REFORESTATION ON THE NATIONAL FORESTS. 3 



be so situated that the plantation will serve as an excellent object 

 lesson. 



The economic importance of field planting or sowing, the expense 

 attending it, the even greater proportionate expense of replanting or 

 resowing parts of areas where the first operation failed, and the 

 high percentage of mortality which is almost sure to attend ill-advised 

 and hasty work have led to two stages in reforestation work on the 

 National Forests; first, experiments conducted on a small scale; 

 and, second, extensive field operations. Successful field planting or 

 sowing on a large scale is not a simple operation. The task of plant- 

 ing or sowing so many acres to forest trees or seed in a given period 

 of time is merely a matter of providing the seed or nursery stock and 

 employing a crew of sufficient size, but the success of the operation 

 depends on much more than this. The object of experimental plant- 

 ing and sowing is to determine the factors which make for success or 

 failure. These in turn serve as a guide for reforestation operations 

 on a large scale. Experimental planting or sowing is usually inten- 

 sive and necessarily expensive. Practical reforestation on a large 

 scale takes advantage of the facts learned through experimental 

 work, and the foremost consideration is to make the costs reasonable 

 and yet secure success. 



COLLECTION OF SEED. 



SEED CROPS. 



All planting and sowing must begin with the collection of seed. 

 Trees, unlike some other plants, do not bear a good crop of seed every 

 year. Conifers in particular are very irregular about this. A few 

 cones are produced every year, but with most species it is only at 

 intervals of from two to five years, or more, varying with the species 

 and the climatic conditions, that a heavy crop occurs. Years when 

 seed of any species is produced in abundance are known as " seed 

 years " for that species, and the intervening years are called " off 

 years." During " off years " seed is produced only in small quanti- 

 ties; it is difficult to obtain because of the concentrated demand for 

 it by rodents and birds, and there is a smaller yield per bushel of 

 cones. 



In a " seed year " the seed crop of any species is usually abundant 

 throughout the tree's range, though much better in some places than 

 in others. Even during an " off year " a species may produce some- 

 where within its range a fair crop over a limited territory. The sea- 

 son of 1910 was an " off year " for both Douglas fir and western yel- 

 low pine, the two most important trees of the West, yet cones of 

 sufficient quantity were collected in widely separated localities to 

 furnish 30 tons of clean seed of these species. Studies made to de- 



