1.1. Introduction: Silviculture and Definitions

Silviculture is the art and science of controlling the establishment, growth, composition, health, and quality of forests and woodlands to meet the diverse needs and values of landowners and society on a sustainable basis (Adams et al. 1994). It is often described as the tending of a forest or the growing of trees. Essentially silviculture is a discipline concerned with meeting human needs by manipulating a forest. Because forests typically require long time periods to grow, silviculture usually relies on management of ecosystems that closely mimic those found in nature. For this reason silviculture is often described as applied forest ecology.

To understand silviculture you must understand the complex interactions of three key themes:

  • Any management action must be ecologically feasible.
  • Any management action must be conducted within all economic constraints.
  • Any management action must consider the context of the governing society.

Silviculture Venn diagram showing silviculture at the intersection of economics, ecology, and society.

Figure 1.1.1. The three aspects of silvicultural decision-making.

Historical examples of poor silvicultural decisions can invariably be attributed to the failure of the foresters involved to fully consider at least one of these critical themes. For instance:

  • Litter raking, or removing leaves or needles from the forest floor, was a common management practice from the 12th until the early 20th century in Germany and central Europe (Sayer 2006). However, litter raking removed necessary nutrients from the forest floor and reduced subsequent growth of the trees. The foresters involved did not fully understand the effects of their actions on the ecology of these forests until the late 1800s, and thus managed in a way that was not sustainable on a long-term basis.
  • The Monongahela National Forest (West Virginia) clearcutting controversy in the 1960s and 1970s fundamentally changed how our National Forests are managed, and played a major role in the passage of the 1976 National Forest Management Act (Fairfax and Achterman 1977). While the foresters involved were making decisions that were both ecologically and economically sound, the controversy arose because they failed to fully consider the societal context in which they were operating. The result was public outcry, lawsuits, and more than a decade where forests went unmanaged while the controversy was settled.
  • Cottonwood (Populus deltoides) was widely planted across the US South from the 1960s to 1980s (Hodges 1995). Cottonwood is among the fastest growing hardwood species in this region, where plantation forests are a socially acceptable means of producing wood and fiber. However, costs were eventually deemed prohibitive due to the intensive site preparation required. Relatively few plantations have been established since the 1980s.

It is always important to remember that forests are diverse and may be managed for many different goals:

  • To maximize timber production and economic returns, as exemplified by loblolly pine plantations managed by corporations in the southern US.
  • To create preferred wildlife habitat, as exemplified by the old-growth longleaf pine stands managed for red-cockaded woodpecker on many military bases in the southern US.
  • To protect water quality, as exemplified by northern hardwood stands managed in the Catskill Mountains of New York to provide clean drinking water for New York City.
  • To restore ecosystem function, as exemplified by bottomland hardwood stands replanted on former agricultural lands in the Lower Mississippi Alluvial Valley.
  • To preserve natural forest ecosystems and wilderness, as exemplified by the management of forests in National Parks from the spruce-fir forests in Acadia, Maine to high elevation mixed stands in the Guadalupe Mountains in Texas, to coastal redwood stands in Redwood National Park in California.

Silvicultural systems may be applied to an individual stand to meet any one or several of these goals. While it is sometimes possible to meet more than one management objective on a single stand, it is not possible to optimize management for all possible objectives. Some objectives are inherently contradictory to one another (e.g. preservation and timber). The objectives of the forest landowner should always guide the forester in choosing the appropriate treatments for a stand. While not every stand is managed to maximize financial profits, every stand must be managed under whatever economic constraints are dictated by the landowner.

Depending on the management objectives, silvicultural inputs will vary in their intensity. For example, a late-successional northern hardwood stand in a state park being managed for recreation will likely require a low intensity of silvicultural inputs. The trees are growing relatively slowly due to the short growing season, and the stand structures desired are large, older trees that take a long time to grow. Thus rotation length will be long, there will likely be a high diversity of understory and midstory species, and stand structure (dead trees, canopy gaps, etc.) will be complex. Little may need to be done from a silvicultural standpoint, as this stand will naturally regenerate itself as new canopy gaps are formed in winter storms. However, there will be little profit from timber harvests.

Contrast this forest with a pine plantation in the US South being managed for timber. This stand will grow quickly due to the long growing season, will produce a large volume of wood, and thus will be harvested at a young age (i.e. a short rotation). To achieve this level of productivity, silvicultural inputs will be more intense, including site preparation, planting of genetically improved seedlings, fertilizer application, competition control with forest herbicides, and thinning. From an economic perspective, this stand will yield a greater rate of return and higher profits to the landowners. However, the stand will be very structurally simple and will have a lower diversity of understory and midstory vegetation, and perhaps less value as wildlife habitat.

Management spectrum diagram depicting the relationship between an increasing intensity of silvicultural inputs and increasing economic return and productivity but decreasing biodiversity, stand structural complexity, and rotation length.

Figure 1.1.2. Silvicultural systems range from extensive to intensive in terms of their cultural inputs.

The remainder of this textbook will attempt to give practical and applied information that will improve your understanding of how these themes interact, informing management decisions to meet landowner objectives. While understanding silviculture is essential to successfully managing a forest in a sustainable fashion, a thorough knowledge of local stand dynamics, market conditions, and legal regulations are all required. This online textbook is not intended to guide the user in the management of any specific forest stand. Research has shown that the use of a knowledgeable consulting forester who works in your local area increases the financial return you receive from forest management (Hubbard and Abt 1989). Lists of certified professional foresters in your area are maintained by the Society of American Foresters:


Some Important Definitions

Sustainability: The capacity of forests, ranging from stands to ecoregions, to maintain their health, productivity, diversity, and overall integrity, in the long run, in the context of human activity and use (Adams et al. 1994). For a management action to be sustainable, it must first:

  • Be goal driven
  • Remain within the ecological capacity of the forest
  • Achieve intergenerational equality

Age Class or Cohort: A distinct aggregation of trees originating from a single natural event or regeneration activity, or a grouping of trees, e.g., 10-year age class, as used in inventory or management (Adams et al. 1994).

Composition: The proportion of each tree species in a stand expressed as a percentage of either the total number, basal area, or volume of all tree species in the stand (Adams et al. 1994).

Forest Health: A forest condition that has overall structure, function, and characteristics that enable it to be resilient to disturbance and to maintain normal rates of change commensurate with its stage of development (Adams et al. 1994).

Stand: A contiguous group of trees sufficiently uniform in age class distribution, composition, and structure, and growing on a site of sufficiently uniform quality, to be a distinguishable unit (Adams et al. 1994).

Rotation: The period of time required for an entire stand to be successfully established, grown, harvested, and re-established.

Silvicultural System: A planned process whereby a stand is tended, harvested, and reestablished (Adams et al. 1994).

Regeneration Method: A cutting method by which a new age class is created (Adams et al. 1994).

Intermediate Treatment: A collective term for any treatment designed to enhance growth, quality, vigor, and composition of the stand after establishment or regeneration and prior to final harvest (Adams et al. 1994).

Succession: A series of dynamic changes by which Organisms succeed one another through a series of plant community (seral) stages leading to potential natural community or climax (Adams et al. 1994).


Adams, D. L., J. D. Hodges, D. L. Loftis, J. N. Long, R. S. Seymour, and J. A. Helms. 1994. Silviculture Terminology with Appendix of Draft Ecosystem Management Terms. Silviculture Instructors Subgroup of the Silviculture Working Group of the Society of American Foresters. https://www.bugwood.org/silviculture/terminology.html

Fairfax, S. K. and G. L. Achterman. 1977. The Monongahela Controversy and the Political Process. Journal of Forestry 75:485-487. https://academic.oup.com/jof/article-abstract/75/8/485/4643738

Hodges, J. D. 1995. The southern bottomland hardwood region and brown loam bluffs subregion. Pages 227-270 in J. W. Barrett, editor. Regional Silviculture of the United States. John Wiley & Sons, Inc., New York, NY. ISSN: 0471598178

Hubbard, W. G. and R. C. Abt. 1989. The effect of timber sale assistance on returns to landowners. Resource Management and Optimization 6:225-234.

Sayer, E. J. 2006. Using experimental manipulation to assess the roles of leaf litter in the functioning of forest ecosystems. Biological Reviews 81:1-31. http://dx.doi.org/10.1017/S1464793105006846