United States

Department of

Agriculture

Forest Service

Southern

Research Station

General Technical

Report SRS-44

Southern Pine

Seed Sources

R.C. Schmidtling
August 2001

Southern Research Station

P.O. Box 2680

Asheville, NC 28802

The Author

Front cover: A provenance test in southern Arkansas at age 25 years

(Wells and Lambeth 1983). The trees on the right are from the nearby,

southeast Oklahoma seed source; those on the left are from the Coastal

Plain of South Carolina.

Back cover: The Southeastern portion of the U.S. Department of

Agriculture (1990) Plant Hardiness Zone Map to be used to more

accurately determine minimum temperatures for seed transfer.

R.C. Schmidtling, Research Geneticist, U.S. Department of Agriculture,

Forest Service, Southern Research Station, Saucier, MS.
Southern Pine Seed Sources

R.C. Schmidtling

iii

Foreword

The purpose of this handbook is to guide landowners and consulting foresters in selecting appropriate seed sources for planting

southern pines. It replaces the booklet “A Guide to Southern Pine Seed Sources” written by Clark Lantz and John Kraus (1987).

Both are now retired from USDA Forest Service. Important changes based on more recent research have been made. The biggest

changes are in the seed movement guidelines themselves. The new guidelines avoid the term “zones” because it implies distinct

boundaries. North-south variation in growth and survival traits is considered continuous (clinal), and east-west movement to

areas of similar climate is generally permissible, with some major exceptions for loblolly pine.

The Geographic Variation and Seed Movement Subcommittee of the Southern Forest Tree Improvement Committee guided the

writing of this handbook. The subcommittee is a cooperative of Federal, State, university, and industrial foresters organized in

1950 to foster information exchange in genetics and breeding of forest trees. Members of the subcommittee who guided the

development of this handbook, supplied information, and reviewed drafts are:

Ron Schmidtling, Chairman, USDA Forest Service, Southern Research Station, Southern Institute of Forest Genetics, Saucier,

MS;

Steve McKeand, North Carolina State University Tree Improvement Cooperative, Raleigh, NC;

Tim LaFarge and George Hernandez, USDA Forest Service, Southern Region, Atlanta, GA;

Clem Lambeth and Mike Waxler, Weyerhaeuser Company, Hot Springs, AR;

Bill Lowe and Tom Byram, Western Gulf Forest Tree Improvement Program, Texas Forest Service, College Station, TX;

Siroos Jahromi and Richard Bryant, International Paper Company, Southlands Experimental Forest, Bainbridge, GA;

George Rheinhardt, Arkansas Forestry Commission, Little Rock, AR; and

Tim White (ex officio), University of Florida Cooperative, Forest Genetics Research Program, Gainesville, FL.

Sponsored Publication Number 49 of the Southern Forest Tree Improvement Committee.

v

Table of Contents

Page

Foreword ....................................................................................................................................................................... iii

Introduction ................................................................................................................................................................... 1

Select the Best Species for Your Site ......................................................................................................................... 1

What Causes Geographic Variation in Southern Pines? ............................................................................................ 2

Fusiform Rust............................................................................................................................................................. 2

Capitalizing on Genetic Improvement......................................................................................................................... 3

Risks and Benefits of Moving Seeds and Seedlings ................................................................................................. 3

Getting Help ............................................................................................................................................................... 4

Seed and Seedling Certification ................................................................................................................................. 5

Gene Conservation .................................................................................................................................................... 5

General Seed Movement Guidelines .............................................................................................................................. 6

Loblolly Pine .................................................................................................................................................................. 6

Geographic Variation .................................................................................................................................................. 6

Genetic Improvement ................................................................................................................................................. 7

Recommended Sources .............................................................................................................................................. 8

Slash Pine....................................................................................................................................................................... 9

Geographic Variation .................................................................................................................................................10

Genetic Improvement ................................................................................................................................................11

Recommended Sources .............................................................................................................................................11

Longleaf Pine ................................................................................................................................................................12

Geographic Variation .................................................................................................................................................13

Genetic Improvement ................................................................................................................................................14

Recommended Sources .............................................................................................................................................14

Shortleaf Pine ................................................................................................................................................................14

Geographic Variation .................................................................................................................................................14

Genetic Improvement ................................................................................................................................................14

Recommended Sources .............................................................................................................................................14

Virginia Pine ..................................................................................................................................................................15

Geographic Variation .................................................................................................................................................16

Genetic Improvement ................................................................................................................................................16

Recommended Sources .............................................................................................................................................17

Sand Pine ......................................................................................................................................................................17

Geographic Variation .................................................................................................................................................17

Genetic Improvement ................................................................................................................................................17

Recommended Sources .............................................................................................................................................17

Other Species and Hybrids .......................................................................................................................................... 18

Literature Cited ............................................................................................................................................................ 20

Glossary ....................................................................................................................................................................... 24

1

Abstract

The selection of an appropriate seed source is critical for successful

southern pine plantations. Guidelines for selection of seed sources are

presented for loblolly (Pinus taeda L.), slash (P. elliottii Engelm.),

longleaf (P. palustris Mill.), Virginia (P. virginiana Mill.), shortleaf (P.

echinata Mill.), and sand [P. clausa (Chapm. ex Engelm.) Vasey ex

Sarg.] pines. Seed movement guidelines in this handbook are based on

climatic similarities between the seed source origin and the planting

site. Because yearly average minimum temperature is the most

important climatic variable related to growth and survival, it has been

used to define the rules of seed movement. This variable, which

defines plant hardiness zones, has been used for many years by

horticulturists to guide the transfer of plant materials. East-west

movement to areas of similar climate is permissible, with the

exception of loblolly pine.

Keywords: Fusiform rust, geographic variation, loblolly pine,

longleaf pine, provenance tests, sand pine, seed movement, seed

sources, shortleaf pine, slash pine, Virginia pine.

Introduction

Establishing a forest plantation is hard work and expensive.

The site must be properly prepared for planting. Seedlings

must be bought, cared for before they are planted, and

carefully placed in the ground, one at a time. Finally, as it

develops, the plantation must be protected from insects,

disease, fire, and competing vegetation. The cost of the

seedlings is only a small part of the total expense. Yet a poor

choice of planting stock frequently reduces the productivity

of plantations and sometimes causes outright failures.

Choosing the proper species for the planting site is only the

first of several choices. Among southern pines, the most

commonly planted species in the Southern United States,

seed source is also important. If you are in coastal South

Carolina, should you plant stock from local, Virginia, or

Louisiana seeds? This handbook can help you to make these

critical choices for southern pines and hybrids. It also gives

specific guidelines for the six most common pine species:

loblolly (Pinus taeda L.), slash (P. elliottii Engelm.), longleaf

(P. palustris Mill.), Virginia (P. virginiana Mill.), shortleaf (P.

echinata Mill.), and sand [P. clausa (Chapm. ex Engelm.)

Vasey ex Sarg.].

Research shows that seed source can govern survival and

subsequent growth of southern pines. Perhaps the most

important early results came from Philip C. Wakeley’s 1927

Bogalusa planting. He showed that through age 22, loblolly

pines grown from local seeds (Livingston Parish, LA)

Southern Pine Seed Sources

R.C. Schmidtling

produced about twice the wood volume as those grown from

Arkansas, Georgia, and Texas seeds. These differences

persisted through age 35 (Wakeley and Bercaw 1965).

Following Wakeley’s pioneering study, much work was done

to learn about geographic variation in southern pines,

including the Southwide Southern Pine Seed Source Study

(SSPSSS) initiated in 1951 by the Southern Forest Tree

Improvement Committee to discover the patterns of

geographic variation in the southern pines (Dorman 1976;

Schmidtling 1995; Schmidtling and White 1990; Wakeley

1961; Wells 1969, 1983; Wells and Wakeley 1966).

These studies showed that southern pine species react to

differences in environmental conditions by developing

different traits in different places through the process of

natural selection. Therefore, some races of southern pines

may grow faster in certain areas, whereas others may be

more resistant to disease or more tolerant of cold. The

recognition of these patterns of geographic variation was

the first step in the genetic improvement of the southern

pines. All successful southern pine breeding programs take

into account geographic variation before utilizing withinpopulation genetic variation. Important gains in growth and

disease resistance can result from simply selecting the best

seed source for a given planting location. With many

species, additional gains can result from using the improved

stock developed by tree breeding programs.

Planting seedlings from a seed source that is poorly adapted

to the site and climatic conditions can cause devastating

losses. Even if the trees survive, their reduced growth will

mean lower yields throughout the timber rotation.

Postponing planting for a year would be more profitable than

risking the results of planting ill-adapted seedlings.

Select the Best Species for Your Site

Choosing the species for site regeneration is often your

most critical decision. If healthy, fast-growing trees are

abundant on the site, the safest choice is usually to replant

the same species. However, faced with no trees or with only

a few trees that are slow growing, poorly formed, and

obviously not well suited to the site, you will be wise to

consider another species or possibly another seed source of

the same species. Avoid the common mistake of planting a

single species over a large area without considering the

variation in site quality within the area (Balmer and Williston

1974). The best indicator for success on a particular site is a

healthy, vigorous plantation growing on a similar site. Good
2

survival and growth through at least half the rotation usually

is a reliable predictor of success.

Other important considerations are the primary product

desired, secondary uses such as hunting or grazing, and

local fire and disease hazards.

The following checklist may be helpful in choosing a

species:

Are pines already growing in the area?

What species are they?

Are these trees healthy and fast growing?

What products do you desire?

Will the land be hunted or grazed?

Is the area prone to local disease hazards?

Is the land vulnerable to wildfire or arson?

What is the likelihood of flooding, extreme drought, or ice

storms?

Careful consideration of these questions should help you

select the best species to plant, as should the classic

textbooks on species selection by Balmer and Williston

(1974) and Dorman (1976).

What Causes Geographic Variation in Southern Pines?

In general, the natural distribution of southern pine species

is limited to the north by low temperature and to the west by

low rainfall. Within these limits, native races have developed

that are adapted to the local climate. This adaptation to local

climatic variation is generally referred to as geographic

variation.

Geographic variation of the major southern pine species has

been well studied. Seed collected from different geographic

areas vary greatly in their potential for growth and survival,

depending upon where they are planted. Although a

conservative approach would be to rely on locally obtained

seed, native sources are not always the best, especially for

economically important traits. For instance, seed source

studies of forest tree species often show that seed sources

from warmer climates tend to grow faster than local sources,

if the difference in climate is not great. In loblolly pine, this is

at least partly due to the warm-climate sources growing

longer in the fall than the sources from colder climates

(Jayawickrama and others 1998).

Climatic modeling of data from many southern pine seed

source studies has shown that the most important factor

influencing growth and survival within natural ranges is

average yearly minimum temperature at the seed source

(Schmidtling 1997). Horticulturists have used this climatic

variable, not coincidentally, to determine plant hardiness

zones (U.S. Department of Agriculture 1990). These zones

help predict the probable success of planting ornamentals.

They are also the basis of the seed transfer guidelines in this

publication.

For the three southern pine species that occur naturally on

both sides of the Mississippi River, only one—loblolly

pine—has important differences between eastern and

western sources. This difference between loblolly pine and

other species is probably rooted in the Pleistocene geologic

era. During the last ice age, which lasted 100,000 years and

ended 15,000 years ago, the South was covered by a boreal

forest and the southern pines grew south of their present

location. Patterns of genetic variation in allozymes indicate

that longleaf resided in one refugium in south Texas and or

north Mexico and migrated northward and eastward when

the ice retreated (Schmidtling and Hipkins 1998). Loblolly

pine probably originated from two isolated refugia, one in

southeast Texas and or northeast Mexico, and the other in

south Florida and or Caribbean (Schmidtling and others

1999). The 100,000-year isolation of the two populations in

differing environments resulted in the differences we see

today.

Soil has little effect on seed source variation in southern

pines. For instance, longleaf stands from deep sand sites do

not differ in adaptive traits from nearby stands on heavier

soils (Schmidtling and White 1990). Similarly, wet-site

ecotypes in loblolly pine do not seem to exist, although

some individual genotypes are well adapted to wet sites.1

This lack of ecotypic differentiation, which is not surprising

in light of studies showing extensive long-distance pollen

flow in southern pines (Friedman and Adams 1985),

simplifies seed transfer.

Fusiform Rust

Fusiform rust [Cronartium quercuum (Berk.) Miyabe ex

Shirai f. sp. fusiforme] is a disease that inflicts heavy damage

on loblolly and slash pines. It has also been known to infect

longleaf pine, but so rarely that it is not considered a

problem. In areas of high rust hazard, landowners and

1

 Personal communication. 1999. C.G. Williams, Associate Professor,

Genetics Department, Texas A&M University, College Station, TX

77843.
3

foresters often had to choose between unimproved

seedlings with some natural resistance to fusiform rust and

susceptible but faster growing seed orchard seedlings.

Fortunately, seed orchards are now producing enough seeds

of fast-growing, rust-resistant sources to satisfy most

planting requirements throughout the South. In high-hazard

areas where local shortages of resistant, improved seedlings

exist, it may still be necessary to choose between seedlings

from rust-susceptible orchards that have been genetically

improved for growth rate and form or to use seedlings from

unimproved but resistant woods-run seeds, e.g., Livingston

Parish or east Texas loblolly. Ideally, the decision should be

made by integrating several factors: degree of improvement

in traits expected from orchard seeds (other than resistance),

degree of improvement expected in resistance from woodsrun seeds, and the hazard rating of the area to be planted.

Research aimed at quantifying this decision is now

underway. Growth-and yield-models incorporating fusiform

rust can be used in this effort (Nance and others 1983) as

well as economic analyses (Bridgwater and Smith 1997).

Capitalizing on Genetic Improvement

Tree improvement programs have been initiated all across

the South and have been successful in securing substantial

genetic gains in growth and form. In many programs,

second- and third-generation breeding cycles are in

progress. Seed orchards established to supply genetically

improved seeds are now producing enough seeds to satisfy

most planting needs in the South.

A tree is selected for seed orchard use on the basis of its

performance in competition with its neighbors on specific

sites for a specific period of time. Although the majority of

these sites are on the Coastal Plain, some may not be typical

sites. Planting a sufficiently large number of trees in the

orchard ensures some degree of variation in the selection

process. The resulting natural cross-pollination within the

orchard will create many new genotypes that should be

adapted to a wide range of planting sites.

Progeny tests estimate the breeding value of the selected

trees. If the progeny of certain selections do not perform

well, the grafts of those selections will be rogued (removed)

from the orchard. If the test sites are a good representation

of regeneration sites, the progeny tests will save the expense

of planting the poorly adapted families.

If the progeny of a select tree performs well on one site but

poorly on another site compared with other seedlings, the

cause is often a genotype X environment interaction. These

genotype X environment interactions have usually been

small in most southern pine progeny tests, suggesting that

seed orchards are producing trees with a wide range of

adaptability (Li and McKeand 1989, McKeand and others

1997).

Risks and Benefits of Moving Seeds and Seedlings

Moving seeds or seedlings to an area where they have not

been tested involves some degree of risk, whether the

source is orchard seeds or woods-run seeds. Drought, ice, or

extreme cold can devastate trees from seed lots that are not

adapted to that specific hazard. The decision to plant fastgrowing seedlings that may not be adapted to local hazards

should only be made after comparing the potential gain with

the risk of loss.

Some have elected to accept some risk in the belief that the

additional wood produced by fast-growing sources will

outweigh the possible loss (fig. 1). For example, loblolly

seedlings from North Carolina coastal seed orchards have

prospered for many years in Oklahoma and Arkansas

(Lambeth and others 1984). In addition, a 25-year study in a

south Arkansas plantation showed that a South Carolina

source outperformed an Oklahoma source by 10 to 20 feet

(ft) (Wells and Lambeth 1983). Gains have been reported with

other Atlantic coastal loblolly sources (Lantz and Hofmann

1969, Wells and Switzer 1971). Likewise, Livingston Parish

loblolly seedlings planted over hundreds

of thousands of acres in the southern Coastal Plain have

exhibited both substantial rust resistance and good growth

rates (Wells 1985).

Specific seed orchard families of nonlocal and distant

sources that grow faster in their new environment than many

local families may also have an acceptable level of

adaptation. If adaptation risk is significant, avoid the use of

the nonlocal family until progeny tests have shown at least

15 years of excellence in survival and growth.

A related, more philosophical, issue in seed transfer risk is

how nonlocal genotypes will affect the native gene pool.

Even if these trees are harvested completely in a pulpwood

rotation, their pollen will affect the seed produced in

surrounding native stands. Certainly, the resulting increase

in genetic diversity would add value. Recent studies suggest

new characteristics are being introduced into native stands

in Arkansas, perhaps from the Atlantic coastal seed sources

being planted there (Schmidtling and others 1999). Arkansas

seed sources are naturally resistant to fusiform rust; Atlantic

coastal sources are not. Could the transfer of Atlantic

coastal sources to Arkansas result in increased rust in
4

naturally regenerated native stands? Certainly the

susceptibility of the native stands could be increased, but

one of the reasons there is little fusiform rust in Arkansas is

its dry climate. The high humidity required at the time of

infection (Snow and Froelich 1968) is rare in Arkansas and is

likely to become rarer because most global change scenarios

predict that the climate in Arkansas will be drier in the future

(Prentice and others 1992). Countering the rust threat would

be the positive effect of increasing genetic variability in the

native stands. Genes conferring poor adaptability would

eventually be eliminated by natural selection.

Planting nonlocal seeds or seedlings can have long-term as

well as immediate consequences. Even well-established

plantation programs encounter new hazards, for example,

Dothistroma needle blight (Mycosphaerella pini) in

Monterey pine (P. radiata D. Don.) plantings in Brazil, South

Africa, and New Zealand (Zobel and Talbert 1984). In

addition, new pathogens or disastrous weather patterns can

radically change survivability and productivity. Witness the

growing concern over pitch canker in the South and recently

on the west coast (Storer and others 1994) and the frequent

hurricane damage on the gulf coast.

Getting Help

Because they serve a diversity of interests, State forestry

organizations take a more conservative approach to seed

acquisition than forest industry. Few nonindustrial private

forest landowners have access to advice on the specific

Figure 1—Major seed movement of southern pines since the Great Depression. Natural distributions of species adapted from Critchfield and Little (1966);

minimum temperature isotherms from USDA (1990).

MS

AL

GA

MO

TX

OK AR

LA

TN

FL

SC

NC

VA

WV

PA

MD

25

25

20

20

20

20

15

15

10

10

5

5

0

0

KY

IL

IN

OH DE

NJ

-5

-5

-10

-10

30

30

35

2

1

1

3

Natural distribution of loblolly pine

Limits of the natural distribution of slash pine

Area of high (>50% rust) fusiform rust incidence

(Squillace 1976)

Wet-site tolerant slash pine

Rust-resistant Livingston Parish, LA, loblolly

1 Fast-growing Atlantic Coast loblolly

2

3

25 25 Minimum temperature isotherms (°F)
5

in which the selected trees have been progeny tested and the

poorest trees removed on the basis of the test results.

2. Selected tree seeds (green tag). These tree seeds are from

untested but rigidly selected trees or stands that have

potential, but not proof, of genetic superiority.

3. Source-identified seeds (yellow tag). These seeds may be

from natural stands, plantations of known provenance, or

seed production areas of known geographic origin. Only the

geographic location is certified.

The international certification of forest reproductive material

is governed by the Organization for Economic Cooperation

and Development (Rudolf 1974).

Gene Conservation

Much has been written in recent years about conservation

of gene pools in breeding programs. With the exception of a

few isolated populations, none of the southern pines are

threatened or endangered. However, longleaf pine has been

placed on a list of vulnerable species (Farjon and Page 1999),

because the occurrence of the species has been greatly

diminished since the turn of the century.

In general, southern pines are highly variable and widely

adapted. Forests in the South contain a rich gene pool that is

not likely to be depleted by tree breeding. Although tree

improvement programs concentrate on genes and gene

complexes that are only a sample of the entire gene pool,

they also conserve genetic resources in clone banks, seed

orchards, and genetic tests. They create new genetic

variability by breeding trees from widely separated areas and

using their offspring for reforestation. Much of the natural

gene pool of southern forest species is also preserved in the

preponderance of stands that are regenerated by natural

methods.

A successful program for encouraging the preservation of

existing southern gene pools and assuring a wide genetic

diversity for the future would

1. promote the use of genetically sound practices for all

forest stands regardless of how they are regenerated;

2. discourage practices, such as high grading and diameterlimit logging that promote the regeneration of genetically

inferior seedlings;

3. encourage landowners to leave enough of the highest

quality seed trees during natural regeneration to maintain

gene pool diversity;

seed sources that would be suitable for their own land.

Because far too few service foresters are in a position to

work with individual landowners, most State nursery

programs provide seedlings from local or nearby sources. In

the past, however, several States have grown loblolly

seedlings from Livingston Parish seed because of their good

fusiform rust resistance and fast growth.

With the exception of industry seed orchards that include

clones from nonlocal seed sources, the genetic quality of

clones in State seed orchards is equal to that in industry

seed orchards. All Southern State forestry agencies are

members of large cooperative tree improvement programs

and, thus, share genetic resources with industry

cooperators. While slight differences may exist in the choice

of clones for inclusion into seed orchards, the clones are

selected from a common genetic base.

If nonlocal genotypes prove to be well adapted over a range

of sites and are superior to local genotypes based on longterm trials, then both State agencies and industry will usually

use them. To illustrate, for sites in Alabama and the lower

gulf coast (Sierra-Lucero 1999), tree improvement foresters

now recognize that loblolly seedlings from the Atlantic

Coastal Plain provide a high-return, low-risk alternative to

seedlings from the lower gulf coast. In the lower gulf Coastal

Plain, future orchards will include a mix of the best clones

whether they come from the Atlantic coast or from the lower

gulf.

Seed and Seedling Certification

Certification programs identify and control the quality of

forest tree seeds and seedlings (Barber 1975). Most States in

which southern pines are major species have laws to certify

forest tree seeds. Under these laws, certification is available

for seeds originating in natural stands, seed production

areas, or seed orchards. Some seed orchard certifications

include the expected amount of improvement in growth and

disease resistance.

Certified seeds must also meet established standards of

purity, percentage of filled seed, and germination. These

requirements protect the buyer and encourage the seller to

offer only seeds of known origin and quality.

Most States have established three levels of seed

certification:

1. Certified tree seeds (blue tag). These seeds are produced

from trees of proven genetic superiority using methods that

assure genetic identity. They are usually from seed orchards
6

delineate approximately 5 o

F intervals, they are purposely

shown in dotted lines to emphasize that minimum

temperatures vary continuously from south to north and

from coastal to inland areas (see back cover).

Loblolly Pine

Loblolly pine is the most widely planted southern pine,

producing over half of the total softwood volume (Dorman

1976) and accounting for about 80 percent of all southern

pine seedling production in the United States (Boyer and

South 1984). It is also commonly planted in China, South

America, Australia, and southern Africa.

Within its natural range, which extends from southern New

Jersey to southeast Texas (fig. 2), loblolly pine occupies a

great diversity of sites. It grows faster than any of the other

southern pines on well-drained, productive sites. It is not the

best choice, however, on poor sites such as very dry sands

or on wet flatwoods (Shiver and others 2000).

Geographic Variation

Geographic variation in loblolly pine is more complex than in

the other southern pines because of important differences

between eastern and western seed sources. Geographic

variation has been well documented for growth rate, disease

resistance, cold tolerance, drought resistance (Dorman 1976),

and stem form (Schmidtling and Clark 1989). Loblolly pines

from west of the Mississippi River are usually slower

growing than east coast varieties, but they are more resistant

to fusiform rust and drought (Wells 1985) and more tolerant

of crowding (Schmidtling 1988, Schmidtling and Froelich

1993).

The slower growth of the western sources is undoubtedly

part of an evolved drought-avoidance tactic. The slower

relative growth of shortleaf and longleaf pines may also be a

manifestation of this tactic, as those two species often grow

on droughty sites (deep sand in the case of longleaf, shallow

and rocky soils for shortleaf). The natural ranges of shortleaf

and longleaf pines, however, do not extend as far west into

the drought-prone regions of Texas as loblolly pine,

explaining why loblolly has a higher drought tolerance.

Dendrochronological analyses of loblolly provenance tests

have shown that the western seed sources cease growth

immediately at the onset of a drought, whereas the eastern

varieties tend to keep growing (Grissom and Schmidtling

1997).

4. keep the public informed about the risks of planting

poorly adapted seeds or seedlings; and

5. monitor status of minor, threatened, and endangered

forest species; establish natural areas for the preservation of

these species if necessary; and plant these species

whenever suitable sites are available.

General Seed Movement Guidelines

Southern pine species vary widely in natural range,

economic value, and degree of genetic improvement. This

section describes the natural range, geographic variation,

genetic improvement, and recommended planting areas and

seed sources for the southern pine species that are

commonly used in forest plantations: loblolly, slash,

longleaf, Virginia, shortleaf, and sand.

Local conditions such as soils, slope, and competing

vegetation must be carefully considered in any site analysis.

The planting recommendations in this section are based on

the majority of sites within the area, but it is important to be

aware of local exceptions.

The seed movement recommendations in this handbook are

based on the degree of climatic similarity between the seed

source origin and the planting site. Because climatic

modeling using provenance test data from a number of

southern pine species has shown that the most important

climatic variable related to growth and survival is the yearly

average minimum temperature, the minimum temperature

isotherms shown on the map on the back cover of this report

have been used to define the rules of seed movement. The

isotherms define plant hardiness zones that, for many years,

have guided horticulturists in transferring plant materials

(U.S. Department of Agriculture 1990). Although they

General Guidelines

Seedlings will survive and grow well if they come from

any area having a minimum temperature within 5 oF of the

planting site’s minimum temperature. Seedlings from an

area with warmer winters will grow faster than seedlings

from local sources; seedlings from an area with cooler

winters will grow slower (Schmidtling 1994). The

difference in winter lows can be as much as 10 oF, but with

increased risk of damage at the cold end of the range and

growth loss at the warm end. East-west transfers within

districts are usually successful, and in some instances

may be desirable if improved stock is available.
7

Loblolly pines from west of the Mississippi River and from

the northeastern extremity of their range (Maryland and

Virginia) are the most resistant to fusiform rust. Seed sources

from just east of the Mississippi River, in southeast

Louisiana and southwest Mississippi, centered around

Livingston Parish, LA (Wells and others 1991), are

moderately resistant. All other loblolly populations are

generally susceptible, with the exception of resistant families

(McKeand and others 1999). Of the rust-resistant seed

sources, only Livingston Parish produces loblolly pines that

grow as fast as the populations from the Atlantic and gulf

coasts. Livingston Parish seedlings are prone to cold and ice

damage, however, and tend to exhibit poor form if planted

north of the 10 o

F minimum temperature isotherm (Wells 1985,

Wells and Lambeth 1983).

The loblolly pine planting areas have been divided into three

districts to reflect the complexity of that species’ geographic

variation (fig. 2). The eastern district is east of the

Mississippi River, and the Texas and or Louisiana-Arkansas

border separates the western and far-western districts

somewhat arbitrarily. Because it is more likely to experience

drought, the far-western district produces seedlings that are

more drought tolerant (Long 1980).

Genetic Improvement

Because of loblolly pine’s commercial importance, its

breeding and planting programs are the largest in the world.

Genetic improvement of loblolly pine started in the mid-1950s

with the establishment of seed production areas and seed

orchards. Seed production areas were high-quality natural

stands thinned to the best 10 to 20 trees per acre and

managed for cone production. Although the genetic gain

calculated from seed production areas was small (Easley

1963), they were convenient sources of seeds from aboveaverage trees in known geographic areas.

Figure 2—Loblolly pine distribution with seed transfer guidelines. Natural distributions of species adapted from Critchfield and Little (1966); minimum

temperature isotherms from USDA (1990).

25 25 Minimum temperature isotherms (°F)

Natural distribution of loblolly pine

Seed transfer guidelines

Eastern

Western district

district

Far-west

district

MO

TX

OK AR

LA MS

TN

AL

FL

GA

SC

NC

VA

WV

PA

MD

25

25

20

20

20

20

15

15

10

10

5

5

0

0

KY

IL

IN

OH DE

NJ

-5

-5

-10

-10

30

30

35
8

Seed orchards of loblolly pine were established primarily by

grafting. The parent trees were selected for fast growth,

good form, high-quality wood, and no insect or disease

symptoms. Progeny tests indicate first-generation gains of

from 10 to 20 percent in volume and up to 32 percent in value

(Talbert and others 1985) as well as significant gains in the

second and third generations (Li and others 1999). Although

fusiform rust losses can still be high, breeding programs and

the use of western seed sources have decreased the

incidence of fusiform rust in the South (Pye and others 1997)

and seeds from first- and second-generation seed orchards

are currently available on the open market.

Information from progeny tests is especially important in

assessing the suitability of improved seed. For instance,

orchard selections from the lower gulf area of the North

Carolina State University Cooperative have performed below

expectations (Sierra-Lucero 1999). These selections are from

southern Alabama and adjacent Mississippi between 5 and

15 o

F in minimum temperature (fig. 2), and should perform

about the same as selections from the Coastal Plain of North

and South Carolina. The reason for their disappointing

performance is not known but it may be related to

clearcutting practices that started around the turn of the

century or gene flow from slower growing western

populations (Schmidtling and others 1999). Selections from

nearby Livingston Parish, however, do perform well

compared to Atlantic coastal sources (Schmidtling and

Nelson 1996, Wells and Wakeley 1966).

Recommended Sources

Unless you intend to practice intensive management, your

safest choice would be to use seed sources from within your

district. Transferring seed sources from the eastern to the

western district would introduce danger of losses due to

drought and fusiform rust damage. By the same token,

transferring seed from the west to the east may be warranted

for droughty sites or areas with high fusiform rust incidence

(see General Guidelines). Keep in mind, however, that the

western sources generally grow slower.

Within a district, the same General Guidelines apply for

transferring improved seed and unimproved seed although

seedlings from progeny-tested seed orchards are always

preferred. If advanced generation selections have been

derived from controlled crosses of superior trees from areas

of different minimum temperature, use the average of these

two temperatures to assess the suitability of the seed

sources.

High-rust-hazard sites—The first choice for high-rusthazard sites would be seedlings from progeny-tested and

rogued seed orchards, which include exposure to a highrust-hazard site. If improved seed are not available, sites with

minimum temperatures above 10 o

F would be hospitable for

seeds from Livingston Parish or east Texas. On Coastal Plain

sites, longleaf pine would be an excellent alternative.

Sandhills sites—Sandhills sites are a real challenge for

reforestation. Often the key to success is the correct

analysis of the site followed by the correct choice of species

and seed source. Species alternates include longleaf pine

(Dennington and Farrar 1983), Choctawhatchee sand pine

(Outcalt and Brendemuehl 1985), and drought-hardy loblolly

pine from Texas (Jett and Guiness 1992).

Carolina sandhills sites have traditionally been planted with

either longleaf pine or slash pine even though slash pine

seedlings often begin well on deep sand sites only to

stagnate later. Choctawhatchee sand pine and droughthardy loblolly seedlings from Texas survived and grew better

than other loblolly sources and other species on South

Carolina sandhills sites after 17 years (Jett and Guiness

1992). The drought-hardy Texas loblolly source grew well

and had very little fusiform rust. Longleaf pine was the

original species on these sites and should be the preferred

species for the long term, if products beyond pulpwood are

desired. These results, however, provide some new

alternatives for regenerating sandhills sites.

Western sites—Several long-term tests have shown that the

eastern district produces faster growing loblolly pine than

the western and far-western districts (Wells 1983, Wells and

Lambeth 1983). Trees from some eastern sources have grown

about 8 ft taller than western trees in 25 years (Wells and

Lambeth 1983) (see front cover). Since the results of these

studies became well known, forest products manufacturers

have transferred substantial amounts of Atlantic coastal

seed sources to sites ranging from southern Arkansas and

General Guidelines

Seedlings will survive and grow well if they come from

any area having a minimum temperature within 5 oF of the

planting site’s minimum temperature. Seedlings from an

area with warmer winters will grow faster than seedlings

from local sources; seedlings from an area with cooler

winters will grow slower (Schmidtling 1994). The

difference in winter lows can be as much as 10 oF, but with

increased risk of damage at the cold end of the range and

growth loss at the warm end. East-west transfers within

districts are usually successful, and in some instances

may be desirable if improved stock is available.
9

southeastern Oklahoma to the Ouachita Mountains

(Lambeth and others 1984).

Seed source movement entails a certain amount of risk but

just how much is not certain. In the Wells and Lambeth

(1983) long-term tests, certain eastern sources suffered

heavy mortality at about age 20 compared to local sources,

which survived well. Survival was poorest for coastal Florida

sources that came from the mildest climates, but other

randomly distributed eastern sources were also hard hit. The

researchers suggested that the damage was caused by a

combination of very high stand densities and bark beetle

attack. Their results show that Atlantic coast sources of

loblolly can successfully grow in Arkansas and Oklahoma if

they are restricted to soils with good water retention and if

stands are kept thrifty by judicious thinning, competition

control, and fertilization. However, the level of management

required is generally available only in large industrial

holdings.

Planting loblolly from the Atlantic Coastal Plain is probably

not a viable strategy for nonindustrial landowners west of

the Mississippi River. Doing so requires the careful

assessment of the geographic location and site quality, with

emphasis on moisture-holding capacity. It also requires the

resources to carry out thinnings for as long as necessary

and the ability to absorb losses in severe drought years.

Northern sites—Loblolly pine has grown successfully north

of its natural range if planted according to the General

Guidelines. In western Kentucky and western Tennessee,

Barbour (1980) showed that loblolly seedlings from northern

Mississippi, northern Alabama, and northwestern Georgia

perform much better than other sources, and that sources

from eastern Virginia, northern North Carolina, and central

Arkansas also perform well.

In a provenance test in southern Illinois, a coastal South

Carolina source grew well and had satisfactory survival after

5 years (Wisehuegel 1955) and 10 years (Zarger 1961). By 35

years, however, only 3 percent survived, compared to

between 33 and 42 percent for the seed sources that

originated in Tennessee, northern Alabama, and northern

Georgia (Wells and Rink 1984). The southern Illinois site was

7 or 8 o

F cooler than the Tennessee seed source. Height

differences were not significant.

Minckler (1950) established a similar experiment in two colder

southern Illinois locations. After 27 years, survival of

sources from Maryland, Virginia, and Arkansas was about 60

percent compared to about 40 percent for Carolina and

Mississippi sources (Gilmore and Funk 1976). After 37 years,

survival averaged only 14 percent (Rink and Wells 1988).

Height differences were not significant. The Maryland

source in this experiment was from the most northern extreme

of the loblolly range, 11 to 15 o

F warmer than the two Illinois

locations. The other sources were from even warmer

locations.

Gilmore (1980) recommended that loblolly pine not be

planted north of the 180-day contour of frost-free days in

Illinois. As evidence, he cited a 30-year-old planting of a

Maryland source just 60 miles north of this contour that

suffered almost complete mortality in the record freeze of

1977. The fact that mortality was freeze-related reinforces

guidelines that stress average minimum temperatures rather

than growing season length. In Illinois, the 180-day isoline is

just north of the -10 o

F minimum temperature isotherm, 15 oF

colder than the Maryland seed source. For even the most

cold-hardy sources this represents a more drastic change

than recommended in the General Guidelines.

Slash Pine

Slash pine has the southernmost natural range of any of the

southern pines, extending from coastal South Carolina west

to eastern Louisiana and south to the Florida Keys (fig. 3).

The two recognized varieties are the South Florida slash pine

(P. elliottii var. densa Little & Dorman) and slash pine

(typical) (P. elliottii Engelm. var. elliottii), which occur from

central Florida northward. Commercially, the typical variety is

more important, as many active breeding and planting

programs worldwide are based on trees selected from this

variety.

The most important characteristic that distinguishes South

Florida slash pine variety from the typical variety is its early

delayed height growth, often referred to as a grass stage, a

term that is used to describe the early development of

longleaf pine. Although delayed height growth is probably

an adaptation to frequent fires in both species, their growth

patterns are quite different. Squillace (1966) found that 1-

year-old seedlings from north Florida averaged around 10

inches (in.) in height, while those from south Florida

averaged around 4 in. in height. Longleaf pine seedlings, on

the other hand, do not grow in height at all the first year,

unless hybridization with other southern pines is involved

(Lott and others 1996). The difference between longleaf pine

and slash pine of all races is evident very early. Germinating

longleaf seedlings have no hypocotyl, whereas all slash pine

have distinctive hypocotyls. Figure 3 implies a distinct

transition between the two varieties that is not really

accurate. In central Florida where the two varieties overlap,
10

all traits vary in a clinal pattern (Fisher 1983, Nikles 1966,

Squillace 1966) making it difficult to classify populations.

The southernmost source of the SSPSSS slash pine phase

was collected in the transition zone, but specifically

identified as a representative of the typical variety. However,

this source proved to have more characteristics in common

with the South Florida variety (Wakeley 1961). Cold

adaptation could certainly be a factor in varietal differences.

The 25 o

F minimum temperature isotherm (fig. 3)

approximates the transition between the two varieties. This

isotherm corresponds almost exactly to Squillace’s (1966) 8-

in. isoline for first-year seedling height growth, which is

used to distinguish the two varieties.

Geographic Variation

Typical variety—The major differences among slash pine

populations can be traced to the traits of the two varieties.

Differences within the more commercial typical variety are

small and difficult to detect. This is not surprising since most

of it is in an area where minimum temperatures vary by little

more than 5 oF. Goddard and others (1983) tested a number of

seed sources for geographic differences in two plantings at

the northern extreme of the slash pine range at age 10. The

sources from a narrow area running from coastal South

Carolina to southeastern Louisiana produced the tallest

trees, but the differences were small enough to be obscured

in tree improvement programs.

Predicting seed source success in warmer temperate climates

requires examining plantings outside the United States.

Barrett (1973) established extensive provenance tests of

slash pine in Argentina. In his tests, the best performing

sources were from an area just north of the transition to the

South Florida variety. Rockwood and others (in press) and

Schmidtling and others (1997) echoed these findings. Even

Figure 3—Natural range of slash pine showing minimum temperature isotherms. Natural distributions of species adapted from Critchfield and Little (1966);

minimum temperature isotherms from USDA (1990).

25 25 Minimum temperature isotherms (°F)

Typical variety

South Florida variety

TX

OK

MO

AR

LA MS

TN

AL

FL

GA

SC

NC

VA

WV

25

25

20

20

20

20

15

15

10

5 10

5

0

0

KY

IL

-5

-5

-10

30

30

35

-10 -5 -5 -5 -5
11

though the range of minimum temperatures within the

natural distribution of the typical variety is small, South

American tests show that the minimum temperature has the

same relationship with slash pine growth2 as other southern

pines (Schmidtling 1997) and that the same General

Guidelines apply for transferring seed sources. However,

these guidelines are really only relevant for seed sources

from peninsular Florida or in plantings outside the United

States, because of the small range in minimum temperatures

elsewhere.

South Florida variety—The South Florida variety was

named densa partly because of the higher specific gravity of

its wood (Little and Dorman 1952). This must have been an

environmental effect, however, since in common garden

studies the wood of the typical variety has higher specific

gravity (Saucier and Dorman 1969). The most important

morphological traits distinguishing the two varieties are

seedling traits such as a thicker stem and delayed height

growth (Little and Dorman 1954).

When planted within the natural range of the typical variety,

the South Florida variety has much lower productivity than

the typical variety (Snyder and others 1967), showing that

movement of seed sources from warmer climates does not

always produce faster growth. Keep in mind, however, that

moving the South Florida variety northward to where most

of the provenance tests were located usually involved a

minimum temperature change move of more than 10 o

F.

Unfortunately, definitive studies involving the South Florida

variety planted in south Florida are lacking. Squillace’s

(1966) planting near Ft. Meyers was destroyed by fire at an

early age, as was the SSPSSS planting near Tampa (Wakeley

1961). The best trials involving the South Florida variety are

in Africa, where Mullin and others (1978) showed that

although the typical variety had superior growth and

productivity in the highlands, the South Florida variety

performed best in the lowlands. Anecdotal evidence also

supports the view that the South Florida variety does as well

as, or better than the typical variety in southern Florida.3

Fusiform rust—No clear geographic pattern of fusiform rust

resistance has been identified within the natural range of the

typical variety (Goddard and others 1983). Much less natural

resistance exists in slash pine than in loblolly pine. Doudrick

and others (1996) showed that the South Florida variety is

even more susceptible to fusiform rust than the typical

variety, a trait it shares with its closely related neighbor,

Caribbean pine (P. caribaea Morelet).

Genetic Improvement

Typical variety—Slash pine seedlings from first- and

second-generation seed orchards are available on the open

market. In addition to improved growth rate, an important

regeneration need is for improved resistance to fusiform rust.

Kraus and LaFarge (1984) found that seedlings from firstgeneration slash pine seed orchards demonstrated

substantial growth gains, but that fusiform rust infection

rates were higher than expected even though selection for

rust-free phenotypes was incorporated in all programs. All

tree improvement programs test their selections for

susceptibility to rust at the Resistance Screening Center

(Anderson and Powers 1985), as well as in progeny tests.

Rust-resistant slash pine seedlings are usually available for

planting in high-hazard areas.

South Florida variety—A small tree improvement program

for the South Florida variety was established, but the

orchard location was not conducive to seed production (see

footnote 3). A better location has been selected, but seed

will not be available for some time.

Recommended Sources

Within the natural range of typical slash pine, guidelines for

seed movement are not very critical. Most of the commercial

range of typical slash pine above peninsular Florida hardly

varies by more than 5 o

F in minimum temperature. The same

General Guidelines apply for transferring either seed orchard

or unimproved seed. Because of the limited distribution of

slash pine, the guidelines make little difference except at the

edges of the distribution. The most important seed source

recommendation is to avoid the South Florida variety for

plantings north of Tampa, FL. The typical variety will

perform much better. The South Florida variety should be

considered for planting south of Tampa, however.

The most common commercial seed source of slash pine—

encompassing southern Georgia and northern Florida—

shares a few characteristics with the South Florida variety in

that it is less drought hardy and less cold resistant than

slash pine from the northern or western extremities of the

range (Snyder and others 1967), located north of the 15 oF

minimum temperature isotherm (fig. 3). These characteristics

are of little importance if the plantings are to be made within

the natural range of slash pine where drought and cold do

2

 Schmidtling, R.C. Geographic variation in the southern pines.

Manuscript in preparation. U.S. Department of Agriculture, Forest

Service, Southern Research Station, Saucier, MS.

3

 Personal communication. 2000. Jim Bryan, Manager, Forestry

Division, Lykes Brothers Forestry, P.O. Box 102, Palmdale, FL

39574.
12

not reach critical levels, but could become important if

plantings are north or west of the natural range. When

planting north or west of the species’ natural range, choose

seeds from South Carolina, Mississippi, or Louisiana or from

areas north of the 15 oF minimum temperature isotherm. For

well-drained sites, improved loblolly pine may grow and

survive better and should be considered.

The Civilian Conservation Corps planted many thousands of

acres of slash pine west of the Mississippi River during the

Great Depression. More recently, the Western Gulf Forest

Tree Improvement Program and USDA Forest Service,

Southern Region Tree Improvement Program have used

selections from these old plantings to develop a land race of

improved slash pine suitable for planting west of the

Mississippi River. Planting of slash pine west of the river is

usually limited to wet (flatwoods) sites, however.4

Considering the lack of definitive provenance-test data from

central Florida southward, sources from within 5 oF

temperature are safest. Dorman (1976) had limited data to

support his recommendation that seeds from the latitude of

Alachua County (Gainesville) were best suited for sites

south of Tampa. Certainly, plantings of the typical variety

within the range of the South Florida variety have been

successful, but the long-term value of this transfer is in

question, especially given the high incidence of pitch canker

(Fusarium moniliforme Sheld. var. subglutinans Wollenw. &

Reink) observed when more northern seed sources were

planted in southern Florida (Dorman 1976). Considering the

strong ecosystem restoration movement in south Florida, the

local variety would probably be a prudent choice. The South

Florida variety appears to be more susceptible to fusiform

rust (Doudrick and others 1996), but this disease is not a

problem in south Florida plantations.

Fusiform rust—When regenerating sites with a high

fusiform rust hazard, select seeds and seedlings according to

the following descending order of preference:

1. seed orchards specifically established for increased rust

resistance or rogued for increased rust resistance;

2. seed production areas established in highly infected

stands where selection of disease-free trees was intensive;

and

3. seed orchard cone collections restricted to the most rustresistant clones in the orchard.

Pitch canker—Natural stands in areas with a high incidence

of pitch canker have experienced strong selection pressure

against susceptible trees. Collecting seed from the best trees

in these local natural stands appears, therefore, to be the

best procedure for establishing stock with some resistance

to the disease (Goddard and others 1983). Another

alternative is to collect seeds from the most resistant clones

in established seed orchards (McRae and others 1985).

High gum yield—Tapping trees for gum naval stores is a

practice that has largely disappeared in the United States.

Currently, products formerly derived from gum are now

obtained from tall oil, a by-product of the pulping process. If

high gum yield were to become a primary management

objective again, seedlings would be available from State

seed orchards established for high gum yield. Most of these

orchards were established with plant material from the USDA

Forest Service naval stores breeding program at Olustee, FL.

These seedlings should produce about 50 percent higher

gum yields than nursery-run seedlings, with some

improvement in growth rate and yield of tall oil (Squillace

1965).

Longleaf Pine

Longleaf pine is adapted primarily to Coastal Plain sites from

southeastern Virginia to east Texas (fig. 4), where originally it

was the predominant species. The area of longleaf pine in

the South has declined from 12.2 to 3.8 million acres over the

past 30 years (Kelly and Bechtold 1990). It is the preferred

species on sandy sites and in many ways the most valued of

the southern pines (Croker 1990), and there is now a

concerted effort to restore longleaf to its historical and

4

 Personal communication. 2000. Tom Byram, Geneticist, Western

Gulf Forest Tree Improvement Program, Texas Forest Service,

College Station, TX 77843.

General Guidelines

Seedlings will survive and grow well if they come from

any area having a minimum temperature within 5 oF of the

planting site’s minimum temperature. Seedlings from an

area with warmer winters will grow faster than seedlings

from local sources; seedlings from an area with cooler

winters will grow slower (Schmidtling 1994). The

difference in winter lows can be as much as 10 oF, but with

increased risk of damage at the cold end of the range and

growth loss at the warm end. East-west transfers within

districts are usually successful, and in some instances

may be desirable if improved stock is available.
13

ecological prominence. Longleaf planting programs are also

being expanded by a number of organizations because the

species has excellent form, high-quality wood, and natural

resistance to fusiform rust.

Survival has long been a problem with planted longleaf. The

delayed height growth (grass stage) of this species is

unique. Seedlings need to be grown at low density in the

nursery and they require special care in storage,

transportation, and planting. However, more recent

silvicultural research has made the planting of longleaf pine

much more successful (Farrar 1990) and the use of

containerized seedlings has been very effective.

Geographic Variation

Although longleaf, like loblolly pine, grows on both sides of

the Mississippi River, geographic variation in longleaf pine

is less complicated and differences between eastern and

western sources are minor. Longleaf from west of the

Mississippi River is more susceptible to brown-spot needle

blight (Mycosphaerella dearnessii Barr) than longleaf from

the gulf coast east of the Mississippi River (Henry and Wells

1967), but this difference has had no impact on final yields

(Schmidtling and White 1990).

Growth of longleaf in provenance tests is well described by

the same seed transfer model as loblolly, with the lack of

east-west differences producing an even better statistical fit.

The longleaf pine model originated from a provenance test

that sampled the entire latitudinal range of seed sources and

planting sites from south Florida to north Georgia

(Schmidtling and Sluder 1995). Its results were verified with

25-year data from the rangewide SSPSSS longleaf phase

(Schmidtling 1997), as well as data from a north-south

Figure 4—Longleaf pine distribution with seed transfer guidelines. Natural distributions of species adapted from Critchfield and Little (1966); minimum

temperature isotherms from USDA (1990).

25 25 Minimum temperature isotherms (°F)

Natural distribution of longleaf pine

Seed transfer guidelines

TX

OK

MO

AR

LA MS

TN

AL

FL

GA

SC

NC

VA

WV

PA

MD

25

25

20

20

20

20

15

15

10

10

5

5

0

0

KY

IL

IN

OH DE

NJ

-5

-5

-10

-10

30

30

35
14

transect in Alabama (data from Duba and others 1984,

reanalyzed in Schmidtling 1997).

Some of the sampling for the SSPSSS longleaf phase was

specifically designed to determine if seed sources from deep

sand sites were better adapted to these sites than sources

from nearby sites with heavier soils (Schmidtling and White

1990). No differences were found. Similarly, the north-south

transect in Florida and Georgia (Schmidtling and Sluder 1995)

showed no differences attributable to physiographic

province.

Genetic Improvement

Although 443 acres of first-generation longleaf pine seed

orchards were established in the South by 1982 (Dennington

and Farrar 1983), very few improved seedlings are currently

available for sale, because of poor early seed production in

the orchards. This should change in a few years. Primary

emphasis has been on breeding for fast initial height growth

(a shorter grass stage) and resistance to brown-spot needle

blight, as these traits are very important in early survival.

Seeds from seed production areas are sometimes available.

The recommended seed movement guidelines should be

observed with seeds from either wild stands or orchards and

seed production areas.

Recommended Sources

The recommendations for seed transfer in longleaf pine

follow the General Guidelines.

Longleaf pine is seldom planted outside of its natural range

and is unlikely to succeed if planted west of its natural

range. Planting north of its natural range should be

successful if you follow the minimum temperature General

Guidelines.

Shortleaf Pine

Shortleaf pine has the most extensive natural range of any

southern pine, but its southern component produces only

half the wood volume of loblolly pine (Dorman 1976). The

natural range of the species extends from New York to

Oklahoma and Texas (fig. 5) over a very wide range of sites.

Shortleaf pine is resistant to all common southern pine

diseases except for littleleaf disease (Phytophthora

cinnamomi Rands).

Geographic Variation

The only rangewide provenance test in shortleaf pine is the

shortleaf phase of the SSPSSS (Wells 1979, Wells and

Wakeley 1970). Analysis of 25-year data showed that the

relationship between climate at the seed source and growth

was stronger than for any other southern pines, but that

east-west differences were not important (Schmidtling 1995).

Seed transfer guidelines are, therefore, based on the General

Guidelines.

Genetic Improvement

Primarily Southern State forestry organizations and the

USDA Forest Service have established clonal seed orchards

of shortleaf pine. The few orchards that forest industries

have established bring the total acreage to 667 (Kitchens

1987).

In recent years, the planting of shortleaf pine has decreased

because loblolly pine survives better and grows faster on

many former shortleaf sites (Lambeth and others 1984). In an

encouraging development, however, shortleaf survival was

22 percent higher for seed orchard than for nursery-run

seedlings on the Ouachita and Ozark National Forests

(Kitchens 1987).

Of the average of 22,600 acres planted annually to shortleaf

pine in the South, 18,500 are on national forests (Kitchens

1987) primarily in Arkansas, Georgia, Kentucky, and

Tennessee.

Seeds from shortleaf pine seed orchards are available from a

number of organizations. The same geographic restrictions

should be applied with seed orchard seeds as with wild

seeds. Genetic improvement is of little value if the seeds are

not well adapted to the planting site.

Recommended Sources

The recommendations for seed transfer in shortleaf pine

follow the General Guidelines.

General Guidelines

Seedlings will survive and grow well if they come from

any area having a minimum temperature within 5 oF of the

planting site’s minimum temperature. Seedlings from an

area with warmer winters will grow faster than seedlings

from local sources; seedlings from an area with cooler

winters will grow slower (Schmidtling 1994). The

difference in winter lows can be as much as 10 oF, but with

increased risk of damage at the cold end of the range and

growth loss at the warm end. East-west transfers within

districts are usually successful, and in some instances

may be desirable if improved stock is available.
15

Littleleaf disease is the only disease of any importance that

affects survival of shortleaf pine. Because of the erratic

nature of infection, resistance is difficult to incorporate into

a breeding program. In a seed source study of shortleaf pine

planted on littleleaf sites in Georgia, South Carolina, and

Virginia, Ruehle and Campbell (1971) found that upland

sources had fewer disease symptoms than coastal sources.

The Prince Edward County area in Virginia, an area

characterized by high incidence of littleleaf disease, was the

best overall source for all test plantings. The Prince Edward

source may have benefited from natural selection for disease

resistance similar to that cited by Goddard and others (1983)

in their recommendations for improving the resistance of

slash pine to pitch canker.

Figure 5—Shortleaf pine distribution with seed transfer guidelines. Natural distributions of species adapted from Critchfield and Little (1966); minimum

temperature isotherms from USDA (1990).

General Guidelines

Seedlings will survive and grow well if they come from

any area having a minimum temperature within 5 oF of the

planting site’s minimum temperature. Seedlings from an

area with warmer winters will grow faster than seedlings

from local sources; seedlings from an area with cooler

winters will grow slower (Schmidtling 1994). The

difference in winter lows can be as much as 10 oF, but with

increased risk of damage at the cold end of the range and

growth loss at the warm end. East-west transfers within

districts are usually successful, and in some instances

may be desirable if improved stock is available.

25 25 Minimum temperature isotherms (°F)

Seed transfer guidelines

Natural distribution of shortleaf pine

TX

OK

MO

AR

LA MS

TN

AL

FL

GA

SC

NC

VA

WV

PA

MD

25

25

20

20

20

20

15

15

10

10

5

5

0

0

KY

IL

IN

OH DE

NJ

-5

-5

-10

-10

30

30

35
16

Virginia Pine

Virginia pine occupies a wide range from New York south to

Alabama and Mississippi (fig. 6) and is widely planted for

pulpwood and Christmas trees.

Geographic Variation

Studies of geographic variation in Virginia pine are limited

but, in general, the results follow the same pattern as in other

provenance tests: sources from warmer climates tend to

grow faster than local sources if they are not moved to

greatly differing climates. For instance, the best sources of

Virginia pine for Tennessee plantings were from areas of

milder climate found in the central part of the great valley of

Tennessee (Todd and Thor 1979).

In a rangewide provenance study of Virginia pine, Genys

(1966) found that sources from Alabama, South Carolina,

Tennessee, and Virginia had high mortality when planted in

the colder climate of Pennsylvania and variable performance

when planted in Maryland and Tennessee. A study with 38

seed sources planted at 5 locations in Oklahoma showed

that the best growing sources were from stands located

between the 0 and 5 oF isotherms of minimum temperature

(fig. 6) and that the best predictor of performance in

Oklahoma was the average yearly minimum temperature at

the seed source (Tauer and others 1998). Analysis showed a

curvilinear relationship between growth and minimum

temperature at the seed source that is almost identical to

loblolly pine (Schmidtling 1994).

Figure 6—Virginia pine distribution with seed transfer guidelines. Natural distributions of species adapted from Critchfield and Little (1966); minimum

temperature isotherms from USDA (1990).

25 25 Minimum temperature isotherms (°F)

Natural distribution of Virginia pine

Seed transfer guidelines

TX

OK

MO

AR

LA MS

TN

AL

FL

GA

SC

NC

VA

WV

PA

MD

25

25

20

20

20

20

15

15

10

10

5

5

0

0

KY

IL

IN

OH DE

NJ

-5

-5

-10

-10

30

30

35
17

Genetic Improvement

Federal, State, and forest industry organizations in the South

have established a number of seed orchards of Virginia pine.

Early flowering and heavy cone production of the species

have allowed these orchards to produce commercial

quantities of seeds for many years and to make rapid

improvement for Christmas tree production. Some orchards

have specialized in producing Virginia pine trees with the

best form and color for Christmas trees to meet heavy

consumer demand. Seeds and seedlings from the central

Alabama source in the U.S. Alliance Corporation seed

orchard are popular with Christmas tree growers because of

their exceptional form and good growth rates.

Recommended Sources

The recommendations for seed transfer in Virginia pine

follow the General Guidelines.

Virginia pine is often planted west and south of its natural

range, mainly for Christmas trees. For plantings west of its

natural range, the General Guidelines should be followed.

South of the natural range, central Alabama and other

southernmost sources should be the best for establishing

plantings. Pitch canker has caused problems5 when

Tennessee sources were planted in coastal Mississippi.

These problems, similar to those of north Florida slash pine

planted in south Florida (Dorman 1976), did not appear until

well after the normal Christmas tree rotation age.

Sand Pine

The natural range of sand pine is restricted to deep sands in

Florida and the gulf coast of Alabama east of Mobile Bay

(fig. 7). The Ocala variety (var. clausa) is found in the central

part of peninsular Florida and the Choctawhatchee variety

(var. immuginata D.B. Ward) is located in the western end of

the Florida panhandle and southern Alabama. The primary

characteristic that distinguishes the Ocala variety from the

Choctawhatchee variety is its serotinous cones, which can

remain on the tree for many years, until a wildfire causes

them to open.

Geographic Variation

The few studies of geographic variation in sand pine have

been limited to comparisons of the two varieties. In field

tests, Choctawhatchee sand pine generally had higher

planting survival, higher resistance to root rot, superior form,

and greater tolerance to freezing (Burns 1973, 1975).

Genetic Improvement

Clonal seed orchards of Choctawhatchee sand pine have

been established by several organizations in the South,

primarily in Georgia and Florida. The USDA Forest Service

operates a seedling seed orchard of Ocala sand pine on the

Ocala National Forest (Lewis and others 1985).

Recommended Sources

Planting of sand pine should be limited to deep sand sites.

On heavier soils, the root rot fungi (Phytophthora

cinnamomi Rands) and Clitocybe tabescans (Scop.: Fr.)

Bres. cause massive mortality (Ross 1973).

Choctawhatchee sand pine has grown and survived well 17

years after being planted on sandhills sites as far north as

South Carolina, at its northern limit for seed movement (Jett

and Guiness 1992). This variety had the highest volume of all

other species and no fusiform rust. It also performed better

than any other pine species tested in the Georgia sandhills

(Outcalt and Brendemuehl 1985).

The South Carolina planting site would seem to be very far

north of the natural distribution of Choctawhatchee sand

pine. This move, however, represents a transfer to a colder

climate of only 5 o

F (fig. 7). These results, plus those of

Burns (1973), support the use of the General Guidelines for

seed sources of sand pine.

Planting the Ocala variety of sand pine should be restricted

to peninsular Florida. Direct seeding of Ocala sand pine has

5

 Observations (1976 to 1990) by personnel at the USDA Forest

Service, Southern Research Station, Southern Institute of Forest

Genetics, Saucier, MS.

General Guidelines

Seedlings will survive and grow well if they come from

any area having a minimum temperature within 5 oF of the

planting site’s minimum temperature. Seedlings from an

area with warmer winters will grow faster than seedlings

from local sources; seedlings from an area with cooler

winters will grow slower (Schmidtling 1994). The

difference in winter lows can be as much as 10 o

F, but with

increased risk of damage at the cold end of the range and

growth loss at the warm end. East-west transfers within

districts are usually successful, and in some instances

may be desirable if improved stock is available.
18

been successful on some sites on the Ocala National Forest,

but the survival of planted seedlings has usually been poor.

Other Species and Hybrids

Dorman (1976) is the source of the scant information

available on the minor southern pine species: pitch pine (P.

rigida Mill.), pond pine (P. serotina Michx.), spruce pine (P.

glabra Walt.), and Table Mountain pine (P. pungens Lamb.).

Certainly, using local sources would be the safest. However,

there is no reason to believe that the General Guidelines

would not apply to the minor species, especially considering

that they all occur east of the Mississippi River, and that

east-west population differentiation is unlikely for any of

them.

The southern pine species often hybridize in areas where

different species occupy the same sites. The most common

natural hybrids are a longleaf X loblolly pine called

Sonderegger (Chapman 1922), a loblolly X shortleaf pine

General Guidelines

Seedlings will survive and grow well if they come from

any area having a minimum temperature within 5 oF of the

planting site’s minimum temperature. Seedlings from an

area with warmer winters will grow faster than seedlings

from local sources; seedlings from an area with cooler

winters will grow slower (Schmidtling 1994). The

difference in winter lows can be as much as 10 oF, but with

increased risk of damage at the cold end of the range and

growth loss at the warm end. East-west transfers within

districts are usually successful, and in some instances

may be desirable if improved stock is available.

Figure 7—Natural range of sand pine showing minimum temperature isotherms. Natural distributions of species adapted from

Critchfield and Little (1966); minimum temperature isotherms from USDA (1990).

TX

OK

MO

AR

LA MS

TN

AL

FL

GA

SC

NC

VA WV

25

25

20

20

20 20

15

15

10

5 10

5

0

0

KY

IL

-5

-5

-10

-10

30

30

35

-5 -5

25 25 Minimum temperature isotherms (°F)

Ocala variety

Choctawhatchee variety
19

(Zobel 1953), and a loblolly X pond pine (Saylor and Kang

1973).

The pitch X loblolly pine hybrid has been produced

artificially in Korea for many years (Hyun 1970) and is

currently planted on cold, dry sites on the Cumberland

Plateau (Little and Trew 1976).

The hybrid of slash pine with Caribbean pine has been very

successful in tropical and subtropical climates, especially in

Queensland, Australia. Because it combines the continuous

growth of Caribbean pine with slash pine’s tolerance of

poorly drained soils (Nikles 1995), this hybrid has promise

for south Florida.

Research in the South has indicated that shortleaf X slash

pine hybrids often outgrow the parental species (Nelson

1991, Wells and others 1978). Research on loblolly X

shortleaf pine hybrids indicates the potential for improved

fusiform rust resistance in offspring (LaFarge and Kraus

1980). However, using hybrids as a source of rust resistance

may no longer be cost-effective, considering the

advancements made in breeding for resistance in standard

(nonhybrid) stock.

The successful planting of hybrids requires a very careful

site analysis, since hybrid stock is likely to be considerably

more expensive than standard stock. Both the pitch X

loblolly hybrid and the shortleaf X loblolly hybrid will

perform well when the planting sites are properly selected.

Additional information on southern pine hybrids may be

found in Dorman (1976).
20

Literature Cited

Anderson, R.L.; Powers, H.R., Jr. 1985. The resistance screening

center - screening for disease resistance as a source for tree

improvement programs. In: Proceedings IUFRO rust of hard pines

working party conference; 1985 June; Athens, GA. Athens, GA:

University of Georgia, Georgia Center for Continuing Education:

59–65.

Balmer, W.E.; Williston, H.L. 1974. Guide for planting southern

pines. Atlanta: U.S. Department of Agriculture, Forest Service,

State and Private Forestry, Southeastern Area. 17 p.

Barber, J.C. 1975. Seed certification. In: Faulkner, Roy, ed. Seed

orchards. For. Comm. Bull. 54. London: Her Majesty’s Stationery

Office: 143–149.

Barbour, H.F. 1980. Loblolly seed sources for west Kentucky. In:

Lantz, Clark W., comp. Proceedings of the 1980 southern nursery

conference; 1980 September 2–4; Lake Barkley, KY. Tech. Publ.

SA–TP–17. Atlanta: U.S. Department of Agriculture, Forest

Service, State and Private Forestry, Southeastern Area: 15–23.

Barrett, W.H. 1973. Variación geográfica en Pinus elliottii Engelm. y P.

taeda L. II. Cinco años de crecimiento en el nordeste argentino.

(Geographical variation in Pinus elliottii and P. taeda. II. Five years of

growth in northeastern Argentina). Idia: Supplemento Forestal. 8:

18–39. In Spanish.

Boyer, J.N.; South, D.B. 1984. Forest nursery practices in the

South. Southern Journal of Applied Forestry. 8: 67–75.

Bridgwater, F.E.; Smith, W. 1997. Economic impact of fusiform

rust on the value of loblolly pine. Southern Journal of Applied

Forestry. 21: 187–192.

Burns, R.M. 1973. Comparative growth of planted pines in the

sandhills of Florida, Georgia, and South Carolina. In: Sand pine

symposium, Proceedings; 1972 December 5–7; Panama City

Beach, FL. Gen. Tech. Rep. SE–2. Asheville, NC: U.S. Department

of Agriculture, Forest Service, Southeastern Forest Experiment

Station: 124–134.

Burns, R.M. 1975. Sand pine: fifth-year survival and height on

prepared and unprepared sandhill sites. Res. Note SE–217.

Asheville, NC: U.S, Department of Agriculture, Forest Service,

Southeastern Forest Experiment Station. 5 p.

Chapman, H.H. 1922. A new hybrid pine (Pinus palustris X Pinus taeda).

Journal of Forestry. 20: 729–734.

Critchfield, W.B.; Little, E.L., Jr. 1966. Geographic distribution of the

pines of the world. Misc. Publ. 991. Washington, DC: U.S. Department

of Agriculture, Forest Service. 97 p.

Croker, T.C., Jr. 1990. Longleaf pine - myths and facts. In: Proceedings,

symposium management of longleaf pine; 1989 April 4–6; Long Beach,

MS. Gen. Tech. Rep. SO–75. New Orleans: U.S. Department of

Agriculture, Forest Service, Southern Forest Experiment Station: 2–10.

Dennington, R.W.; Farrar, R.M., Jr. 1983. Longleaf pine

management. For. Rep. R–8–FR3. Atlanta: U.S. Department of

Agriculture, Forest Service, Southern Region. 17 p.

Dorman, K.W. 1976. The genetics and breeding of southern pines. Agric.

Handb. 471. Washington, DC: U.S. Department of Agriculture, Forest

Service. 407 p.

Doudrick, R.L.; Schmidtling, R.C.; Nelson, C.D. 1996. Host relationships of fusiform rust disease: I. Infection and pycnial production on

slash pine and nearby tropical relatives. Silvae Genetica. 45: 142–149.

Duba, S.E.; Goggans, J.F.; Patterson, R.M. 1984. Seed source

testing of Alabama loblolly pine: implications for seed movement

and tree improvement programs. Southern Journal of Applied

Forestry. 8: 189–193.

Easley, L.T. 1963. Growth of loblolly pine from seed produced in a

seed production area vs. nursery-run stock. Journal of Forestry.

61(5): 388–389.

Farjon, A.; Page, C.N., comps. 1999. Conifers: status survey and

conservation action plan. International Union for Conservation

of Nature and Natural Resources/Species Survival Commission

(IUCN/SSC) conifer specialist group. Gland, Switzerland; Cambridge, UK: International Union for Conservation of Nature and

Natural Resources. 121 p.

Farrar, R.M., ed. 1990. Proceedings, symposium management of

longleaf pine; 1989 April 4–6; Long Beach, MS. Gen. Tech. Rep.

SO–75. New Orleans: U.S. Department of Agriculture, Forest

Service, Southern Forest Experiment Station. 294 p.

Fisher, R.F. 1983. Silvical characteristics of slash pine (Pinus elliottii

Englem. var elliottii). In: Stone, E.L., ed. The managed slash pine

ecosystem: Proceedings of a symposium; 1981 June 9–11;

Gainesville, FL. Gainesville, FL: University of Florida, School of

Forest Resources and Conservation: 48–55.

Friedman, S.T.; Adams, W.T. 1985. Estimation of gene flow into two seed

orchards of loblolly pine (Pinus taeda L.). Theoretical & Applied

Genetics: 69: 609–615.

Genys, J.B. 1966. Geographic variation in Virginia pine. Silvae

Genetica. 15(l): 72–76.

Gilmore, A.R. 1980. Extending the range of loblolly pine in the

Mississippi River Valley: factors relating to growth and longevity.

In: Lantz, Clark W., comp. Proceedings, 1980 southern nursery

conference; 1980 September 2–4; Lake Barkley, KY. Tech. Publ.

SA–TP–17. Atlanta: U.S. Department of Agriculture, Forest

Service, State and Private Forestry, Southeastern Area: 8–14.

Gilmore, A.R.; Funk, D.T. 1976. Shortleaf and loblolly pine seed

origin trials in southern Illinois: 27-year results. In: Proceedings of

the 10th Central States forest tree improvement conference; 1976

September 22–23; West Lafayette, IN. [Place of publication

unknown]: [Publisher unknown]: 115–124.

Goddard, R.E.; Wells, O.O.; Squillace, A.E. 1983. Genetic

improvement of slash pine. In: Stone, E.L., ed. The managed slash

pine ecosystem: Proceedings of a symposium; 1981 June 9–11;

Gainesville, FL. Gainesville, FL: University of Florida, School of

Forest Resources and Conservation: 56–68.
21

Grissom, J.E.; Schmidtling, R.C. 1997. Genetic diversity of loblolly pine

grown in managed plantations: evidence of differential response to

climatic events [Abstract]. In: Proceedings of the 24th southern forest

tree improvement conference; 1997 June; Orlando, FL: 410. Available

from: National Technical Information Service, U.S. Department of

Commerce, 5285 Port Royal Road, Springfield, VA 22161.

Henry, B.W.; Wells, O.O. 1967. Variation in brown-spot infection of

longleaf pine from several geographic sources. Res. Note SO–52. New

Orleans: U.S. Department of Agriculture, Forest Service, Southern

Forest Experiment Station. 4 p.

Hyun, S.K. 1970. The growth performance of pitch-loblolly hybrid

pine produced by different geographic races of loblolly pine in

their early age. In: Second world consultation on forest tree

breeding; 1969 August 7–16; Washington, DC. Rome: Food and

Agriculture Organization of the United Nations: 803–814. Vol. 1.

Jayawickrama, K.J.S.; McKeand, S.E.; Jett, J.B. 1998. Phenological variation in height and diameter growth in provenances and

families of loblolly pine. New Forests. 16: 11–25.

Jett, J.B.; Guiness, W.M. 1992. Growth and wood properties in a

Carolina sandhills pine seed source study. Southern Journal of

Applied Forestry. 16: 164–169.

Kelly, J.F.; Bechtold, W.A. 1990. The longleaf pine resource. In:

Proceedings symposium on management of longleaf pine; 1989

April 4–6; Long Beach, MS. Gen. Tech. Rep. SO–75. New Orleans:

U.S. Department of Agriculture, Forest Service, Southern Forest

Experiment Station: 11–22.

Kitchens, R.N. 1987. Trends in shortleaf pine tree improvement. In:

Murphy, Paul A., ed. Symposium on the shortleaf pine ecosystem;

1986 March 31–April 2; Little Rock, AR. Fayetteville, AR:

University of Arkansas, Cooperative Extension Service: 89–100.

Kraus, J.F.; LaFarge, T. 1984. Early results of a slash pine variety

trial. Southern Journal of Applied Forestry. 8(l): 41–43.

LaFarge, T.; Kraus, J.F. 1980. A progeny test of (shortleaf x

loblolly) x loblolly hybrids to produce rapid-growing hybrids

resistant to fusiform rust. Silvae Genetica. 29(5–6): 197–200.

Lambeth, C.C.; Dougherty, P.M.; Gladstone, W.T. [and others].

1984. Large-scale planting of North Carolina loblolly pine in

Arkansas and Oklahoma: a case of gain versus risk. Journal of

Forestry. 82(12): 736–741.

Lantz, C.W.; Hofmann, J.C. 1969. Geographic variation in growth

and wood quality of loblolly pine in North Carolina. In: Proceedings of the 10th southern forest tree improvement conference;

1969 June 17–19; Houston, TX: 175–188. Available from:

National Technical Information Service, U.S. Department of

Commerce, 5285 Port Royal Road, Springfield, VA 22161.

Lantz, C.W.; Kraus, J.F. 1987. A guide to southern pine seed

sources. Gen. Tech. Rep. SE–43. Asheville, NC: U.S. Department

of Agriculture, Forest Service, Southeastern Forest Experiment

Station. 34 p.

Lewis, R.A.; LaFarge, T.; McConnell, J.L. 1985. A seven-year-old

Ocala sand pine seedling seed orchard. In: Proceedings of the 18th

southern forest tree improvement conference; 1985 May 21–23;

Long Beach, MS: 204–207. Available from: National Technical

Information Service, U.S. Department of Commerce, 5285 Port Royal

Road, Springfield, VA 22161.

Li, B.; McKeand, S.E. 1989. Stability of loblolly pine families in the

Southeastern U.S. Silvae Genetica. 38: 96–101.

Li, B.; McKeand, S.E.; Weir, R.J. 1999. Tree improvement and

sustainable forestry impact of two cycles of loblolly pine breeding in

the U.S.A. Forest Genetics. 6(4): 229–234.

Little, E.L., Jr.; Dorman, K.W. 1952. Slash pine (Pinus elliottii), its

nomenclature and varieties. Journal of Forestry. 50: 918–923.

Little, E.L., Jr.; Dorman, K.W. 1954. Slash pine (Pinus elliottii),

including south Florida slash pine. Nomenclature and description.

Pap. 36. Asheville, NC: U.S. Department of Agriculture, Forest

Service, Southeastern Forest Experiment Station. 82 p.

Little, S.; Trew, I.F. 1976. Breeding and testing pitch x loblolly pine

hybrids for the Northeast. In: Garrett, Peter W., ed. Proceedings

of the 23rd northeastern forest tree improvement conference;

1975 August 4–7; New Brunswick, NJ: 71–85. Available from:

National Technical Information Service, U.S. Department of

Commerce, 5285 Port Royal Road, Springfield, VA 22161.

Long, E.M. 1980. Texas and Louisiana loblolly pine study confirms

importance of local seed sources. Southern Journal of Applied

Forestry. 4(3): 127–132.

Lott, L.A.; Schmidtling, R.C.; Snow, G.A. 1996. Susceptibility to brownspot needle blight and fusiform rust in selected longleaf pine and

hybrids. Tree Planters’ Notes. 47: 11–15.

McKeand, S.E.; Eriksson, G.; Roberds, J.H. 1997. Genotype by

environment interaction for index traits that combine growth and

wood density in loblolly pine. Theoretical & Applied Genetics. 94:

1015–1022.

McKeand, S.E.; Li, B.; Amerson, H.V. 1999. Genetic variation in

fusiform rust resistance in loblolly pine across a wide geographic

range. Silvae Genetica. 48: 255–260.

McRae, C.H.; Rockwood, D.L.; Blakeslee, G.M. 1985. Evaluation

of slash pine for resistance to pitch canker. In: Proceedings of the

18th southern forest tree improvement conference; 1985 May 21–

23; Long Beach, MS: 351–357. Available from: National

Technical Information Service, U.S. Department of Commerce,

5285 Port Royal Road, Springfield, VA 22161.

Minckler, L.S. 1950. Effect of seed source on height growth of pine

seedlings. Journal of Forestry. 48: 430–431.

Mullin, L.J.; Barnes, R.D.; Prevôst, M.J. 1978. A review of the

southern pines in Rhodesia. Res. Bull. 7. Harare, Zimbabwe:

Rhodesia (Zimbabwe) Forestry Commission. 331 p.

Nance, W.L.; Froelich, R.C.; Dell, T.R.; Shoulders, E. 1983. A

growth and yield model for unthinned slash pine plantations

infected with fusiform rust. In: Jones, Earle P., Jr., ed. Proceedings

of the second biennial southern silvicultural research conference;

1982 November 4–5; Atlanta. Gen. Tech. Rep. SE–24. Asheville,

NC: U.S. Department of Agriculture, Forest Service, Southeastern

Forest Experiment Station: 275–282.

Nelson, C.D. 1991. Fusiform rust incidence and volume growth in a firstgeneration backcross population. (shortleaf X slash) x slash. In:

Proceedings of the 21st southern forest tree improvement conference;

1991 June 17–21; Knoxville, TN: 152–159. Available from: National

Technical Information Service, U.S. Department of Commerce, 5285

Port Royal Road, Springfield, VA 22161.
22

Nikles, D.G. 1966. Comparative variability and relationship of Caribbean

pine (Pinus caribaea Mor.) and slash pine (Pinus elliottii Engelm.).

Raleigh, NC: North Carolina State University. 201 p. Ph.D. dissertation.

Nikles, D.G. 1995. Hybrids of the slash - Caribbean - Central American

pine complex: characteristics, bases of superiority and potential utility

in South China and elsewhere. In: Shen, Xihuan, ed. Forest tree

improvement in the Asia-Pacific region. Beijing: China Forestry

Publishing House: 168–186.

Outcalt, K.W.; Brendemuehl, R.H. 1985. Growth of

Choctawhatchee sand pine plantations in Georgia. Southern

Journal of Applied Forestry. 9(1): 62–64.

Prentice, I.C.; Cramer, W.; Harrison, S.P. [and others]. 1992. A global

biome model based on plant physiology and dominance, soil properties,

and climate. Journal of Biogeography. 19: 117–134.

Pye, J.M.; Wagner, J.E.; Holmes, T.P.; Cubbage, F.W. 1997.

Positive returns from fusiform rust research. Res. Pap. SRS–4.

Asheville, NC: U.S. Department of Agriculture, Forest Service,

Southern Research Station. 55 p.

Rink, G.; Wells, O.O. 1988. Productivity comparisons of 37-yearold loblolly-shortleaf pine seed sources in southern Illinois.

Northern Journal of Applied Forestry. 5: 155–158.

Rockwood, D.L.; Huber, D.A.; White, T.L. [In press]. Provenance

and family variability in slash pine grown in southern Brazil and

northeastern Argentina. New Forests.

Ross, E.W. 1973. Important diseases of sand pine. In: Sand pine

symposium, Proceedings; 1972 December 5–7; Panama City

Beach, FL. Gen. Tech. Rep. SE–2. Asheville, NC: U.S. Department

of Agriculture, Forest Service, Southeastern Forest Experiment

Station: 199–206.

Rudolf, P.O. 1974. Tree-seed marketing controls. In: Seeds of woody

plants in the United States. Agric. Handb. 450. Washington, DC:

U.S. Department of Agriculture: 153–166.

Ruehle, J.L.; Campbell, W.A. 1971. Adaptability of geographic

selections of shortleaf pine to littleleaf sites. Res. Pap. SE–87.

Asheville, NC: U.S. Department of Agriculture, Forest Service,

Southeastern Forest Experiment Station. 8 p.

Saucier, J.R.; Dorman, K.W. 1969. Intraspecific variation in

growth and wood characteristics of two slash pine varieties grown

in south Florida. In: Proceedings of the 10th southern forest tree

improvement conference; 1969 June 17–19; Houston TX: 49–57.

Available from: National Technical Information Service, U.S.

Department of Commerce, 5285 Port Royal Road, Springfield, VA

22161.

Saylor, L.C.; Kang, K.W. 1973. A study of sympatric populations of Pinus

taeda L. and Pinus serotina Michx. in North Carolina. Journal of Elisha

Mitchell Scientific Society. 89(1 & 2): 101–110.

Schmidtling, R.C. 1988. Racial variation in self-thinning trajectories in loblolly pines. In: Proceedings International Union of

Forest Research Organizations forest growth modeling and

prediction; 1987 August 23–27; Minneapolis. SAF–87–12.

Washington, DC: Society of American Foresters: 134–142. Vol. 1.

Schmidtling, R.C. 1994. Using provenance tests to predict response to

climatic change: loblolly pine and Norway spruce. Tree Physiology. 14:

805–817.

Schmidtling, R.C. 1995. Seed transfer and genecology in shortleaf

pine. In: Edwards, M. Boyd, comp. Proceedings of the eighth

biennial southern silvicultural research conference; 1994 November 1–3; Auburn, AL. Gen. Tech. Rep. SRS–1. Asheville, NC: U.S.

Department of Agriculture, Forest Service, Southern Research

Station: 373–378.

Schmidtling, R.C. 1997. Using provenance tests to predict response

to climatic change. In: Ecological issues and environmental impact

assessment. Houston, TX: Gulf Publishing Co.: 621–642. Chapter

27.

Schmidtling, R.C.; Carroll, E.; LaFarge, T. 1999. Allozyme

diversity of selected and natural loblolly pine populations. Silvae

Genetica. 48: 35–45.

Schmidtling, R.C.; Clark, A., III. 1989. Loblolly pine seed sources

differ in stem form. In: Miller, James H., comp. Proceedings of

the fifth biennial southern silvicultural research conference; 1988

November 1–3; Memphis, TN. Gen. Tech. Rep. SO–74. New

Orleans: U.S. Department of Agriculture, Forest Service, Southern

Forest Experiment Station: 421–426.

Schmidtling, R.C.; Froelich, R.C. 1993. Thirty-seven year

performance of loblolly pine seed sources in eastern Maryland.

Forest Science. 39: 706–721.

Schmidtling, R.C.; Hipkins, V. 1998. Genetic diversity in longleaf pine

(Pinus palustris Mill.): influence of historical and prehistorical events.

Canadian Journal of Forest Research. 28: 1135–1145.

Schmidtling, R.C.; Marcó, M.; LaFarge, T. 1997. A slash pine

progeny test in Argentina and USA. In: Proceedings of the 24th

southern forest tree improvement conference; 1997 June 9–11;

Orlando, FL: 384–386. Available from: National Technical

Information Service, U.S. Department of Commerce, 5285 Port

Royal Road, Springfield, VA 22161.

Schmidtling, R.C.; Nelson, C.D. 1996. Interprovenance crosses in

loblolly pine using selected parents. Forest Genetics. 3(1): 53–66.

Schmidtling, R.C.; Sluder, E.R. 1995. Seed transfer and

genecology in longleaf pine. In: Proceedings of the 23rd southern

forest tree improvement conference; 1995 June 20–22; Asheville,

NC: 78–85. Available from: National Technical Information

Service, U.S. Department of Commerce, 5285 Port Royal Road,

Springfield, VA 22161.

Schmidtling, R.C.; White, T. 1990. Genetics and tree improvement of longleaf pine. In: Proceedings symposium management

longleaf pine. Gen. Tech. Rep. SO–75. New Orleans: U.S.

Department of Agriculture, Forest Service, Southern Forest

Experiment Station: 114–127.

Shiver, B.D.; Rheney, J.W.; Hitch, K.L. 2000. Loblolly pine

outperforms slash pine in southeastern Georgia and northern

Florida. Southern Journal of Applied Forestry. 24: 31–36.

Sierra-Lucero, V. 1999. Genetic parameter estimates of loblolly

pine grown in the lower Coastal Plain of the Southeastern United

States. Gainesville, FL: University of Florida. 86 p. M.S. thesis.
23

Snow, G.A.; Froelich, R.C. 1968. Daily and seasonal dispersal of

basidiospores of Cronartium fusiforme. Phytopathology. 58: 1532–

1536.

Snyder, E.B.; Wakeley, P.C.; Wells, O.O. 1967. Slash pine provenance

tests. Journal of Forestry. 65: 414–420.

Squillace, A.E. 1965. Combining superior growth and timber quality

with high gum yield in slash pine. In: Proceedings of the 8th

southern forest tree improvement conference; 1965 June 16–17;

Savannah, GA: 73–76. Available from: National Technical

Information Service, U.S. Department of Commerce, 5285 Port

Royal Road, Springfield, VA 22161.

Squillace, A.E. 1966. Geographic variation in slash pine. Monogr.

10. Forest Science. 56 p.

Squillace, A.E. 1976. Geographic patterns of fusiform rust infection

in loblolly and slash pine plantations. Res. Note SE–232.

Asheville, NC: U.S. Department of Agriculture, Forest Service,

Southeastern Forest Experiment Station. 4 p.

Storer, J.; Gordon, T.R.; Dallara, D.L.; Wood, D.I. 1994. Pitch

canker kills pines, spreads to new species and regions. California

Agriculture. 48: 9–12.

Talbert, J.T.; Weir, R.J.; Arnold, R.D. 1985. Costs and benefits of

a mature first-generation loblolly pine tree improvement program.

Journal of Forestry. 83(3): 162–166.

Tauer, C.G.; Shah, S.R.S.; Schmidtling, R.C. 1998. Virginia pine (Pinus

virginiana Mill.) provenance and progeny performance in Oklahoma.

Southern Journal of Applied Forestry. 22: 209–215.

Todd, D.; Thor, E. 1979. Variation and estimated gains in height, diameter,

and volume growth for open-pollinated progeny of Virginia pine (Pinus

virginiana Mill.). In: Proceedings of the 15th southern forest tree

improvement conference; 1979 June 19–21; Starkville, MS: 42–57.

Available from: National Technical Information Service, U.S.

Department of Commerce, 5285 Port Royal Road, Springfield, VA

22161.

U.S. Department of Agriculture. 1990. USDA plant hardiness zone map.

Misc. Publ. 1475. Washington, DC: U.S. Department of Agriculture,

Agricultural Research Service. 1: 6,000,000 scale; 48 x 48 in.; colored.

Wakeley, P.C. 1961. Results of the southwide pine seed source study

through 1960–61. In: Proceedings of the 6th southern forest tree

improvement conference; 1961 June 7–8; Gainesville, FL: 10–24.

Available from: National Technical Information Service, U.S.

Department of Commerce, 5285 Port Royal Road, Springfield, VA

22161.

Wakeley, P.C.; Bercaw, T.E. 1965. Loblolly pine provenance test at

age 35. Journal of Forestry. 63: 168–174.

Wells, O.O. 1969. Results of the southwide pine seed source study

through 1968–69. In: Proceedings of the 10th southern forest tree

improvement conference; 1969 June 17–19; Houston, TX: 117–

129. Available from: National Technical Information Service, U.S.

Department of Commerce, 5285 Port Royal Road, Springfield, VA

22161.

Wells, O.O. 1979. Geographic seed source affects performance of planted

shortleaf pine. In: Proceedings: symposium management pines of

the interior South; 1978 November 7–8; Knoxville, TN. Tech. Publ.

SA–TP–2. Atlanta: U.S. Department of Agriculture, Forest Service,

Southeastern Area, State and Private Forestry: 48–57.

Wells, O.O. 1983. Southwide pine seed source study-loblolly pine at 25

years. Southern Journal of Applied Forestry. 7(2): 63–71.

Wells, O.O. 1985. Use of Livingston Parish, Louisiana loblolly pine

by forest products industries in the Southeast. Southern Journal of

Applied Forestry. 9(3): 180–185.

Wells, O.O.; Barnett, P.E.; Derr, H.J. [and others]. 1978.

Shortleaf X slash pine hybrids outperform parents in parts of the

Southeast. Southern Journal of Applied Forestry. 2(1): 28–32.

Wells, O.O.; Lambeth, C.C. 1983. Loblolly pine provenance test

in southern Arkansas: 25th year results. Southern Journal of

Applied Forestry. 7(2): 71–75.

Wells, O.O.; Rink, G. 1984. Planting loblolly pine north and west

of its natural range. In: Shoulders, Eugene, ed. Proceedings of the

third biennial southern silvicultural research conference; 1984

November 7–8; Atlanta. Gen. Tech. Rep. SO–54. New Orleans:

U.S. Department of Agriculture, Forest Service, Southern Forest

Experiment Station: 261–264.

Wells, O.O.; Switzer, G.L. 1971. Variation in rust resistance in

Mississippi loblolly pine. In: Proceedings of the 11th southern

forest tree improvement conference; 1971 June 15–16; Atlanta:

25–30. Available from: National Technical Information Service,

U.S. Department of Commerce, 5285 Port Royal Road, Springfield, VA 22161.

Wells, O.O.; Switzer, G.L.; Schmidtling, R.C. 1991. Geographic

variation in Mississippi loblolly pine and sweetgum. Silvae

Genetics. 40: 105–118.

Wells, O.O.; Wakeley, P.C. 1966. Geographic variation in

survival, growth, and fusiform-rust infection of planted loblolly

pine. Monogr. 11. Forest Science. 40 p.

Wells, O.O.; Wakeley, P.C. 1970. Variation in shortleaf pine from

several geographic sources. Forest Science. 16(4): 415–423.

Wiesehuegel, E.C. 1955. Five year’s results of loblolly pine

geographic seed source tests. In: Proceedings of the 3rd southern

forest tree improvement conference; 1955 January 5–6; New

Orleans: 16–25. Available from: National Technical Information

Service, U.S. Department of Commerce, 5285 Port Royal Road,

Springfield, VA 22161.

Zarger, T.G. 1961. Ten-year results of a cooperative loblolly pine

seed source test. In: Proceedings of the 6th southern forest tree

improvement conference; 1961 June 7–8; Gainesville, FL: 45–50.

Available from: National Technical Information Service, U.S.

Department of Commerce, 5285 Port Royal Road, Springfield, VA

22161.

Zobel, Bruce J. 1953. Are there natural loblolly-shortleaf pine

hybrids? Journal of Forestry. 51(7): 494–495.

Zobel, Bruce; Talbert, John. 1984. Applied forest tree improvement. New

York: John Wiley. 505 p.
24

Glossary

adaptation: the process of evolutionary (genetic)

adjustments fitting individuals or groups to their

environment

allozyme: (isozyme, isoenzyme) multiple forms of a single

enzyme, which catalyze the same reaction but differ in their

electrical charge when separated by electrophoresis. Minor

variations in allozymes are considered to be nonadaptive,

but are useful in studies of population genetics.

cline: a geographical gradient of phenotype or genotype

within the species’ range. Determining whether a cline is

genetic requires testing in at least a single environment.

Usually clinal variation results from an environmental

gradient. Portions of populations exhibiting such continuous

(clinal) change from one area to another should not be

designated as ecotypes, races, or taxa.

clone: a group of genetically identical plants derived

asexually from a single individual, produced by grafting,

rooting cuttings, or tissue culture

ecotype: a race adapted to the selective action of a particular

climatic or soil environment. Most differences among

ecotypes show up only when different ecotypes are tested

in a uniform environment.

edaphic: pertaining to the soil in its ecological relationships

electrophoresis: a method to separate charged molecules in

an electrical field, exploiting differences in net electrical

charge, shape and size of the molecules. Electrophoretic

separation in free solution is possible, but usually it is

performed in a matrix (gel electrophoresis) or on filter paper.

gene: a chromosomal segment involved in producing a

polypeptide chain or RNA molecule. The fundamental

physical and functional unit of heredity that carries

information from one generation to the next.

genotype: (1) an individual’s hereditary constitution, with or

without phenotypic expression of the one or more characters

it underlies. Also the gene classification of this constitution

expressed in a formula. The genotype is determined chiefly

from performance of progeny and other relatives. It interacts

with the environment to produce the phenotype. (2)

Individual(s) characterized by a certain genetic constitution.

genotype-environment interaction: the failure of

genotypes (families, clones, provenances) to maintain the

same relative performance when tested in different

environments

geographic race: the race native to a geographic area

geographic variation: the visible differences among native

trees growing in different portions of a species’ range. If the

differences are largely genetic rather than environmental, the

variation is usually specified as racial, ecotypic, or clinal.

grass stage: delayed early growth in pine seedlings in which

the seedlings have very limited stem elongation and

resemble grass

hypocotyl: in a freshly germinated pine seedling, the segment

(stem) between the roots and the cotyledons (embryonic

needles)

isoline, isotherm: a line on a map or chart along which there

is constant value such as temperature, growing season, or

growth potential

local seed source: source native to the locality in which the

seedlings are grown; belonging to the indigenous

geographic race. Its seed collection area is usually defined

experimentally as being within a certain distance or elevation

of the planting site.

nursery-run seedlings: seedlings from unselected trees,

usually from general forest collections made in natural

stands

phenotype: the plant or character as we see it; state,

description, or degree of expression of a character; the

product of the interaction of the genes of an organism

(genotype) with the environment. When the total character

expressions of an individual are considered, the phenotype

describes the individual. Similar phenotypes do not

necessarily breed alike.

plus stand: a stand of trees with exceptional phenotypic

characteristics in growth, form, and disease resistance.

These stands are usually thinned intensively to eliminate the

poorer trees.

progeny test: evaluation of parents by comparing the

performance of their numbers of offspring under conditions

more controlled than would be possible for the parent

provenance: the geographic origin of a seed source
25

race: a population that exists within a species and exhibits

general genetic characteristics distinct from those of other

populations. When the distinguishing characteristics of a

race are adaptive rather than simply phenotypic, the term is

synonymous with ecotype, and the race is described by the

nature of its adaptation, such as climatic or edaphic.

refugium: a place where species exist (refuge) during times

of generally unfavorable climatic conditions

roguing: systematic removal of individuals not desired for

the perpetuation of a population; culling

seed orchard: a plantation consisting of clones or seedlings

from selected trees isolated to reduce pollination from

outside sources, rogued of undesirables, and cultured for

early and abundant production of seeds

seed production area: a plus stand that is generally

upgraded and opened by removal of undesirable trees and

then cultured for early and abundant seed production

seed source: the locality where a seed lot was collected; also

the seed itself. If the stand from which collections were made

was, in turn, from nonnative ancestors, the original seed

source should also be recorded and designated as the

provenance.

selection: often synonymous with artificial selection, which

is the choice by the breeder of individuals for propagation

from a larger population. Artificial selection may be for one

or more desired characteristics. It may be based on the tree

itself (phenotypic), or on the tree’s progeny or other

relatives (genotypic). Refers also to the tree selected.

serotinous: a term usually applied to cones that, though

mature, remain closed for a year or more

SSPSSS: the Southwide Southern Pine Seed Source Study.

A major study of geographic variation (provenance test)

initiated by Phil Wakeley and the Southern Forest Tree

Improvement Committee.

variety: a subdivision of a species, usually separated

geographically from the typical, having one or more

heritable, morphological characteristics which differ from the

typical even when grown under the same environmental

conditions

woods-run: unselected, wild, or natural stands of trees
The use of trade or firm names in this publication is for reader information and does not

imply endorsement by the U.S. Department of Agriculture of any product or service.

The Forest Service, United States Department of Agriculture (USDA), is

dedicated to the principle of multiple use management of the Nation’s forest

resources for sustained yields of wood, water, forage, wildlife, and recreation.

Through forestry research, cooperation with the States and private forest

owners, and management of the National Forests and National Grasslands, it strives—as

directed by Congress—to provide increasingly greater service to a growing Nation.

The USDA prohibits discrimination in all its programs and activities on the basis of race,

color, national origin, sex, religion, age, disability, political beliefs, sexual orientation, or

marital or family status. (Not all prohibited bases apply to all programs.) Persons with

disabilities who require alternative means for communication of program information

(Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202)

720-2600 (voice and TDD).

To file a complaint of discrimination, write USDA, Director, Office of Civil Rights,

Room 326-W, Whitten Building, 1400 Independence Avenue, SW, Washington, D.C.

20250-9410 or call (202) 720-5964 (voice and TDD). USDA is an equal opportunity

provider and employer.

Schmidtling, R.C. 2001. Southern pine seed sources. Gen. Tech. Rep. SRS-XX. Asheville,

NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. 25 p.

The selection of an appropriate seed source is critical for successful southern pine plantations.

Guidelines for selection of seed sources are presented for loblolly (Pinus taeda L.), slash (P.

elliottii Engelm.), longleaf (P. palustris Mill.), Virginia (P. virginiana Mill.), shortleaf (P.

echinata Mill.), and sand [P. clausa (Chapm. ex Engelm.) Vasey ex Sarg.] pines. Seed

movement guidelines in this handbook are based on climatic similarities between the seed

source origin and the planting site. Because yearly average minimum temperature is the most

important climatic variable related to growth and survival, it has been used to define the rules

of seed movement. This variable, which defines plant hardiness zones, has been used for

many years by horticulturists to guide the transfer of plant materials. East-west movement to

areas of similar climate is permissible, with the exception of loblolly pine.

Keywords: Fusiform rust, geographic variation, loblolly pine, longleaf pine, provenance tests,

sand pine, seed movement, seed sources, shortleaf pine, slash pine, Virginia pine.
USDA Plant Hardiness Zones

Average Annual

Temperature (oF)

Minimum Temperature

Below –50

–10 to –15

–15 to –20

–20 to –25

–25 to –30

–30 to –35

–35 to –40

–40 to –45

–45 to –50

–5 to –10

5 to 0

0 to –5

40 to 35

35 to 30

30 to 25

25 to 20

20 to 15

15 to 10

10 to 5

40 and above