NORTHEASTERN FOREST EXPERIMENT STATION 

Chemical Control Of Hardwoods On 

Pine Sites Of Marvland9s Eastern Shore 

Relatively worthless hardwoods often take over space 

that should be growing loblolly pine on Maryland's Eastern 

Shore. In many cut-over areas, hardwoods are suppressing 

small pines that would become a part of the next crop if released. One way of controlling these hardwoods is with 

chemicals such as ammate and 2,4,5-T. 

But there are several ways of applying these; and the 

method, species treated, and type of chemical used greatly 

affect costs and results. To determine what might be best 

locally, the Maryland Department of Forests and Parks and 

the Northeastern Forest Experiment Station tested several 

possible methods in January 1953. 

The test, made in the Pocomoke State Forest, was limited to hardwoods more than 4 inches in diameter (breast 

high), since control of these is usually of most importance 

in cut-over areas on the Eastern Shore. On the average acre 

the stand included 130 of these hardwoods--85 white and post 

oaks; 17 black, southern red, and willow oaks; 18 redmaples; 

5 blackgums; 4 sweetgums; and 1 holly. 

Treatments 

Ten treatments were tried--9 with chemicals, either 

ammate or 2,4,5-T. The tenth aas a girdling treatment. 

The chemical treatments included: 

l~he only formulation of 2,4,5-T used in this test 

contained the low-volatile propylene glycol butyl ether 

esters of 2,4,5-T, and is marketed as Esteron 245 by the Dow 

Chemical Company. 
1-2. Basal spraying with 2 and 4 percent of 2,4,5-T in oil 

(8 or 16 pounds of acid equivalent per 100 gallons of 

kerosene) . 3. Ammate crystals in notches or cups. 

4. Ammate solution (2 pounds of mate per gallon of 

water) in frills. 

5-7. 1, 2, and 4 percent of 2,4,5-T in water in frills. 

8-9. 1 and 2 percent of 2,4,5-T in oil in frills. 

The two basal-spraying treatments were tried on 24 and 77 

trees; each of the other treatments, on 127 to 178 trees. 

Both water and oil carriers for 2,4,5-T were tried 

because of variable results reported elsewhere. In the 

Southeast, Chaiken (2) had recornended the use of 2,4,5-T in 

water; but Arend and Coulter (2) reported this was not always effective in lower Michigan, although 2,4,5-T in oil 

was. 

Treated trees were examined in August 1953, 1954, and 

1955-7, 19, and 31 months after treatment. Chief results 

on the killing of stems above the treated spots, or on 

sprouting below these spots in 1955, were as follows: 

Treatment 

Stems killed by: Sprouting of 

Aug 1953 Aug 1955 killed stems 

Percent Percent Percent 

2,4,5-T basal spraying: 

2 percent in oil 12 29 5 

4 percent in oil 33 67 0 

hate: 

Crystals in cups 29 61 

Water solution in frills 73 94 

2,4,5-T in frills: 

1 percent in water 28 77 27 

2 percent in water 17 81 31 

4 percent in water 25 85 28 

1 percent in oil 83 95 29 

2 percent in oil 86 99 33 

Girdling 49 92 37 

Different species reacted differently to some of the 

treatments. For example, basal spraying with a &-percent 

mixture killed all red maples by August 1953, and 64 percent 

of the oaks by August 1955, but only 1 of the 7 blackgums 
and sweetgums. In contrast, ammate crystals in cups killed 

all sweetgums, and about 90 percent of the blackgums, but 

only 7 percent of the red maples. Both blackgum and red 

maple proved relatively resistant to 2,4,5-T applied in 

frills, particularly when water was used as the carrier. 

The use of 2,4,5-T i n f r i l l s did not greatly reduce 

the number of killed stems that produced basal sprouts; but 

sprouts there were relatively short and usually started at 

the base. In contrast, many of the sprouts on girdled stems 

started along the bole just below the girdle. 

Apparently the 2,4,5-T treatments were not made in 

the best way to minimize sprouting. In the Lake States, 

less sprouting resulted when 2,lt,5-T in oil was applied to 

frills between July and October than when used in other 

months, and hardly any sprouting developed after the mixture 

was applied to frills made just above the root collar in any 

season (1). 

Also according to studies in other regions, treatments in this test might have been more effective in killing 

stems if they had been made in other seasons. For example, 

2,4,5-T in water applied to frills was least effective during the dormant season in the Lake States (g). In Pennsylvania, amte applied in cups in July or September killed 

more than 90 percent of the red maples; but when applied in 

the early part of the dormant season, only 17 percent (9. 

And girdling in the spring, particularly in May, caused more 

rapid kill of southern red oak and post oak in southern 

Arkansas than girdling in other seasons (4). 

Relative Costs 

Frilling treatments were the least expensive of those 

tried in this test. Girdling was somewhat.rnore expensive, 

chiefly because making a good girdle is more time-consuming 

than frilling. Basal spraying and using ammate crystals in 

cupswere themost expensive. As foundelsewhere, basal 

spraying should not be used on large trees because of the 

high cost. Ammate in cups was expensive, in part because 

the axmen were not experiencedin making cups, but also because the material cost more than twice as much as that used 

in the frilling treatments, Frills were also easier to make 

than cups in the study area. 

While a water solution of mate i n f r i l l s is effective, it is corrosive and more expensive than using 2,4,5-T. 

For the latter an oil carrier is recommended, since it costs 

very little more, does not freeze, and is more effective 

than water. Also, since the 2-percent concentration is more 
effective, it is recommended over the 1-percent strength. 

Application 

During the last 3 years hardwoods on about 2,000 

acres of State and private lands have been treated by applying 2 percent of 2,&,5-T in NO. 2 fuel oil to frills. Satisfactory results have been obtained at a cost of $13 to $15 

an acre for treating about 385 trees with an average diameter of 6 inches. 

This poisoning has been done chiefly by 4-man crews 

employed by the Maryland Department of Forests and Parks 

under a revolving-fund program. State foresters inspect and, 

if advisable, recommend the treatment for specific areas. 

Then contracts are signed before the crews start. On private 

land the owner, sometimes nith the aid of ACP pa.yments, reimburses the State when the job is completed. 

Literature Cited 

1. Arend, J. L. 

1955. CHEMTCAL FRILL GIRDLING IN SUMMER AND FALL GIVES 

BEST RESULTS IN LOWER MICHIGAN. Lake States 

Forest Expt. Sta. Tech. Note 438. 1 p. 

2 ---- - - --- - and Coulter, L. L. 

1952. FRILL GIRDLE TESTS ETTH 2,4, 5-T IN LOWER MICHIGAN. Lake States Forest Expt. Sta. Tech. Note 

385. 1 p. 

3. Chaiken, L. E. 

1951. THE USE OF CHEXICALS TO CONTROL INFERIOR TIZEES 

IN THE MANAGEXENT OF LOBLOLLY PINE. Southeast. 

Forest Expt. Sta., Sta. Paper 10. 34 pp., 

illus. 

4. Grano, C. X. 

1955. BEHAVIOR OF SOUTH ARKANSAS OAKS GIRDLED IN DIFFERENT SEASONS. Jour . Forestry 53 : 886-888. 

5. McQuilkin, W. E. 

1955. USE AMMATE IN NOTCHES FOR DEADENING TREES ONLY 

DURING THE GROWING SEASON. Northeast. Forest 

Expt. Sta., Forest Res. Note 52. 2 pp. 

--S . LITTLE 

Northeastern Forest Experiment Station 

Forest Service, U.S. Dept. Agriculture 

and 

J. J. MOHR 

riaryland Department of Forest and Parks