____________

The Authors:

____________

William B. Batista is on leave from Departamento de Ecologia, 

Facultad de Agronomia, Universidad de Buenos Aires, Av.

San Martin 4453, 1417 Buenos Aires, Argentina; and William J. Platt,

Professor, Department of Plant Biology, Louisiana State University,

Baton Rouge, LA 70803.

Preface

Old growth is widely acknowledged today as an essential part of managed forests, particularly on public lands. However, this

concept is relatively new, evolving since the 1970's when a grassroots movement in the Pacific Northwest began in earnest to

define old growth. In response to changes in public attitude, the U.S. Department of Agriculture, Forest Service, began

reevaluating its policy regarding old-growth forests in the 1980's. Indeed, the ecological significance of old growth and its

contribution to biodiversity were apparent. It was also evident that definitions were needed to adequately assess and manage the

old-growth resource. However, definitions of old growth varied widely among scientists. To address this discrepancy and other

old-growth issues, the National Old-Growth Task Group was formed in 1988. At the recommendation of this committee, old

growth was officially recognized as a distinct resource by the Forest Service, greatly enhancing its status in forest management

planning. The committee devised "The Generic Definition and Description of Old-Growth Forests" to serve as a basis for

further work and to ensure uniformity among Forest Service Stations and Regions. Emphasis was placed on the quantification

of old-growth attributes.

At the urging of the Chief of the Forest Service, all Forest Service Stations and Regions began developing old-growth

definitions for specific forest types. Because the Southern and Eastern Regions share many forest communities (together they

encompass the entire Eastern United States), their efforts were combined, and a cooperative agreement was established with

The Nature Conservancy for technical support. The resulting project represents the first large-scale effort to define old growth

for all forests in the Eastern United States. This project helped bring the old-growth issue to public attention in the East.

Definitions will first be developed for broad forest types and based mainly on published information and so must be viewed

accordingly. Refinements will be made by the Forest Service as new information becomes available. This document represents

1 of 35 forest types for which old-growth definitions will be drafted.

In preparing individual old-growth definitions, authors followed National Old-Growth Task Group guidelines, which differ

from the standard General Technical Report format in two ways—the abstract (missing in this report) and the literature

citations (listed in Southern Journal of Applied Forestry style). Allowing for these deviations will ensure consistency across

organizational and geographic boundaries.

April 1997

Southern Research Station

P.O. Box 2680

Asheville, NC 28802
An Old-Growth Definition for

Southern Mixed Hardwood Forests

William B. Batista and William J. Platt

Introduction

The southern mixed hardwood forest, one of the

southernmost mesic temperate forest types in North

America, occurs along the southeastern Coastal Plain of the

United States from the Carolinas to eastern Texas. These

forests contain a diverse mixture of evergreen and deciduous

broad-leaved trees combined with evergreen coniferous

trees. Typically, they are dominated by American beech

(Fagus grandifolia Ehrh.), southern magnolia (Magnolia

grandiflora L.), and Pinus spp. (Quarterman and Keever

1962; Monk 1965, 1967, 1968; Marks and Harcombe 1975;

Clewell 1985; Godfrey 1988; Platt and Schwartz 1990;

Vankat 1990). As the climate of the southeastern Coastal

Plain, at least along the coast of the Gulf of Mexico,

remained relatively constant during the Pleistocene, present

mesic hardwood forests may represent relicts derived from

the early Tertiary flora (Axelrod 1958, 1966; Platt and

Schwartz 1990). In addition, they would have served as

refuges for many northern temperate species during the

Pleistocene glaciations (Davis 1981, Delcourt and Delcourt

1987, Webb 1990).

Before European settlement, stands of southern mixed

hardwood forests formed narrow bands of vegetation

between floodplain forests and upland xeric forests or

savannas dominated by longleaf pine (Pinus palustris

Mill.). These sites were naturally protected from frequent

flooding and from growing-season fires initiated in the pine

savannas (Williams 1827; Delcourt and Delcourt 1974,

1977; Marks and Harcombe 1981; Schafale and Harcombe

1983; Platt and Schwartz 1990; Ware et al. 1993; Schwartz

1994; Harcombe et al. 1993). After European settlement,

virtually all pine savannas were clearcut, and their

characteristic growing-season fires were suppressed.

Following such disruption, hardwood species and pines,

especially loblolly pine (P. taeda L.), replaced longleaf pine

forming woodlands and forests that replaced most of the

savannas. Stands of southern mixed hardwood forests are

frequently affected by hurricanes along the Coastal Plain

(Jarvinen et al. 1984, Neumann et al. 1992). These

disturbances, which recur within the lifespan of most

canopy trees, greatly influence the dynamics of these forests

(Glitzenstein et al. 1986, Platt and Schwartz 1990).

Preservation or restoration of the southern mixed hardwood

forests requires criteria for recognizing the so-called oldgrowth stands (Thomas et al. 1988). The concept of old

growth was originally developed for Pacific Northwest

forests, based on the notion that those forests undergo a

directional autogenic succession toward a steady-state

climax that is disrupted by natural devastations (Franklin et

al. 1981, 1986; Franklin and Spies 1984). In this context,

old-growth condition becomes essentially synonymous with

climax state. Application of the old-growth concept in other

regions has tended to result in transferral of this connotation

to different forests (e.g., Barnes 1989, Hayward 1991). This

created difficulties for characterizing the old-growth

condition of forests that, being affected by frequent

disturbances (Tyrrell 1992), may not approach a climax or a

steady state (Jones 1945, Raup 1964, White 1979, Denslow

1980, Pickett and White 1985, Platt and Schwartz 1990). In

these cases, an old-growth forest would be one that has not

been recently cleared and whose dynamics are essentially

the same as those that historically shaped forest structure

and composition ("age" and "disturbance" criteria) (Hunter

1989). The old-growth definition would then contain

attributes expected in a forest likely to change under a

natural disturbance regime, rather than attributes expected

in a steady-state community.

In this report, we characterize the old-growth condition for

the southern mixed hardwood forests based on published

accounts and on data from five exemplary stands that show

no evidence of having been cleared by humans or by natural

agents during the last 200 years. The two easternmost

stands are located near each other, one (Woodyard

Hammock) in northern Florida and the other (Titi

Hammock) in southern Georgia; two central stands

(Zemurray Forest and Tunica Hills) are in eastern

Louisiana, and the westernmost stand (Weir Forest) is in

eastern Texas (see appendix for a detailed presentation of

the exemplary forests). Structure and composition data were

compiled from mapped-plot data bases and published

reports related to all five forests. Description of immediate

hurricane effects was based on censuses conducted after

1985 Hurricane Kate in Woodyard Hammock and Titi

Hammock. Dynamics over a 14-year period were described

based on an ongoing long-term study in Woodyard
2

Hammock. This forest type was defined by Quarterman and magnolia, and sweetgum (Liquidambar styraciflua L.);

Keever (1962) and corresponds to the lower slope some of the oak species, water oak (Quercus nigra L.),

hardwood pine forest of Marks and Harcombe (1981), to white oak (Q. alba L.), swamp chestnut oak (Q. michauxii

forest type 66 in Vankat (1990), and partially to Southern Nutt.); and, except in Tunica Hills, either spruce pine (P.

Research Station types 31, 37, 46, and 59, as well as glabra Walt.), or loblolly pine (tables 2 and 3). In each

Society of American Foresters (SAF) types 82 and 89 (Eyre exemplary forest, there were about 13 species of large

1980). overstory trees [d.b.h. $20 inches (50 cm)], about one-half

Old-Growth Characteristics

Distribution in the Landscape

Old-growth southern mixed hardwood forests are small

stands whose origin predates extensive European settlement

in the United States. All of the exemplary forests occupied

mesic sites associated with streams or lakes. These sites are

moister than the uplands and therefore are relatively

protected from the lightning-initiated fires that frequently

burned the upland pine savannas (Platt and Schwartz 1990,

Harcombe et al. 1993).

Strata and Growth Forms

Southern mixed hardwood forests have an overstory of

evergreen and deciduous broad-leaved species and

evergreen needle-leaved species, mostly composed of trees

66 to 98 feet [20 to 30 meters (m)] tall, and an understory of

trees less than 49 feet (15 m) tall, usually of evergreen and

deciduous broad-leaved species (Harcombe and Marks

1977, Platt 1985, Platt and Hermann 1986). Trees support

lianas and sometimes fairly abundant epiphytes. Except in

gaps, the ground cover of herbs is sparse, probably as a

result of the abundance of evergreen trees (Marks and

Harcombe 1975, Platt and Schwartz 1990).

Overall Diversity

The exemplary forests averaged 37 tree species $1 inch [2

centimeters (cm)] in diameter at breast height (d.b.h.).

About 28 of these species reached at least 4 inches (10 cm)

in d.b.h. (table 1). The rest were large shrubs and a few

species dispersed from nearby environments and present

only as juveniles. Diversity index N1 (= e ) indicates that H' 

about 15 of the species in each stand contributed

significantly to total density, and N2 (= 1/D) that about 11

shared dominance (table 1).

Overstory Species

Dominant species of large overstory trees in the exemplary

forests always included American beech, southern

of which shared dominance (respectively, N0 and N1, table

1). Thus, the composition of the overstory was fairly

constant among the exemplary forests despite some

variation in species abundance. American beech was always

either the first or the second most abundant species in the

overstory. An additional 30 native overstory species were

represented in the exemplary forests (table 2).

Understory and Vine Species

The understory of the exemplary forests contained small

individuals of overstory species and several species that

never reach the overstory (table 2). Among the latter,

American holly (Ilex opaca Ait.), American hornbeam

(Carpinus caroliniana Walt.), and eastern hophornbeam

[Ostrya virginiana (Mill.) K. Koch] frequently shared

dominance (table 2). However, species abundance in the

understory was variable among sites. The dominant 

Table 1—Tree species diversity in five southern mixed

hardwood forests

 Number

Sizes Range Median of sites

D.b.h. $2 cm

N0 28-60 37 4

a

N1 5-20 15 4

b

N2 3-12 11 4

c

D.b.h. $10 cm

N0 25-43 28 4

a

N1 12-16 14 4

b

N2 9-11 10 5

c

D.b.h. $50 cm

N0 8-15 13 5

a

N1 8-15 7 5

b

N2 4-12 6 5

c

 N0 is the total number of species. a

 N1 = e , where H' is the Shannon-Wiener index, measures the number of b H'

nonrare species.

 N2 = 1/D, where D is the Simpson index, measures the number of c

dominant species (Hill 1973). All indices were calculated with overall

stand tree-density data.
3

Table 2—Large and small tree presence (number of sites out of five), density ranges, and density

averages (median number of trees per hectare) for common species in five old-growth southern

mixed hardwood forests

Large trees Small trees

d.b.h. >50 cm 10 cm < d.b.h. #50 cm

________________________________ __________________________________

Density Density Density Density

Species Presence range median Presence range median

Overstory species: a

Fagus grandifolia 5 6.0-18.0 9.0 5 3.0-102.0 38.5

Magnolia grandiflora 5 2.0-24.7 5.4 5 10.0- 59.0 19.6

Liquidambar styraciflua 5 0.3- 5.0 3.0 5 10.6- 66.9 36.0

Quercus nigra 4 0.2- 5.0 3.0 5 0.8- 22.0 12.7

Q. alba 4 0 - 5.0 2.0 5 1.5- 40.5 5.0

Q. michauxii 4 0.4- 2.0 0.9 4 1.8- 28.0 6.5

Liriodendron tulipifera 4 0.9- 5.4 2.0 4 1.0- 6.5 1.8

Nyssa sylvatica 4 0.5- 3.5 0.8 4 13.0- 22.4 18.9

Pinus glabra 3 4.4-16.5 4.4 3 10.9- 25.4 10.9

P. taeda 3 1.6-22.0 1.6 4 0.2- 48.0 0.4

Carya glabra 3 0.7- 2.4 0.7 3 1.0- 9.4 1.0

Q. hemisphaerica 3 0.2- 1.8 0.2 4 0.4- 15.8 1.0

Q. shumardii 2 0.4- 9.0 0 2 0.9- 6.0 0

M. virginiana 1 1.4- 1.4 0 4 0.7- 10.6 4.0

C. tomentosa 1 0.4- 0.4 0 3 0.8- 2.2 0.8

C. cordiformis 1 1.0- 1.0 0 2 1.0- 8.4 0

Tilia americana 1 0.8- 0.8 0 2 4.0- 5.2 0

All overstory species: 40.0-70.0 46.0 140.0-275.0 227.0

Understory species: b

Ilex opaca 5 1.0- 59.0 30.4

Carpinus caroliniana 5 1.3- 41.0 21.1

Ostrya virginiana 4 8.0- 69.8 27.0

Cornus florida 4 2.4- 30.0 7.8

Acer rubrum 4 0.8- 32.0 1.0

Symplocos tinctoria 4 0.4- 5.5 1.0

Prunus serotina 4 0.2- 3.0 0.4

Aralia spinosa 2 0.2- 1.0 0

Cercis canadensis 2 0.2- 2.4 0

Halesia diptera 2 5.0- 8.5 0

Oxydendron arboreum 2 5.8- 16.0 0

All understory species: 114.0-163.2 125.0

All species: 40.0-70.0 46.0 304.0-389.0 351.6 c

 Overstory: Carya illinoiensis, Castanea pumila, Celtis laevigata, Gleditsia triacanthos, Juglans nigra, Magnolia pyramidata, a

Paulownia tomentosa, Pinus echinata, Platanus occidentalis, Quercus falcata, Q. marilandica, Q. muehlenbergii, Q. nuttallii,

Q. pagodaefolia, Q. phellos, Q. stellata, Q. virginiana, Tilia americana, Ulmus alata, U. americana.

 Understory: Acer negundo, A. saccharum, Bumelia lanuginosa, Fraxinus americana, F. caroliniana, F. pennsylvanica, b

Lindera benzoin, Morus rubra, Osmanthus americana, Persea borbonia, Planera aquatica, Prunus caroliniana, Sassafras

albidum, Ulmus rubra, Viburnum rifidulum. 

 Includes additional species found in only one exemplary forest. All nomenclature follows Godfrey (1988). c
4

Table 3—Range and median basal area (m /ha) for hectare (ha) (m /ha)] range reported by Parker (1989) for 2

common overstory species, for all trees, and for small

and large trees in five old-growth southern mixed

hardwood forests 

Basal area

Group Range Median

Fagus grandifolia 2.6- 9.3 5.4

Magnolia grandiflora 1.5-11.6 4.0

Liquidambar styraciflua 1.1- 4.3 3.7

Quercus nigra 0.7- 3.2 1.9

Q. alba 0.2- 3.0 1.0

Q. michauxii 0.1- 1.1 0.9

Liriodendron tulipifera 0.4- 2.7 0.8

Nyssa sylvatica 0.7- 2.3 1.1

Pinus glabra 3.9- 6.9 3.9

P. taeda 0.1-10.5 0.5

Carya glabra 0.5- 1.8 0.5

Q. hemisphaerica 0.3- 1.0 0.3

Q. shumardii 0.1- 3.1 0

M. virginiana 0.1- 1.2 0.1

C. tomentosa 0 - 0.5 0

C. cordiformis 0.3- 0.3 0

Tilia americana 0.2- 0.6 0

All trees 29.0-40.0 33.0

Small trees

(d.b.h. $10 cm) 27.0-38.0 33.0

Large trees

(d.b.h. $50 cm) 12.0-24.0 13.0

Minimum d.b.h. of trees included in the calculation of basal area for

common species and for all trees was 2 cm for Woodyard Hammock, Titi

Hammock, and Tunica Hills; 1 cm for Zemurray Forest; and 4.5 cm for

Weir Woods. All nomenclature follows Godfrey (1988).

understory species were eastern hophornbeam in

Woodyard Hammock, flowering dogwood (Cornus florida

L.) in Titi Hammock, two-wing silverbell (Halesia diptera

Ellis) and Florida anise (Illicium floridanum Ellis) in

Zemurray Forest, American hornbeam in Tunica Hills, and

American holly in Weir Forest. In stands not recently

affected by a hurricane, understory trees may be clumped

in localized gaps (Platt and Hermann 1986). Characteristic

species of lianas in the exemplary forests were cross-vine

(Bignonia capreolata L.), wood-vamp (Decumaria

barbara L.), poison-ivy [Toxicodendron radicans (L.)

Kuntze], bullbriar (Smilax rotundifolia L.), and summer

grape (Vitis aestivalis Michx.); the main epiphyte was

Spanish-moss [Tillandsia usneoides (L.)].

Density and Basal Area

Total basal area in the exemplary forests was similar to the

269 to 377 square feet per acre [25 to 35 square meters per

2

hardwood forests of the central hardwood region (table 3).

However, density of trees 4 inches (10 cm) in d.b.h. or

larger ranged from 139 to 176 trees per acre (344 to 435

trees per ha) [median 160 trees per acre (396 trees per ha)],

while the density range reported for the central hardwood

region was 65 to 173 trees per acre (161 to 427 trees per

ha) (Parker 1989). In addition, the median tree density in

the exemplary forests exceeds the 101 trees per acre (250

trees per ha) reported by Martin (1992) for a mixed

mesophytic forest in Kentucky. High density in the

exemplary forests resulted largely from the large number of

small trees (table 2). Reported density and basal area of

large overstory trees [d.b.h. $20 inches (50 cm)] were

extremely high in Zemurray Forest [28 trees per acre (70

trees per ha)], [258 square feet per acre (24 m /ha)] (White 2

1987). In the rest of the exemplary forests, density of large

overstory trees ranged from 16.2 and 19.0 trees per acre (40

and 47 trees per ha) and basal area from 129 to 151 square

feet per acre (12 to 14 m /ha) (table 2). 2

Size/Age Distributions

Few overstory trees in the exemplary stands reached 39

inches (100 cm) in d.b.h., but many exceeded 20 inches (50

cm) (table 4). In the overstory of these forests, long-lived

species, such as American beech, southern magnolia, and

sweetgum, were mixed with short-lived trees, such as

spruce pine or loblolly pine (table 4). When all tree species

were combined, density of trees in these forests decreased

with tree size (Harcombe and Marks 1978, White 1987,

Platt and Schwartz 1990). Populations of Pinus spp.,

however, usually had a scarcity of small sized classes,

suggesting a single-aged condition. For long-lived dominant

overstory species, small trees were scarce in some forests

but not in others. For example, southern magnolia had very

few juveniles in Woodyard Hammock, but many in Weir

Forest (see also Harcombe and Marks 1978, Hirsh 1981,

Glitzenstein et al. 1986, White 1987).

Gaps

Expanded gaps (Runkle 1982) in Woodyard Hammock

occupied about 30 percent of the area before Hurricane

Kate. Before Hurricane Kate, small individuals of hickories

(Carya spp.), water oak, and swamp chestnut oak in

Woodyard Hammock were associated with old gaps (Platt

and Hermann 1986). In addition, rapidly growing, shortlived, deciduous understory species (such as eastern

hophornbeam, American hornbeam, and flowering

dogwood) were associated with new gaps, while the slowgrowing, long-lived, evergreen American holly and

sweetleaf [Symplocos tinctoria (L.) L'Hér.] were associated 
5

Table 4—Ranges and averages (medians) of forest absence of remains of mapped trees that died in Woodyard

structural characteristics observed in southern mixed

hardwood forests

Structural Number

characteristic Range Median of sites

Cm Cm

D.b.h. of largest tree

Magnolia grandiflora 72-126 95 5

Fagus grandifolia 77- 98 86 5

Nyssa sylvatica 58- 86 81 4

Pinus glabra 72- 81 80 3

Liriodendron tulipifera 54-116 78 4

P. taeda 47- 80 72 4

Quercus alba 48- 82 71 4

Carya glabra 60- 78 70 3

Q. nigra 31- 79 68 5

Liquidambar styraciflua 54- 91 63 5

Q. michauxii 39- 74 61 5

Q. hemisphaerica 38- 55 54 3

Age of old trees in yearsa

M. grandiflora 214 1

F. grandifolia 210 1

L. styraciflua 210 1

Q. alba 170 1

P. taeda 94 1

P. glabra

Variation in tree diameter

No. of 10-cm d.b.h. classes 8- 11 9 4

Evergreen species

Basal area (percent of total) 7- 52 43 5

Dead trees 

Standing dead (snags per ha) 11 1

Downed logs (m per ha) 72 1

3

 Percentile 95 of the age frequency distribution. All nomenclature a

follows Godfrey (1988).

with old gaps (Platt and Schwartz 1990). After Hurricane

Kate, many juvenile spruce pine and eastern hophornbeam

reached 1 inch (2 cm) in d.b.h. in gaps enlarged by the

disturbance.

 Dead Component

Density of standing dead trees observed in Woodyard

Hammock 7 years after Hurricane Kate [5 snags per acre

(11 snags per ha)] was lower than the 8 to 18 snags per

acre (19 to 44 snags per ha) range reported for the central

region mixed mesophytic forest (Parker 1989). Total

volume of dead wood on the forest floor in Woodyard

Hammock in 1992 was probably influenced by Hurricane

Kate (table 4). Twice as much dead wood per unit area

occurred in gaps as beneath closed canopy. It took about 9

years for one-half of the dead trees [d.b.h. $4 inches (10

cm)] to disappear (estimated in 1992 from the presence or

Hammock between 1978 and 1990). Logs of spruce pine

and eastern hophornbeam disappeared more slowly than

logs of southern magnolia, American beech, American

hornbeam, and American holly.

Regional and Local Variation

Southern mixed hardwood forest species composition,

diversity, and proportion of evergreen and deciduous trees

vary throughout the Coastal Plain. The geographical

distributions of some tree species terminate or are

interrupted within the Coastal Plain, presumably in relation

with climatic gradients or geological history. For example,

the distributions of spruce pine and sourwood (Oxydendron

arboreum) do not extend west of the Mississippi River, and

the distribution of yellow-poplar (Liriodendron tulipifera

L.) terminates in central Louisiana (Beck 1990, Kossuth

and Michael 1990, Overton 1990). Before European

settlement, no pines grew near the Mississippi River

(Delcourt and Delcourt 1974), explaining the absence of

pines in the Tunica Hills old-growth forest.

The number of evergreen species in the southern mixed

hardwood forests decreases to the north, while the number

of deciduous species decreases to the south (Blaisdell et al.

1974, Greller 1980, Ware et al. 1993). The northernmost

limit of southern magnolia occurs at the southeastern corner

of North Carolina (Ware 1970, Ware et al. 1993). This limit

has been proposed to be associated with seed and seedling

sensitivity to freezing (Evans 1933). American beech and

white oak do not grow in southeastern Georgia and the

peninsula of Florida (Ward 1967). Ranges of the other

temperate tree species terminate progressively from north to

south along the central ridge of the peninsula of Florida,

and very little mixing occurs with tropical tree species. As a

result, tree-species diversity in temperate hardwood forests

decreases southward along the peninsula (Greller 1980,

Schwartz 1988, Platt and Schwartz 1990). Diversity of

epiphytes and ferns, however, increases in this direction by

the addition of tropical species (Schwartz 1988, Platt and

Schwartz 1990). In mesic hardwood forests of northern

Florida, less than one-third of the overstory species are

evergreen; but farther south in the peninsula, evergreens are

more than one-half of the overstory species (Greller 1980).

Located west of the Florida peninsula, the exemplary

forests contained less than one-third evergreen species in

the overstory, but the basal area of these evergreen species

was 43 to 52 percent (table 4) of total basal area of

overstory species (except in the Tunica Hills, where it was

7 percent).
6

Old-growth composition of southern mixed hardwood In Woodyard Hammock, a summer drought in 1981 killed

forests varies with local soil conditions and subtle many small trees and slowed the growth rate of trees.

topographic gradients. In northern Florida, Monk (1965) Intermittent streams, changing their course across the forest,

found that the proportion of evergreen trees in hardwood have also caused localized tree mortality in Woodyard

forests was highest on dry, sterile soils and that maximum Hammock.

community diversity occurred on mesic calcareous soils. In

ordination analyses of the original 30 quantitative censuses The most conspicuous disturbances affecting southern

from Quarterman and Keever (1962), Ware (1978, 1988) mixed hardwood forests are hurricanes. All of the

found that higher abundance of laurel oak (Q. exemplary forests were exposed to four to six storms with

hemisphaerica Michx.) and lower abundance of American winds over 62 miles per hour [100 kilometers per hour

beech were apparently associated with relatively low (km/hour)] between 1886 and 1992 (see appendix). In

moisture and coarse soil texture. In eastern Texas, Marks 1985, Hurricane Kate passed near Woodyard Hammock

and Harcombe (1981) found that species composition and Titi Hammock with winds of about 100 miles per hour

varied with changes of soil texture over the landscape. (160 km/hour). In Woodyard Hammock, this storm

Their lower slope hardwood pine forest, which had the extensively disrupted the canopy; expanded gaps (Runkle

maximum proportion of evergreen species, occurred in the 1982) were increased from 31 to 62 percent of the area, and

middle of the soil texture gradient. In northwest Florida, 58 percent of large hardwood trees and 80 percent of large

Gibson (1992) found that topography accounted for the pines were damaged. However, tree mortality was low; 98

main compositional differences within a forest dominated percent of all hardwoods, 95 percent of large [d.b.h. $18

by laurel oak. inches (45 cm)] hardwoods, 65 percent of all pines, and 61

Both Platt and Schwartz (1990) and Harcombe et al. (1993) Kate on species diversity was minor; the number of

suggested that fire occurrence interacts with edaphic factors common species (measured as N1 = e ) was 12.0 in 1984

and topography to determine the distribution of hardwood and 11.7 in 1986. In Titi Hammock, the patterns of tree

forest tree species. According to Platt and Schwartz (1990), damage and mortality were similar. None of the hurricanes

low intensity, growing-season fires on the uplands may recorded near the exemplary forests between 1886 and

prevent some species from mesic and hydric forests, such 1992 greatly exceeded the intensity of Hurricane Kate

as sweetgum, water oak, loblolly pine, and American (Jarvinen et al. 1984). Hence, none of these forests has

hornbeam, from invading upslope. A similar situation was undergone a hurricane of the magnitude of Camille (1969)

proposed for the Kisatchie National Forest in western or Hugo (1991). Such major hurricanes are, however, very

Louisiana, where fire was hypothesized to play a key role in unlikely to impact on these forests because they have a low

determining the differences between mesic stands, frequency of landfall along the Gulf of Mexico coastline.

dominated by American beech, southern magnolia, swamp

chestnut oak, white oak, and water oak, and drier stands In Woodyard Hammock, disruption of the canopy by

dominated by post oak (Q. stellata), blackjack oak (Q. Hurricane Kate prompted marked changes in tree

marilandica), southern red oak (Q. falcata), black oak (Q. recruitment, growth, and mortality in subsequent years.

velutina), white oak, Carya spp., shortleaf pine (P. echinata Before the disturbance, recruitment rates were low, and

Mill.), and loblolly pine (Martin and Smith 1991). thinning of juveniles and small trees was intense. Tree

Old-Growth Dynamics

Tree recruitment, growth, and mortality in old-growth

southern mixed hardwood forests do not seem to have

occurred at steady annual rates. Instead, these processes

would have had pulses as a result of natural disturbances

(Harcombe and Marks 1978, Glitzenstein et al. 1986, Platt

and Schwartz 1990). In the past, creeping fires that started

in the uplands might have frequently killed seedling and

understory trees and damaged adult trees (especially

American beech) (Blaisdell et al. 1974). In contrast, crown

or devastating fires have not been recorded in these forests.

percent of large pines survived. The effect of Hurricane

H' 

mortality decreased with increasing size, and large tree

mortality was very low. Average growth rates of large trees

were high, and juveniles were almost completely

suppressed (table 5). As a result, total density was

decreasing, and basal area was becoming increasingly

concentrated in large trees. After the Hurricane, there was a

massive recruitment into the juvenile size class [d.b.h. $1

inch (2 cm)], which mostly resulted from release of small

individuals present at the time of the storm. Juvenile

mortality decreased and juvenile annual growth rate more

than doubled (table 5). Mortality of large trees increased

greatly, and large-tree annual growth rate was halved (table

5). As the result, total tree density (d.b.h. $1 inch (2 cm)]

increased 36 percent in 6 years, even though total tree basal
7

Table 5—Average rates of recruitment, tree growth, and

mortality observed in Woodyard Hammock during hardwood forests is characterized by high frequency (several

periods before (1978-84), including (1984-86), and after

(1986-92) Hurricane Kate

Vital rates 1978-84 1984-86 1986-92

Recruitment 13.8 43.3 81.0

 (trees/ha/yr)

Annual growth (mm/yr)

Juveniles .66 (.02) 1.27 (.04) 1.61 (.03)

Small trees 1.90 (.05) 1.30 (.04) 1.94 (.06)

Large trees 4.07 (.19) 1.64 (.15) 1.96 (.16)

Annual mortality (percent)

Juveniles 5.58 (.21) 5.31 (.38) 3.41 (.15)

Small trees 2.58 (.15) 4.04 (.33) 1.98 (.14)

Large trees .71 (.23) 4.73 (.99) 2.03 (.39)

Standard errors shown in parentheses. Juveniles (2 cm # d.b.h. <10 cm);

small trees (10 cm # d.b.h. <50 cm); large trees (50 cm # d.b.h.).

area remained stable. As most of the new recruits were

spruce pine or eastern hophornbeam, forest species

composition [d.b.h. $1 inch (2 cm)] changed rapidly in the

years that followed Hurricane Kate. In contrast, the rate of

change in species composition of trees ›4 inches (10 cm) in

d.b.h. declined from the prehurricane period, mainly

because ongoing thinning of suppressed spruce pine and

American hornbeam ceased.

The Nature of Old Growth

The southern mixed hardwood forests were presented by

Quarterman and Keever (1962) as the “climatic climax” in

the southeastern Coastal Plain, as part of a long tradition of

assigning climax status to the mesic hardwood forests of the

region (Gano 1917; MacGowan 1937; Kurz 1944; Braun

1950; Monk 1965, 1967, 1968; Blaisdell et al. 1974;

Delcourt and Delcourt 1974, 1977; Ware et al. 1993). The

main basis for this argument has been that fire suppression

in the upland pine-savannas is followed by hardwood

encroachment. This concept was based on the assumption

that southern mixed hardwood forests were essentially

equilibrium forests that resulted from a directional

autogenic succession (Quarterman 1981). However, this

concept gave little consideration to hurricanes that

frequently impact the Coastal Plain (Jarvinen et al. 1984,

Neumann et al. 1992). These disturbances constitute a

strong allogenic influence that may prevent these forests

from approaching an equilibrium (Glitzenstein et al. 1986,

Platt and Schwartz 1990).

The hurricane regime affecting the southern mixed

per century) of storms that, while extensively damaging the

canopy, result in low tree mortality. In contrast, complete

forest devastation by natural agents, such as very intense

hurricanes or crown fires, appears to be extremely rare. In

each site, recurrence time of hurricanes may be highly

variable, and patterns of hurricane damage may vary among

storms. Frequent, nondevastating hurricanes would account

for the larger proportion of the area occupied by gaps, lower

density of standing dead trees, and relatively smaller sizes of

canopy trees than in northern temperate old-growth forests

(Quigley and Platt 1996). High tree density would occur

because mortality of suppressed trees is likely to be

interrupted by a disturbance. Repeated canopy disruption,

with the consequent increases in light in the understory,

would account for high rates of recruitment and growth.

Hurricanes can be followed by waves of tree recruitment,

growth, and death resulting in changes in the density and

structure of tree populations and in consequent fluctuations

in forest species composition. Under a regime of frequent

low intensity hurricanes, stands of southern mixed

hardwood forests are not likely to reach an equilibrium

structure and composition. Regeneration in periodic canopy

openings would prevent the long-lived, shade-tolerant

canopy trees from displacing the short-lived, shadeintolerant pines and the small statured understory species

(Connell 1978). However, the nondevastating nature of

such disturbances also results in shade-tolerant species

surviving frequent disruptions. In addition, since hurricanes

may disrupt large proportions of the canopy, changes in

disturbed patches are likely to be reflected throughout the

stand (O'Neill et al. 1986, Smith and Urban 1988). The

classical interpretation of these effects of frequent,

nondevastating disturbances, consistent with the directional

succession model, is that disturbances produce a

retrogression to preclimax seral stages followed by a new

autogenic succession toward the climax (MacGowan 1937).

However, because hurricanes often occur at intervals shorter

than the lifespan of trees, and because their immediate

effects can be variable, successional tendencies due to

tolerance and competitive displacement would be minor

compared to the processes of regeneration and change that

result from the timing and immediate effects of the

disturbances (Platt and Schwartz 1990). One strong

suggestion against the retrogression notion is that spruce

pine, a light-demanding species that is recruited into the

canopy in gaps enlarged by the hurricanes, does not behave

as a pioneer, but instead is endemic to these old-growth

forests. As the climate of the southeastern Coastal Plain

along the Gulf of Mexico coastline remained relatively
8

unchanged during the Pleistocene age, chronic disturbance

of these forests may have selected traits in the life history of

the tree species that make them adapted for, or even

dependent on, the disturbance (Denslow 1980, Platt and

Schwartz 1990).

Disturbances affecting the southern mixed hardwood forests

appear to be critical for both regeneration and change in

old-growth stands. Allogenic disturbances would have been

necessary for recruitment or growth of many of the tree

species into the canopy of these forests and, therefore, for

their continued coexistence. Wide variation in the frequency

of disturbances and probably in their immediate effects

would have determined changes in stand structure and

composition. As complete stand devastation by natural

agents was probably very rare in this forest type, old-growth

stands may have existed for many generations of trees under

the effects of frequent, nondevastating disturbances.

Regeneration and change associated with these disturbances,

rather than the hypothesized directional succession

(Quarterman and Keever 1962, Bormann and Likens 1979,

Quarterman 1981), are likely to have dominated the natural

dynamics of these forests over most of their history.

Acknowledgments

Funding for this research was provided by Cooperative

Research Agreement 29-834 with the Southern Research

Station and the U.S. Department of Agriculture, Forest

Service. We thank Jeff Glitzenstein and Paul Harcombe for

permission to use data from the Weir Woods; Martin

Quigley for data from the Tunica Hills; and Julie Denslow,

Margaret Devall, Paul Harcombe, David White, and Bob

Wray for reviews of earlier versions of this report. Tall

Timbers Research Station and The Nature Conservancy

provided support for mapping and monitoring the plots in

Woodyard Hammock and in Titi Hammock, respectively. America. Springer-Verlag, New York. 439 p.

Over the years, many people, including Steve Rathbun, Don

Hirsh, Greg Evans, Mary Davis, Bruce Means, Margaret

Platt, Sharon Hermann, Martin Quigley, Paul Drewa, Jason

Bill, Charles Kwit, and especially Maynard Hiss, have

helped with the field work in Woodyard Hammock and Titi

Hammock.

Literature Cited

Axelrod, D.I. 1958. Evolution of the madro-tertiary geoflora. Bot. Rev.

24:432-509.

Axelrod, D.I. 1966. Origin of deciduous and evergreen habits in temperate

forests. Evolution 20:1-15.

Barnes, B.V. 1989. Old-growth forests of the Northern Lake States: 

a landscape ecosystem perspective. Nat. Areas J. 9:45-57.

Beck, D.E. 1990. Liriodendron tulipifera L., yellow poplar. P. 406-416 in

Silvics of North America, Vol. 2, Hardwoods, Burns, R.M., and B.H.

Honkala (tech. coords.). U.S. Dep. Agric. Handb. 654.

Blaisdell, R.S., J. Wooten, and R.K. Godfrey. 1974. The role of magnolia

and beech in forest processes in the Tallahassee, Florida, Thomasville,

Georgia area. P. 363-397 in Proc. Tall Timbers Fire Ecology Conf. 13; 

Tall Timbers Research Station., Tallahassee, FL.

Bormann, F.H., and G.E. Likens. 1979. Catastrophic disturbance and the

steady state in northern hardwood forests. Am. Sci. 67:660-669.

Braun, E.L. 1950. Deciduous forests of eastern North America. Hafner,

New York. 596 p.

Clewell, A.F. 1985. Guide to the vascular plants of the Florida panhandle.

Univ. of Florida, Tallahassee. 605 p.

Connell, J.H. 1978. Diversity in tropical rain forests and coral reefs.

Science 199:1302-1310.

Davis, M.B. 1981. Quarternary history and the stability of forest

communities. P. 132-153 in Forest succession: concepts and

application. West, D.C., H.H. Sugart, and D.B. Botkin (eds.). SpringerVerlag, New York.

Delcourt, H.R., and P.A. Delcourt. 1974. Primeval magnolia-holly-beech

climax in Louisiana. Ecology 55:638-644.

Delcourt, H.R., and P.A. Delcourt. 1977. Presettlement magnolia-beech

climax of Gulf Coastal Plain: quantitative evidence from the

Apalachicola river bluffs. North-central Florida. Ecology 58:1085-1093.

Delcourt, P.A., and H.R. Delcourt. 1987. Long-term forest dynamics of the

temperate zone. A case study of late-quarternary forests in eastern North

Denslow, J.S. 1980. Patterns of plant species diversity during succession

under different disturbance regimes. Oecologia 46:18-21.

Evans, C.R. 1933. Germination behavior of Magnolia grandiflora. Bot.

Gaz. 94:724-754.

Eyre, F.H. (ed.). 1980. Forest cover types in the United States and Canada.

Soc. Am. For., Washington, DC. 148 p.

Franklin, J.F., and T. Spies. 1984. Characteristics of old-growth Douglasfir forests. P. 328-334 in Proc. of the Soc. of Am. For. Nat. Conv., 1984.

Franklin, J.F., et al. 1981. Ecological characteristics of old-growth

Douglas-fir forests. U.S. Dep. Agric. For. Serv. Gen. Tech. Rep. 

PNW-118. 46 p.
9

Franklin, J.F., et al. 1986. Interim definitions for old-growth Douglas-fir Marks, P.L., and P.A. Harcombe. 1975. Community diversity of Coastal

and mixed-conifer forests in the Pacific Northwest and California. U.S. Plain forests in southern east Texas. Ecology 56:1004-1008.

Dep. Agric. For. Serv. Res. Note PNW-447. 7 p.

Gano, L. 1917. A study in physiographic ecology in northern Florida. Bot. Thicket, southeast Texas. Ecol. Monogr. 5:287-305.

Gaz. 63:337-372.

Gibson, D.J. 1992. Vegetation-environment relationships in a southern communities of the Kisatchie National Forest, Winn and Kisatchie

mixed hardwood forest. Castanea 57:174-179. districts. Louisiana Dep. of Wildl. and Fish., Baton Rouge, LA. 371 p.

Glitzenstein, J.S., P.A. Harcombe, and D.R. Streng. 1986. Disturbance, Martin, W.H. 1992. Characteristics of old-growth mixed mesophytic

succession, and maintenance of species diversity in an east Texas forest. forests. Nat. Areas J. 12:127-135.

Ecol. Monogr. 56:243-258.

Godfrey, R.K. 1988. Trees, shrubs and woody vines of northern Florida Ecol. Monogr. 35:335-354.

and adjacent Georgia and Alabama. Univ. of Georgia Press, Athens,

GA. 734 p. Monk, C.D. 1967. Tree species diversity in the eastern deciduous forest

Greller, A.M. 1980. Correlation of some climate statistics with distribution 101(918):173-187.

of broadleaved forest zones in Florida, USA. Bull. Torrey Bot. Club

24:153-166. Monk, C.D. 1968. Successional and environmental relationships of the

Harcombe, P.A., and P.L. Marks. 1977. Understory structure of a mesic

forest in southeast Texas. Ecology 58:1144-1151. Neumann, C.J., B.R. Jarvinen, A.C. Pike, and J.D. Elms. 1992. Tropical

Harcombe, P.A., and P.L. Marks. 1978. Tree diameter distributions and maps updated through 1992]. NOAA Historical Climatology Series 6-2,

replacement processes in southeast Texas forests. For. Sci. 24:153-166. Nat. Climatic Data Cent., Asheville, NC.

Harcombe, P.A., et al. 1993. Vegetation of the longleaf pine region of the O'Neill, R.V., D.L. Deangelis, J.B. Waide, and T.F.H. Allen. 1986. A

West-Gulf Coastal Plain. P. 83-105 in The longleaf pine ecosystem: hierarchical concept of ecosystems. Monographs in Population Biology

Ecology, restoration and management. Proc. of the Tall Timbers fire 23, Princeton Univ. Press, Princeton, NJ. 253 p.

ecol. conf., Hermann, S.M., K. Ross, and K. Gainey (eds.). Tall Timbers

Research, Inc., Tallahassee, FL. 418 p. Overton, R.P. 1990. Oxydendrum arboreum (L.) DC., sourwood. P. 497-

Hayward, G.D. 1991. Using population biology to define old-growth B.H. Honkala (tech. coords.). U.S. Dep. Agric. Handb. 654.

forests. Wildl. Soc. Bull. 19:111-116.

Hill, M.O. 1973. Diversity and evenness: a unifying notation and its Areas J. 9:5-11.

consequences. Ecology 54:427-432.

Hirsh, D.W. 1981. Physiognomy and spatial patterns of a beech-magnolia disturbance and patch dynamics. Academic Press, Orlando, FL. 472 p.

hammock in north-central Florida. M.S. Thesis, Florida State Univ.,

Tallahassee. Platt, W.J. 1985. The composition and dynamics of the mixed-species

Hunter, M.L. 1989. What constitutes an old-growth stand? Toward a Rep. for The Nature Conservancy.

conceptual definition of old-growth forests. J. For. 87:33-35.

Jarvinen, B.R., C.J. Neumann, and M.A.S. Davis. 1984. A tropical cyclone syndrome and characteristics of populations of trees in a mixed-species

data tape for the North Atlantic Basin, 1886-1983: contents, limitations forest. P. 309-321 in Estrada, A., and T.H. Fleming (eds.). Frugivores

and uses (updated to include storms through 30 October 1992). NOAA, and seed dispersal, Chapter 23. Dr. Junk Publishers, Dordrecht.

Nat. Hurricane Cent., Miami.

Jones, E.W. 1945. The structure and reproduction of the virgin forest of the P. 194-229 in Ecosystems of Florida, Myers, R., and J. Ewell (eds.).

north temperate zone. New Phytol. 44:130-147. Univ. of Central Florida Press, Orlando, FL.

Kossuth, S.H., and J.L. Michael. 1990. Pinus glabra Walt., spruce pine. Quarterman, E. 1981. A fresh look at climax forests of the Coastal Plain.

P. 355-358 in Silvics of North America, Vol. 1, Conifers, Burns, R.M., ASB Bull. 28:143-148.

and B.H. Honkala (tech. coords.). U.S. Dep. Agric. Handb. 654.

Kurz, H. 1944. Secondary forest succession in the Tallahassee Red Hills. climax in the southeastern Coastal Plain, U.S.A. Ecol. Monogr. 32: 

Proc. Fla. Acad. Sci. 7:1-100. 167-185.

MacGowan, W.L. 1937. Growth-ring studies of trees of northern Florida. Quigley, M.F. 1994. Latitudinal gradients in seasonal forests. Ph.D.

Proc. Fla. Acad. of Sci. 1:57-65. Dissertation, Louisiana State Univ., Baton Rouge, LA.

Marks, P.L., and P.A. Harcombe. 1981. Forest vegetation of the Big

Martin, D.L., and L.M. Smith. 1991. A survey of the natural plant

Monk, C.D. 1965. Southern mixed hardwood forest of northcentral Florida.

with particular reference to north central Florida. Am. Nat.

forest vegetation of north central Florida. Am. Mid. Nat. 79:441-457.

cyclones of the North-Atlantic Ocean, 1871-1986 [with storm track

500 in Silvics of North America, Vol. 2, Hardwoods, Burns, R.M., and

Parker, G.R. 1989. Old-growth forests of the central hardwood region. Nat.

Pickett, S.T.A., and P.S. White (eds.). 1985. The ecology of natural

hardwood forest in Titi Hammock Preserve, Thomas County, Georgia.

Platt, W.J., and S.M. Hermann. 1986. Relationships between dispersal

Platt, W.J., and M.W. Schwartz. 1990. Temperate hardwood forests. 

Quarterman, E., and C. Keever. 1962. Southern mixed hardwood forest:
10

Quigley, M.F., and W.J. Platt. 1996. Structure and pattern in temperate Ward, D.B. 1967. Southeastern limit of Fagus grandifolia. Rhodora 

seasonal forests. Vegetatio 123:117-138. 69:51-54.

Raup, H.M. 1964. Some problems in ecological theory and their relation to Ware, S. 1970. Southern mixed hardwood forest in the Virginia Coastal

conservation. J. Ecol. 52:19-28. Plain. Ecology 51:921-924.

Runkle, J.R. 1982. Patterns of disturbance in some old-growth mesic Ware, S. 1978. Vegetational role of beech in southern mixed hardwood

forests of eastern North America. Ecology 63:1533-1546. forest and the Virginia Coastal Plain. Va. J. Sci. 29:231-235.

Schafale, M.P., and P.A. Harcombe. 1983. Presettlement vegetation of Ware, S. 1988. Ordination of Quarterman and Keever's original southern

Hardin County, Texas. Am. Mid. Nat. 109:355-366. mixed hardwood forest. Castanea 53:197-206.

Schwartz, M.W. 1988. Species diversity patterns in woody flora of three Ware, S., C. Frost, and P.D. Doerr. 1993. Southern mixed hardwood forest:

North American peninsulas. J. Biogeography 15:759-774. The former longleaf pine forest. P. 447-493 in Biodiversity of the

Schwartz, M.W. 1994. Natural distribution and abundance of forest W.H., S.G. Boyce, and A.C. Echternacht (eds.). Wiley, New York.

species and communities in northern Florida. Ecology 75:687-705.

Smith, T.M., and D.L. Urban. 1988. Scale and resolution in forest Florida, Myers, R., and J. Ewel (eds.). Univ. of Central Florida Press,

structural pattern. Vegetatio 74:143-150. Orlando, FL. 

Thomas, J.W., et al. 1988. Management and conservation of old-growth White, D.A. 1987. An American beech dominated original growth forest in

forests in the United States. Wildl. Soc. Bull. 16:252-262. southeast Louisiana. Bull. Torrey Bot. Club 114:127-133.

Tyrrell, L.E. 1992. Characteristics, distribution, and management of old- White, P.S. 1979. Pattern, process, and natural disturbance in vegetation.

growth forests on units of the U.S. National Park Service: results of a Bot. Rev. 45:229-299.

questionaire. Nat. Areas J. 12:198-205. 

Vankat, J.L. 1990. A classification of the forest types of North America. Philadelphia. 167 p.

Vegetatio 88:53-66.

Southeastern United States/Lowland Terrestrial Communities, Martin,

Webb, S.D. 1990. Historical biogeography. P. 70-100 in Ecosystems of

Williams. J.L. 1827. A view of west Florida. H.S. Tanner Co.,
11

Appendix

Exemplary Forests

Woodyard Hammock is a 74-acre [30-hectare (ha)]

hardwood forest located 20 miles [32 kilometers (km)] north

of Tallahassee, Leon County, in northern Florida 

(30°35' N, 84°20' W). It occupies flat terrain along the Zemurray Forest is an 87-acre (35-ha) hardwood forest

northern shore of Lake Iamonia. Part of an antebellum located in Tangipahoa Parish in eastern Louisiana, 50 miles

plantation established in the early 1800's, it has been (80 km) north of New Orleans (30°37' N, 90°21' W). It

managed as a part of Tall Timbers Research Station since occupies a level site with acid soil, in the floodplain of

1959 (Blaisdell et al. 1974, Hirsh 1981, Platt and Hermann Chappepeela Creek (White 1987). According to NOAA

1986, Platt and Schwartz 1990). According to records of the records (Jarvinen et al. 1984), between 1886 and 1992 four

National Oceanic and Atmospheric Administration (NOAA) hurricanes passed within 62 miles (100 km) of this location

(Neumann et al. 1992), between 1886 and 1992 four with wind of more than 62 miles per hour (100 km/h).

hurricanes with winds over 62 miles per hour [100 Quarterman and Keever (1962) included this forest in their

kilometers per hour (km/h)] in 1886, 1894, 1941, and 1985 extensive survey of the southern mixed hardwood forest. In

(Hurricane Kate), passed within 62 miles (100 km) of this report, detailed information on structure and

Woodyard Hammock. Even though creeping fires composition of this forest was obtained by White (1987),

originating in surrounding pine land entered the forest in the and was based on the analysis of ten 1-acre (0.2-ha) plots.

past, this has not happened recently, at least since 1959

(Hirsh 1981). During the early 1900's, dead trees were

salvaged for firewood and some large loblolly pine (Pinus

taeda) were cut. In 1978, an 11-acre (5-ha) permanent study

plot was established in the middle of Woodyard Hammock

(Hirsh 1981, Platt and Hermann 1986). All trees in the plot

1 inch [2 centimeters (cm)] in d.b.h. or larger were

measured, mapped, and tagged. Censuses were repeated

biennially to record tree recruitment, growth, and death.

Gaps were periodically mapped as polygons formed by

connecting the bases of their bordering canopy trees

(expanded gaps) (Runkle 1982). After Hurricane Kate in

1985, damage to each mapped tree was assessed. Trees that

died between 1978 and 1992 and extant dead material were

sampled in 1992 to estimate density of snags, volume of

downed logs, and rates of disappearance.

Titi Hammock is a 289-acre (117-ha) hardwood forest

located in Thomas County, in southern Georgia, 22 miles

(14 km) south of Thomasville (30°41' N, 84°00' W). It is

part of Springhill Plantation, was established in the early

1800's, and is currently managed by The Nature

Conservancy. This forest occupies steep terrain with a 66-

feet [20-meters (m)] change in elevation along the bluffs of

Titi Creek. Along the slope, three different plant

associations can be distinguished (Platt 1985). In the past,

dead trees were salvaged for firewood and some large pines

may have been selectively cut on the upper slope. A

creeping fire entered the forest in 1968 (Blaisdell et al.

1974). The site is near Woodyard Hammock and was

exposed to the same hurricanes as that forest. A 12-acre (5-

ha) permanent study plot was established in Titi Hammock

in 1985 before Hurricane Kate struck the area. All trees in

the plot 1 inch (2 cm) in d.b.h. or larger were tagged,

measured, and mapped. Damage to mapped trees by

Hurricane Kate was assessed in 1986, and in 1990 the whole

plot was surveyed for tree growth and survival.

Tunica Hills is a forest tract located in West Feliciana

Parish in eastern Louisiana, 38 miles (60 km) northwest of

Baton Rouge and 1 mile (2 km) east of the Mississippi River

(30°47' N, 91°29' W). It has second-growth pine forests on

the uplands and old-growth hardwood forests on steep

ravine slopes (Delcourt and Delcourt 1974). The forest is

being managed as a preserve by The Nature Conservancy.

According to NOAA records (Jarvinen et al. 1984), between

1886 and 1992 six hurricanes with winds more than 62 miles

per hour (100 km/h) passed within 62 miles (100 km) of this

site. Data used in this report were obtained by Quigley

(1994), who measured, tagged, and mapped all trees that

were 0.4 inches (1 cm) in d.b.h. or greater in 16 randomly

located hardwood plots of 0.2 acres (1/16 ha) each.

Weir Forest is located 10 miles (16 km) north of

Beaumont, in Hardin County in eastern Texas, (30°16' N,

94°12' W). It occupies gently sloping terrain, slightly

dissected by intermittent streams near the Neches River

(Harcombe and Marks 1977). According to Glitzenstein et

al. (1986), this forest was not directly affected by humans

before the late 1800's. Around 1917, pines were selectively

logged. According to NOAA records (Jarvinen et al. 1984),

four hurricanes with winds more than 62 miles per hour (100

km/h) passed within 62 miles (100 km) of this forest. An 8-

acre (3-ha) plot in Weir Woods has been mapped and

monitored since 1980. Data on species composition and tree

sizes were provided by J. Glitzenstein and P. Harcombe.

Additional information was taken from detailed analyses of

structure and dynamics of this forest (Harcombe and Marks

1978, Glitzenstein et al. 1986).
Batista, William B.; Platt, William J. 1997. An old-growth definition for southern mixed

hardwood forests. Gen. Tech. Rep. SRS-9. Asheville, NC: U.S. Department of Agriculture,

Forest Service, Southern Research Station. 11 p.

This report provides an old-growth definition for the southern mixed hardwood forests based on

five exemplary stands that show no evidence of having undergone any natural catastrophe or

clearcutting for at least 200 years. This forest type occurs in the U.S. southeastern Coastal Plain

from the Carolinas to eastern Texas. The exemplary old-growth stands were restricted to slopes or

slightly elevated terraces between uplands and river- or lake-margin floodplains. They had a diverse

overstory, typically dominated by Fagus grandifolia, Magnolia grandiflora, and Pinus spp., and a

particularly diverse woody understory. Observed rates of tree recruitment, growth, and death were

rather high. These processes would occur in pulses, associated with the frequent but nondevastating

effect of hurricanes, that may result in fluctuations of species composition. We suggest that under

this disturbance regime, old-growth southern mixed hardwood forests would not undergo a

directional succession.

Keywords: Coastal Plain, conservation, disturbance, Fagus grandifolia, hurricane, Magnolia

grandiflora, old growth, restoration, southern mixed hardwood forests, temperate forest.
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