Soil Physical Properties of 

 Raised Planting Beds in a 

 Northern Idaho Forest 



Deborah S. Page-Dumroese 

 Martin F. Jurgensen 

 Russell T. Graham 

 Alan E. Harvey 



INTRODUCTION 



With demands for rapid reforestation, foresters are 

 increasingly turning to planting to achieve good regener- 

 ation after timber harvesting (Gutzwiler 1976). Achieve- 

 ment of full stocking following cutting is a primary 

 management objective on most harvested lands (Fiedler 

 1982). The Northern Rocky Mountains hold 12,000 

 hectares of nonstocked timberland created from fires or 

 past harvesting. Here, site preparation is often a critical 

 prerequisite to attaining satisfactory initial stocking of 

 seedlings in either reforestation or afforestation situa- 

 tions (Gutzwiler 1976). 



Before the advent of large-scale mechanical site prepa- 

 ration, plantings often failed because of inadequate 

 nutrients and moisture. A major goal of preparation is 

 to provide favorable moisture, nutrient, and micro- 

 climatic conditions for establishing a new stand (Coile 

 and Schumacher 1964; McClurkin and Moehring 1978). 

 Selection of either a suitable site preparation method or 

 combination of methods is, therefore, critical to proper 

 seedling growth (Shiver and Fortson 1979). 



CONVENTIONAL SITE 

 PREPARATION 



Site preparation techniques that involve physical 

 removal or burning of woody material usually reduce 

 competition, prepare the site for mechanical planting, 

 and condition the soil to enhance seedling survival. In 

 the Northern Rocky Mountains, competition for 

 nutrients and moisture from invading or residuEil species 

 after harvest can be a major problem for regeneration 

 (Stewart 1974). Conifer establishment becomes more dif- 

 ficult and costly if the site is not prepared immediately 

 after harvest. 



Site preparation in the western States is achieved 

 primarily by mechanical means or by burning. Chemical 

 preparation is also used in some instances (Ferdinand 

 1982). Mechanical treatment is usually some variation of 

 soil scarification, including dozer-blade patching and 

 scalping, done by dozer-blading, ripping, or dragging a 

 chain. On steep slopes, clearcuts are usually broadcast 

 burned to prepare for either natural or artificial regener- 

 ation. Second to burning, scalping to mineral soil is most 

 often used to remove competing vegetation to help 

 ensure moisture for the planted seedlings (Stewart 1974). 



Hall (1971) indicated that all the competing vegetation 

 and the top 10 cm of mineral soil had to be removed 

 when scalping before planting ponderosa pine (Pinus 

 ponderosa [Laws.]). Although scalping, burning, and 

 scarification are effective for ease of planting, seedling 

 survival is often poor (Beebe 1982). 



In contrast, forest management in the Gulf States has 

 relied heavily on very intensive site preparation tech- 

 niques, such as chopping, disking, and bedding, for suc- 

 cessful establishment and rapid growth of southern 

 pines (Worst 1964; Wilhite and Harrington 1965; 

 McMinn 1969). Site preparation is almost universal in 

 the pine flatwoods of the South, where low relief, sandy 

 soils, and large block ownerships favor use of machines. 

 Techniques that improve aeration, such as creation of 

 elevated beds, have become popular because of the high 

 water tables, which may persist most of the year. 



Planting Beds on Lowland Sites 



Planting beds are soil mounds of varying heights 

 formed by earth-moving machines. Bedding concentrates 

 surface organic matter and mineral layers into long, nar- 

 row, raised planting beds. Shultz and Wilhite (1974) 

 found 30 cm to be the optimum bed height for planting 

 loblolly pine {Pinus taeda L.) in the South. Beds 15 cm 

 high and approximately 1.3 m wide, separated by a shal- 

 low furrow from which the organic matter had been 

 scraped, also produced favorable growth responses. 



Soil bedding or mounding has been shown to have 

 favorable effects on seedling growth. McMinn (1969) 

 reported that bedding a poorly drained, acid soil in 

 southern Florida caused a significant increase in south 

 Florida slash pine (Pinus elliottii var. densa Little & 

 Dorman) growth after 5 years. Shoulders and Terry 

 (1978) found that bedding improved soil aeration by 

 increasing porosity. Bedding has also been used to offset 

 soil compaction incurred during harvesting and to 

 decrease soil resistance for root penetration (McKee and 

 Shoulders 1974; Fox 1977). 



Planting Beds on Upland Sites 



Although bedding has been done mainly on wet, 

 lowland sites in the southeastern United States, it has 

 been tried elsewhere. Francis (1979) found that bedding 

 on shallow, fragipan soils increased yellow-poplar 

 {Liriodendron tulipifera L.) growth by keeping roots 



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