Reproduction Cutting Methods 



Cleavoutting . — Seed production and seedling survival records enable the forester 

 to estimate the size of cone crop needed to attain a reasonable goal of 1,000 seedlings 

 per acre. A test in small clearcuts in central Idaho determined the ratio of seeds to 

 established seedlings to be 55:1 on scarified soil in weather somewhat warmer and 

 drier than normal (Foiles and Curtis 1965b) . Under these conditions an adequate seed- 

 fall would be 55,000 seeds per acre in the center of the clearcut openings. In Oregon, 

 a study of seed dissemination into a clearcut from the edge of an uncut stand showed 

 that seedfall 2 chains from the timber edge was only about one-fourth as much as seed- 

 fall under the timber (Barrett 1966). Therefore, the margin of a timber stand must 

 produce at least 250,000 seeds per acre to result in the required 55,000 seeds 2 chains 

 from the timber. Only a very heavy cone crop produces this seedfall (Foiles and Curtis 

 1965a, Barrett 1966); only such a crop, therefore, can be considered adequate to 

 regenerate small clearcut openings in one year. In bumper crop years, dominant trees 

 40 years old and older are heavily laden with cones, obvious even to the casual 

 observer. Not all sites are regenerated in one year, however. In areas with favorable 

 climatic conditions, several medium cone crops over a period of 3 to 6 years might be 

 as good as one bumper crop. 



On clearcuts, then, the longer dimension should be at right angles to the pre- 

 vailing wind and the shorter dimension should not be more than 260 feet as a maximum 

 width; 200- foot widths would be preferable for better assurance of adequate seed 

 distribution. 



Of course, clearcuts can be larger if a combination of natural and artificial 

 regeneration methods is used. Natural regeneration may be planned for a distance of 

 about 130 feet from the timbered edges; the remaining interior of the tract can be 

 planted or seeded artificially. 



Seed-tree and shelterwood. — Both seed-tree and shelterwood cuttings remove only a 

 part of the stand; the remaining trees are cut after the reproduction is established. 

 Though insuring a supply of seed, the two cutting methods have the disadvantage of 

 subsequent reproduction losses from logging the residual stand. Dominant, vigorous 

 seed trees should be selected for either the seed-tree or shelterwood system. Such 

 trees, if they are free of disease, are likely to be good seed producers and resistant 

 to wind and other damaging agents. 



Seed-tree and shelterwood cuttings have been used successfully by private industry 

 and on the National Forests in western Montana and northern Idaho (figs. 12, 13). Seed- 

 fall and reproduction resulting from one trial of these methods were measured in 

 southern Idaho. Two L-shaped areas on the Boise Basin F.xperimental Forest at Idaho 

 City, totaling about 10 acres, were chosen prior to the very heavy seed crop of 1958. 

 Each area contained an east and a south aspect. One area was scarified by a land- 

 clearing blade, the other by 12 disks, 36 inches in diameter; both devices were front- 

 mounted on a D-7 tractor. Both areas supported deep and shallow soils and 90-year-old 

 ponderosa pine singly and in groups. These areas resembled seed-tree and shelterwood 

 cuttings only on a limited scale, but nevertheless provided interesting comparisons of 

 first-year seedfall, seedling numbers, and stocking 3 years after dissemination 

 (table 3) . 



For natural regeneration on cutting areas wider than 260 feet, with reproduction 

 density that will provide adequate stocking after 3 years, the seed-tree method rather 

 than clearcutting should be used. Assuming the seed trees are mature (over 150 years 

 old), the number needed will depend on the seed yield. At the 55:1 ratio of seeds to 

 established seedlings, two or three spaced trees per acre are required for full coverage 

 of the area if a heavy crop of seed (100,000 per tree) can be predicted. We estimate 



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