What is Silviculture?

E. R. Wilson | Silviculturist

A brief intorduction to the science and practice of silviculture with an overview of key concepts, terminology and priorities.

Silviculture is the science and practice of cultivating and managing forest stands. The term “silviculture” comes from the Latin words silva (forest) and cultura (cultivation). The aim is to understand and ensure the long-term productivity, health, and resilience of forest ecosystems (stands) while meeting the diverse needs and values of society.

The practice of silviculture involves a range of activities that influence the structure, function and growth of forest stands, specifically site preparation, natural and artificial regeneration, thinning, pruning, harvesting, and the management of pests, diseases, and invasive species. Silviculture integrates knowledge from various disciplines, most notably forest ecology, tree physiology, forest genetics, forest inventory, and forest economics. In effect, much of silviculture practice can be viewed as applied forest ecology (Ashton and Kelty 2018).

Foresters with specialist interest, training and expertise in silviculture are known as silviculturists (Jain 2019). Silviculture interventions must be carefully planned and require detailed knowledge of the site, past management and forest stand dynamics, and an inventory of the current stand condition. The silviculturist uses this information to prepare stand-level plans, generally called stand prescriptions, that outline immediate and longer-term actions required to meet individual stand management objectives (Figure 1). Prescriptions for each stand are collated and included within management plans for the entire forest. These are developed and revised on a planning cycle, usually every five years.

Silviculture is one of the main branches of forestry, which is the broader field of science and management of forests. As such, silviculture underpins virtually all forestry planning decisions.

Figure 1. Silviculturists must make informed decisions about the nature, scale and timing of stand interventions. Significant scientific and technical knowledge underpins the preparation and implementation of stand prescriptions. The example here is a plantation of Douglas fir (Pseudotsuga menziesii) in the early stages of transformation to an irregular structure, Vosges Mountains, Alsace, France. Photo credit: © 2018 Edward Wilson/Silviculture Research International.

Silvicultural Practices

A wide range of silvicultural practices have been developed to influence the form and function of managed forest stands. However, before looking into the elements of silviculture further, it is important to clarify some of the key terms commonly used in silviculture:

  • Forest stand. A forest stand is a distinct area of woodland, generally composed of a uniform group of trees in terms of species composition and the spatial distribution, age class distribution and size class distribution of the trees (Jenkins et al. 2012). The site will be of uniform quality and the overall character of the stand will be distinct from adjacent communities. This is often considered to be the basic unit of management in silviculture, with a forest comprising an aggregation of stands across a wooded landscape. A related term often used in plantation forests is compartment and sub-compartment, to designate related areas managed separately.
  • Forest and Woodland: These are areas of predominantly treed and wooded land composed of a variety of species, species assemblages and ecosystems. A forest/woodland can incorporate a number of forest stands, open areas, watercourses, ponds and lochs (lakes). In the Irish and UK context, this would include ancient woodland and semi-natural woodland, which are given a special/separate designation due to their rarity and special attributes. The objectives and management requirements for different stands and woodland types vary greatly and could be entirely protective. A clear distinction between “forest” and “woodland” is not possible; often a forest is thought to be a more extensive area of land composed of many forest stands, while a woodland might be somewhat smaller and composed of fewer stands.
  • Management and intervention. These two terms may seem synonymous, but there are important distinctions between management and intervention in the context of forestry.
    • Management refers to the active oversight of a whole forest/woodland to ensure that any management activities deliver the intended benefits in accordance with best-practice guidance or regulations (e.g., in the UK the primary reference document for sustainable forestry is the UK Forestry Standard [UKFS]).
    • Intervention means a specific activity or group of activities intended to meet a specific management objective, for example, establishing a new woodland, pruning trees of high value potential, conducting a thinning operation, selecting specific trees for harvest.

The approach to management depends on the objectives, which are different for each site and each landowner, whether the priorities are environmental, social, economic or multi-functional. Generally speaking, a management plan embraces the requirements for each stand and specifies the interventions required over a set planning horizon. Typically plans are written for a rolling timescale of 20-25 years (depending on jurisdiction) and are divided into 5-year management periods; the plan is updated every 5 years and includes a high level of detail and scheduling of interventions required during the immediate 5-year period. This includes prescriptions for interventions in some stands but it can also embrace minimum- or non-intervention recommendations in other stands. These are usually where specific features or stand attributes require protection or conservation. Biodiversity or habitat condition monitoring might be the prescribed activity in such stands – a prescription does not necessarily mean felling trees in each management period.

Some of the most important practices in silviculture include:

  1. Site preparation: This involves clearing vegetation, removing obstacles, and preparing the soil to create suitable conditions for tree establishment and growth.
  2. Tree planting: Seedlings or young trees are planted in designated areas to establish new forests or regenerate areas that have been harvested or disturbed.
  3. Stand tending: This includes activities such as thinning, pruning, and weeding, which help manage the density and growth of trees within a stand, promoting healthy development and regulating competition.
  4. Harvesting and regeneration: Mature trees are selectively harvested, and appropriate methods are employed to ensure the establishment of new trees or natural regeneration to maintain the forest’s productivity. The method used to harvest trees in a stand is used to classify silvicultural systems (see below).
  5. Pest and disease management: Silviculture involves monitoring and managing pests, diseases, and invasive species to protect the health and vitality of forests.
  6. Fire management: Silviculturists may use controlled burning techniques to mimic natural fire regimes, reduce fuel loads, and enhance ecosystem health. This is a practice used only in certain regions, usually where fire is part of the natural forest ecology. It is subject to strict certification and guidelines.
  7. Monitoring and research: Continuous monitoring and research are important aspects of silviculture to assess forest health, growth rates, biodiversity, and the effectiveness of management practices.

Silvicultural Systems

Silvicultural systems are strategies or approaches used in forest management to achieve specific objectives while considering the ecological and economic aspects of forest ecosystems. There are several major silvicultural systems, each with its own characteristics and applications. They are applied separately to high forests (where the forest condition is characterized by the presence of fully developed, mature trees that form a continuous, closed canopy) and other forms of silviculture, such as coppice systems or agro-forestry systems.

High Forest Silvicultural Systems

Here are some of the main silvicultural systems used in managing high forests (Figure 2):

  1. Clearcutting: This system involves the complete removal of all trees within a designated area. It is often used for maximizing timber production or creating openings for natural regeneration. Clearcutting can be followed by replanting or rely on natural regeneration, depending on the site conditions and management goals.
  2. Seed-tree: In the seed-tree system, a few mature trees are retained in the stand to act as a source of seed for regeneration. The majority of the trees are removed, allowing ample light to reach the forest floor and promote regeneration. It is especially effective where the main species is shade intolerant and where full sunlight is required for regeneration (e.g., Scots pine). Once the new trees are established, the seed trees are removed. Stability of the seed trees and exposure to wind are important considerations before this silvicultural system can be adopted.
  3. Shelterwood: In the shelterwood system, trees are removed in a series of planned interventions to create favorable conditions for the regeneration of shade-intolerant tree species. Initially, a partial cut is made to create a seed source, and then subsequent cuttings are done to gradually increase light levels for regeneration. Eventually, the mature overstory trees are removed.
  4. Group selection: This system involves the removal of small groups of trees, typically ranging from a few trees to an opening of several hundred m2. By creating openings of different ages and sizes across the stand, a more diverse forest structure can be achieved, providing habitat heterogeneity and facilitating species diversity.
  5. Single-tree Selection: The selection system involves the selective removal of individual trees or small groups of trees at regular intervals throughout the stand. It is often used in uneven-aged forests to promote a mix of different tree age classes and maintain a continuous forest cover. This system is suitable for species that can tolerate shade and allows for a more sustainable and continuous flow of timber.
Figure 2. A visual representation of the major silvicultural systems in terms of the mode of intervention and the desired forest stand structure. We can view silvicultural systems along a continuum from uniform to irregular structure. Generally a stand becomes irregular when there are three or more distinct cohorts/tree size classes. Irregular shelterwood can be considered transitional because the interventions can be at a scale and time-frame where there are multiple cohorts of regeneration within the stand before the overstorey is replaced. Terminology is subject to variation from region to region and according to different traditions of silviculture.

Clearcutting and seed-tree are generally classed as even-aged or uniform silvicultural systems because they create conditions for the whole site to regenerate at the same time. In most cases the stands within these systems are relatively uniform and managed on rotations, giving rise to the term Rotational Forest Management (RFM) (Figure 3). Group selection and single-tree selection give rise to stands with an uneven-aged or irregular structure. Generally the concept of rotation does not apply to these systems because the complex dynamics within a forest stand results in highly variable growth rates; trees of similar size can be very different in age, and vice versa (Figure 4). The types of sustainable forestry that employ group and single-tree selection systems include Continuous Cover Forestry, Irregular Forest Management and Closer-to-Nature Forest Management. However, it is important to note that silviculture terminology and precise definitions for silvicultural systems vary in different regions, countries and forest types.

Figure 3. Even-aged stand of Sitka spruce (Picea sitchensis) managed on the clear-cut system. The stand in this image is unthinned and in the process of being harvested. The stand will then be re-stocked by planting to initiate the nexxt rotation. Kielder Forest, England. April 2023. Photo credit: © 2023 Edward Wilson/Silviculture Research International.
Figure 4. Stand dominated by Norway spruce (Picea abies) managed on the single-tree selection system. The stand has an irregular structure, with stems in all age/size classes from regeneration to the target size for final felling. Freudenstadt, Black Forest, Germany, August 2008. Photo credit: © 2008 Edward Wilson/Silviculture Research International.

Shelterwood systems lie intermediate between even-aged (stand) and individual tree silvicultural systems, and merit a more detailed description. Shelterwood systems achieve new tree regeneration by gradually reducing the overhead tree canopy in a sequence of stages (Figure 5). The goal is to use the existing canopy to regenerate and nurture the succeeding forest stand or to develop a more complex forest structure than before. As a result, the regeneration across a forest stand can be uniform and even-aged or irregular and more-or-less uneven-aged, depending on the shelterwood system being applied.

Figure 5. Scots pine (Pinus sylvestris) being managed on a uniform shelterwood silvicultural system. The overstorey has been reduced in stages to allow for natural regeneration of the stand. This is especially effective for shade intolerant species such as Scots pine. The overstorey can be completely removed at the final stage to leave a more-or-less even-aged stand; a few veteran trees/ha might be retained for habitat and conservation values. Kinveachy, Strathspey, Highlands, Scotland, December 2023. Photo credit: © 2023 Edward Wilson/Silviculture Research International.

Each form of shelterwood system has its specific application and variations depending on factors such as tree species, site conditions, desired regeneration outcomes, and management objectives. The terminology tends to vary across different jurisdictions and some bespoke terms are also used in specific management treatments. However, all shelterwood systems aim to balance the need for regeneration with the maintenance of some level of canopy cover to provide protection, shade, and favorable growing conditions for the new tree cohort.

The major types of shelterwood represent a spectrum from uniform to irregular patterns of regeneration across the stand being managed. Four of the more common types of shelterwood are described here to illustrate how the succeeding stand structure is more or less uniform (even-aged) or irregular:

  1. Uniform Shelterwood System: In this system, the overstorey is gradually removed in a series of stages. At the initial stage (often called the preparatory intervention), the entire stand is thinned to promote individual tree stability and to allow increased levels of light to reach the forest floor. The remaining trees (residual stand) provide a seed source, shade and protection for natural regeneration to become established. Subsequent interventions (stages) remove the overstory trees over a period of several years, releasing the understorey regeneration from shade and allowing a new strata to form. Typically, there are two or three stages before the over-storey is completely removed, depending on the prior history of the stand and the amount of natural regeneration present at the time of initiating the shelterwood. The number of stages gives rise to the terms two-stage or three-stage uniform shelterwood. During the regeneration phase, there are two age classes, or cohorts, in the stand (i.e., the overstorey and the understorey). Once the final trees are removed from the overstorey, the new stand is generally classed as being even-aged.
  2. Strip Shelterwood: In this system, interventions are made in relatively narrow strips that advance progressively through a stand over the time-frame of the regeneration period. Interventions take place in the stand as uniformly-staggered linear strips at right angles to the prevailing wind. Seed is blown from the residual stand into the opened strip and any edge trees that are windblown are salvaged at the next intervention. Succeeding strips are added beside the initial strips and progress into the wind until the entire overstorey is removed and the understorey fully established. Harvesting in each strip may occur gradually and following in a sequence of preparatory, regeneration and removal interventions.
  3. Group Shelterwood System: The group shelterwood system is a variation in which groups of trees are removed, rather than uniformly or in strips, to create small openings within the forest stand. These openings vary in size and shape (typically one to two tree lengths in diameter) and provide favorable conditions for the establishment of regeneration. In successive stages, the gaps are expanded or new gaps created to allow for release and more complete regeneration of the stand. The timing and extent of each regeneration stage determines the structure of the future stand. This approach can be used as a pathway to continuous cover forestry due to the irregular structure that can arise from the distribution of openings across space and time.
  4. Irregular Shelterwood System: The irregular shelterwood system is defined by timing of regeneration establishment not by spatial arrangement. This system draws on elements from other systems, notably group and single tree selection, and potentially a combination of approaches. The regeneration period for the stand is extended so long that the new stand is not even-aged. “Irregular” refers to the variation in tree heights in the new stand. As such, the irregular shelterwood system is specifically used to promote structural diversity. Objectives for aesthetics, wildlife and biodiversity conservation are generally compatible with this system.

Other Silvicultural Systems

Several other silvicultural systems are also commonly applied, but not classed as high forest systems:

  1. Coppice: Coppicing is a system in which the stand is composed of trees that resprout from cut stumps or root systems (Figure 6). The trees are harvested at regular intervals, and new shoots rapidly regrow from the stumps. This system is commonly used for species that have the ability to regenerate through vegetative reproduction, such as some hardwoods and shrubs.
  2. Agroforestry: Agroforestry systems integrate trees with agricultural crops (silvo-arable systems) or livestock (silvo-pastoral systems) on the same land. These systems combine the benefits of both agriculture and forestry, such as improved soil conservation, increased biodiversity, and diversified income sources for farmers.
Figure 6. Example of a coppice system in a mixed-broadleaf woodland. This is a very ancient form of silviculture that takes advantage of the capacity of certain species to regenerate from adventitious shoots or stump sprouts. Stands are often managed on relatively short rotations to harvest small-dimension material. Where individual stems are allowed to grow into the overstorey the system is generally called coppice-with-standards. South Cumbria, England. May 2010. Photo credit: © 2010 Edward Wilson/Silviculture Research International.

Another common silvicultural system is known as coppice with standards, which has elements of both high forest and coppicing systems:

  1. Coppice with standards: This is a traditional silvicultural system that combines two different management approaches within the same forested area. It involves the simultaneous management of a coppice system and a high forest or standards component.

    In this system, certain trees are regularly coppiced, which means they are cut back near ground level to stimulate the growth of new shoots from the stump or root system. Coppicing is typically done on relatively short rotations, usually ranging from a few years to a couple of decades, depending on the tree species and management objectives.

    The coppiced trees are usually shade-intolerant species that have the ability to resprout vigorously from the cut stumps. Examples of commonly coppiced species include certain hardwoods like hazel (Corylus spp.), oak (Quercus spp.), ash (Fraxinus spp.), and chestnut (Castanea spp.). The regrowth from coppicing often consists of multiple stems or poles that grow rapidly and can be harvested for various uses such as firewood, poles, fencing material, or wood products.

    In addition to the coppiced component, the system incorporates a stand of high forest trees or ‘standards’. These standards are typically long-lived, shade-tolerant species that are allowed to grow to maturity without being cut or heavily managed. The standards provide several benefits, including structural diversity, habitat for wildlife, and the potential for timber production from larger, high-quality trees.

    The standards are usually selected for their commercial value, long-term growth potential, or ecological functions. They may include species like oak, beech (Fagus spp.), or other valuable timber species. Standards are spaced out within the coppice area, allowing them to develop into larger, dominant trees that provide canopy cover and contribute to the overall structure and diversity of the forest.

    Coppice with standards systems offer a balance between the shorter-term, regular harvests of the coppiced trees and the longer-term timber production potential of the standards component. This approach allows for the sustainable production of smaller wood products from coppice poles while preserving larger trees for timber or other purposes. It also supports biodiversity by creating a mosaic of different-aged stands and providing a range of habitats within the forest.

    Coppice with standards systems have historical roots and have been practiced for centuries in many parts of the world. Today, they are still used in certain regions for timber production, conservation, and land management purposes, particularly in areas with a tradition of coppicing or where the ecological benefits of such systems are recognized.

The suitability and application of individual silvicultural systems is closely linked to the biological and ecological requirements of the tree species being managed within the stand. For example, early seral stage/pioneer species and those that are shade intolerant are best suited to even-aged silvicultural systems. Species associated with later seral stages and with higher levels of shade tolerance are better suited for irregular-structure/uneven-aged silvicultural systems. Ultimately, in addition to silvical characteristics of trees species, the choice of a silvicultural system depends site conditions, management goals, wider ecological considerations, and the desired balance between timber production, biodiversity conservation, and other ecosystem services. Adaptive management or freestyle silviculture approaches that combine different silvicultural systems can also be employed to meet specific objectives and address the complexity of forest ecosystems.

Silvicultural Science

Silviculture is a complex and ever-evolving field, as scientists and foresters continue to learn more about how forests function and how to manage them sustainably. Silvicultural science encompasses various disciplines and knowledge areas that contribute to the understanding and application of effective forest management practices. Here are some of the major scientific components of silviculture:

  1. Forest Ecology: Forest ecology examines the relationships between organisms and their environment within forest ecosystems. It provides insights into forest stand dynamics, species interactions, nutrient cycling, succession, and the ecological processes that influence forest growth and development.
  2. Tree Physiology: Tree physiology focuses on the biological processes and functions of individual trees, including photosynthesis, water and nutrient uptake, growth patterns, reproduction, and responses to environmental factors. Understanding tree physiology helps optimize silvicultural practices to enhance tree health and productivity.
  3. Silvicultural Systems and Practices: Silvicultural systems are based on scientific principles and knowledge of forest ecology. The design and implementation of silvicultural practices, such as tree planting, thinning, regeneration methods, and stand treatments, draw from scientific research to achieve specific management goals and maintain the long-term sustainability of forest ecosystems.
  4. Forest Genetics and Tree Breeding: Forest genetics involves studying the heredity and variation of forest tree species. It helps in selecting and breeding trees with desirable traits, such as growth rate, disease resistance, and wood quality, to improve forest productivity and adaptability to changing environmental conditions.
  5. Forest Inventory and Monitoring: Forest inventory and monitoring provide data on the composition, structure, and health of forest stands. Scientific sampling methods and remote sensing techniques are used to assess forest resources, monitor growth rates, track changes in forest cover, and evaluate the effectiveness of silvicultural treatments.
  6. Forest Soils: Forest soils play a crucial role in supporting tree growth and nutrient cycling. Understanding soil properties, such as fertility, moisture content, and texture, is important for site selection, species suitability, and soil management practices, including fertilization and erosion control.
  7. Forest Economics: Forest economics provides essential information that supports decision-making about stand productivity and financial performance. Timber production has traditionally been the primary concern of forest economics. More recently, the scope of forest economics has expanded to consider the multi-functional role of forests in delivering a range of economic, environmental, social and cultural benefits.
  8. Forest Management Planning: Scientific principles are applied in forest management planning to develop strategies and prescriptions for achieving desired outcomes. This includes setting objectives, considering ecological and socioeconomic factors, assessing risks, and employing adaptive management approaches that integrate scientific knowledge into decision-making processes.
  9. Ecological Restoration: Silviculture often involves ecological restoration efforts to recover and rehabilitate degraded forest ecosystems. Restoration science contributes to the understanding of ecological processes, biodiversity recovery, invasive species management, and the use of native species in reforestation and habitat restoration projects.

These scientific components of silviculture are interconnected and inform each other to guide sustainable forest management practices. By integrating scientific knowledge, forest managers can make informed decisions that promote healthy and resilient forests while considering ecological, economic, and social objectives.

Current Challenges in Silviculture

At present, silviculture faces several significant challenges that impact forest management practices and the sustainability of forest ecosystems. Some of the major challenges in silviculture include:

  1. Climate Change: Climate change poses one of the most pressing challenges for silviculture. Rising temperatures, altered precipitation patterns, and increased frequency and intensity of extreme weather events can impact forest growth, regeneration, and the distribution of tree species. Silviculturists must adapt management strategies to mitigate the effects of climate change, such as promoting species diversity, assisting natural regeneration, and selecting climate-resilient tree species.
  2. Invasive Species: Invasive species can have detrimental impacts on forest ecosystems, outcompeting native species and disrupting ecological processes. Silviculturists need to identify and manage invasive species effectively to minimize their negative effects on forest health, productivity, and biodiversity.
  3. Forest Health Issues: Forests face various health challenges, including pests, diseases, and pathogens. Outbreaks of insects, such as bark beetles, can cause widespread tree mortality. Diseases, such as Dutch elm disease, sudden oak death and ash dieback disease, can devastate tree populations. Silviculture must integrate effective pest and disease management strategies to maintain forest health and prevent the spread of harmful agents. In addition, regulation of wildlife populations is important for forest health and regeneration, especially deer, squirrels and other animals that browse/feed on seedlings and trees.
  4. Transformation of forest structures: In many regions there is an increasing requirement for forests that deliver multifunctional outputs and ecosystem services at the stand and landscape levels. This has led to greater interest in individual tree management and the adoption of “closer to nature” (CTN) and continuous cover forestry (CCF) systems. Significant research and technical development is required where individual tree management is not the orthodox approach and where even-aged/plantation systems are currently dominant. The transformation requires investment in basic silviculture research and technical development/knowledge transfer.
  5. Wildfire Management: The increasing severity and frequency of wildfires pose a significant challenge for silviculture. Uncontrolled wildfires can have devastating effects on forests, including loss of timber resources, destruction of habitat, and increased risk of soil erosion. Early detection and control are important interventions to reduce fire impact where people, property and protected habitats are at risk. In many regions, silvicultural practices, such as prescribed burning and fuel reduction techniques, can be important fire management strategies to mitigate the risk of catastrophic wildfires and promote ecosystem resilience.
  6. Sustainable Timber Production: Balancing timber production with ecological sustainability is an ongoing challenge. Silviculturists must implement practices that optimize timber yields while minimizing environmental impacts, protecting water quality, and conserving biodiversity. Promoting sustainable forestry certifications and adopting responsible harvesting practices can help address this challenge.
  7. Social and Community Engagement: Silviculture involves addressing diverse stakeholder interests and engaging with local communities. Balancing economic development, recreational opportunities, cultural values, and conservation goals requires effective communication, collaboration, and participatory decision-making processes. Silviculturists must consider the social dimensions of forest management and foster partnerships with local communities to ensure sustainable outcomes.
  8. Policy and Governance: The development and implementation of effective forest policies and governance frameworks can be complex and challenging. Silviculture requires supportive policies that encourage sustainable practices, provide incentives for forest management, and address the needs of diverse stakeholders. Adaptive management approaches that integrate scientific research into policy-making processes are crucial for addressing the challenges facing silviculture.
  9. Long-term research: Developing and maintaining long-term research programmes remains a critical challenge in silviculture. Much research in forest stand dynamics and silvicultural systems requires large teams and multi-year funding packages. Most forest research tends to be funded in 3 or 5 year cycles, and so novel approaches are required to ensure adequate support for research that may only deliver significant results over longer time-frames, sometimes decades.

It is widely recognised that increased genetic, species and structural diversity are required to enhance the resilience of managed forest landscapes. One strategy is to consider the forested landscape as a mosaic that comprises different stands being managed for a range of objectives, some perhaps prioritising production, others prioritising environmental or cultural services. Broadly speaking, we can think in terms of three classes of managed woodland that influences the silvicultural choices and decisions: woodlands primarily managed for economic outputs; woodland primarily managed for ecological values; and an intermediate class where multi-functionality is required. This implies that in addition to matching appropriate genotypes and species to sites, that silviculturists are increasingly required to apply a diverse range of silvicultural systems.

Addressing the challenges in modern sustainable forestry requires a multidisciplinary approach, collaboration among professionals and stakeholders, and the application of innovative strategies informed by scientific research and local knowledge. Silviculturists play a vital role in adapting and evolving forest management practices to overcome these challenges and ensure the long-term health and sustainability of forest ecosystems.


See the following page for key references in silviculture.