sustainability.

Figure 2. Factors affecting tree growth in spruce stands under different management regimes. This figure illustrates the factors influencing tree growth in continuously covered and periodically managed spruce stands at various stages of stand development. The +/- symbols compare the effects between the two cultivation methods.