Silviculture

Silvics: The branch of forestry that provides the scientific basis for the cultural treatment of forest stands.

Silviculture:  The art of producing and tending forest stands, or the application of the knowledge of silvics; bringing together biological and economic concepts to prescribe and apply treatments to help us reach our land management objectives.

The Control Functions of Silviculture

With proper silvicultural techniques we can control forest establishment, composition, and growth and density.

Controlling Establishment

We can influence the time and place when regeneration occurs.  Regeneration can take place naturally or, as is more common in the southeast, artificially by seeding or planting.

Controlling Composition

Forest composition can be controlled by restricting species to ones biologically and or economically suited to the site. This can be done by: 

  • regulating intensity of cutting
  • influencing the character of the seedbed
  • scheduling the time and placement of cuttings
  • seeding or planting

During subsequent tending, we can restrict forest composition to the most valuable trees by keeping:

  • the best-formed trees
  • fastest growing trees
  • most valuable species

Controlling Growth and Density

We can control growth by regulating stand density (or number of trees per unit area).  There are 2 ways this can be done.

  1. Seek optimum stocking: to achieve complete site utilization and capture mortality before it occurs.
  2. Channel growth to selected trees: concentrate growth onto selected species and individual trees, and channel the full productive capacity of the site onto fewer trees per acre.

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The Silvicultural System

In forestry, we think of forests at 2 distinct levels: the stand level and the forest level.

Stand Management

In stand management we are working with a community of trees that are sufficiently uniform in composition, age, spatial arrangement, or other condition to distinguish it from adjacent communities.

There are 2 broad groups of stands:

  1. Even-Aged: a group of trees having no or a small difference in ages; by convention, with a spread of ages not exceeding 20% of the rotation* length.
  2. Uneven-Aged: a group of trees that differ significantly in ages; by convention, with a spread of ages exceeding 25% of the planned life span for an age class.
  • * Rotation: the planned number of years between stand formation and cutting.

Note:  Even-aged stands never have regeneration, tending, and harvest occurring simultaneously.  Uneven-aged stands alwaysdo.

Reproduction Methods

Many methods of reproduction have been developed.  The details of applying the same method vary widely because they are altered for each species, forest region, and management objective. The following are broad categories of reproduction methods, in order of a decreasing percentage of the canopy removed during the cut:

Even-Aged Stands:

high percentage of canopy removed

  • Clearcutting - removal of entire stand in one cutting
  • Seed tree method - removal of mature timber in one cutting, except for a small number of seed trees left singly or in small groups in order to provide a seed source
  • Shelterwood method - removal of mature timber in a series of cuttings which extend over a relatively short portion of the rotation, that is, even-aged reproduction under the partial shelter of seed trees.

Uneven-Aged Stands:

low percentage of canopy removed 

  • Selection method - removal of mature timber, usually the oldest or largest trees, either as single scattered individuals or in small groups at relatively short intervals, so that an uneven-aged stand is maintained.

To see the advantages and disadvantages associated with using these reproduction methods, visit our Even- vs. Uneven-Aged Reproduction Methods page.

Forest Management

In forest management we are working with the collection of stands that make up the forest ownership.  Through forest management, we are integrating plans for stands into a well-organized program for the entire ownership. See this diagram of the Silvicultural System for more information.

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What Trees Should You Grow?

photo by Chris DemersOne of the first decisions to make in the process of making plans for your land is the selection of tree species to grow. This will depend on your objectives and the site conditions on your land. For more information, see our Guide to Soils and Tree Species page.

The market for pines is strong in most of Florida and pines are suited to sandy soils that are either too wet or too dry for agricultural purposes. Pine timber can be used for many products such as posts, pulpwood, lumber, plywood, and poles. For these reasons, pines are often the species of choice for planting here when timber products are the objective.

For more information on southern pines, see our Common Pines of Florida.

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