Fire. — Burning is a common method of disposing of slash from logging operations. 

 Slash may be piled, or burned where it fell. Disposal of slash and accumulated unmer- 

 chantable material makes the area more accessible to planting or seeding crews and 

 usually reduces plant competition to a degree that allows planted trees to survive. 

 Burned areas, however, are rapidly invaded by plants, either from seed in the soil or 

 by sprouting from surviving root systems. 



The seed of some species of forest shrubs such as Ceanothus velutinus have imperme- 

 able seed coats and remain dormant until exposed and warmed by fire. Therefore, fire 

 can actually result in prolific germination of old seed stored in the soil (U.S. Forest 

 Service 1948; Curtis 1952). As many as 72,745 viable Ceanothus velutinus seed per acre 

 have been found in the top soil layer of the ponderosa pine type (Krygier 1955) . A 

 combination of fire and spraying with herbicides may be necessary to prepare such sites 

 adequately for pine regeneration. 



Meohanioal techniques. — On gentle slopes, where machines can operate safely, 

 mechanical site preparation can be efficient and economical (Gordon 1956; Curtis 1964) . 

 Toothed land-clearing blades (fig. 6), bulldozer blades, and disks, mounted on the 

 front of tractors, as well as disks or plows mounted on the rear, have all been used 

 successfully in Intermountain Station territory. On sale areas where clearcuts are 

 made and slash is dozer-piled and burned, planting is sometimes successful without 

 further site modification, although plowing in addition usually results in higher 

 survival . 



In brushfields, tractors with angle dozer blades can be used to prepare sites by 

 stripping or terracing, depending on the steepness of slope. Stripping can be used 

 on slopes of less than 40 percent gradient. By this technique, vegetation is pushed 

 from a strip the width of the dozer blade. Angling the dozer blade removes only enough 

 soil to eliminate the vegetation (fig. 7). To minimize the possible erosion hazard, 

 the strips are made parallel to the slope contour, and a band of vegetated ground is 

 left undisturbed as a barrier to soil movement between strips. Rows of trees are then 

 planted in the prepared strips. 



On slopes steeper than 40 percent gradient, tractors cannot safely traverse the 

 slope and do the stripping unless a terrace is constructed. The degree to which such 

 structures approach the level varies in actual practice. Sometimes a trail is con- 

 structed for the uphill track of the tractor only, and the surface of the terrace 

 slopes down toward the outside. This type of construction is common in shallow, rocky 

 soils where a deep cut may remove too much soil to retain a productive site. On other 

 sites the terraces may be level or slanted inward to catch more precipitation and 

 ameliorate the harsh microclimate. 



Site preparation can be accomplished on fairly steep ground by use of a small 

 tractor equipped with a reversible double disk plow and hydraulic vertical lift. This 

 machine will make a single furrow about 12 inches deep and 24 inches wide on ground up 

 to about 40 percent slope. The furrow slice is cut by one disk and cast downhill by 

 the second disk. A tree-planting machine can then ride nearly level with one wheel 

 on each side of the furrow. 



Mechanical site preparation should be completed in the summer preceding the year 

 of planting. Then, most soil settling and sloughing will have occurred by the time 

 trees are planted and stock is less likely to be buried. Site preparation by tractors 

 is more efficient when the ground is bare of snow, the soil is below field capacity, 

 and weather is conducive to efficient working conditions. 



in 



