February 1990

Southeastern Forest Experiment Station

P.O. Box 2680

Asheville, North Carolina 28802
Abstract

Nursery Cultural Practices and Morphological

Attributes of Longleaf Pine Bare-Root Stock as

Indicators of Early Field Performance

Glyndon E. Hatchell, Research Forester (Retired)

Institute for Mycorrhizal Research and Development

Athens, Georgia

and

H. David Muse, Professor

Department of Mathematics

University of North Alabama

Florence, Alabama

Seven morphological characteristics of 1-O longleaf pine (Pinus pahstris Mill.) stock

were evaluated on a total of 1,600 seedlings representing eight combinations of

nursery cultural treatments. Seedlings were outplanted completely at random, with

respect to rows and planting positions, on a deep sandy site in South Carolina.

Field performance of individual seedlings was evaluated after two growing seasons

that were extremely dry. Statistical tests were derived for determining differences in

field performance of groups of seedlings, both within and between treatments. Groups

of seedlings that received vertical root-pruning treatment (sidecutting) in the nursery

and possessed key attributes-either 14 or more strong, first-order lateral roots for a

low-fibrosity root system or a minimum of 6 strong laterals for medium- or high-fibrosity

root system-met the preset goal of 80 percent survival and 60 percent of planting

stock in active height growth after two growing seasons, Within a pruning treatment,

all seedlings possessing these key morphological attributes, regardless of root-collar

diameters, performed equally well in the field. For each of the three fibrous-root

ratings, seedlings that received vertical root pruning in nursery beds had significantly

higher survival than unpruned seedlings. Vertical root pruning also significantly

increased the proportion of planting stock in active height growth after the second

growing season.

Keywords: Seedling quality, morphological grades, vertical root pruning, Pinus

palusrris.
Introduction Morphological and physiological characteristics of southern pine planting stock and

genetic factors influence seedling quality (Wakeley 1949). The ultimate measure of

seedling quality is generally considered to be field performance (Brissette 1984).

The relationship of morphological characteristics of bare-root nursery stock of the

southern pines to field survival has eluded researchers for the past 50 years. Their

objective was to provide guides or rules for separating seedlings according to their

potential for survival after transplanting. Wakeley (1954) concluded that neither the

grading rules that he had developed nor morphological grades in general could be

given an unqualified recommendation. He found that grade 1 seedlings usually grew

best among three grades, but generally did not survive as well as grade 2 stock

and sometimes did not survive as well as grade 3 stock, which ordinarily was culled.

His specifications for plantable (grades 1 and 2) longleaf pine (Pinus palustris Mill.)

stock required the culling of seedlings that (1) lacked secondary needles, (2) had a

root-collar diameter (RCD) less than 4.8 mm, or (3) had a root system (taproot) less

than 13 cm long. Unfortunately, he did not specify desirable characteristics of lateral

roots. Planting small stock necessitates a long period in the ‘grass stage’ until seedling

RCD reaches approximately 25 mm, a size associated with height growth initiation.

In one study, Wakeley (1935) found that only 11 percent of the larger grade 1 seedlings

were more than 15 cm 4 years after transplanting.

South (1987) reexamined Wakeley’s (1954) ‘critical test” of longleaf pine grades and

suggested that lack of significant differences in field performance among grades

may have been due to the small size (RCD ranged from 4.8 to 12.7 mm) of seedlings

produced at the standard, high seedbed density (323 seedlings per m*). More recent

research has shown the benefits of producing larger longleaf pine planting stock at

seedbed densities of 65 to 129 seedlings per m* (Derr 1955; Hatchelll985; Scarbrough

and Allen 1954; White 1981). Currently the minimum RCD specified for plantable

seedlings is 12.7 mm (May 1985).

Recent nursery and outplanting studies of longleaf pine indicate that certain nursery

practices, including inoculation of fumigated nursery soil with Pisolirhus tincforius

(Pt) during spring sowing, greatly increase survival and early growth of seedlings

planted on deep sandy soils (Hatchell 1985, 1986). Improved field performance also

was associated with nursery cultural practices that produced a fibrous root system,

such as vertical root pruning, maintaining low to medium seedbed density to give

individual seedlings ample growing space, and providing enough nutrients for optimum

growth. This research showed that seedlings with abundant fibrous roots and abundant

ectomycorrhizae performed better in the field than seedlings with fewer fibrous roots

and few ectomycorrhizae.

Unsatisfactory plantation survival and delayed initiation of height growth have led

forest managers to convert most of the approximately 24 million ha that once supported

virgin longleaf pine to other pine species (Mann 1969). For example, only a small

portion of the approximately 3.2 million ha of forest land in the Sandhills of Georgia

and the Carolinas, and of similar deep sands of northern Florida, is currently stocked

with longleaf pine. Longleaf pine once dominated the Sandhills, and its deep root

system probably makes it the most desirable pine to plant on these fast-draining

soils. But planting longleaf pine there makes little sense unless high survival and

rapid height growth initiation can be assured (Hatchell and Marx 1987).
Methods

The objectives of the research described here were (1) to test the effects of nursery

cultural practices on morphological attributes of bare-root seedlings and on field

performance after outplanting on a Sandhills site, and (2) to associate key morphological attributes of the seedlings with field performance for a better understanding of

seedling quality and for possible use as a guide for culling poor-quality seedlings.

The goal set for field performance was a minimum of 80 percent survival and 60

percent of stock in active height growth at the end of two growing seasons. Performance

was observed in 1986 and 1987, two extremely dry years. Thus, stress was higher

than normal and the field success we attained should be easily achievable in normal

field plantings.

The nursery phase of this research involved a factorial experiment replicated in four

randomized complete blocks at the Whitehall Experimental Nursery, Athens, GA,

during 1985 (Hatchell 1987). The three factors and levels of each were: (1) vertical

root pruning (sidecutting) three times (June 25, August 16, and September 30) to a

depth of 15 cm vs. unpruned control; (2) seedbed densities of 65 (low) or 129 (medium)

seedlings per m2; and (3) spacings of seed drills at either 15 cm (single drill, current

standard) or 30 cm (double drills 2.5 cm apart). The eight treatment combinations

were:

Treatment Vertical

number root pruning

Seedbed

density

Drill

spacing

(cm)

Pruned

Pruned

Pruned

Pruned

Unpruned

Unpruned

Unpruned

Unpruned

Low

Low

Medium

Medium

Low

Low

Medium

Medium

1 5

3 0

1 5

3 0

1 5

3 0

1 5

3 0

Pt vegetative inoculum was applied to the fumigated nursery soil during spring sowing

(March 20, 1985). Wooden frames used to support the raised seedbeds prevented

undercutting and root-wrenching treatments.

Seedlings were lifted during December 1985, and 50 seedlings that met Wakeley’s

(1954) minimum specification for grade 2 stock were randomly selected from each

of 32 nursery plots. Numbered tags were attached to 1,600 seedlings, and seven

morphological attributes of each seedling were recorded: (1) RCD (mm); (2) fresh

weight (g); (3) number of strong, first-order lateral roots (NSFOLR) with diameters

larger than 1 mm (Kormanik 1986); (4) visual rating of the abundance of fibrous

roots as low = 1, medium = 2, or high = 3; (5) visual estimate of the percentage of

short roots ectomycorrhizal with Pt; (6) visual estimate of the percentage of short

roots ectomycorrhizal with all fungi; and (7) needle length (cm). Seedlings were

placed in kraft bags and held in cold storage for 9 or 10 days before outplanting.

Ten seedlings having grades 1 or 2 characteristics were also collected at random

from each nursery plot for destructive analysis.
The outplanting site, which was located on the Savannah River Forest Station, Aiken,

SC, was prepared by applying a herbicide and by burning. Brown-spot needle blight

(Scirrhia a&o/a (Dearn.) Sigg.) was not a problem on the study area. The soil type

is Lakeland sand (thermic, coated Typic Quartzipsamments), which is excessively

well drained. A dark-gray layer of sand extends from the surface to a lo-cm depth.

Below it are 2 m or more of loose sand. The soil is typical of deep sand in the Sandhills

Province; ft has low moisture holding capacity and low nutrient availability. Average

nutrient contents (in p/m) in samples of the 0- to 15cm depth collected in July of

the second growing season were: total N, 324; available P, 10; extractable K, 34;

extractable Ca, 24; and extractable Mg, 12; pH was 4.8, organic matter content was

1.8 percent, and cation exchange was 0.6 meq/l 00 g (Analyses by A&L Laboratories,

Inc., Memphis, TN).

Seedlings were machine planted at approximately a 2- by 3-m spacing. Planting

was completely randomized with respect to nursery cultural treatments and nursery

plots. After planting, the number and location of each seedling were recorded to

allow the association of field responses of individual seedlings with nursery cultural

treatments and morphological attributes.

At the end of the second growing season, RCD and height of each seedling were

measured and mortality was recorded, by seedling number. These field data, the

nursery cultural treatment, and the seven morphological attributes were analyzed on

an individual seedling basis. Seedling volume index (D*H) was calculated as a

nondestructive surrogate of seedling biomass (Hatchell and others 1985; Ruehle

and others 1984). A stem height 110 cm was considered evidence of active height

growth. The percentage of the seedling stand in active height growth was based on

the number of seedlings initially planted. Thus, proportions of seedlings having certain

morphological characteristics, and their performance in terms of both survival and

height growth initation, had the same base.

Responses of individuals and groups of seedlings to treatments were subjected to

correlation and regression analyses. Analyses of variance (ANOVA’s) of the factorial

experiment were made for morphological attributes and for field responses, and

means were separated with Duncan’s multiple range test at P = 0.05. For other

comparisons, probability levels of 0.001, 0.01, or 0.05 were used.

The field-planting design, in which each seedling essentially constituted a plot, was

selected to provide great flexibility for innovative analysis. In a forthcoming publication,

Muse and Hatchell describe the design in detail, so the discussion of analysis here

is brief. Large numbers of plots permitted the study of individual seedling attributes

in relation to early field performance. After nursery seedling attributes that contributed

to high survival and early initiation of height growth had been determined, “target

zones” for desirable characteristics were established, and field performance of

seedlings falling inside the target zones was compared with that of seedlings that

simply qualified by Wakeley’s (1954) grading criteria.
Where appropriate, the usual two-sample independent proportions test was applied.

For comparisons involving partially dependent samples, the test statistic was adjusted

to account for the associated correlation between sample proportions. For example,

all target-zone seedlings also met Wakeley’s criteria for standard seedlings. Therefore,

comparisons of sample proportions involved seedlings common to each group as

well as non-target-zone Wakeley’s (1954) standard seedlings. The associated adjusted

test statistic was given by

t = W/Var(W)

Where

W = X,/n, - (X, + XJ/(n, + nJ,

X, = number of surviving (or active height growth) target-zone seedlings,

n, = total number of target-zone seedlings,

x2 = number of surviving (or active height growth) non-target-zone Wakeley’s

standard seedlings,

r-r2 = total number of non-target-zone Wakeley’s standard seedlings,

x, + x2 = number of surviving (or active height growth) Wakeley’s standard

seedlings,

n, + r-r2 = total number of Wakeley’s standard seedlings,

f, = X,/n,, f, = X2/n,,

and

Var (W) = n22[f, (1 -f,)/n, +f,(l -f,)/n,l/(n, +nJ2.
l-t-l ;I

-10 L

NDJFMAMJJASONOJFMAMJJASO

1985 1986 1987

MONTHS

Figure 1 -Deviation of monthly precipitation from normal precipitation. Data were

recorded at a weather station 7.2 km from the study area.

Results and

Discussion

The 1986 and 1987 growing seasons were very dry (fig. 1). In the spring and early

summer of 1986, the rainfall deficit was more than 20 cm before heavy rain occurred

in August. Furthermore, average daily temperature was high, especially during July

when the record for the past century was broken.

Results 1 year after outplanting were reported (Hatchell 1987). Vertical root pruning

and seedbed density altered morphological attributes of seedlings (Hatchell 1987).

Seedling survival and vigor were strongly correlated with abundance of fibrous roots,

NSFOLR, and the interaction of these attributes. Vertical root pruning significantly

increased survival (mean = 71.6%) compared with unpruned seedlings (51.2%).

At the end of the second growing season, seedling survival dropped only slightly

from the first year (69.1% for pruned vs. 47.8% for unpruned); however, no nursery

treatment combination reached the goals of 80 percent survival and 60 percent of

initial stand in active height growth. Without culling of unsatisfactory nursery seedlings,

therefore, planters cannot anticipate satisfactory initial longleaf survival in the Sandhills

in dry years, Producing satisfactory seedlings at nurseries requires a combination of

appropriate cultural practices and appropriate grading criteria.

Effects of Nursery

Cultural Practices

Vertical root pruning significantly (P = 0.001) increased not only the fibrosity of seedling

root systems but also the second-year survival and growth of seedlings (table 1).

Seedbed density significantly affected all morphological attributes except needle

length. Seedbed density also significantly affected initiation of height growth but not
survival. At the low and medium densities, respectively, average values for morphological attributes were: RCD, 12.6 vs. 10.2 mm; fresh weight, 108 vs. 69 g; NSFOLR 9.3

vs. 5.1; fibrous root rating, 1.7 vs. 2.0; Pt ectomycorrhizae, 54 vs. 62 percent; and all

ectomycorrhizae, 62 vs. 68 percent. Among the eight nursery cultural treatments,

the combination of low seedbed density, vertical root pruning, and the 15cm drill

spacing was the only one that resulted in 60 percent of stock in active height growth

at age 2. The only significant effect (P = 0.05) of drill spacing was observed at the

wider spacing where total fresh weight was increased 4 g, apparently due to additional

root mass.

Certain data obtained in destructive analysis of seedlings: e.g., shoot dry weight,

root dry weight, and shoot-root ratio, provided little help for interpreting field

performance of outplanted stock. Shoot-root ratio (with overall mean of 3.72) was

not affected by nursery cultural practices and did not affect field performance. A

similar shoot-root ratio was observed for spring-sown longleaf pine produced at

medium seedbed density (Hatchell 1986).

Effects of

Morphological

Attributes

Linear correlations among six morphological attributes of vertically root-pruned or

unpruned seedlings are presented in table 2; needle-length data are omitted because

they were not correlated with the other attributes and they were not related to the

field responses of seedlings. With 800 observations for each pruning treatment,

several correlations that were statistically significant had relatively low r values. But

some of these relationships may be useful in the understanding of seedling quality.

RCD was positively correlated with total fresh weight and NSFOLR. RCD and fibrous

root rating were negatively correlated. NSFOLR and total fresh weight had high positive

correlations (r ~0.77). The fibrous root rating was positively correlated with the two

ectomycorrhizal attributes and was negatively correlated (r = -0.16) with NSFOLR.

Linear correlations between field response variables and morphological attributes of

vertically root-pruned and unpruned stock presented in table 3 were based on

individual seedlings or on the 25seedling groups used in computing the percentage

of seedlings surviving or in active height growth after two growing seasons. To

investigate a single curve form, reciprocals of independent variables and certain

interaction variables were tested. Survival of pruned seedlings was significantly (P =

0.05) correlated with the reciprocal of the ectomycorrhizal variables. Survival of

unpruned seedlings was correlated with the reciprocal of fibrous root rating and

percentage of short roots ectomycorrhizal either with Pt or with all fungi. High

correlations (r 10.45) were observed between percentage of seedling stands in

active height growth and the interaction variable, NSFOLR X the fibrous root rating.

Height, RCD, and D*H of individual seedlings were significantly correlated with nearly

all of the independent variables.

Although multiple linear regression analyses based on first-year data showed promise

with regard to identifying useful indicators of seedling quality (Hatchell 1987)

subsequent analyses using second-year data were unacceptable because of relatively

low multiple correlation coefficients (R* ~0.41 for survival and R* co.66 for active

height growth). The difficulty in developing reliable regressions arose from the

intercorrelation of morphological attributes (table 2) and from the limited number of

significant linear relationships with respect to survival and height growth initiation

(table 3).
5-B 9-10 11-12 13-14 15-16 1 17

RCD (mm) CLASSES

Figure 2-Percent distributions of planting stock among root-collar diameter (RCD)

classes after specific nursery treatments. Nursery cultural treatments: LD = low

seedbed density; MD = medium seedbed density; P = vertical root pruning; UP =

unpruned roots.

RCD as Indication of Figure 2 shows the frequency distributions of RCD at outplanting time for combinations

Field Performance of seedbed density and vertical root-pruning treatments. Pruning had little effect on

the distributions. The RCD class with the highest frequency was 11-12 mm for low

seedbed density and 9-10 mm for medium seedbed density. An average of 6 percent

of the planting stock had a RCD of 5 to 8 mm at the low seedbed density compared

with 25 percent at the medium seedbed density. Some 9 percent of the seedlings

produced at the low seedbed density had an RCD of 17 mm or larger compared

with only 2 percent at the medium density.

Percentages of both survival and planting stock in active height growth after 2 years

in the field are shown in figure 3. Among seedlings whose roots were pruned, the

only RCD classes that approached the goals of 80 percent survival and 60 percent

height growth initiation at age 2 were: at low seedbed density, 13-14 mm RCD (79%

survival and 62% in active height growth) and 15-16 mm RCD (80 and 73%,

respectively), and at medium seedbed density, 1 l-1 2 mm (80 and 57%, respectively),

and 13-14 mm (73 and 60%, respectively). For seedlings with unpruned roots, all

RCD classes were well below the performance goal.

Because White (1981) had found that only seedlings with RCD 213 mm survived up

to 3 weeks of cold storage without loss in survival, May (1985) recommended planting

of stock with minimum RCD of 13 mm. May’s (1985) recommendation was intended

to direct nurseries away from Wakeley’s (1954) recommendations for high seedbed

density and specifications for RCD ~6.4 mm for grade 1 and RCD ~4.8 mm for

grade 2 stock. Lauer (1987) reported that longleaf pine stock with RCD c 11 mm

was slow to initiate height growth and that the highest response at age 2 was from

stock with RCD 119 mm. Smaller stock @CD, 5 to 11 mm) was more susceptible to

damage by brown-spot needle blight.
6 0

5 0

4 0

3 0

2 0

5 10

r,

60

7 0

6 0

5 0

4 0

3 0

2 0

10

E ~~ [,, - ii-12 13-14 15-16 2 17 5-8 9-10 ii-12 13-14 15-16 2 17

6o :MD, UP -A- 2No-WI SWIVIVAL

70 -

..i). ACTIVE HT

60 -

0 ’

5-6 9-10 Ii-12 13-14 15-16 2 1 7 5-6 9-10 ii-12 13-14 15-16 2 17

RCD (mm) CLASSES

Figure 3-Percent survival and percent of longleaf pine seedlings in active height

growth 2 years after planting, by root-collar diameter (RCD) of stock. Nursery cultural

treatments: LD = low seedbed density; MD = medium seedbed density; P = vertical

root pruning: UP = unpruned roots.

Effects of Root

Morphology

Root fibrosity and NSFOLR strongly influenced the performance of individual seedlings

in this study. Vertical root pruning increased fibrosity of roots. Visual fibrosity ratings

were 18.5 percent low, 60.2 percent medium, and 21.2 percent high for pruned

seedlings and 39.2 percent low, 52.6 percent medium, and 8.1 percent high for

unpruned seedlings. Furthermore, for any of the three fibrosity ratings, seedlings

receiving vertical root pruning performed significantly better than unpruned seedlings.

Perhaps, vertical root pruning improved field performance by altering certain

physiological characteristics. Although vertical root pruning influenced key morphological attributes and seedling performance in the field, it did not alter the frequency

distributions of either NSFOLR or RCD. To simplify the data set and to derive statistical

analyses, we listed the data as frequency distributions consisting of (1) the number

of grades 1 and 2 (Wakeley 1954) seedlings that were randomly selected from the

9
nursery for outplanting, (2) the number or proportion of stock surviving the second

growing season, and (3) the number or proportion of seedlings in active height

growth at age 2. This concept is illustrated in figure 4, with 10 classes of NSFOLR, 3

fibrosity classes, and pruned vs. unpruned treatments. These data are also presented

in figure 5 as a percentage of initial stand surviving or in active height growth at age

2 for combinations of seedbed density and pruning treatments. These illustrations

PRUNED

0D PLANTED

a& SURVIVING

m I HEIGHT> iOcm

LOW FIBROSITY

2 0

10

80

,k

70

60

50

40

30

20

10

I

00

70

60

50

40 1

--

MEDIUM FIBROSITY

HIGH FIBROSITY

30

20

10

NSFOLR o-t 2-3 4-5 6-7 8-g 10-1112-1314-1516-17 Lie

Figure 4-Initial distribution of nursery stock, number of surviving seedlings, and

seedlings in active height growth 2 years after planting, by fibrosity class and number

of strong, first-order lateral roots (NSFOLR) for vertical root-pruned and unpruned

(page 11) seedlings.

1 0
show that even with the vertical root-pruning treatment, seedlings with limited NSFOLR,

regardless of fibrosity rating, performed poorly. However, seedlings with low fibrosity

and an exceedingly large NSFOLR performed well. Distributions are tabulated

henceforth as seven classes of NSFOLR and two classes of fibrosity, with the medium

and high ratings combined, thereby increasing the number of observations at the

extremities,

UNPRUNED

80

f

0 # PLANTED

7 0 pz] 4 SURVIVING

m I HEIGHTI 10~01

LOW FIBROSITY

80

7 0

6 0

5 0

40

3 0

2 0

10

80

7 0

6 0

5 0

4 0

3 0

2 0

1

MEDIUM FIBROSITY

H :CH FIBROSITY

10

rcD

NSFOLR o-i 2-3 4-5 6-7 s-9 10-1112-1314-1516-17 518

11
100

6 0

4 0

6 0

4 0

2 0

* Pruned-Low Density

’ Unpruned-Low Density

Pruned-Med. Density

0

I

I

Unpruned-Med. Densj ty

-0 - Survival

T&T Active Ht Growth

0

/

R

I 1

I \ P

NSFOLR 0-5 6-9 10-a a4 O-5 5-910~13*4 O-5 6-9 10-13 214 O-6 6-910-U 214

LOW MED-HIGH LOW MED-HIGH

FIBROSITY

Figure 5-Percent survival and percent of longleaf pine seedlings in active height

growth 2 years after planting, by fibrosity class and number of strong, first-order

lateral roots (NSFOLR).

1 2
Identification of

Target Zone

Mexal and South, in press, discussed the concept of an ideotype-an ideal target

seedling, having minimum RCD, etc. In the present study, the “target zone’ included

the ranges in key morphological attributes for which seedling field performance

under critical moisture stress met or closely approached the standards of 80 percent

survival and 60 percent of planting stock in active height growth at the end of the

second growing season. All target seedlings met Wakeley’s (1954) specifications for

grade 1 stock based on RCD ~6.4 mm.

The initial distribution of 800 vertically root-pruned seedlings is listed in table 4, by

NSFOLR and fibrosity classes and distributions of surviving seedlings and seedlings

in active height growth at age 2. RCD is also tabulated with the key attributes to

show its distribution and to test the hypothesis that seedlings meeting minimal

quantities of the key attributes perform alike regardless of whether their RCD was

L 13 mm. The range of RCD within the target zone for vertically root-pruned seedlings

was 8 to 17 mm or larger. The target zone is shown by the underlined counts of

seedlings that met the performance standards previously described for combinations

of key morphological attributes. The target-zone characteristics included 14 or more

NSFOLR with low root fibrosity and 6 or more NSFOLR with medium to high fibrosity.

The reduction in NSFOLR for a medium- to high-fibrosity system was supported by

a significant (P = 0.01) positive correlation between active height growth and the

fibrosity X NSFOLR interaction variable for both vertically pruned and unpruned

stock (table 3).

The overall field performance of the 800 vertically root-pruned seedlings was 69.1

percent survival and 48.8 percent in active height growth. Performance of the 377

seedlings in the target zone was 81.7 percent survival and 69.5 percent in active

height growth (table 4). The significance levels observed in the comparison of these

correlated proportions were 0.001 for both survival and height growth initiation. Within

the target zone were 170 seedlings with initial RCD of 8 to 12 mm whose 2-year

performance was 85.3 percent survival and 67.6 percent active height growth. Among

the 207 target-zone seedlings with initial RCD ~13 mm, 78.7 percent survived and

71.0 percent were in active height growth at age 2. The probability that these two

RCD groups had statistically similar field performance is 0.093 for survival and 0.478

for height growth initiation.

The overall field performance of the 800 unpruned control seedlings was 47.8 percent

survival and 26.0 percent in active height growth. The 319 seedlings in the target

zone showed 58.9 percent survival and 39.2 percent active height growth (table 5).

Comparison of these proportions resulted in significance at the 0.001 level for survival

and also for active height growth. Within the target zone, 153 seedlings with initial

RCD of 8 to 12 mm showed a 2-year performance of 62.7 percent survival and 37.3

percent active height growth; 166 seedlings with initial RCD 113 mm showed 55.4

percent survival and 41.0 percent active height growth. The probability that these

two RCD groups had statistically similar field performance is 0.1836 for survival and

0.4966 for active height growth.

1 3
Testing Effectiveness Distributions of initial seedling stands, of surviving stands, and of seedlings in active

of Target Zone height growth 2 years after outplanting, by fibrosity rating, NSFOLR, and RCD, are

presented in tables 6-l 3 for each of the eight nursery cultural treatments. The seedlings

within the previously defined target zone were denoted to provide the counts or

percentage of seedlings within the target zone for various distributions. These statistics

were used in tests designed to answer two questions: (1) Did seedlings in the target

zone perform significantly better than the overall performance shown for the treatment?

(2) Was performance of target seedlings with an RCD of 8 to 12 mm significantly

different from that of seedlings with RCD 113 mm? Counts for treatment Nos. 1 and

3, each with an overall survival of 74.0 percent, provided interesting contrasts.

Table 6 lists data for treatment No. 1 (vertical root pruning, low seedbed density,

and 15 cm-drill spacing). Some 117 of 200 seedlings receiving the treatment were in

the target zone. Survival of target-zone seedlings was 84.6 percent, and 74.4 percent

were in active height growth at age 2 (see table 6 footnote). Thus, the 117 target

seedlings exceeded the performance standards. The target seedlings showed

increases (P = 0.001) of 10.6 percentage points in survival and 14.4 percentage

points in active height growth compared with Wakeley’s (1954) standard stock (table

14). For treatment 1, the 43 seedlings with an RCD of 8 to 12 mm had 83.7 percent

survival, and 69.7 percent were in active height growth at age 2. Of 74 treatment 1

seedlings with an RCD 113 mm, 85.1 percent survived and 77.0 percent had initiated

height growth by age 2. There was no significant difference in the field performance

between seedlings with RCD of 8 to 12 mm and seedlings with RCD 113 mm (f =

0.841 for survival and P = 0.134 for percent of initial stand in active height growth).

Table 8 lists data for treatment No. 3 (vertical root pruning, medium seedbed density,

and 15 cm-drill spacing). Some 67 of the 200 seedlings receiving treatment 3 were

in the target zone. Survival of target seedlings was 89.6 percent, and 76.1 percent

were in active height growth. Compared with standard stock, target seedlings had

15.6 percentage points higher survival and the proportion in active height growth

was 30.1 percentage points higher (table 14). The differences were statistically

significant at P = 0.001. In the target zone, 42 seedlings with initial RCD of 8 to 12

mm had 88.1 percent survival and 73.8 percent active height growth at age 2.

Twenty-five seedlings with initial RCD 213 had 92.0 percent survival and 80.0 percent

in active height growth (table 8). There was no significant difference in the performance

of the two RCD groups (P = 0.596 for survival and P = 0.555 for active height growth).

Testing differences in second-year performance of target-zone seedlings vs. Wakeley’s

(1954) standard grades 1 and 2 stock showed: for vertically root-pruned seedlings,

target-zone seedlings had significantly (P = 0.01 or 0.001) higher performance than

standard stock, with ranges among the four treatments (Nos. l-4) from 10.6 to 15.6

percentage points higher in terms of survival and 14.4 to 30.1 percentage points

higher for active height growth; and for unpruned seedlings (treatment Nos. 5-8),

only seedlings produced at the low density (treatments 5 and 6) had both significantly

higher survival and height growth initiation, with an advantage of 11.9 to 18.4

percentage points for survival and of 8.1 to 17.0 percentage points for height growth

initiation (table 14). Treatment 8 did show a significant advantage of 15.7 percentage

points in terms of height growth initiation, but the performance for the target zone

(37.7%) was far below the standard goal of 60 percent.

1 4
In each of the eight nursery cultural treatments, no significant differences were

observed in the field performance of the two RCD groups (8 to 12 mm vs. 113 mm),

either in terms of survival or height growth initiation (table 15). This finding strengthens

the conclusion that root fibrosity and NSFOLR were key morphological attributes

affecting field performance.

Two-sample independent proportion tests were conducted on the performance of

target-zone seedlings by the RCD group to determine significant (P = 0.05) differences

among individual nursery cultural treatments receiving either vertical root pruning or

the unpruned control (table 15). However, emphasis should be placed on the

performance of vertically root-pruned seedlings because even the unpruned control

seedlings having target-zone attributes failed to meet standards set for field

performance. The 8-12 mm RCD group did not significantly differ in performance

among treatments 1, 2, 3, and 4 and the performance standards were met, with

ranges of 83.0 to 88.1 percent for survival and of 57.9 to 73.8 percent for height

growth initiation; however, for the 113 mm group, the survival goal (80%) was not

reached with treatments No. 2 (72.7%) and No. 4, (67.7%) and the latter did differ

significantly from treatment No. 3 (92.0%). Poorer survival associated with the greater

drill spacing of treatment Nos. 2 and 4 may have been due to a potential problem in

planting seedlings with longer lateral roots (vertical cutting laterals at approximately

15 cm from drills with the 30-cm drill spacing of treatment Nos. 2 and 4 vs. vertical

cutting at approximately 7.5 cm with the 15-cm drill spacing of treatment Nos. 1 and

3). However, closer seed spacing within the double seed drills of treatment Nos. 2

and 4 may have adversely affected the physiological characteristics of stock.

Summary and Results strongly indicate that root fibrosity and NSFOLR are key morphological

Conclusions attributes affecting seedling field performance of longleaf pine during the critical first

2 years after outplanting. The effects of RCD tended to be indirect because of the

strong relationship between RCD and NSFOLR, and this relationship was modified

by seedbed density. Thus, statistical comparisons, similar to those used in this study,

should be made in future studies of the effects of nursery cultural practices and

morphological attributes on performance after outplanting.

This study supports several important conclusions about the field performance of

longleaf pine bare-root stock:

(1) Abundance of fibrous roots and NSFOLR are key morphological attributes for

estimating the field performance of nursery stock.

(2) Vertical root pruning in the nursery increases field survival and the proportion of

seedlings that initiate height growth within 2 years after outplanting.

(3) Among root-pruned seedlings, low-fibrosity seedlings with 14 or more NSFOLR

or medium- to high-fibrosity seedlings with 6 or more NSFOLR can be expected to

have 80 percent survival and 60 percent or more can be expected to be in active

height growth 2 years after outplanting on a deep sandy site.

1 5
(4) Conventional statistical analyses, including ANOVA’s of treatment effects in a

factorial experiment, the correlations of seedling attributes with field response, and

regression of attributes and response variables, failed to provide conclusive information

about seedling quality.

(5) Single-tree plots in field plantings permit statistical evaluation of seedling

distributions, both initially and as surviving stands and seedlings in active height

growth.

(6) Seedlings having target attributes perform significantly better than Wakeley’s

(1964) standard grades 1 and 2 seedlings.

(7) Field performance of target-zone seedlings with RCD of 8 to 12 mm is not

significantly different from that of seedlings with RCD 113 mm. Thus, nurserymen

should place less importance on the current longleaf pine ideotype of RCD 113 mm

(Mexal and South, in press) and focus more attention on increasing root fibrosity in

combination with NSFOLR.

(8) The statistical procedures for comparing groups of seedlings within the target

zone vs. average performance or the performance of target-zone seedlings among

various cultural treatments should have application to other species, especially when

testing two or more morphological attributes.

Vertical root pruning of longleaf pine seedlings in the nursery markedly improves

seedling quality and should be a standard practice. When pruning is done, culling

planting stock based on certain key morphological attributes should further enhance

seedling quality and subsequent field performance.

16
Literature Cited Brissette, John C. 1984. Summary of discussions about seedling quality. In:

Proceedings, 1984 Southern nursery conferences, Western Session, 1984 June

11-14; Alexandria, LA; Eastern Session, July 24-27; Asheville, NC. Atlanta, GA:

U.S. Department of Agriculture, Southern Region: 127-I 28.

Derr, H.J. 1955. Seedbed density affects longleaf pine survival and growth. Tree

Planters’ Notes 20:28-29.

Hatchell, G.E.; Berry, CR.; Muse, H.D. 1985. Nondestructive indices related to

aboveground biomass of young loblolly and sand pines on ectomycorrhizal and

fertilizer plots. Forest Science 31:419-427.

Hatchell, Giyndon E. 1985. Seedling quality and field performance of longleaf pine

seedlings affected by ectomycorrhizae and nursery cultural practices. In:

Shoulders, Eugene, ed. Proceedings of the 3d biennial silvicultural research

conference; 1984 November 7-8; Atlanta, GA. Gen. Tech. Rep. SO-54. New Orleans,

LA: US. Department of Agriculture, Forest Service, Southern Forest Experiment

Station:395402.

Hatcheli, Giyndon E. 1986. Nursery cultural practices affect field performance of

longleaf pine. In: South, David B., ed. Proceedings of the international symposium

on nursery management practices for the southern pines; 1985 August 4-9;

Montgomery, AL. Auburn, AL: Auburn University:1 48-l 56.

Hatcheli, Giyndon E. 1987. Nursery cultural practices, seedling morphology, and

field performance of longleaf pine. In: Phillips, Douglas R., camp. Proceedings of

the 4th biennial southern silvicultural conference; 1986 November 4-6; Atlanta,

GA. Gen. Tech. Rep. SE-42. Asheville, NC: U.S. Department of Agriculture, Forest

Service, Southeastern Forest Experiment Station:61 -66.

Hatcheil, Giyndon E.; Marx, Donald H. 1987. Response of longleaf, sand, and loblolly

pines to Pisolithus ectomycorrhizae and fertilizer on a sandhills site in South

Carolina. Forest Science 33:301-315.

Kormanik, Paul P. 1986. Lateral root morphology as an expression of sweetgum

seedling quality. Forest Science 32:595-604.

Lauer, Dwight K. 1987. Seedling size influences early growth of longleaf pine. Tree

Planters’ Notes 38(3):16-l 7.

Mann, William F., Jr. 1969. At last-longleaf pine can be planted successfully. Forest

Farmer 28(6):6-7, 18-I 9.

May, Jack T. 1985. Seedling quality, grading, culling and counting. In: Lantz, Clark

W., ed. and camp. Southern pine nursery handbook. Atlanta, GA: U.S. Department

of Agriculture, Forest Service, Southern Region. Chapter 9.

Mexai, John G.; South, David B. [In press]. Bareroot seedling culture. In: Duryea,

M.L.; Dougherty, P., eds. Regeneration manual for the southern pines. Amsterdam:

Martinus Nijhoff. Chapter 6.

17
Ruehle, J.L.; Marx, D.H.; Muse, H.D. 1984. Calculated nondestructive indices of

growth response for young pine seedlings. Forest Science 30:469-474.

Scarbrough, NM.; Allen, R.M. 1954. Better longleaf seedlings from low-density

nursery beds. Tree Planters’ Notes 18:29-32.

South, David B. 1987. A re-evaluation of Wakeley’s “critical tests” of morphological

grades of southern pine nursery stock. South African Forestry Journal 14256-59.

Wakeley, Philip C. 1935. Artificial reforestation in the southern pine region. Tech.

Bull. 429. Washington, DC: US. Department of Agriculture. 115 pp.

Wakeley, Phlllp C. 1948. Physiological grades of southern pine nursery stock. In:

Proceedings of the Society of American Foresters’ meeting; 1948 December

16-18; Boston, MA. Washington, DC: Society of American Foresters:31 l-323.

Wakeley, Philip C. 1954. Planting the southern pines, Agric. Monogr. 18. Washington,

DC: U.S. Department of Agriculture, Forest Service. 233 pp.

White, John B. 1981. The influence of seedling size and length of storage on longleaf

pine survival. Tree Planters’ Notes 32(4):3-4.

1 8
Tables
Table l--Means and significance levels of ANOVA's of the effects of nursery cultural practices on the morphological attributes

of longleaf pine planting stock and on field responses of seedlings 2 years after outplanting on a deep sandy site

Nursery cultural

treatment: (No.)

vertical root Morphological attributes of 1-O stock

pruning, seedbed

Field responses at age 2

Strong,

density, and

spacing of

seed drills

Root- first- Fibrous- Short roots ecto- Active Rootcollar Fresh order root

rating1

mycorrhizal with-- height collar

dia. weight laterals Pt All fungi Survival growth Height dia. D2H

mm- ii No* % % % cm mm - - 5 - - (cm21

Vertical pruning ----~~~-------_-_________ Treatment means2 - - - - - - - - - - - - - - - -

Density, drills

Low, 15cm (1) 12.5a 104a 9.3a 1.8b 56ab

Low, 30 cm (2) 12.6a 109a 9.3a 1.8b 57ab

Medium, 15 cm (3) lO.lbc 64b 4.6b 2.2a 63ab

Medium, 30 cm (4) 10.5b 71b 5.lb 2.2a 66a

63ab

64ab

69ab

72a

74.0a

63.0a

74.0a

65.5a

60.0a 31.0a 35.la 476a

48.0b 27.9a 34.6ab 439a

46.0b 20.6b 32.5abc 284b

41.0bc 20.9b 31.9bc 286b

Unpruned controls

Density, drills

Low, 15 cm (5)

Low, 30 cm (6)

Medium, 15 cm (7)

Medium, 30 cm (8)

Source of

variation

Pruning (PI

Density (D)

Drill spacing (S)

PxD

PXS

DxS

PxDxS

12.6a 108a 9.la 1.5c 53b 60b 49.0b 33.5cd 21.9b 31.8bc 281b

12.7a 1lOa 9.5a 1.6bc 52b 59b 47.5b 28.5de 19.5b 32.2abc 275b

9.9c 68b 5.2b 1.9b 60ab 66ab 47.0b 20.0e 12.3~ 29.5cd 158~

10.3bc 72b 5.6b 1.8bc 61ab 67ab 47.5b 22.0de 13.5c 27.9d 158~

0.561 0.167 0.347 0.001 0.094 0.076 0.001 0.001 0.001 0.001 0.001

.OOl .OOl .OOl .OOl .OOl .002 .971 .OOl .OOl .OOl .ooi

.080 .033 .258 .784 .586 .595 -142 .085 .394 .384 .619

.291 .993 ,365 .226 .852 .958 .744 .930 .706 .627 .202

.882 .447 .798 .837 .633 .628 .184 .225 ,707 .938 ,716

.348 .494 .778 .343 .641 .662 .744 .225 .132 .460 .596

.814 .926 .625 .632 .942 .887 .971 1.000 .974 .469 .700

Significance level

Means within a column followed by a common letter are not significantly different at p = 0.05.

1 Low fibrosity = 1; medium fibrosity = 2; high fibrosity = 3.

2 Means for morphological attributes are based on measurements of 50 seedlings per nursery plot with four replications in a

randomized block design; means for field responses are based on 8 groups of 25 seedlings with seedlings randomly distributed

throughout study area.
Table P--Linear correlation coefficients among morphological attributes of 1-O longleaf pine seedlings, by vertical

root-pruning treatments

Morphological attributes

of stock

Root- Total No. of strong Fibrous- % short roots % short roots

collar fresh first-order root with Pt ecto- with all ectodiameter weight lateral roots rating mycorrhizae mycorrhizae

--m------e- - r value and significance level - - - - - - - - - - - -

Pruned seedlings

Root-collar diameter

Total fresh weight

NSFOLRl

Fibrous-root rating

% short roots with Pt ecto.

% short roots with all ecto.

Root-collar diameter

Total fresh weight

NSFOLRl

Fibrous-root rating

% short roots with Pt ecto.

% short roots with all ecto.

- -

+o. 799***

+.785***

-.142***

+.059

+.064

--

+.842***

+.758*-k*

-.178***

-.029

-.017

+o .7 99*** +0.785*** -0.142***

- - +.814*** -.192***

+.814*** - - -.156***

-.192*** -.156*** - -

-.025 +.039 +.601***

-.020 +.045 +.612***

Unpruned seedlings

+.842***

--

+.774-k**

-.183***

-.119***

-.103**

+.758*** -.178***

+.774*** -.183***

-- -.157***

-.157*** --

-.027 +.578***

-.020 +.596***

+0.059

-.025

+.039

+.601***

- -

+.992***

-.029

-.119***

-.027

+.578***

- -

+.991***

+0.064

-.020

+.045

+.612***

+. 992***

--

-.017

-.103**

-.020

+. 596***

+. 991***

--

***, **, and * significant at O.l%, l%, and 5% level, respectively; N = 800 for each pruning treatment.

1 NSFOLR = Number of strong, first-order lateral roots with diameter >l mm.
Table 3--Linear correlations between response variables of longleaf pine 2 years after outplanting on a deep sandy site

and morphologial attributes of bare-root stock, based on 25-seedling groups or individual seedlings, and listed by vertical

root-pruning treatments

- -

Morphological attributes

of stock, the reciprocal

of attributes, and certain

interaction variables

Field response 2 yearsafter outplanting based on--

25-seedling groups1 Individual seedlings 2

Active Root- Rootheight Height collar Height collar

Survival growth (H) dia. (D) D2H (H) dia (D) D2H

Root-collar diameter (RCD)

l/RCD

Total fresh weight

l/total fresh weight

NSFOLR3

~/NSFOLR

RCD x NSFOLR interaction

Fibrous-root rating (FRR)

l/FRR

NSFOLR x FRR interaction

X short roots with Pt ecto.

l/4 short roots with Pt ecto.

% short roots with all ecto.

i/Z short roots with all ecto.

Root-collar diameter (RCD)

l/RCD

Total fresh weight

l/total fresh weight

NSFOLR3

~INSFOLR

RCD x NSFOLR interaction

Fibrous-root rating (FRR)

~/FRR

NSFOLR x FRR interaction

% short roots with Pt ecto.

l/% short roots with Pt ecto.

X short roots with all ecto.

l/X short roots with all ecto.

----_-_______ - r value and significance level - - - - - - - - - - - - - - -

-0.072

+.073

-.080

+.129

-.074

+.I37

-.061

+.330

-.342

+.044

+.286

-.442*

+.290

-.439x

-.065

+.020

-.134

+.078

+.113

+.042

+.060

+.346

-.379*

+.284

+.402*

-.274

+.385*

-.373*

+0.287 +0.484** +0.333

-.265 -.443* -.316

+.277 +.517** +.326

-.208 -.412* -.239

+.340 +.592*** +.430*

-.240 -.468** -.379*

+.345 +.590*** +.417*

+.105 -.146 +.026

-.124 +.121 -.079

+.459*x +.658*** +.570***

+.192 +.113 +.073

- .394* -.202 -.203

+.186 +.092 +.077

-.360* -.181 -.188

+.313

-.350*

+.235

-.264

+.414*

-.123

+.402*

+.150

-.207

+.480**

+.401*

-.428*

+.401*

-.435*

Pruned seedlings

Unpruned seedlings

+.638*** +.543**

-.639*** -.551**

+.596*X +.485**

-.569*** -.404

+.619*** +.452**

-.334 -.163

+.653*** +.498**

-.141 -.065

+.094 +.006

+.540** +.396*

+.I50 +.222

-.356* -.383*

+.175 +.263

-.277 -.316

+0.520**

-.492*X

+.557***

-.447*

+.626***

-.513**

+.617***

-.230

+.201

+.662***

+.009

-.127

-.OOB

-.105

+.630***

-.626***

+.586***

-.552**

+.642***

-.340

+.667***

-.131

+.07a

+.590***

+.157

-.323

+.174

-.261

+0.453***

-.429***

+.458***

-.310***

+.490***

-.329***

+.492***

+.109*

-.097*

+.519***

+.212***

-.159***

+.210***

-.179***

+.382***

-.349***

+.411***

-.348***

+.391***

-.219***

+.420***

+.117*

-.113*

+.413x**

+.147**

-.112*

+.141**

-.123*

+0.355*x*

-.34a***

+.324X**

-.239***

+.355***

-.287***

+.352***

+.097*

-.107*

+.373x**

+.165***

-.13a***

+.171***

-.151***

+.311***

-.302***

+.307***

-.305***

+.276***

-.164**

+.299***

+.154**

-.130**

+.330***

+.176***

-.114*

+.171***

-.129*

+0.428***

-.402***

+.436***

-.282***

+.470*x*

-.312***

+.457***

+.080

-.074

+.485***

+.189***

-.151***

+.192**

-.169***

+.373***

-.332***

+.405***

-.330***

+.365***

-.186***

+.399***

+.147**

-.141**

+.421***

+.166**

-.125*

+.158**

-.133**

***, **, and * significant at 0.1X, l%, and 5% level, respectively.

1 With 25-seedling groups, N = 32 for each pruning treatment.

2 Initially, 800 seedlings represented each pruning treatment; however, evaluations on surviving seedlings

after two growing seasons were: N = 553 for pruned seedlings and N = 282 for unpruned seedlings.

3 NSFOLR = Number of strong, first-order lateral roots.
Table C--Initial distribution of 800 vertically root-pruned longleaf pine seedlings (treatment Nos. l-4) and

distributions in terms of survival and height-growth initiation 2 years after outplanting, by fibrosity rating,

number of strong, first-order lateral roots (NSFOLR) of stock, and root-collar diameter (RCD)~

RCD

(mm>

Low fibrosity and NSFOLR of-- Medium or high fibrosit y and NSFOLR of--

O-3 4-5 6-7 8-9 lo-11 12-13 114 Totals O-3 4-5 6-7 8-9 lo-11

-----------e-----eInitial number of seedlings - - - - - - - - - - - - - - - -

5-8 6

9-10 1 6

11-12

13-14 1

15-16

>17 1

Totals z

- -

5-8 3

9-10 7

11-12

13-14 1

15-16

>17 0

Totals ii

2

11 13 1

5 13 4

5 6

11 2

19 32 i3

0

2 9 1

2 4 1

3 4

0 0 2

-6 16 77

1 9 100 9 1

i 43 82 50 3i 15 4

3 1 2 2 8 1 7 28 46 43 li 4

5 5 ii 33 3 13 15 18 28 25

2 7 -5 1 8 2 2 5-i 4

1 3 -

l-5 17 1 - 5 E E

14 16 -30 148 204 101 95--84 E33-

- - - - - Number of seedlings surviving at age 2 - - - - - - -

1 4 52 5 1

0 1 9 54 38 29 14 2

0 0 2 9 9 24 36 39

5 15 12 16

g 3

4 2 7 1 5 22 15

1 3 5 11 1 o-3 -x 3

2 3

- 0 1 0 1 1 z 2

6 m 25 80 ii-i 73 78 75 a 24 - - - -

-

1

b

lb

34

i3-

74-

- -

1

a

17

30

ii61-

-----------Number of seedlings in active height growth at age 2 - - - - - -

5-8 2 0 1 3 21 4 1

9-10 11 3 1 0 6 25 20 22 12 1 1

11-12 12 1 0 0 2 6 6 18 28 55 F 3 c

13-14 0 2 3 1 2 3 1 7 149 14 1s 14 1:

15-16 0 0 1 1 3 3 10 0 3 35 2 29

>17 0 0 2 8 1 0 1 j T 5 10 - - -

Totals 3-T'T-s 7 24-

52 53 47 izJ 62 - -zz z- 58-

110

183

161

111

54

33

652

58

138

129

84

43

2 1

473

26

8 1

100

72

39

20

338

1 Underlined numbers denote the "target zone." There were initially 377 seedlings in the target zone, and after

two growing seasons in the field 308 seedlings survived (81.7% survival) and 262 seedlings (69.5%) were in

active height growth. Within the target zone, 170 seedlings with initial RCD of 8-12 mm showed 85.3% survival

and 67.6% in active height growth at age 2, and 207 seedlings with initial RCD 113 showed 78.7% survival and

71.0% in active height growth; tests of differences in responses between these RCD groups showed that g = 0.093

for survival and 2 = 0.478 for active height growth, based on the two-tailed alternative hypothesis.
Table 5--Initial distribution of 800 unpruned control longleaf pine seedlings (treatment Nos. 5-8) and distributions-in terms of survival and height-growth initiation 2 years after outplanting, by fibrosity rating, number

of strong, first-order lateral roots (NSFOLR) of stock, and root-collar diameter (RCD)~

RCD Low fibrosity and NSFOLR of-- Medium or hi h fibrosit gy and NSFOLR of--

(mm) O-3 4-5 6-7 .8-9 lo-11 12-13 ~14 Totals O-3 4-5 6-7 8-9 lo-11 12-13 ~14 Totals

5-a 17 12 2

9-10 15 24 15 6

11-12 6 15 23 29

13-14 2 6 6 14

15-16 2 8

>17 1 2

Totals

5-8 3 10

9-10 3 9 7 4

11-12 1 5 7 12

13-14 0 11 5

15-16 0 1

>17 0 1

Totals 7 16 15 ‘23

5-8

9-10

11-12

13-14

15-16

>17

------------------Initial number of seedlings - - - - - - - - - - - - - - - -

40 57 49 59

2

14

1 1

9

3

31 84 9 5

1 63 47 37 45 11

4 9 1 6 1 7 37 30

13 1 1 63 3 5 15

1 1 18 48 3 i7

2 lo1 8 i?- -

39 31 39- 314 13769 89-65-

- Number of seedlings surviving at age 2

1

4

2 5

37 6 2

25 23 20 9

3 35 2 10 24 2ii

4 5 22 1 47

4 15 1 7 0 0 2

0 4 6 5 tT

i-7 12 19-109 64 40 50-38-

1

7 1 -

Ti 175 3

1T 16 21

6 4 ii

3 E 8

41- 35- -50

__--------

3

'5 1 9

0

3

15 ii 1T

4 2 10

0 T -3

-

22 25-34

----m-e--- - Number of seedlings in active height growth at age 2 - - - - - - -

0 0 0 0 11 1 2 0

13 4 1 0 1 10 11 11 12 3 1 1 -

0 13 5 3 1 1 3 1 7 15 1iT z a 3

0 0 0 3 4 3 3 13 1 25 5 7 l'i:

0 1 1 3 lb 1 5 0 i5 ? 3 i9

0 1 1 0 2 4 2 5 5 5 z

Totals -i 4 7 ii-7 8 15-

55 23 20 31--20 13-17- -29

99

143

111

77

38

18

486

45

81

73

48

18

8

273

14

39

46

32

1 5

7

153

1 Underlined numbers denote the "target zone." There were initially 319 seedlings in the target zone, and after

two growing seasons 188 seedlings survived (58.9% survival) and 125 seedlings (39.2%) were in active height

growth. Within the target zone, 153 seedlings with initial RCD of 8-12 mm showed 62.7% survival and 37.3% in

active height growth at age 2, and 166 seedlings with initial RCD >13 showed 55.4% survival and 41.0% in active

height growth; tests of differences in responses between these RCD-groups showed that P = 0.1836 for survival

and P = 0.4966 for active height growth, based on the two-tailed alternative hypothesi;.
Table 6--Initial distribution of 200 longleaf pine seedlings receiving treatment No. 1 and distributions in

terms of survival and height-growth initiation 2 years after outplanting, by fibrosity rating, number of strong,

first-order lateral roots (NSFOLR) of stock, and root-collar diameter (RCD)~

RCD Low fibrosit y and NSFOLR of-- Medium or high fibrosity and NSFOLR of--

(mm> O-3 4-5 6-7 8-9 lo-11 12-13 ~14 Totals O-3 4-5 6-7 8-9 lo-11 12-13 214 Totals

em-_--___--___--- - Initial number of seedlings - - - - - - - - - - - - - - - -

5-8

9-10

11-12

13-14

15-16

>17

Totals

5-8

9-10

11-12

13-14

15-16

>17

Totals

5-8

9-10

11-12

13-14

15-16

>17

Totals

1 1 2 10 3

2 4 3 2 6

1 1 5 T

3 3

1 5

7

1 7

9

8

12

1

5

7

1

48 10-F 7 10 14-

58 -23 16 27-18-

---0-------w-q - Number of seedlings surviving at age 2

1 0 1 5 2

0 2 4 0 6 9 3 11

11 0 1 3 0 5611

2 3 3 2 T 1 6 0 z 4

0 1 3 2 6 i

2 I 7 i

13743 7% 39 14 10 -21 -i-7

1

b

a

3

1

E

2

13

29

38

30

15

1 7

16-ii- -

31 142

7

0 23

5 1 29

4 -

a

1

5 23

1Z 15

2 L 77 12

ii--3 28 109 - -

-----------Number of seedlings in active height growth at age 2 - - - - - - - - - -

1 0 1 2 2 4

0 13 0 4 4 2 2 0 15

0 1 0 1 2 0 4 5 9 i; 1 1 24

2 3 1 2 7 13 0 5 3 4 I 19

0 0 3 T 5 i 1$ 15

2 I 7 i 2 1. I 1 1

1163 -i 7 i-3

-

32 6-K 17 14 10 -2 26 8 8 - - - -

1 Underlined numbers denote the "target zone." There were initially 117 seedlings in the target zone, and after

two growing seasons 99 seedlings survived (84.6% survival) and 87 seedlings (74.4%) were in active height growth.

Within the target zone, 43 seedlings with initial RCD of 8-12 mm showed 83.7% survival and 69.8% in active height

growth at age 2, and 74 seedlings with initial RCD ~13 showed 85.1% survival and 77.0% in active height growth;

tests of differences in responses between these RCD groups showed that P

active height growth, based on the two-tailed alternative hypothesis. -

= 0.841 for survival and p = 0.134 for
Table 7--Initial distribution of 200 longleaf pine seedlings receiving treatment No. 2 and distributions in

terms of survival and height-growth initiation 2 years after outplanting, by fibrosity rating, number of strong,

first-order lateral roots (NSFOLR) of stock, and root-collar diameter (RCD)~

RCD

(mm>

Low fibrosity and NSFOLR of-- Medium or high fibrosit y and NSFOLR of--

O-3 4-5 6-7 8-9 lo-11 12-13 ~14 Totals O-3 ,4-5 6-7 8-9 lo-11 12-13 - - >14 Totals

-------_-m______

- - Initial number of seedlings - - - - - - - - - - - - - - - -

5-8

9-10 3 3 3

11-12 3 6 3

13-14 3 2

15-16 1 1

>17

Totals -5-3 13 -z

--me--___

5-8

9-10 2

11-12

13-14

15-16

>17

0

1

1

2 0

1 1

0 1

5-8

9-10 1

11-12

13-14

15-16

>17

i

- -

0

1

0

0 0

0 0

0 1

Totals i i 01

1

2

2

1

6

- -

0

1

1

0

2

8 2

9 1 0 10 1 5

1 1 1 5 3 1z 1 li

3 7 14 2 3 - -z

1 7 8 1 i i

a 7 1-

5 z 53 19 18 19- -29

- - Number of seedlings surviving at age 2

0 1

3 3 9 14

0 1 4 1 13 1%

3 7 9 1 2-F

0 $ 5 2 1 1-5 - i

3 -3 23 4 13 15- 24-

1

i

15

3

i

5-

1

'4:

8 i;

3 lb

i 5

12- 28-

1

z

6 b

T ii

i-i

10- 21-

- Number of seedlings in active height growth at age 2 - - - - - - - - - -

0 0 0

10

28

25

16

4

0 1

0 3

0 7

?

1 5 0 2 1

1 ii5 15 i

1 2 4 g

0 5i 7

i-- i1

z

6 s

5 15

i 1.

109 13 18 12 19 14 20 - - - 9 -

10

28

41

35

24

9

147

1

1 9

32

28

1 9

4

103

8 3

1 Underlined numbers denote the "target zone." There were initially 124 seedlings in the target zone, and after

two growing seasons 95 seedlings survived (76.6% survival) and 83 seedlings (66.9%) were in active height growth.

Within the target zone, 47 seedlings with initial RCD of 8-12 mm showed 83.0% survival and 68.1% in active height

growth at age 2, and 77 seedlings with initial RCD ~13 showed 72.7% survival and 66.2% in active height growth;

tests of differences in responses between these RCD groups showed that 1 = 0.168 for survival and P = 0.826 for

active height growth, based on the two-tailed alternative hypothesis.
Table 8--Initial distribution of 200 longleaf pine seedlings receiving treatment No. 3 and distributions in

terms of survival and height-growth initiation 2 years after outplanting, by fibrosity rating, number of strong,

first-order lateral roots (NSFOLR) of stock, and root-collar diameter (RCD)~

RCD

(mm)

Low fibrosity and NSFOLR of-- Medium or high fibrosity and NSFOLR of--

O-3 4-5 6-7 8-9 lo-11 12-13 214 Totals O-3 4-5 6-7 8-9 lo-11 12-13 >14 Totals

5-8

9-10

11-12

13-14

15-16

>17

Totals

5-8

9-10

11-12

13-14

15-16

>17

Totals

5-8

9-10

11-12

13-14

15-16

>17

Totals

__-_-___-__-------Initial number of seedlings - - - - - - - - - -

3

4

7

- -

2

1

3

1

0

-l

-

1

1 2

1 1

-T -5

- - - -

0

0 2

0 1

-6 -3

- - - -

0

0 0

0 1

0 -i

1

1

1

-2 -i

------

1

1

1

2 -i

5 41 1 1

8 35 13 15 6 1

3 8 9 14T 7

2 82 z 5

i I

2

I 1

- - 16 8 6 -3-i - - 30 i-7 10- 4

- Number of seedlings surviving at age 2 - - - - - - -

3 27 0 1

4 25 10 l'i;j 6 0

2 5 9 -ET 7

1 2 2b ‘5

i i

i-

- - 9 58 21 26- 17- -2

---- Number of seedlings in active height growth at age 2 -

1 2 8 0 1

1 1 12 3 7 6 0

1 2 4 6 fi s; 5

122 z ?

i

i

I

21--- 5 35 ii -20 -16 7

2

1

2

-

2

1

2

-w-e--

43

67

39

29

4

2

184

- - - -

4

i

a

- .

2

2

1

28

51

34

20

4

2

Iss

9

28

27

3 17

5 4

2

1 87

' Underlined numbers denote the "target zone." There were initially 67 seedlings in the target zone, and

after two growing seasons 60 seedlings survived (89.6% survival) and 51 seedlings (76.1%) were in active height

growth. Within the target zone, 42 seedlings with initial RCD of 8-12 mm showed 88.1% survival and 73.8% in

active height growth at age 2, and 25 seedlings with initial RCD 113 showed 92.0% survival and 80.0% in active

height growth; tests of differences in responses between these RCD groups showed that g = 0.596 for survival and

P- 0.555 for active height growth, based on the two-tailed alternative hypothesis.
Table g--Initial distribution of 200 longleaf pine seedlings receiving treatment No. 4 and distributions in

terms of survival and height-growth initiation 2 years after outplanting, by fibrosity rating, number of strong,

first-order lateral roots (NSFOLR) of stock, and root-collar diameter (RCD)~

RCD Low fibrosit y and NSFOLR of-- Medium or high fibrosity and NSFOLR of--

(mm) O-3 4-5 6-7 8-9 lo-11 12-13 ~14 Totals O-3 4-5 6-7 8-9 lo-11 12-13 ~14 Totals

------------------ Initial number of seedlings - - - - - - -

5-8 2 41 3

9-10

11-12

13-14

15-16

>17

Totals

5-8

9-10

11-12

13-14

15-16

>17

Totals

5-8

9-10

11-12

13-14

15-16

>17

Totals

2

6 2

1

1

-ET

1 1 25 22 7 4 1

3 8 9 8 !f 7

1 2 1 2 7 x 7

3 43

i L1 1 7

i z 11

1 5 5

1 - 1 1 iT TT

1 2 ii

-i 2 -5 7636 19-- 20 i3 -

- - Number of seedlings surviving at age 2 - - - -

0 20 2

-

- -

-

0

4

1

0

-3

0

0

0

0

-5

22

0 45

-6

1 7

4

0

0

16

9

2

2

0

-3

2 1 34

i i 13

i7 5 5

5 T 3

-

-

-

2 2 122

- -- Number of seedlings in active height growth at age 2 - - - - - - - - - -

0 0

0

0 -5

0 1 1 2 13

0 8 10 6 4 0 28

0 2 7 T F i 2 1 21

1 1 0 1Y 7 5 i i 1 1

0 - 0 0 2 0 i 5 5 4

1 1 i- E 1 3

- -5 2 2 21 20 iii-3 -

5 2 1. 80

1 Underlined numbers denote the "target zone." There were initially 69 seedlings in the target zone, and after

two growing seasons 54 seedlings survived (78.3% survival) and 41 seedlings (59.4%) were in active height growth.

Within the target zone, 38 seedlings with initial RCD of 8-12 mm showed 86.8% survival and 57.9% in active height

growth at age 2, and 31 seedlings with initial RCD 213 showed 67.7% survival and 61.3% in active height growth;

tests of differences in responses between these RCD groups showed that P = 0.057 for survival and P = 0.772 for

active height growth, based on the two-tailed alternative hypothesis. -
Table lo--Initial distribution of 200 longleaf pine seedlings receiving treatment No. 5 and distributions in

terms of survival and height-growth initiation 2 years after outplanting, by fibroaity rating, number of strong,

first-order lateral roots (NSFOLR) of stock, and root-collar diameter (RCD)~

RCD Low fibrosity and NSFOLR of-- Medium or high fibrosity and NSFOLR of--

(mm> O-3 4-5 6-7 8-9 lo-11 12-13 ~14 Totals O-3 4-5 6-7 8-9 lo-11 12-13 114 Totals

_--------__-------Initial number of seedlinns - - - - - - - - - - - - - - - -

5-8

9-10

11-12

13-14

15-16

>17

3 1

4 7

2

1 2

9

18

29

24

12

5

97

2

1 1

1 9

18

8

2

60

4 8 1

1 1 6 3 71 1

3 32 2 4 s 9 7;

7 5 25 1 3 5 T

4 13 24 iiP

1 k

- -

7 2

15 22-ii53 168 20 16 ii -- -

- Number of seedlings surviving at age 2 - - -

1 1 -1

2

z 7

i 7

2

9

ii-

_-----

10 10

4 4

1 3

1

i3 18

- - - -

Totals 8 12 13

- - - - - - - - - -

5-8

9-10

11-12

13-14

15-16

a17

Totals

1 0

0 4

1

0 0

4

1 3

8

9

3

1

1

2

2

1

a

3

i

6

? J

5 i

s

5

7

12-

3

i

T

- - - - Number of seedlings in active height growth at age 2 - - - -

0 0 1

1 1 lz: 1 s!

3 1 1 6 12 z z 2 1

1 0 2 2 5 1 2 2 ti z

0 0 2 T 9 5i i 5

0 1 0 I 2 - - y -

42 5 10- 23 24 ii - 3 2 1.

- .-mm--

1

7

14

5 14

'z 6

2 2

ii4 4

5-8

9-10

11-12

13-14

15-16

>17

Totals 0 i

1 Underlined numbers denote the "target zone." There were initially 95 seedlings in the target zone, and after

two growing seasons 64 seedlings survived (67.4% survival) and 48 seedlings (50.5%) were in active height growth.

Within the target zone, 33 seedlings with initial RCD of 8-12 mm showed 75.8% survival and 51.5% in active height

growth at age 2, and 62 seedlings with initial RCD ~13 showed 62.9% survival and 50.0% in active height growth;

tests of differences in responses between these RCD groups showed that p = 0.180 for survival and p = 0.889 for

active height growth, based on the two-tailed alternative hypothesis.
Table 11--Initial distribution of 200 longleaf pine seedlings receiving treatment No. 6 and distributions in

terms of survival and height-growth initiation 2 years after outplanting, by fibrosity rating, number of strong,

first-order lateral roots (NSFOLR) of stock, and root-collar diameter (RCD)~

RCD

(mm)

Low fibrosity and NSFOLR of-- Medium or high fibrosity and NSFOLR of--

O-3 4-5 6-7 8-9 lo-11 12-13 >14 Totals O-3 4-5 6-7 8-9 lo-11 12-13 ~14 Totals

---~--__-~-_-____- Initial number of seedlings - - - - - - - - - - - - - - - -

5-8

9-10

11-12

13-14

15-16

>17

Totals

5-8

9-10

11-12

13-14

15-16

717

Totals

5-8

9-10

11-12

13-14

15-16

717

Totals

3 3

2 3

2 3

2

7 -ii

- - - -

0 0

0 1

0 1

0

--G 2

3

8 5 4

2 8 7

1 5 3

1 1 2

i3 19 16

0 4

4 4

1 2

1 0

-i5 10

--_--_

0 0

0 10

0 11

0 0

0

0

-5 2 -i

6 5 11

8 16 z 3 3 1

1 23 2 3 b Ti i i;

4 6 29 1 i2 K 7

5 5 1 9 i -5 i T

1 1 10 i iz

ii 16- 95 8-E -- 14 18 12 -17

- Number of seedlings surviving at age 2 - - - - - - -

0 2 10

1 13 i; 3 1 1

1 9 0 2 -6 7 Ti z

1 2 1 2 0 10 2 7

2 7 8 0 ii 2

0 T 3 0 5 z

33 3-Z 9 -3 4 12-

-

1

3

'ii

7

z

2 4-

- -

!?

3

B

t

4

19-

-

8

20

28

25

14

10

105

- - -

3

13

18

14

8

6

- - - - Number of seedlings in active height growth at age 2 - - - - - - - - - - -

0

1 1 1

0 2 0 4 0 2

2 4 1 1 8 0 'ii E

1 1 1 3 6

1 0 0 i 2

0 0 0 5! 0

ii 0 1 5

i7 iT 5 3 12

0

5

- Ti

1 3 7

i z 7

5 4 P 3 5

1 Underlined numbers denote the "target zone." There were initially 101 seedlings in the target zone, and after

two growing seasons 60 seedlings survived (59.4% survival) and 37 seedlings (36.6%) were in active height growth.

Within the target zone, 38 seedlings with initial RCD of 8-12 mm showed 65.8% survival and 34.2% in active height

growth at age 2, and 63 seedlings with initial RCD 113 showed 55.6% survival and 38.1% in active height growth;

tests of differences in responses between these RCD groups showed that P = 0.303 for survival and P = 0.689 for

active height growth, based on the two-tailed alternative hypothesis. -
Table 12--Initial distribution of 200 longleaf pine seedlings receiving treatment No. 7 and distributions in

terms of survival and height-growth initiation 2 years after outplanting, by fibrosity rating, number of strong,

first-order lateral roots (NSFOLR) of stock, and root-collar diameter (RCD)~

RCD Low fibrosity and NSFOLR of-- Medium or high fibrosity and NSFOLR of--

(mm) o-3 4-5 6-7 8-9 lo-11 12-13 ~14 Totals O-3 4-5 6-7 8-9 lo-11 12-13 114 Totals

5-a

9-10

11-12

13-14

15-16

>17 -

Totals

5-8

9-10

11-12

13-14

15-16

>17

Totals

5-a

9-10

11-12

13-14

15-16

>17

Totals

--------__--_____-Initial number of seedlings - - - - - - - - - - - - - - - -

6 6 1

4 8 5 2

1 3 2 6

2 1

ii 19

-----

1 1

1 2

1 2

1

7-x

- - - ^

0 0

1 0

0 0

0

--

1 0

8 -3

- - - -

0

3 2

0 2

0

-3 4

. - - - -

0

2 1

0 1

0

2 2

13 38 5 3 46

1 1 2 1 19 14 1x 3 3 55

12 2 4 X5? 1 21

1 1 5 c G 5 2 1 7

2 1 3 2 5 z 1 6

1 1

4 31 5 5 59 2 5 28 14 12 3 2 145 -- -

- - - - - Number of seedlings surviving at age 2 - - - - - - - - - - - - -

2 17 3 1 21

0 1 9 10 8 5 3 1 27

5 1 3 3 T i 1 16

1 0 2 T '; T 0 1 1

0 0 0 0 ci y - 1

0 0

-i -i -iJ 18 2 8 14 i-z - 3 T

2 2 7 6

- Number of seedlings in active height growth at age 2 - - - - - - - - - -

0 7 0 1 a

0 1 5 3 4 2 0 1 10

1 0 3 i i 0 9

0 0 0

z 5 T

io 6

0 0 0 0 Oi y 1

0 0 -

-5 -i -g 6 lo-72 4 1. X-Tj 3 4

1 Underlined numbers denote the "target zone." There were initially 62 seedlings in the target zone, and after

two growing seasons 34 seedlings survived (54.8% survival) and 17 seedlings (27.4%) were in active height growth.

Within the target zone, 40 seedlings with initial RCD of 8-12 mm showed 55.0% survival and 25.0% in active height

growth at age 2, and 22 seedlings with initial RCD ~13 showed 54.5% survival and 31.8% in active height growth;

tests of differences in responses between these RCD groups showed that p =: 0.968 for survival and p = 0.575 for

active height growth, based on the two-tailed alternative hypothesis.
Table 13--Initial distribution of 200 longleaf pine seedlings receiving treatment No. 8 and distributions in

terms of survival and height-growth initiation 2 years after outplanting, b fibrosity rating, number of strong,

first-order lateral roots (NSFOLR) of stock, and root-collar diameter (RCD) Y

RCD Low fibrosity and NSFOLR of-- Medium or high

(mm>

y and NSFOLR of-- fibrosit

0-3 4-5 6-7 8-9 lo-11 12-13 ~14 Totals O-3 4-5 6-7 8-9 lo-11 12-13 214 Totals

5-8

9-10

11-12

13-14

15-16

>17

Totals

5-8

9-10

11-12

13-14

15-16

->17

Totals S--z--c6 2

-------------

5 2 1

5 6 7 4 1

3 7 3 8 3

1 1 1

1

14 15 ii 13 3

10 0

2 2 4 2 1

0 12 4 1

0 0 0

0

- - - - - Initial number of seedlings - - - - - - - - - - - - - - - -

8 33 3 36

23 21 14 11 4 50

24 6 14 T 1

1 4 1 -lT 7

2 33

- 4 11

1 2 TT 5 6

1 i- 1 - 3 - -

2 - 61 54 24 27 ii - - a k 2 139

- - Number of seedlings surviving at age 2 - - - - - - - - - - - - - -

0

0

-5

1

1 1

8

0

0

20

1 7

13

30

2

10

3

0

15

5

i

5

0

12-

-------m-w- - Number of seedlings in active height growth at age 2 -

5-8 0 0 0 0 4 1

9-10 0 12 0 0 3 6 5 5 1

11-12 0 0 1 1 0 2 0 ii T 1

13-14 0 0 0 0 0 0 ifi iT 5

15-16 0 0 0 5

>17

P

0 P

Totals T-i-7-i 0 0 - 5 10-G ii

- 2 4

2

2

i

0 -

2 2

. - - - -

2

2

i

0

2 4

19

30

20

5

1

0

7 5

- - -

5

1 7

1 1

5

1

0

39

1 Underlined numbers denote the "target zone." There were initially 61 seedlings in the target zone, and after

two growing seasons 30 seedlings survived (49.2% survival) and 23 seedlings (37.7%) were in active height growth.

Within the target zone, 42 seedlings with initial RCD of 8-12 mm showed 57.1% survival and 40.5% in active height

growth at age 2, and 19 seedlings with initial RCD ~13 showed 31.6% survival and 31.6% in active height growth;

tests of differences in responses between these RCD groups showed that p = 0.052 for survival and P = 0.496 for

active height growth, based on the two-tailed alternative hypothesis.
Table 14--Comparison of field performance of Wakeley's (1954) standard grades 1 and 2 longleaf pine

seedlings vs. seedlings having values of key morphological attributes within the "target zone for higher

quality," by nursery cultural treatment

Nursery cultural

treatment: (No.)

vertical root pruning,

seedbed density,

and spacing of

seed drills

Field performance through two

growing seasons on deep sandy site

-

Grade 1 and 2 Target seedlings1

Active Active

height height

Survival growth Survival growth

Difference and significance

level in performance of

seedling within target zone

vs. standard stock

Active

height

Survival growth

Vertical pruning

Density, drills

Low, 15 cm (1)

Low, 30 cm (2)

Medium, 15 cm (3)

Medium, 30 cm (4)

Unpruned controls

Density, drills

Low, 15 cm (5)

Low, 30 cm (6)

Medium, 15 cm (7)

Medium, 30 cm (8)

% of initial

74.0 60.0 84.6 74.4 +10.6*** +14.4***

63.0 48.0 76.6 66.9 +13.6*** +18.9***

74.0 46.0 89.6 76.1 +15.6*** +30.1***

65.5 41.0 78.3 59.4 +12.8** +18.4***

49.0 33.5 67.4 50.5 +18.4*** +17.0***

47.5 28.5 59.4 36.6 +11.9*** +8.1**

47.0 20.0 54.8 27.4 +7.8 +7.4

47.5 22.0 49.2 37.7 +1.7 +15.7***

% of initial

target seedling Percentage points and P

***, **, *, Significant at 0.1X, 1X, and 5% level, respectively, based on the two-tailed

alternative hypothesis.

1 See tables 6-13 for seedling distributions, by treatments.
Table 15--Comparison of second-year field response of target-zone planting stock having root-collar diameter (RCD) of 8-12 mm VS. RCD >13

mm, by nursery cultural treatment1

Nursery cultural

treatment: (No.)

Field performance after two growing seasons

vertical root pruning, Difference in performance

seedbed density, Initial number of seedlings of stock with RCD of

and spacing of

seed drills

with RCD of-- Survival by RCD group Active height growth by RCD 8-12 mm vs. >13 mm

8-12 mm >13 mm All 8-12 mm 213 mm All 8-12 mm 213 mm All Survival Height growth

Vertical pruning

Density, drills

Low, 15 cm (1)

Low, 30 cm (2)

Medium, 15 cm (3)

Medium, 30 cm (4)

Number (% of total)2 % of initial target seedlings3 Percentage points (P4)

4 3 74 117c58.5)

4 7 77 124c62.0)

4 2 25 67t33.5)

3 8 31 69C34.5)

83.7a 85.lab 84.6ab 69.8a 77.0a 74.4a -1.4 (0.841)

83.0a 72.7b 76.6b 68.la 66.2a 66.9ab +10.3 (0.168)

88.la 92.0a 89.6a 73.8a 80.0a 76.la -3.9 (0.596)

86.8a 67.7b 78.3ab 57.9a 61.3a 59.4b +19.1 (0.057)

-7.2 (0.134)

+1.9 (0.826)

-6.2 (0.555)

-3.4 (0.772)

Unpruned controls

Density, drills

Low, 15 cm (5)

Low, 30 cm (6)

Medium, 15 cm (7)

Medium, 30 cm (8)

33 62 95C47.5)

38 6 3 lOl(50.5)

40 22 62c31.0)

4 2 19 61c30.5)

75.8a 62.9a 67.4a 51.5a 50.0a 50.5a +12.9 (0.180) +1.5 (0.889)

65.8a 55.6ab 59.4ab 34.2ab 38.la 36.6b +10.2 (0.303) -3.9 (0.689)

55.0a 54.5ab 54.8ab 25.0b 31.8a 27.4b +0.5 (0.968) -6.8 (0.575)

57.la 31.6b 49.2b 40.5ab 31.6a 37.7ab +25.5 (0.052) +8.9 (0.496)

1

See tables 6-13 for seedling distributions, by treatments.

2 Percentage of seedlings having target-zone attributes = (number in target zone divided by 200) x 100.

3 Within a pruning treatment, means in a column followed by a common letter are not significantly different at g = 0.05.

4 Based on the two-tailed alternative hypothesis.
Hatchell, Glyndon E.; Muse, H. David. 1990. Nursery cultural

practices and morphological attributes of longleaf pine bare-root

stock as indicators of early field performance. Res. Pap. SE-277.

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

Southeastern Forest Experiment Station. 34 pp.

Longleaf pine seedlings performed satisfactorily after planting on

deep sands in South Carolina in dry years when: (1) They were

vertically root-pruned in the nursery. (2) They had 14 or more first-order

lateral roots and nonfibrous root systems. (3) They had six or more

first-order lateral roots and highly fibrous root systems.

Keywords: Seedling quality, morphological grades, vertical root

pruning, Pinus palustris.

Hatchell, Glyndon E.; Muse, H. Davld. 1990. Nursery cultural

practices and morphological attributes of longleaf pine bare-root

stock as indicators of early field performance. Res. Pap. SE-277.

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

Southeastern Forest Experiment Station. 34 pp.

Longleaf pine seedlings performed satisfactorily after planting on

deep sands in South Carolina in dry years when: (1) They were

vertically root-pruned in the nursery. (2) They had 14 or more first-order

lateral roots and nonfibrous root systems. (3) They had six or more

first-order lateral roots and highly fibrous root systems.

Keywords: Seedling quality, morphological grades, vertical root

pruning, Pinus palustris.