                          PUBLISHED

UNITED STATES COURT OF APPEALS
                FOR THE FOURTH CIRCUIT


UNITED STATES DEPARTMENT OF            
LABOR,
                 Plaintiff-Appellee,
                 v.
NORTH CAROLINA GROWERS                          No. 03-2380
ASSOCIATION, INCORPORATED; SEXTON
TREE FARMS AND SEXTON ASSOCIATES;
HIGHLAND FRASER FIRS; NEW RIVER
TREE COMPANY, as joint employers,
              Defendants-Appellants.
                                       
           Appeal from the United States District Court
     for the Western District of North Carolina, at Statesville.
              Richard L. Voorhees, District Judge.
                           (CA-99-7-5)

                       Argued: June 2, 2004

                      Decided: August 2, 2004

        Before WIDENER and WILLIAMS, Circuit Judges,
           and Robert R. BEEZER, Senior Circuit Judge
    of the United States Court of Appeals for the Ninth Circuit,
                       sitting by designation.



Reversed, vacated, and remanded with instructions by published opin-
ion. Judge Williams wrote the opinion, in which Judge Widener and
Senior Judge Beezer joined.
2           U.S. DEPT. LABOR v. NORTH CAROLINA GROWERS
                              COUNSEL

ARGUED: William Randolph Loftis, Jr., CONSTANGY, BROOKS
& SMITH, L.L.C., Winston-Salem, North Carolina, for Appellants.
Paula Wright Coleman, UNITED STATES DEPARTMENT OF
LABOR, Washington, D.C., for Appellee. ON BRIEF: Robin E.
Shea, Kristine M. Howard, CONSTANGY, BROOKS & SMITH,
L.L.C., Winston-Salem, North Carolina, for Appellants. Howard M.
Radzely, Solicitor of Labor, Steven J. Mandel, Associate Solicitor,
Paul L. Frieden, Counsel for Appellate Litigation, UNITED STATES
DEPARTMENT OF LABOR, Washington, D.C., for Appellee.


                               OPINION

WILLIAMS, Circuit Judge:

   In this case, the North Carolina Growers Association, Inc.,1 Sexton
Tree Farms and Sexton Associates, Highland Fraser Firs, and New
River Tree Co. (collectively the Growers) appeal the district court’s
ruling in favor of the United States Department of Labor (the DOL).
The district court found that the Growers violated § 207 of the Fair
Labor Standards Act of 1938, 29 U.S.C.A. §§ 201-219 (West 1998 &
Supp. 2003) (FLSA), by failing to pay overtime to their workers
involved in Christmas tree farming. On appeal, the Growers argue
that, because their employees are "employed in agriculture," they are
exempted from the FLSA’s overtime pay provisions under
§ 213(b)(12), and that the district court erred in finding that Christmas
tree farming was not "agriculture" as that term is defined by § 203(f)
of the FLSA. The Growers also appeal the grant of a permanent
injunction against future violations of the FLSA. Because we find that
Christmas tree farming is "agriculture," we reverse the grant of sum-
mary judgment in favor of the DOL and remand the case to the dis-
trict court with instructions to enter judgment in favor of the Growers.
We also vacate the permanent injunction against the Growers.
    1
   North Carolina Growers Association is a trade association that aids its
members in obtaining seasonal farm labor by assisting with the compli-
cated legal matters that arise in the hiring of such labor.
            U.S. DEPT. LABOR v. NORTH CAROLINA GROWERS                 3
                                   I.

    The facts of this case are essentially undisputed. Although consum-
ers decorate their homes with Christmas trees for just a few weeks
each year, cultivating a proper Christmas tree takes substantial effort
and management.2 The process begins with the planting of tree seed-
lings in a nursery. While the trees grow in the nursery, they are
treated with fertilizer, herbicides, and pesticides to encourage growth
and reduce the incidence of weeds, insects, and disease. After approx-
imately three years, the seedlings are transplanted into lineout beds,
where they remain for two more seasons. The small trees are then
lifted and planted into cultivated soil that is tested by the North Caro-
lina Department of Agriculture on a yearly basis to determine whether
mineral or fertilizer applications are necessary. The trees are planted
in rows, about four or five feet apart, and they remain in the ground
until they are harvested for use as seasonal trees, generally seven to
ten years after being planted in the ground. While in the soil, the trees
are pruned and sheared yearly; they also are treated twice a year with
herbicides and fertilized once or twice a year. When necessary, pesti-
cides are applied. Most Christmas tree farms use sprinklers to water
the tree seedlings while they grow in the nurseries and lineout beds
and sometimes when the trees are planted in the field.

   Christmas trees are usually harvested with chainsaws at the rate of
1,000 per day, although some are bagged for sale with the root ball
intact. In choosing which trees to harvest, Christmas tree farmers
grade the trees based on "uniform density, good shape, color and nee-
dle retention" as well as height. (J.A. at 353.) Christmas trees are har-
vested individually based on these criteria; growers do not harvest
entire rows at a time. After the sorted trees are cut down, they are
baled, taken to storage, and then hauled in bulk to their end destina-
tions. Christmas trees are sold for ornamental purposes, typically dur-
ing the Christmas season. At the close of the Christmas season,
  2
   Christmas tree farming has evolved since the FLSA was enacted in
1938. Before the 1960’s, Christmas tree harvesting was more in the
nature of "enterprising individuals who took what nature provided." (J.A.
at 353.) However, since the mid 1960’s, Christmas tree farming has
evolved into the current system where growers plant and cultivate the
trees for harvest.
4           U.S. DEPT. LABOR v. NORTH CAROLINA GROWERS
purchased trees usually are discarded, although consumers who pur-
chase Christmas trees with the root ball intact usually replant them for
ornamental purposes after the Christmas season.

                                  II.

   This appeal results from an enforcement action brought by the
DOL against the Growers for their failure to pay overtime to their sea-
sonal workers, as required by § 207 of the FLSA. The FLSA requires
employers to pay overtime to most hourly workers, but employees
who are "employed in agriculture" are exempt from the FLSA’s over-
time provisions. 29 U.S.C.A. § 213(b)(12) (West 1999). Because
Christmas tree farm operations intensify as the Christmas season
approaches, most farms require seasonal labor to help harvest the
trees. In 1993, the Growers sought to hire a workforce of legal aliens
to perform these seasonal services on their Christmas tree farms. The
Growers applied for and received permission to hire seasonal alien
workers as non-agricultural employees under the Immigration Reform
and Control Act (IRCA). 8 U.S.C.A. § 1188 (West 2004). Because
the DOL classified these alien workers as non-agricultural employees
in granting the applications, the Growers considered Christmas tree
farming to be non-agricultural and accordingly paid the seasonal
workers overtime. In 1995, however, the DOL informed the Growers
that it considered the seasonal workers to be agricultural employees
for purposes of IRCA. Under IRCA, employers of seasonal agricul-
tural employees must provide the employees with certain statutorily
defined benefits, such as free housing, meals, and transportation. See,
e.g., 8 U.S.C.A. § 1188(c)(4); 20 C.F.R. § 655.102(b). After receiving
notice of the DOL’s position, the Growers began providing the bene-
fits required by IRCA to their seasonal employees but ceased paying
their workers overtime, believing that the DOL considered their
employees agricultural and thus exempt from the overtime provisions
of the FLSA.

  Contrary to the Growers’ belief, the DOL informed them that it
considered the Growers’ seasonal employees to be agricultural
employees under IRCA, but that they were not employees engaged in
agriculture under the FLSA.3 The Growers objected to this system of
    3
   IRCA defines agricultural laborers as those whose work qualifies as
"agricultural labor" under Section 3121(g) of the Internal Revenue Code
            U.S. DEPT. LABOR v. NORTH CAROLINA GROWERS                  5
dual classification, whereby they were required to provide free hous-
ing and other benefits while also paying overtime to the laborers, and,
until the filing of this enforcement action, they refused to pay over-
time to their seasonal workers.4

   The Secretary of Labor filed an enforcement action against the
Growers on August 5, 1998, requesting back pay and an injunction
for the Growers’ alleged violation of the FLSA. Following discovery,
both parties moved for summary judgment on the issue of whether
Christmas tree farming fell within the agricultural exemption to the
FLSA. On September 4, 2003, by published opinion, the district court
granted summary judgment in favor of the DOL and awarded back
pay in an amount to be determined by the parties. The district court
also issued an injunction against the Growers to ensure their future
compliance with the FLSA.5 See Chao v. North Carolina Growers
Ass’n, 280 F. Supp. 2d 500, 511-12 (W.D.N.C. 2003). The Growers
appeal, and we have jurisdiction under 28 U.S.C.A. § 1291 (West
1993). On appeal, the Growers argue that Christmas tree farming falls
within the definition of "agriculture" in § 203(f), while the DOL con-
tends that, as determined by the district court, § 203(f) is ambiguous,

and as those employed in "agriculture" as defined in the FLSA. 8
U.S.C.A. § 1101(a)(15)(H)(ii)(a). As relevant here, Section 3121(g) pro-
vides that "agricultural labor" includes labor done "on a farm, in the
employ of any person, in connection with cultivating the soil, or in con-
nection with raising or harvesting any agricultural or horticultural com-
modity." 26 U.S.C.A. § 3121(g)(1) (West Supp. 2004). The DOL
maintains that the Growers’ seasonal workers qualify under the defini-
tion of "agricultural labor" found in the Internal Revenue Code, but not
as workers employed in "agriculture" as defined in the FLSA.
   4
     Although the DOL’s complaint alleged that the Growers began violat-
ing the FLSA on March 25, 1996, the parties later stipulated that back
pay should be calculated from August 4, 1996 to August 5, 1998 in con-
formity with the FLSA’s two year limitations period. See 29 U.S.C.A.
§ 255(a) (West 1998).
   5
     The district court found an "inherent unfairness" in the DOL’s treat-
ment of Christmas tree farmers, but it believed that redress should be
pursued in Congress. (J.A. at 47.) The DOL’s brief notes that two bills
have been introduced in Congress that would specifically add Christmas
tree farming to the definition of agriculture in § 203(f).
6           U.S. DEPT. LABOR v. NORTH CAROLINA GROWERS
and we should defer to its interpretive bulletins, which define Christ-
mas tree farming as forestry, and not agriculture. Although we recog-
nize that the DOL’s interpretation is long standing, we agree with the
Growers that Christmas tree farming falls within the definition of
agriculture in § 203(f).

                                  III.

                                   A.

   We review the district court’s grant of summary judgment in favor
of the DOL de novo. Am. Chiropractic Ass’n v. Trigon Healthcare,
Inc., 367 F.3d 212, 221 (4th Cir. 2004). Summary judgment is appro-
priate "if the pleadings, depositions, answers to interrogatories, and
admissions on file, together with the affidavits, if any, show that there
is no genuine issue as to any material fact and that the moving party
is entitled to a judgment as a matter of law." Fed. R. Civ. P. 56(c)
(West 1994); see Celotex Corp. v. Catrett, 477 U.S. 317, 322 (1986).

                                   B.

   The FLSA is the "minimum wage/maximum hour law." Monahan
v. County of Chesterfield, 95 F.3d 1263, 1266 (4th Cir. 1996) (internal
quotation marks omitted). The congressional purpose in passing the
FLSA was "to protect all covered workers from substandard wages
and oppressive working hours." Barrentine v. Arkansas-Best Freight
Sys., Inc., 450 U.S. 728, 739 (1981). Pursuant to that goal, coverage
under the FLSA is construed "liberally to apply to the furthest reaches
consistent with congressional direction." Mitchell v. Lublin,
McGaughy & Assocs., 358 U.S. 207, 211 (1959). Accordingly,
"[e]xemptions from or exceptions to the Act’s requirements are to be
narrowly construed." Monahan, 95 F.3d at 1267 (quoting Johnson v.
City of Columbia, 949 F.2d 127, 129-30 (4th Cir. 1991)) (alteration
in original). Furthermore, "application [of an exemption is] limited to
those establishments plainly and unmistakably within [its] terms and
spirit." Arnold v. Ben Kanowsky, Inc., 361 U.S. 388, 392 (1960). The
employer bears the burden of proving it falls within an exemption.
Mitchell v. Kentucky Fin. Co., 359 U.S. 290, 291 (1959).
            U.S. DEPT. LABOR v. NORTH CAROLINA GROWERS                  7
   When interpreting statutes we start with the plain language. Lamie
v. United States Tr., 124 S. Ct. 1023, 1030 (2004). "It is well estab-
lished that when the statute’s language is plain, the sole function of
the courts—at least where the disposition required by the text is not
absurd—is to enforce it according to its terms." Id. (internal quotation
marks omitted). In interpreting the plain language of a statute, "[w]e
give the words of a statute their ordinary, contemporary, common
meaning, absent an indication Congress intended them to bear some
different import." Williams v. Taylor, 529 U.S. 420, 431 (2000) (inter-
nal quotation marks omitted.) We also abide by "the cardinal rule that
statutory language must be read in context [because] a phrase gathers
meaning from the words around it." Gen. Dynamics Land Sys., Inc.
v. Cline, 124 S. Ct. 1236, 1246 (2004) (internal quotation marks omit-
ted).

   The statute provides that employees who are "employed in agricul-
ture" are exempt from the overtime provisions of the FLSA. 29
U.S.C.A. § 213(b)(12). Agriculture is defined in § 203(f) of the FLSA
as follows:

     "Agriculture" includes farming in all its branches and
     among other things includes the cultivation and tillage of the
     soil, dairying, the production, cultivation, growing, and har-
     vesting of any agricultural or horticultural commodities
     (including commodities defined as agricultural commodities
     in section 1141j(g) of Title 12), the raising of livestock,
     bees, fur-bearing animals, or poultry, and any practices
     (including any forestry or lumbering operations) performed
     by a farmer or on a farm as an incident to or in conjunction
     with such farming operations, including preparation for mar-
     ket, delivery to storage or to market or to carriers for trans-
     portation to market.

29 U.S.C.A. § 203(f) (West 1998).

   Section 203(f) thus creates both a primary and a secondary defini-
tion of agriculture. See Farmers Reservoir & Irrigation Co. v.
McComb, 337 U.S. 755, 762 (1949). The primary definition of
"‘[a]griculture’ includes farming in all its branches[,] . . . includ[ing]
the . . . cultivation, growing, and harvesting of any agricultural or hor-
8              U.S. DEPT. LABOR v. NORTH CAROLINA GROWERS
ticultural commodities." 29 U.S.C.A. § 203(f). The secondary defini-
tion is broader and "includes any practices, whether or not themselves
farming practices, which are performed either by a farmer or on a
farm, incidently to or in conjunction with ‘such’ farming." Farmers
Reservoir, 337 U.S. at 763. Forestry and lumbering operations are
examples of practices which may fit within the secondary definition
of agriculture but only if performed on a farm or by a farmer as an
incident to other farming operations.6

   Although the placement of forestry in the secondary definition does
not necessarily indicate that Congress intended to exclude forestry
from the primary definition, other provisions of the FLSA make clear
that forestry and lumbering operations are excluded from the primary
definition of agriculture. Section 213(b)(28) exempts:

        [A]ny employee employed in planting or tending trees,
        cruising, surveying, or felling timber, or in preparing or
        transporting logs or other forestry products to the mill, pro-
        cessing plant, railroad, or other transportation terminal, if
        the number of employees employed by his employer in such
        forestry or lumbering operations does not exceed eight.

29 U.S.C.A. § 213(b)(28)(West 1999).

   This exemption would be superfluous if Congress had not intended
to exclude forestry from the primary definition of agriculture in
§ 203(f).7 See Hibbs v. Winn, 124 S. Ct. 2276, 2286 (2004) ("A statute
should be construed so that effect is given to all its provisions, so that
no part will be . . . superfluous.") Thus, § 213(b)(28) evidences the
implicit exclusion of forestry and lumbering operations from the
scope of the primary definition of agriculture under § 203(f) and also
    6
     The Growers concede that because their Christmas tree farming is not
incident to any other farming practice, they cannot fit within the second-
ary definition. The Growers do contend, however, that operations con-
ducted after the harvesting of Christmas trees, such as shipping the trees
to storage facilities, fall within the secondary definition if Christmas tree
farming is within the primary definition of § 203(f).
   7
     On appeal, the Growers have not addressed the applicability of this
exemption to their Christmas tree farms.
            U.S. DEPT. LABOR v. NORTH CAROLINA GROWERS                   9
serves to define the scope of the forestry and lumbering operations so
excluded.8 With this framework in mind, we turn to the question
before us.

  The Growers argue that they are exempt from the FLSA’s overtime
provisions with respect to their Christmas tree workers because
Christmas tree farming is agriculture under § 203(f). Specifically, the
Growers argue that Christmas tree farming involves the cultivation of
an agricultural or horticultural commodity. See 29 U.S.C.A. § 203(f).
Giving the language of § 203(f) its contemporary, ordinary meaning,
we agree.

   Without question, modern Christmas trees are cultivated commodi-
ties, or "economic good[s]."9 Webster’s Third New Int’l Dictionary
458 (1986). As described above, they undergo extensive care and
management before they are eventually harvested for sale to consum-
ers. Thus, if Christmas trees are "agricultural" or "horticultural," their
cultivation, growing, and harvesting is agriculture under § 203(f).
Horticulture is "the science and art of growing . . . ornamental plants."
Id. at 1093. Ornamental plants are those "having decorative quality or
value." Id. at 1592. Because Christmas trees are ornamental plants
that are grown and harvested, we believe that they are horticultural com-
modities.10 Accordingly, the cultivation, growing, and harvesting of
  8
     Congress did not title § 213(b)(28) as the definition section for for-
estry and lumbering operations, but as "there is a natural presumption
that identical words used in different parts of the same act are intended
to have the same meaning," we believe that the activities listed in
§ 213(b)(28) are the "forestry or lumbering operations" excluded by Con-
gress from § 203(f)’s primary definition. Atl. Cleaners & Dyers, Inc. v.
United States, 286 U.S. 427, 433 (1932),
   9
     Our analysis applies only to those growers and practices before us.
We offer no opinion on whether individuals who enter forested lands and
cut wild-growing Christmas trees are workers employed in agriculture.
   10
      The Departments of Agriculture in North Carolina and Oregon, the
states with the two largest productions of Christmas trees in the United
States, both consider Christmas tree farming to be horticulture. See North
Carolina Dep’t of Agric. and Consumer Serv. - Mktg. Div. Green Indus.
Christmas Trees, available at http://www.ncagr.com/markets/commodit/
horticul/xmastree/ (listing Christmas trees as a horticultural commodity);
see also Oregon Dep’t of Agric., Nursery and Christmas Tree Program,
available at http://oda.state.or.us/plant/nursery/index.html. (explaining
that Christmas tree farms are licensed and monitored by horticulturists).
10          U.S. DEPT. LABOR v. NORTH CAROLINA GROWERS
Christmas trees falls squarely within the primary definition of agricul-
ture in § 203(f), and the Growers have met their burden of proving
that they fall "plainly and unmistakably within [the exemption’s]
terms and spirit." Arnold, 361 U.S. at 392.11

   The DOL maintains that even if Christmas tree farming fits within
the express definition of agriculture under § 203(f), it is nonetheless
excluded because it constitutes forestry, which Congress implicitly
has excluded from the primary definition of agriculture. The DOL
points to the many similarities between Christmas tree farming and for-
estry.12 If the FLSA provided no guidance beyond § 203(f) as to what
forestry operations Congress intended to exclude from the primary
definition of agriculture, we might agree with the DOL that Christmas
tree farming is an excluded forestry operation. Given the specific def-
inition of "forestry or lumbering operations" in § 213(b)(28), how-
ever, it is clear that Christmas tree farming is not a "forestry or
  11
      It would also not be unreasonable, however, to find that Christmas
trees were agricultural commodities under § 203(f). Agriculture is,
among other things, "the science or art of . . . harvesting crops," which
are "plant[s] . . . that can be grown and harvested extensively for profit."
Webster’s Third New Int’l Dictionary 44, 540 (1986). Because Christmas
trees are plants that are grown and harvested extensively for profit, it
would also be reasonable to find that they are agricultural commodities.
See Oregon Dep’t of Agric., Story of the Week, available at
http://oda.state.or.us/information/news/2003/031029trees.pdf (defining
Christmas trees as one of Oregon’s "top agricultural commodities").
   12
      Like Christmas tree farming, forestry often involves the planting of
trees in rows, occasional treatment with herbicides, and the cutting down
of trees with chainsaws. There are, however, numerous differences
between forestry and Christmas tree farming. Unlike a forestry tree, the
Christmas tree is the commodity; no further processing is required before
sale to the ultimate consumer. In addition to the distinction in end use,
the cultivation techniques also differ. All of the Growers use mechanical
planters and apply herbicide, pesticide, and fertilizer on an annual basis.
The Growers also manage the Christmas trees during the trees’ entire
rotation. (J.A. at 299.) Forestry trees only receive herbicide, pesticide,
and fertilizer early in their development and are not managed as inten-
sively as Christmas trees. Christmas trees also are sheared and pruned
regularly during growth, while forestry trees are not sheared at all and
are pruned only early in their development.
            U.S. DEPT. LABOR v. NORTH CAROLINA GROWERS                 11
lumbering operation[]" that Congress intended to exclude from the
primary definition of agriculture.

   While the definition of forestry and lumbering operations in
§ 213(b)(28) includes the "planting and tending of trees," reading that
phrase in context, see Cline, 124 S.Ct. 1246, it is apparent that Con-
gress was describing trees being used for traditional forestry purposes
as "timber" and "pulp." Webster’s Third New Int’l Dictionary at 890,
1840. Section 213(b)(28) refers also to "cruising, surveying, or felling
timber," and to "preparing or transporting logs or other forestry prod-
ucts to the mill, [or] processing plant." 29 U.S.C.A. § 213(b)(28).
These provisions help clarify that the phrase "planting and tending of
trees" refers only to trees that will be used for their wood as timber
or pulp.

   The common meaning of other terms associated with traditional
forestry support this reading of § 213(b)(28). Timber is "growing
trees or their wood," specifically, "wood used for or suitable for build-
ing . . . or for carpentry or joinery." Webster’s Third New Int’l Dictio-
nary at 2394. Similarly, "lumbering" is "the business of cutting or
getting timber or logs from the forest for lumber." Id. at 1345. The
production of Christmas trees, which are sold for decorative use, not
as lumber or as wood for building, does not fall within the common
meaning of these terms. Because Christmas trees are not processed
into pulp or harvested as timber, we conclude that Christmas tree
farming is not forestry or lumbering as those terms are used in the
FLSA.13 Accordingly, we hold that the cultivation, growing, and har-
vesting of Christmas trees is agriculture as defined in § 203(f), and
that the employees of the Growers are thus exempt from the overtime
provisions of the FLSA.
  13
    Our reading of § 213(b)(28) is confirmed by its legislative history.
One proposal would have added "forestry in all its branches" to the pri-
mary definition of § 203(f). Its purpose would have been "to exclude the
harvesters of the timber crop" from the overtime protections of the
FLSA. 95 Cong. Rec. H11211 (emphasis added). Furthermore, in adopt-
ing the version codified at § 213(b)(28), supporters of the bill explained
that "the small lumberman in the woods cannot operate in competition
with the big operators." 95 Cong. Rec. H11212 (emphasis added). Thus,
the legislative history also shows that Congress understood forestry to be
the planting and tending of trees to be used as timber.
12         U.S. DEPT. LABOR v. NORTH CAROLINA GROWERS
                                  C.

    We recognize that our interpretation of § 203(f) undercuts a
lengthy history of DOL interpretation. At least since 1956, the DOL
has interpreted § 203(f) to exclude Christmas tree farming. See 29
C.F.R. §§ 780.115, 780.200, 780.208 (2003). The DOL’s interpreta-
tive bulletins, however, were adopted without notice and comment
rulemaking and without a formal adjudication, and accordingly, lack
the force of law. The Supreme Court has made clear that in such situ-
ations, we defer to the agency’s interpretation only to the extent that
the interpretation has the power to persuade. Skidmore v. Swift & Co.,
323 U.S. 134 (1944); see Christensen v. Harris County, 529 U.S. 576,
587 (2000); United States v. Mead Corp., 533 U.S. 218, 234 (2001)
("Chevron did nothing to eliminate Skidmore’s holding that an agen-
cy’s interpretation may merit some deference whatever its form
. . . ."); see also 1 K. Davis & R. Pierce, Administrative Law Treatise
§ 3.5 (3d ed. 1994) ("Congress has not delegated to any agency the
power to make policy decisions that bind courts and citizens through
[interpretive rules].") The weight accorded interpretative bulletins
"depend[s] upon the thoroughness evident in [the agency’s] consider-
ation, the validity of [the agency’s] reasoning, its consistency with
earlier and later pronouncements, and all those factors which give it
the power to persuade." Skidmore, 323 U.S. at 140.

    Although the DOL’s interpretation has been consistent, we con-
clude that it lacks the power to persuade. Because the bulletins were
not adopted after notice and comment rulemaking, they lack the thor-
oughness of such rules. For example, 29 C.F.R. § 780.115 provides
that "[t]rees grown in forests and the lumber derived therefrom are not
‘agricultural or horticultural commodities.’ Christmas trees, whether
wild or planted, are also not so considered." As the Growers note, this
statement begs the question of why Christmas trees are not so consid-
ered. Without an explanation of how the DOL came to its conclusion,
it is impossible for us to be persuaded by the DOL’s reasoning. Simi-
larly, § 788.10 provides that Christmas trees are "other forestry prod-
ucts" without any explanation. 29 C.F.R. § 788.10. Finally, 29 C.F.R.
§ 780.201, entitled "Meaning of ‘forestry or lumbering operations,’"
provides:

     The term "forestry or lumbering operations" refers to the
     cultivation and management of forests, the felling and trim-
              U.S. DEPT. LABOR v. NORTH CAROLINA GROWERS                  13
       ming of timber, the cutting, hauling, and transportation of
       timber, logs, pulpwood, cordwood, lumber, and like prod-
       ucts, the sawing of logs into lumber or the conversion of
       logs into ties, posts, and similar products, and similar opera-
       tions. It also includes the piling, stacking, and storing of all
       such products. The gathering of wild plants and of wild or
       planted Christmas trees are included.

Like §§ 780.115 and 788.10, this section provides no analysis as to
why Christmas trees are included within "forestry or lumbering opera-
tions."

   The bulletins also make an arbitrary distinction between Christmas
tree farming and nursery trees. According to the DOL, trees grown at
a nursery are agriculture. See 29 C.F.R. § 780.205 (defining agricul-
ture to include "[s]owing seeds and otherwise propagating fruit, nut,
shade, vegetable, and ornamental plants or trees (but not Christmas
trees), and shrubs, vines, and flowers.") Under the statutory language
there is no justifiable reason for the distinction between trees grown
at a nursery and trees grown at a modern Christmas tree farm. Nur-
sery operations involve the cultivation of horticultural and agricultural
commodities, so, like Christmas tree farming, they fall within the pri-
mary definition of § 203(f). The DOL is correct that there are distinc-
tions between the cultivation and growth of nursery trees and
Christmas trees, but none of the distinctions are relevant under the stat-
ute.14

   We also note that when the DOL originally promulgated these bul-
letins in the 1950s, Christmas tree farming as we know it today essen-
tially did not exist. Prior to the late 1960s, Christmas trees were either
cut down from the wild or planted and harvested with little or no
management. As discussed above, contemporary Christmas tree oper-
ations involve extensive management. While the DOL’s categoriza-
tion of Christmas tree farming as non-agriculture may have been
  14
     For instance, nursery trees undergo more intensive irrigation and fer-
tilization than Christmas trees and have fewer naturally growing weeds
in their soil. Nursery trees are usually grown in growbags or planted in
fields and are sold individually for ornamental purposes after a shorter
growing period than Christmas trees.
14         U.S. DEPT. LABOR v. NORTH CAROLINA GROWERS
persuasive at the time the bulletins were promulgated, the significant
changes in the industry’s cultivation and management techniques
since that time render the original bulletins unpersuasive. The DOL
has reconsidered its position on Christmas tree farming on three occa-
sions, most recently in 1991. On each occasion, the DOL has issued
opinion letters adhering to its original interpretative bulletins. The
DOL’s letters, however, reject the position that Christmas tree farm-
ing is agriculture without any consideration of the evolution of the
industry. Accordingly, we find that the DOL’s reconsiderations also
lack the power to persuade.

                                 IV.

   Because Christmas tree farming falls within the primary definition
of "agriculture" in § 203(f), we reverse the grant of summary judg-
ment in favor of the DOL and remand the case with instructions for
the district court to enter summary judgment in favor of the Growers.
We also vacate the permanent injunction against the Growers.

                        REVERSED, VACATED, AND REMANDED
                                       WITH INSTRUCTIONS
