Silviculture

Best Management 

Practices

Florida Department of Agriculture and Consumer Services

Charles H. Bronson, Commissioner

James R. Karels, Director

Division of Forestry
S i l v i c u l t u r e Best Management Practices 1

Introduction

This manual establishes the Best Management Practices (BMPs) for silviculture operations in Florida. These practices are designed as the minimum standards 

necessary for protecting and maintaining the State’s water quality as well as certain wildlife habitat values, during forestry activities. As such, they represent 

a balance between overall natural resource protection and forest resource use.

In addition, these practices were developed specifically for silviculture 

and are intended to be applied on all such operations. However, they are not 

intended for use during tree removal or land clearing operations associated 

with development or other activities that have non-forestry objectives.

Best Management Practices for Silviculture in Florida were first established in the mid 1970’s in response to the Federal Clean Water Act of 1972. 

Those original BMPs were designed exclusively to protect Florida’s streams and 

lakes from potential sources of pollution associated with forestry activities.

In 1991, Florida's Agriculture Commissioner established a BMP Technical 

Advisory Committee which included representatives from state and federal 

government, university, forest industry and environmental groups. This 

committee was directed to review the existing BMP Manual and revise the 

practices where necessary to reflect the scientific, social and economic changes 

that have taken place since the original BMP development.

With this revision, some of the original practices have been retained as 

part of the continuing strategy to achieve water quality goals. However, many 

of these practices have been expanded to address additional water resource 

features such as sinkholes, smaller lakes, canals and wetlands. In addition, 

general ecological considerations and wildlife habitat values have been included 

in specific BMP objectives, resulting in expanded versions of original BMP 

concepts such as Special Management Zones, as well as new ones such as 

BMPs for wetlands, and cypress harvesting.

Although many of the relationships between silviculture activities and 

impacts to natural resources have been well quantified, many others have not. 

Consequently, as significant new information has become available, it has 

been incorporated into the practices in this Manual. To that end, the BMP 

Technical Advisory Committee will continue to meet biennially, in concert with 

BMP compliance monitoring, to evaluate the status and progress of BMP 

implementation and effectiveness.

Because of the extensive revisions to this document, some of the technical 

terms used in the Manual have specific definitions that may differ from 

conventional or traditional meanings. The reader is strongly advised to review 

the Glossary of terms prior to reading the Manual or implementing the practices.

Foreword
2 S i l v i c u l t u r e Best Management Practices

BMP Monitoring and Regulatory Requirements

Since 1981 the Florida Division of Forestry has monitored BMP implementation by conducting a biennial Compliance Survey. Like BMPs in general, the 

Survey has traditionally been heavily oriented toward forestry activities 

involving intensive pine management, near streams and lakes. With the new 

and expanded practices in this Manual, BMP compliance monitoring was also 

revised. Following the development of this Manual in 1993, a BMP Monitoring 

Task Force revised the Compliance Survey making it compatible with the new 

BMPs, and more technically and statistically sound. The revised Survey was 

first used in 1995 and includes significant procedural changes such as a 

numerical scoring system for determining BMP compliance, special criteria for 

identifying a significant risk to water quality, and an expansion of the Survey 

into all Florida counties. The Survey has determined a statewide, long-term 

average of 94% compliance with silviculture BMPs.

In addition, a BMP Effectiveness Study was completed using the Survey as 

a measure of BMP compliance and using stream bio-assessment techniques to 

measure water quality. The study concluded that where silviculture BMPs were 

properly applied water quality, aquatic habitat and overall stream ecosystem 

health were protected.

The BMPs in this Manual are intended for implementation on all silviculture 

operations regardless of whether or not the operation is subject to other regulatory 

standards or permits. Anyone who desires to conduct silviculture activities 

that are not in compliance with this Manual must necessarily seek and obtain 

a permit from the appropriate local, state and/or federal government agency 

prior to conducting the operation. In addition, the maintenance of State water 

quality standards is required during all silviculture operations.

For the purposes of this Best Management Practices Manual, the cutting 

and removal of timber and associated activities to prepare land for development 

are not considered silviculture (see Glossary) and are controlled by other 

governmental permitting processes.
S i l v i c u l t u r e Best Management Practices 3

Introduction

The Special Management Zone (SMZ) is a BMP which consists of a specific 

area associated with a stream, lake, or other waterbody that is designated and 

maintained during silviculture operations. The purpose of the SMZ is to protect 

water quality by reducing or eliminating forestry related inputs of sediment, 

nutrients, logging debris, chemicals and water temperature fluctuations that 

can adversely affect aquatic communities. SMZs provide shade, streambank 

stability and erosion control, as well as detritus and woody debris which 

benefits the aquatic ecosystem in general. In addition, the SMZ is designed 

to maintain certain forest attributes that will provide specific wildlife habitat 

values. Snags, den and cavity trees as well as mast producing trees, left in the 

SMZ, are necessary to meet habitat requirements for certain types of wildlife.

As described in the following sections, the SMZ is subject to specific criteria, 

that defines operational restrictions, and special management objectives. In 

addition, the SMZ has a specific width which is based on the size and type of 

waterbody involved, and on the Site Sensitivity Class (SSC). The SSC is based 

on the local soil type and slope percent, which indicate the general potential for 

erosion and sedimentation. For determining the SSC, Florida soils have been 

classified as A, B or C, with A being stable and C being highly erodible. Percent 

ground slope has also been classified as 1 through 6, with 1 being relatively flat 

and 6 being very steep (Appendices 2 and 3).

The SSC for a given site is a combination of soil and slope percent and is 

expressed as A1 through C6. For example, an A1 site would have stable soils 

and flat topography, whereas a C6 site would have highly erodible soil and 

steep slopes. Likewise, the SMZ width associated with an A1 site would be 

relatively narrow compared to the SMZ associated with a C6 site (Appendix 1).

The Special Management Zone has three principal components - the 

Primary Zone, the Secondary Zone and the Stringer. One or more of these 

components may apply on a given forestry operation, depending on the SSC 

and on the type and size of waterbodies on site. The following sections provide 

a detailed description of the three SMZ components and the practices that are 

acceptable or prohibited within each one. Practices that are acceptable within 

all components of the SMZ include direct seeding, hand planting or machine 

planting on the contour of the land, prescribed burning for site preparation on 

slopes less than 18%, and basal application of herbicides and insecticides.

Special Management Zones
4 S i l v i c u l t u r e Best Management Practices

Primary Zone

The Primary Zone applies to perennial streams, perennial lakes, sinkholes 

with perennial water, Outstanding Florida Waters (OFW), Outstanding National 

Resource Waters (ONRW), Class I Waters, and in some cases wetlands (see 

Wetlands Section). Although forestry activities are allowed, this Zone has 

significant timber harvesting restrictions, and varies in width from 35 to 200 

feet per side, depending on the type and size of the waterbody (see Appendix 1 

and Application of SMZs). The Primary Zone provides water quality protection 

to adjacent waterbodies by maintaining shade, and by reducing the disturbance 

to ground cover vegetation and leaf litter. In addition, this Zone also provides 

important wildlife habitat values particularly for those species that require 

snags, cavities, tall trees and other characteristics generally associated with 

older and less disturbed forest conditions.

Selective timber harvesting and other forestry operations are allowed in 

the Primary Zone, subject to the specific management criteria listed below. 

However, selective harvesting within this Zone is intended to be conducted in 

conjunction with harvesting of a specific adjacent area. In addition, forestry 

operations, particularly harvesting and skidding, within the Primary Zone 

should exercise special precautions to maintain as much of the natural forest 

condition as possible. A decision not to harvest at all within this Zone may 

provide additional natural resource benefits.

Primary Zone • Management Criteria

A) Clearcut harvesting is prohibited in the Primary Zone except for special 

conditions described in Appendix 11.

B) Clearcut harvesting is always prohibited within 35 feet of all perennial 

waters and within 50 feet of all waterbodies designated as OFW, ONRW or 

Class I Waters.

C) Selective harvesting may be conducted to the extent that 50% of a fully 

stocked stand is maintained. The residual stand should conform to the following:

1) Trees should be left to maintain the approximate proportion of diameter

classes and species present prior to harvesting, except that oaks (other than 

water oaks) and den trees may be favored. However, in mixed pine/hardwood forests the residual stand may be composed of up to 90% hardwood 

and 10% pine, and den trees may be favored. 

2) Repeated entry into a harvested Primary Zone in short time intervals 

for additional harvesting is prohibited.

3) No trees will be harvested in stream channels or on the immediate stream bank.

D) Special emphasis should be given to the following, within the Primary Zone 

of the SMZ:

1) Protection of very large trees and/or old trees.

2) Protection of snags and cavity trees.
S i l v i c u l t u r e Best Management Practices 5

3) Protection of trees where any part of the canopy overhangs the water.

E) The following forestry activities are prohibited within the Primary Zone of 

the SMZ:

1) Mechanical site preparation.

2) Loading decks or landings, and log bunching points.

3) Main skid trails, except to approach a designated stream crossing.

4) Aerial application, mist blowing or operational application (See Glossary) 

 of pesticides or fertilizer, including any drift from nearby applications.

5) Cleaning spray equipment or discharging rinse water from pesticide or 

 fertilizer applications.

6) Road construction except when crossing a waterbody.

7) Site preparation burning on slopes of 18% or greater.

Secondary Zone

The Secondary Zone applies to all intermittent streams, intermittent lakes 

and sinkholes with intermittent water. In addition, for perennial waterbodies, 

OFWs, ONRWs and Class I Waters, the Secondary Zone may apply as an “addon” to the Primary Zone (Figure 1 and Appendix 1).

For intermittent waterbodies, the Secondary Zone is always at least 35 feet 

wide on each side of a stream or around the circumference of lakes and sinkholes. Depending on the SSC, the width of the Secondary Zone for intermittent 

waterbodies may be as much as 300 feet (See Figure 2 and Appendix 1).

The SSC is used to determine the width of the Secondary Zone, in the case 

of intermittent waters, as well as the necessity for the Secondary Zone, in the 

case of perennial waters, OFWs, ONRWs and Class I waters. Generally, the 

more erodible the soil and the steeper the slope, the wider the Secondary Zone, 

and/or the wider the entire SMZ. Appendix 1 lists the SSC for all combinations 

of soil and slope conditions, and provides the width requirements for the 

applicable Special Management Zone under each condition.

The Secondary Zone has no timber har vesting limitations - unrestricted 

selective harvesting and clearcut harvesting are both permissible anywhere 

within the Secondary Zone. However, the following operational restrictions apply:

Secondary Zone • Operational Restrictions

1) No mechanical site preparation.

2) No main skid trails (except for stream crossings), loading decks or landings.

3) Do not clean spray equipment or discharge rinse water from pesticide 

 and fertilzer applications.

4) No road construction except for stream crossings.

5) No plowed firelines except during fire suppression.

6) No site preparation burning on slopes of 18% or greater.
6 S i l v i c u l t u r e Best Management Practices

Stringer

The Stringer applies only to intermittent streams, intermittent lakes and 

sinkholes with intermittent water, and is composed of trees left on or near the 

bank along both sides of these waterbodies. The Stringer can provide limited 

food, cover, nesting and travel corridors for a number of animals, especially birds.

Stringers are most beneficial when connected to larger Special Management 

Zones where they provide benefits to water quality by reducing the risk of 

sedimentation and bank damage. The presence of a Stringer provides a physical 

barrier, helping to insure that heavy equipment operation in and around the 

water is minimal. Stringers also foster the use of designated crossings, and 

help equipment operators locate and identify streams and other water bodies 

during site preparation and skidding.

There are no specific requirements for species, size or spatial distribution 

of trees left in the Stringer. However, trees left in the Stringer should favor 

hardwood species, potential den trees and snags, and to the extent possible, 

provide a continuous, connected canopy except for designated stream crossings. 

All trees which occupy the immediate stream bank should be included in 

the Stringer.
S i l v i c u l t u r e Best Management Practices 7

Perennial streams are those that have a well defined channel and maintain 

flow or continuous pools of water throughout most of the year under typical 

climatic conditions. This includes natural streams that have been altered by 

dredging and/or straightening (see Canal Section). For perennial streams, 

the overall Special Management Zone is composed of a Primary Zone and, 

depending on the SSC, possibly a Secondary Zone. The Primary Zone for 

perennial streams ranges in width from 35 to 200 feet, depending on stream 

width or type, as shown in Table 1. Primary Zone widths in Table 1 are given 

for one side of the stream only. However, the Zone is applied to both sides of 

the stream. In addition, where the stream is connected to the inflow and/or 

discharge point of a flowing wetland, the Zone extends an additional 50 feet 

beyond the defined channel into the wetland (Figure 4). The Primary Zone is 

measured from the stream, beginning at the break in slope at the top of the 

stream bank, out to the designated width. Stream width is the typical bank to 

bank width of the stream within the harvest unit, measured in feet.

Table 1: Primary Zone Widths for Perennial Streams 

Stream Width/Type Primary Zone

<20’ 35’ per side

20-40’ 75’ per side

> 40’ 200’ per side

OFW 200’ per side

Class I 200’ per side

ONRW 200’ per side

Selective timber harvesting is allowed within the Primary SMZ, consistent 

with the Primary Zone -Management Criteria. Clearcut harvesting is prohibited in the Primary SMZ, unless the operation qualifies as an exception as 

described in Appendix 11.

Depending on the SSC of the harvest unit, a Secondary Zone may also be 

required. If so, the Secondary Zone width is measured beginning at the outer 

boundary of the Primary Zone and continuing landward for the required 

distance as determined by the SSC (Appendix 1). Figure 1 shows examples of 

Primary and Secondary Zones on several different perennial streams, each with 

a different SSC. Note that where there is no Secondary Zone required, the 

Primary Zone is the total SMZ. Likewise, where the SSC is such that a Secondary Zone is required, the total SMZ width is the sum of the Primary Zone and 

Secondary Zone, up to a maximum of 300 feet.

Application of SMZs: Perennial Streams
8 S i l v i c u l t u r e Best Management Practices

Figure 1