54 



ALDERS 



BOTANICAL 



Of nine alder (Alnus) species native to the United States, three 

 commonly produce thickets in bogs or swamps or occur as fringes 

 on the margins of ponds. These are rugosa (formerly incana) 

 and serrulata (formerly rugosa) in the East, and tenuifolia in 

 the West. Though alders occur as far south as Florida, their 

 principal abundance is in north temperate parts of the country. 



IMPORTANCE 



The value of alders for wildlife cover is limited, and their detri- 

 ment to waterfowl habitat is considerable, particularly in im- 

 pounded and dewatered units. 



CONTROL 



Tests by various organizations in different parts of the country 

 have shown that alders can be controlled fairly satisfactorily by 

 2,4,5-T, 2,4-D, or Ammate, though commonly two or more treat- 

 ments are necessary for eradication. Basal spraying (thorough 

 wetting of lowest 2 feet of trunks) was found effective on A. ru- 

 gosa Sit the Dunbar Forest Experiment Station, Mich. (Day, 

 1952). A solution containing 40 pounds of 2,4,5-T ester to 100 

 gallons of diesel oil gave 90% to 100% kill and 80 pounds of 

 2,4,5-T to 100 gallons of oil resulted in practically 100% control 

 in either summer or winter. A commercial mixture of 2,4-D and 

 2,4,5-T gave nearly as good results, but 2,4-D alone was not as 

 effective unless used at a 20% strength. 



At the Patuxent Refuge a recent series of treatments involving 

 complete spraying of alder foliage with 1% 2,4,5-T or 2% silvex 

 in mid-August yielded effective control. Basal spraying of the 

 Pacific Coast tree alder (A. rubra) with 32 pounds of 2,4,5-T in 

 100 gallons of diesel oil gave a 96% kill (Ruth and Bernsten, 

 1956). 



