of the topsoil from a large area would be incompatible with the aim of protecting the 

 soil from erosion and preserving site productivity. Nevertheless, some soil can be 

 moved from spots, strips, or trenches without seriously damaging the site. Probably 

 the fibrous-rooted species of grasses, forbs, and sedges provide more competition 

 (Spence 1937) than shrubs (Baker and Korstian 1931) , if density of root systems and the 

 depths to which they penetrate are criteria. 



Rather drastic site preparation methods have been developed in recent years, out 

 of the need to solve some of the problems of regenerating ponderosa pine stands. For 

 example, attempts to plant ponderosa pine in central Idaho and Utah had failed for 

 nearly 30 years before the Town Creek Planting Study was begun in 1954. Results from 

 that study showed that thorough site preparation (bulldozer stripping), combined with 

 careful planting, brought success. In the years following the Town Creek Study, the 

 method of dozer stripping and planting was employed to reforest thousands of acres of 

 land covered with brushfields resulting from wildfires. Without that treatment, those 

 productive timber-growing sites would have remained unproductive for many years. 

 Such drastic methods as dozer stripping or terracing are neither desirable nor neces- 

 sary in all situations, however. They are discussed here to show their value where they 

 are desirable. 



The use of chemicals and fire has also been criticized and sometimes restricted 

 in recent years because of the dangers of environmental pollution. Forest managers must 

 weigh the advantages and disadvantages of these methods in relation to the overall 

 management objectives for the forest. If chemicals or fire endanger high-priority 

 values of the land, other methods of site preparation can be used. The method should 

 be chosen long before the time arrives to prepare the site, because the choice may 

 affect earlier management decisions, such as the selection of a cutting method. 



Scalping and mulching. — On steep slopes where it is impossible for machinery to 

 work safely and efficiently, ground must be prepared by hand, fire, or chemicals. In 

 hand preparation, a pit (basin) or scalp can be formed on the sidehill (fig. 3). When 

 a pit is made, the tree or seed is planted slightly to one side of the center to avoid 

 being covered by soil sloughing from above. Scalps may vary in size according to the 

 amount of competing vegetation but should be at least 30 inches in diameter. 



Mulching, like scalping, has been used to preserve moisture by reducing evaporation 

 from the soil and by limiting the growth of competing vegetation around planted trees. 

 Straw, sheets of 4-mil black polyethylene, and mats of glass fiber 1/4-inch thick were 

 applied to scalped spots 3 feet square on steep slopes in central Idaho to observe the 

 benefits of mulches (fig. 4) . Four tests over a 3-year period were indecisive in terms 

 of survival of planted trees. Generally, seedlings on scalped and mulched spots sur- 

 vived no better than on spots that were only scalped (Hall 1971). 



DeByle (1969) significantly increased survival of planted Jeffrey pine in Nevada 

 by mulching with 3- by 3-foot sheets of 4-mil black polyethylene. His test was similar 

 to the central Idaho experiment using the same material to mulch planted ponderosa 

 pine. The contrasting results from these experiments indicate that the effectiveness 

 of mulching cannot be generalized. More information is needed on the effects of mulches 

 under different conditions. 



Herbicides .--The reduction and elimination of vegetative competition by chemicals 

 before planting have been frequently tested by foresters in recent years. Perhaps the 

 most common use has been in brushfields where vegetation has invaded forest stands 



Data on file at Intermt . For. § Range Exp. Stn., USDA For. Serv. , Boise, Idaho. 



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