Use of Herbicides for Industrial Forest Vegetation Management in the

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Use of Herbicides for Industrial Forest Vegetation Management in the Southern United States LARRY R. NELSON, DEAN H. GJERSTAD, and PATRICK J. MINOGUE Department of Forestry, Auburn University Agricultural Experiment Station, Auburn, AL 36849

Projections by the U.S.D.A. Forest Service indicate that the Southeastern United States is likely to lead the nation in wood production by the beginning of the next century. The forestry capacity of the South in terms of productive forest acreage is greater than other forested regions such as the Pacific Coast, the Rocky Mountains and the Northeast. Of the 482 million acres of commercial forests in the country, only thirty percent is capable of producing greater than 85 cubic ft. of wood per acre per year. Sixty million acres, or 41 percent of this land occurs in the South while 38, 25, and 13 percent occur in the North, Pacific Coast and Rocky Mountain regions respectively. Approximately half of the remaining acres capable of producing 50 to 85 cubic ft. per acre per year also occurs in the South (Anonymous 1982). In 1976 the Pacific Coast supplied 50 percent of the nations softwood products while the South provided 36 percent. These figures are expected to reverse by 2030 after old growth timber on the Pacific coast has been cut (Anonymous 1982). However, the total forestry land base over this period is expected to remain fairly constant. A major increase in forest management activity will be necessary if the South is to increase production to the predicted levels. Greater exploitation of privately owned forest lands (70$ of the total in the South) and more intensive forest management on all sectors of forest ownership offer possibilities for increasing the wood supply. Significant increases in production from the private sector can be induced over time through incentives programs or from increased stumpage prices. Meanwhile, current attempts at increasing production per acre are being conducted by forest industry. Genetic improvement, fertilization, and tree spacing control are being utilized to increase the growth of southern pines. Another area receiving a 0097-6156/84/0238-0011$06.00/0 © 1984 American Chemical Society

Garner and Harvey; Chemical and Biological Controls in Forestry ACS Symposium Series; American Chemical Society: Washington, DC, 1984.


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CHEMICAL AND BIOLOGICAL CONTROLS IN FORESTRY

great deal of recent i n t e r e s t i s that of c o n t r o l l i n g competition from non crop v e g e t a t i o n . Competition from herbaceous weeds and low q u a l i t y hardwoods i s one of the major f a c t o r s reducing p r o d u c t i v i t y of pine f o r e s t s i n the South. ( F i t z g e r a l d et a l . 1973» Kozlowski 1969, and Schneider and Stranskey 1966). The southern pine s p e c i e s , l o b l o l l y (£inu& iâëâa. L.), s h o r t l e a f (£inus_ echinata M i l l . ) , s l a s h (£iflus_ e l l i o t t i i Engelm), and l o n g l e a f (JEinus. p a l u s t r i s M i l l . ) comprise the g r e a t e s t economic component of the southern f o r e s t s . Because pines grow more r a p i d l y than hardwoods, are c u r r e n t l y e a s i e r to regenerate, and have s u p e r i o r wood p r o p e r t i e s f o r a v a r i e t y o f uses, they are the d e s i r e d commercial s p e c i e s . But, these species are a subclimax component of the f o r e s t . Without i n t e r f e r e n c e by man or f i r e , the majority of pine f o r e s t s i n the the South would e v e n t u a l l y r e v e r t to oak-hickory or southern mixed hardwoods i n the v a r i o u s r e g i o n s (Monk 1965, Hebb and C l e w e l l 1976, and Kuchler 1964). In order to grow pine i n successive r o t a t i o n s on a given acreage, f o r e s t e r s implement c u l t u r a l techniques that favor pine over low quality hardwoods and other non-pine v e g e t a t i o n , i . e . p l a n t succession i s delayed. Such techniques are g e n e r a l l y c a t e g o r i z e d under the term f o r e s t v e g e t a t i o n management and i n v o l v e the use of machinery, f i r e , and or chemicals during s i l v i c u l t u r a l p r a c t i c e s such as s i t e preparation, weed c o n t r o l f o r p l a n t a t i o n establishment, pine r e l e a s e from overtopping brush, timber stand improvement, e t c . Recently, the use of chemical herbicides i n forest v e g e t a t i o n management has gained i n t e r e s t over the use of f i r e or machinery alone. A southwide e f f o r t by i n d u s t r y i s i n progress through the Auburn u n i v e r s i t y S i l v i c u l t u r a l H e r b i c i d e Cooperative to i n v e s t i g a t e the b e n e f i t s of h e r b i c i d e usage and to develop and register effective herbicides for various purposes. The f o l l o w i n g i s a d e s c r i p t i o n of the use of h e r b i c i d e s by the southern forest industry. Reasons for using herbicides information on benefits, and the available chemistry are categorized by s i l v i c u l t u r a l p r a c t i c e . S i t e Preparation U n t i l 1979, the primary h e r b i c i d e used by f o r e s t e r s f o r brush c o n t r o l i n the South was 2,4,5-T. T h i s chemical could be a p p l i e d i n e x p e n s i v e l y ($15 -30/acre) at r a t e s of 4 to 6 pounds per acre for s i t e preparation. Most a p p l i c a t i o n s were conducted with aircraft. Surveys (1977) of h e r b i c i d e usage on i n d u s t r i a l f o r e s t lands i n the South showed that of the 1,175,350 acres s i t e prepared f o r p l a n t i n g , 118,100 acres (10$) were t r e a t e d with 2,4,5-T, 48,700 (4$) were t r e a t e d with other h e r b i c i d e s , and 909,000 acres (77$) were t r e a t e d mechanically (anonymous 1978). Obviously, the m a j o r i t y of the f o r e s t acreage was s i t e prepared with machinery. Nevertheless h e r b i c i d e s f i l l e d an important



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Industrial Forest Vegetation Management

c a p a c i t y . Chemicals were g e n e r a l l y used on m a r g i n a l l y productive s i t e s because of costs r e l a t i v e to mechanical methods and on lands with steep slopes on which machinery could not operate efficiently. In 1979 an i n j u n c t i o n against the use of 2,4,5-T on f o r e s t lands, rights-of-ways, and pasturelands was imposed by the Environmental P r o t e c t i o n Agency. The use of h e r b i c i d e s d e c l i n e d sharply from the previous period of 2,4,5-T availability. A l t e r n a t i v e chemicals were g e n e r a l l y more expensive than 2,4,5-T, f o r e s t e r s were not f a m i l i a r with them, and pressures from environmental groups favored a move away from the use of herbicides. A f t e r four years without 2,4,5-T f o r e s t e r s are expressing increased i n t e r e s t i n the use of h e r b i c i d e s f o r f o r e s t s i t e preparation. Reasons i n c l u d e higher costs of mechanical methods and the f a c t that r e c e n t l y used h e r b i c i d e treatments have been very e f f e c t i v e . Mechanical s i t e p r e p a r a t i o n methods are used to: (1) control brush, (2) remove s l a s h and debris, (3) enhance a e s t h e t i c s , and (4) o c c a s i o n a l l y r e h a b i l i t a t e damaged s o i l s . Methods i n c l u d e shearing c u l l hardwoods and brush with a K G or "V" blade mounted on a b u l l d o z e r , chopping with l a r g e drum choppers mounted behind a b u l l d o z e r , and crushing trees and brush with 40-60 ton devices such as the LeTourneau brush crusher. These and other mechanical methods are a l l h i g h l y energy consumptive and require large investments in mechanical equipment. Costs f o r mechanical s i t e p r e p a r a t i o n range from $50 to more than $150 per acre. Examples are shown i n Table I. n

Table I.

w

Approximate costs of four mechanical s i t e p r e p a r a t i o n methods commonly used by f o r e s t i n d u s t r y i n the South.

Method of S i t e

Preparation S i n g l e pass drum chopper Double pass drum chopper Shear and p i l e Root rake

Cost per

Acre (&) 50 70 90 - 120 90-140 100 - 150

Herbicide usage i n conjunction with burning o f f e r s a v i a b l e a l t e r n a t i v e to machinery on many s i t e s . Products r e g i s t e r e d f o r s i t e p r e p a r a t i o n are l i s t e d i n Table I I . A v a r i e t y of products are registered although several c o n t a i n the same active i n g r e d i e n t under a d i f f e r e n t trade name. Four of the f i v e i n g r e d i e n t s , t r i c l o p y r , hexazinone, fosamine, and glyphosate are


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C H E M I C A L A N D BIOLOGICAL CONTROLS IN FORESTRY

relatively years.

Table I I .

new

having

been

registered

f o r only

three to four

Herbicides registered f o r forest s i t e preparation i n the Southeastern united S t a t e s .


Herbicide Common

Trade

Picloram + 2,4-D Picloram T r i c l o p y r (amine) T r i c l o p y r (ester) 2,4-D 2,4-D 2,4-D + Dicamba 2,4-D + Dicamba Dicamba 2,4-D + 2,4-DP 2,4-DP MSMA Hexazinone Fosamine Glyphosate 2,4-D + Dicamba

Tordon 101 Tordon 10K Garlon 3A Garlon 4 Esteron 99 Verton 2D Banvel 520 Banvel 720 Banvel 4WS Weedone 170 Weedone 2,4-DP Transvert Velpar G r i d b a l l Krenite Roundup Trimec 450-E

Manufacturer Dow Chemical USA Dow Chemical USA Dow Chemical USA Dow Chemical USA Dow Chemical USA Dow Chemical USA V e l s i c o l Chemical Corp. V e l s i c o l Chemical Corp. V e l s i c o l Chemical Corp. Union Carbide Union Carbide Union Carbide E.I. DuPont de Nemours & Co. E.I. DuPont de Nemours & Co. Monsanto Ag. Products Co. PBI Gordon

Some of the more commonly used treatments approach the lower range o f costs ($50-$100) expected f o r mechanical s i t e p r e p a r a t i o n methods (Table I I I ) . Approximately $10 - $15 should be added to the t a b l e values f o r a p p l i c a t i o n costs ( g e n e r a l l y f o r contract a e r i a l a p p l i c a t i o n s ) .

Table I I I .

Approximate Costs o f Some H e r b i c i d e s i n Treatments Commonly Used i n the Southeastern United S t a t e s .

Herbicides Tordon 101 + 2,4-DP Tordon 101 + Garlon 4 Garlon 4

Velpar Gridbâll

Rate (Gal/Ac) or 2 + 1 2 + 1/2 1

(lb/Ac)

40

Cost (t) 64 77 64 1*54

One recent study i n d i c a t e s that h e r b i c i d e s can reduce r e s p r o u t i n g o f hardwood s p e c i e s more e f f e c t i v e l y than drum chopping brush (Table I V ) . Most southern hardwoods are capable


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NELSON ET A L .

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of r e s p r o u t i n g from stumps and root systems a f t e r stem p o r t i o n s are mechanically removed (Grano 1961 and Johnson 1961). The underground portions can be k i l l e d by a p p l i c a t i o n s o f t r a n s l o c a t a b l e h e r b i c i d e s . Future brush competition w i t h newly planted pines can thus be reduced.


Table IV.

Numbers o f stems per acre o f major hardwood species t h a t occurred p r i o r t o the a p p l i c a t i o n o f v a r i o u s s i t e p r e p a r a t i o n treatments and approximately one year a f t e r treatment. The s i t e i n c l u d i n g a l l t e s t p l o t s was c o n t r o l burned a few months a f t e r treatment. 1

Treatment Herbicide

Rate

No. o f stems/ac

%

(Common name) ( g a l / ao) 1st v r ( i n i t i a l ) 2nd year reduction Hexazinone Triclopyr Hexazinone + triclopyr (Drum chopped)

3 1 2 +1/2

2275 2112 3002

225 255 563

89 88 81

1967

1493

24

1

M a j o r species i n c l u d e : white oak, black t u p e l o , sweetgum, r e d oaks, h i c k o r i e s , Prunus spp., dogwood, red maple, UUmis. spp.

A long term comparison o f the r e l a t i v e b e n e f i t s o f chemical versus mechanical s i t e p r e p a r a t i o n w i l l r e q u i r e growth and y i e l d research. Numerous s t u d i e s are p r e s e n t l y being initiated. However, these w i l l not be completed f o r many years. Scientists at Auburn u n i v e r s i t y are attempting t o provide i n t e r i m r e s u l t s by measuring o l d e r s t u d i e s and comparisons. Meanwhile, f o r e s t e r s are l i k e l y t o continue use o f h e r b i c i d e s on steep slopes or s i t e s w i t h f r a g i l e and erodable s o i l s on which machinery cannot be operated or would l i k e l y cause v i s i b l e and long term damage. Release "Release" i s conducted i n young pine p l a n t a t i o n s on which brush has e s t a b l i s h e d a competitive growth advantage over pines. Hardwood sprouts from stumps and r o o t s a r e capable o f e a r l y r a p i d growth and occupation o f a s i t e . This was evidenced i n Arkansas, where sprouts covered 58 and 92 percent o f the s i t e surface area three and s i x years, r e s p e c t i v e l y , a f t e r complete top removal o f the previous stand (Grano 1961). Similarly, i n Mississippi, 7,500 stems per acre o f ash (Fraxinus sp.) and b i t t e r pecan fCarva aquatica (Michx. f ) Nutt.] up t o 15 f e e t i n height dominated a s i t e f i v e years a f t e r b u l l d o z i n g (Johnson 1961).


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Pines g e n e r a l l y do not demonstrate such r a p i d e a r l y growth, p a r t i c u l a r l y when i n competition with other v e g e t a t i o n . Dominant l o b l o l l y pines under o l d f i e l d c o n d i t i o n s range from 8 t o 12 f e e t i n height a f t e r f i v e years on s i t e index25 ^° ^0 lands. However, i f suppressed, pines w i l l respond t o brush c o n t r o l a t an e a r l y age (Malac 1961, Martin 1973). Brush c o n t r o l i n e s t a b l i s h e d pine stands i s nearly always conducted with h e r b i c i d e s . As i n s i t e p r e p a r a t i o n , 2,4,5-T was the primary h e r b i c i d e used u n t i l the i n j u n c t i o n against i t s use i n 1979· I t was the only h e r b i c i d e that c o n t r o l l e d a v a r i e t y o f brush species without badly damaging pine when broadcast sprayed over p l a n t a t i o n s . Research has been conducted t o e s t a b l i s h other e f f e c t i v e h e r b i c i d e s f o r t h i s use. Recently, three other h e r b i c i d e s have been r e g i s t e r e d f o r pine r e l e a s e (Table V). These products have been shown e f f e c t i v e under c e r t a i n c o n d i t i o n s . Registered formulations o f hexazinone are s o i l active products. S e l e c t i v e brush c o n t r o l around pines occurs when l e t h a l amounts o f chemical i s absorbed by brush species but not the pines. Pines are g e n e r a l l y more r e s i s t a n t t o the a c t i v e i n g r e d i e n t than hardwoods. Thus a threshold l e v e l o f chemical can be a p p l i e d without damaging pines. However, s e l e c t i v e r a t e s of t h i s h e r b i c i d e vary by s o i l type and the a p p l i c a t o r must c a r e f u l l y prescribe rates accordingly.


t

Table V.

o

H e r b i c i d e s r e g i s t e r e d f o r r e l e a s i n g pines from brush i n the Southeastern u n i t e d S t a t e s .

Common Najne Hexazinone Hexazinone Glyphosate 2,4-DP

Herbicide Trade Name Velpar Brush K i l l e r (1/2cc) Velpar G r i d b a l l (2cc) Roundup Weedone 2,4-DP

Manufacturer E.I. DuPont de Nemours & Co. E.I. DuPont de Nemours & Co. Monsanto Ag. Products Co. Union Carbide

1

The 2,4-DP product i s r e g i s t e r e d under s t a t e l a b e l s i n AR, AL, MS, LA, GA, NC, and TN.

Glyphosate i s used p r i m a r i l y i n l a t e summer t o e a r l y f a l l applications. I n c e r t a i n regions o f the South, i . e . V i r g i n i a , North C a r o l i n a , and Tennessee, the product has provided good, s e l e c t i v e c o n t r o l o f brush i n l o b l o l l y pine p l a n t a t i o n s . Growth a c t i v i t y o f pines i n these areas d e c l i n e s during the summer t o e a r l y f a l l r e s u l t i n g i n r e s i s t a n c e to glyphosate a t 1 1/2 t o 2



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quarts of product per acre. At the same time, hardwood brush species are more s u s c e p t i b l e to l a t e versus e a r l y growing season applications. S e l e c t i v e brush c o n t r o l has not been demonstrated as widely i n the deep South. The 2,4-DP product i s recommended f o r use i n broadcast a p p l i c a t i o n s to be sprayed a f t e r pines have completed the f i r s t growth f l u s h of the season. I t i s q u i t e e f f e c t i v e on oak species. At present another method of a p p l i c a t i o n i n v o l v e s d i r e c t e d sprays with knapsack sprayers. A l l three of the above h e r b i c i d e s can cause pine damage i f not a p p l i e d under the c o n d i t i o n s s p e c i f i e d on the product l a b e l . Research i s underway to improve r e l e a s e treatments with these h e r b i c i d e s , and to examine other products with p o t e n t i a l f o r t h i s use.

Tree Injection S i n g l e tree i n j e c t i o n i s used to remove c u l l hardwoods from s i t e s during s i t e p r e p a r a t i o n , pine r e l e a s e , or f o r timber stand improvement. Tree i n j e c t i o n i s e f f i c i e n t on s i t e s with a sparse d i s t r i b u t i o n (100 stems per acre, or l e s s ) o f hardwoods g r e a t e r than 1 inch dbh. The method i s u s e f u l f o r c o n t r o l of s p e c i e s r e s i s t a n t to f o l i a r treatments or stems missed during f o l i a r application. Treatments c o n s i s t of i n j e c t i n g h e r b i c i d e through the bark and i n t o the v a s c u l a r system of t a r g e t t r e e s . The most commonly used h e r b i c i d e s are 2,4-D, and Tordon 101 (2,4-D + p i c l o r a m ) . The t o t a l l i s t of r e g i s t e r e d products i s shown i n Table VI.

Table

VI.

Herbicides

registered Southeast.

Common

Trade

Name

Name

2,4-D 2,4-D 2,4-D 2,4-D 2,4-D Triclopyr Picloram + 2,4-D Hexazinone Dicamba Dicamba Glyphosate

DMA-4 Formula 40 Weed Rap 2,4-D Weedone 64 Garlon 3A Tordon 101R Velpar L Banvel Banvel CST Roundup

for

tree

injection

in

Manufacturer Dow Chemical USA Dow Chemical USA Vertac Rhodia Union Carbide Dow Chemical USA Dow Chemical USA E.I. DuPont de Nemours & Co. Velsicol Velsicol Monsanto


the

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C H E M I C A L A N D BIOLOGICAL CONTROLS IN FORESTRY


Two types o f i n j e c t i o n devices are a v a i l a b l e . Long tubular models are used to place chemicals i n t o the base of trees and the a x - l i k e Hypo-hatchet f o r i n j e c t i o n higher on the stem. Both t o o l s are e f f e c t i v e (Holt 1975). Injection treatments are e f f e c t i v e year-round. Various s t u d i e s show that greater than 90 percent c o n t r o l of most species i s p o s s i b l e (Table V I I ) .

Table VII.

Percent k i l l o f hardwood species a f t e r hypo-hatchet i n j e c t i o n with 2,4-D and Tordon 1 0 1 a

Herbicides Species Hickory

2,4-D

Tordon 101

95

95

References McNab and Moyer, 1969; Mover 1967; S t a r r 1972; S t e r r e t t 1969a;

S t e r r e t t 1969b. Southern red oak White oak Post oak Elm Sweetgum Dogwood Red Maple

a

96

100

89 98 91

100 97 100 100

100 79

21

D a t a and references ^Sprouting.

McNab Peevy Starr Starr

and Moyer 1969; Moyer 1967; 1968b; S t a r r 1972. 1973; S t e r r e t t 1969b. 1972.

Peevy 1968a. McNab and Moyer 1969; Peevy 1968b.

8 3

κ 100-S b

McNab and Moyer 1969; Moyer 1967. C a r v e l l 1968; Peevy 1972; S t e r r e t t 1969a; S t e r r e t t 1969b.

from Holt 1975.

C o n t r o l o f Herbaceous Weeds Under i n t e n s e management systems f o r e s t e r s have become i n t e r e s t e d in controlling o f herbaceous weeds around newly planted seedlings. Weed competition can be severe on good sites f o l l o w i n g mechanical s i t e p r e p a r a t i o n . Grasses and f o r b s become abundantly e s t a b l i s h e d w i t h i n months a f t e r s o i l disturbance. Recent s t u d i e s show that c o n t r o l a i d s s u r v i v a l and growth o f the pines ( F i t z g e r a l d 1976, H o l t e t a l 1973, Holt e t a l 1975, Nelson et a l 1981, Knowe 1982). Impressive pine growth response to weed c o n t r o l i s shown i n Table V I I I . Trees r e c e i v i n g two years o f weed c o n t r o l were twice as t a l l and had twice the ground l i n e diameter as i n nonweeded check p l o t s a f t e r three growing seasons. Tree volumes had increased e i g h t - f o l d over the check t r e e s . The q u e s t i o n o f whether the above growth d i f f e r e n c e s w i l l remain throughout the r o t a t i o n o f the stand cannot be answered a t t h i s


2.

NELSON ET AL.


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point i n time. However, a f t e r four growing seasons, d i f f e r e n c e s i n height and diameter between the weeded and nonweeded t r e e s i n the above study are s t i l l d i v e r g i n g (unpublished d a t a ) .


Table V I I I .

Mean height, groundline diameter (GLD), and volume of l o b l o l l y pine t r e e s at the end of three growing season f o l l o w i n g v a r i o u s l e v e l s of weed c o n t r o l . Treatments were i n i t i a t e d during the s p r i n g of the f i r s t growing season. Weeds were c o n t r o l l e d on a broadcast b a s i s ( T o t a l ) and i n a 5 f t . band over the row (band) f o r the f i r s t and second year.^ >2

L e v e l of Weed Control T o t a l - 2 years Band - 2 years T o t a l - 1 year Band - 1 year Check 1

2

Height (feet) 7.61 a 6.26 b 5.30 c 5.35 c 3.64 d

GLD (inches) 2.64 a 2.09 b 1.65 c 1.61 c 1.02 d

Volume ( c u b i c inches) 185 a 108 b 67 c 62 c 21 d

The t a b l e i s from Knowe, 1982. Means followed by the same l e t t e r are not s i g n i f i c a n t l y d i f f e r e n t at the 5 percent l e v e l of Duncan's New M u l t i p l e Range Test.

The b i o l o g i c a l b a s i s f o r the above growth response i s not completely resolved although relief from competition for moisture, n u t r i e n t s , and l i g h t i s a l i k e l y f a c t o r . The e f f e c t s of weed competition on the moisture s t a t u s of young pine i s i n d i c a t e d i n f i g u r e 1 (Nelson et a l . 1981). Pre-dawn water p o t e n t i a l readings were conducted with a pressure bomb on young s e e d l i n g s growing under a stand of pure ragweed and on weeded p l o t s . Seedling moisture s t r e s s reached approximately 15 and 4 bars on unweeded and weeded plots r e s p e c t i v e l y ten days a f t e r r a i n f a l l . Future b i o l o g i c a l research should provide more i n f o r m a t i o n regarding e f f e c t s of s t r e s s from competition on the establishment and e a r l y growth of young pines. Herbicide treatments provide the only p r a c t i c a l means of c o n t r o l l i n g weeds i n pine p l a n t a t i o n s . A p p l i c a t i o n s can be made with a i r c r a f t or with ground equipment such as that used i n a g r i c u l t u r a l row cropping systems. Registered h e r b i c i d e s are shown i n Table IX. Treatments of simazine and a t r a z i n e are e f f e c t i v e only when a p p l i e d preemergence to weeds. Hexazinone has both pre- and postemergence a c t i v i t y but can damage pines i f a p p l i c a t i o n r a t e s are not c a r e f u l l y prescribed. The three



20


D a y s after a 2 inch rainfall Figure 1. E f f e c t s o f weed competition on the moisture s t a t u s ( · ) o f young p i n e .


2. NELSON ET AL.


21

r e g i s t e r e d h e r b i c i d e s g e n e r a l l y c o n t r o l a v a r i e t y o f annual grasses and f o r b s although r e s i s t a n t weeds occur on many s i t e s .


Table IX.

Herbicides r e g i s t e r e d f o r c o n t r o l l i n g herbaceous weeds i n young pine p l a n t a t i o n s i n the southeastern United S t a t e s . Herbicide Trade

Common Simazine Atrazine Hexazinone

Princep Aatrex Velpar L

Manufacturer Ciba-Geigy Corporation Ciba-Geigy Corporation E.I. DuPont de Nemours & Co.

The concept of c o n t r o l l i n g herbaceous weeds i n pine p l a n t a t i o n s i s r e l a t i v e l y new. In most cases i t i s not necessary i n order to e s t a b l i s h a pine stand although e a r l y growth s t u d i e s r e c e n t l y i n d i c a t e that weed c o n t r o l can be very b e n e f i c i a l . As a r e s u l t , h e r b i c i d e technology f o r t h i s purpose i s j u s t beginning to develop. More e f f e c t i v e h e r b i c i d e s and a p p l i c a t i o n methods are c u r r e n t l y being assessed through v a r i o u s u n i v e r s i t y and i n d u s t r i a l research e f f o r t s .

Literature Cited 1. Anonymous. 1978. Current use of weed control on industrial forest lands. Pages 40-43. In Benefits of 2,4,5-T in forest management. American Paper Institute/National Forest Products Association. Washington, D.C. 2. Anonymous. 1982. Projected trends in domestic timber resources. Pages 147-199. In An analysis of the timber situation in the United States 1952-2030. Forest Resource Report No. 23. USDA Forest Service. Washington, D.C. 3·

Carvell, K. L. 1968. "Tordon effective in red maple tree injection studies." Down to Earth 24:17-18.

4. Fitzgerald, C. H., F. A. Peevy and D. E. Fender. 1973· Rehabilitation of forest land — the southern region. J. For. 71:148-153.


22


5. Fitzgerald, C. H. 1976. Postemergence effects of velpar in a piedmont pine plantation. South. Weed Sci. Soc., Proc 29:299.


6. Graco, C. X. sites, p. 7-8. sites. USDA Occasional Pap.

13·

1961. Hardwood reoccupation of bulldozed In: Hardwood sprout development on cleared Forest Serv., South. Forest Exp. Sta. 186.

7. Hebb, Ε. Α., and A. F. Clewell. 1976. A remnant stand of old-growth slash pine in the Florida Panhandle. Bull, of the Torrey Bot. Club 103:1-9. 8. Holt, Η. Α., J. E. Voeller, and J. F. Young. 1973. Vegetation control in newly established pine plantations. South. Weed Sci. Soc., Proc. 28:219. 9. Holt, Η. Α., J. E. Voeller, and J. F. Young. 1975a. herbaceous vegetation control as a forest management practice. South. Weed Sci. Soc. Proc. 28:219. 10. Holt, Η. Α., J. E. Voeller, and J. F. Young. 1975b. The hypo-hatchet injector and timber stand improvement. Purdue university, J. S. Wright Forestry Conf. Proc: 93-197. 11. Johnson R. L. 1961. Hardwood sprouts dominate bottomland clearings, p. 9 In: Hardwood sprout development on cleared sites. USDA Forest Serv., South. Forest Exp. Sta. Occasional Pap. 186. 12. Knowe, S. A. 1982. Third year results for loblolly growth impact. 5 p. Auburn Univ. Silv. Herb. Coop. Res. Note No. 82-4. Kozlowski, T. T. 1969. Soil water and tree growth. 17th Ann. LA. St. Univ. For. Symp., Proc: 30-37. 14. Kuchler, A. W. 1964. Potential natural vegetation of the conterminous united States. Manual to accompany the map. Am. Geogr. Soc. Special Pub. No. 36 (With map, rev. ed., 1965, 1966). 15. Malac, B. F. 1961. Early indications of growth responses following foliar applications of herbicides. South. Weed Conf., Proc. 14:222-227. 16. Martin, J. W. 1973· Pickens County aerial spray release study. Four year Progress Rep., American Can Co., Butler, Ala. 4 p.


2. NELSON ET AL.


23

17. McNab, W. H. and E. L. Moyer, Jr. July 1969. Winter injection of 2,4-D and Tordon 101 for hardwood control, Research Note SE-115, USDA, USFS, 2 pp. Southeastern For. Expt. Sta., Ashville, NC. 18. Monk, C. D. 1965. Southern mixed hardwood forests of northcentral Florida. Ecol. Monogr. 35:335-354. Downloaded by UNIV OF CALIFORNIA SANTA BARBARA on May 25, 2018 | https://pubs.acs.org Publication Date: January 16, 1984 | doi: 10.1021/bk-1984-0238.ch002

19. Moyer, E. L. Jr. 1967. Controlling off-site hardwoods with 2,4-D amine concentrate, Research Note SE-77, USDA, USFS, 2 pp.h, Southeastern For. exp. Sta., Ashville, NC. 20. Nelson, L. R., R. C. Pedersen, L. L. Autry, S. Dudley and J. D. Walstad. 1981. Impacts of herbaceous weeds in young loblolly pine plantations. South. J. Applied For. 5(3):153-158. 21. Nelson, L. R., P. J. Minogue, D. H. Gjerstad, and G. R. Glover. 1982. Second year results of a site preparation study using triclopyr and hexazinone. Auburn Univ. Silv. Herb. Coop. Res. Note No. 82-13. 6 p. 22. Peevy, F. A. 1968a. "Injection undiluted 2,4-D amine for control of bottomland hardwood." Proc. 21st Annual Meeting Southern Weed Conference: 223-227. 23.

. 1968b. "Controlling upland southern hardwoods by injecting undiluted, 2,4-D amine." J. of For. 66(6):483-487.

24.

. 1972. "Injection treatments for controlling resistant hardwood species." Proc. 25th Annual Meeting South. Weed Sci. Soc.: 252-256.

25. Schneider, G. and J. J. Stransky. 1966. Soil moisture and soil temperature under a post oak-shortleaf pine stand. Stephen F. Austin State College, School Forestry Bull. 8:24. 26. Starr, J. W. 1972a. The importance of long term research in forestry. Ind. Veg. Manage. 4(2):15-18. 27. Sterrett, J. P. 1969a. "Injection of red maple and hickory with picloram, 2,4-D and 2,4,5-T." Down to Earth 25(2):18-21. 28.

. 1969b. "Injection of hardwoods with dicamba, picloram, and 2,4-D. J. of For. 67(11):820-821. RECEIVED November 11, 1983


Use of Herbicides for Industrial Forest Vegetation Management in the

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