Artificial Regeneration 



Artificial regeneration by seeding or planting has been tried experimentally since 

 the beginning of the 20th century in the regions being discussed here. In the northern 

 Rocky Mountains large-scale planting and seeding projects were started to reforest 

 extensive areas denuded by the destructive fires of 1910. Planting of ponderosa pine 

 was largely successful; artificial seeding was nearly always unsuccessful. Planting 

 became the dependable and established method of starting new forest crops (Wahlenberg 

 1925). In spite of many failures in these early trials, direct seeding has always 

 appealed to foresters because the procedures appear to be simple and inexpensive, and 

 to provide a method of regenerating large areas in a short period of time. Later, more 

 intensive experiments helped define the conditions under which seeding can succeed 

 (Schopmeyer and Helmers 1947) . Seeding has never been used extensively, however, and 

 planting has continued to be the most common method of artificial regeneration. 



In the Intermountain area seeding and planting trials were started later than in 

 the northern Rocky Mountains, and the results were different. Both seeding and plant- 

 ing were considered failures in early experiments in central Idaho and Utah, and tests 

 continued into the early 1940' s without success. In 1954 a reappraisal of past plant- 

 ing trials led to the establishment of the Town Creek planting study in central Idaho 

 (Curtis and Coonrod 1961) . This large-scale test led to the conclusion that thorough 

 and adequate site preparation and careful handling and planting of the nursery stock 

 were essential to high survival of ponderosa pine. Since the Town Creek study, plant- 

 ing has become an established method of regenerating brushfields and timber sale areas 

 on the National Forests of the Intermountain Region. Although some acres are seeded 

 nearly every year, direct seeding has not been used on an operational scale. 



Seed Source 



Selection of a proper seed source is an important first step in any reforestation 

 project. Ponderosa pine seed source studies have confirmed the long-held belief that 

 the local seed source is best (Weidman 1939, Squillace and Silen 1962). Native trees 

 growing on or near the regeneration site are most likely to be adjusted to the climate, 

 soils, and other environmental factors. 



Elevation of the seed source has been shown to be important in site choice within 

 the local area. On sites where planting stock came from seed sources at various eleva- 

 tions, trees from elevations similar to the planting site have proven superior in the 

 long run (Callaham 1960) . The superiority of similar-elevation sources shows up in 

 growth rate, form, and adaptation to environmental hazards such as temperature and 

 moisture extreme. Latitudinal distance from the planting site is also important, but 

 limitations have not been determined closely. Very likely, some site characteristics 

 such as aspect are as important as horizontal distances, but their importance has not 

 been proven. If local seed collection zones have not been determined, seeds should be 

 collected from stands in the same habitat type, within 500 feet vertically, and as 

 near as possible to the area to be regenerated. Initial survival is no indication of 

 later thriftiness. Trees and stands from distant seed sources may survive and grow 

 well for a time, only to be killed or severely damaged by an extreme local climatic 

 condition such as cold or heat (Kempff 1928, Squillace and Silen 1962), or to decline 

 in vigor as they grow older. 



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