WOODY WEEDS 



In many localities, dense growths of trees or shrubs hinder 

 production of desirable marsh vegetation. Woody weeds are prob- 

 lems in seasonally flooded swamps of the Southeast and various 

 other regions, in bogs of northern States, and in thousands of 

 acres of Southwestern lowlands that are covered by jungles of 

 saltcedar, willows, and poplars. 



Control of woody growths in swamps can be based on chemical 

 or mechanical means, on water-level adjustments, or on combina- 

 tions of these methods. Chemicals most practical for the purpose 

 are 2,4-D, 2,4,5-T, "brush killer" mixtures of the two, Ammate, 

 and under certain conditions, urea compounds. Herbicidal treat- 

 ments include foliage spraying, basal spraying on the lowest foot 

 or two of tree trunks, notch treatment consisting of placement 

 of the chemical in notches of tree trunks, spraying or painting of 

 stumps with herbicides, and ground injections to poison roots. 

 Ground sterilants and basal treatments are of limited importance 

 where flooding causes dispersion of the chemical. 



Mechanical control by means of heavy disks, brush cutters, or 

 similar equipment can be effective in sites suitable for such oper- 

 ations. One of the most effective ways of controlling woody 

 growths is by cutting, followed with flooding of stumps for one 

 growing season. Very few woody weeds can survive this treat- 

 ment. 



An important limiting factor in the control of woody weeds, 

 particularly when applying herbicides to foliage, is insufficiency 

 of knowledge of the stage of growth when control can be applied 

 most effectively. For many species of woody plants, this vulner- 

 able period can be defined in general terms as occurring in late 

 summer or early fall during maximum foliage and before the 

 leaves begin to deteriorate. The best dates for making applica- 

 tions on a particular species in a given locality must be ascer- 

 tained for maximum efficiency. Applications made during other 

 than the most vulnerable period are likely to necessitate extra 

 treatments and costs. 



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