98 MISC. PUBLICATION 4 3 4, U. S. DEPARTMENT OF AGRICULTURE 



With the machine method of trenching and in the average nursery 

 soil found in the prairie-plains, a crew consisting of 2 threaders and 1 

 planter can transplant from 12,000 to 24,000 trees per 8-hour day. 

 This is the equivalent of 500 to 1,000 trees per man-hour. 



A comparatively new development is a four-row unit consisting of 

 four parallel trenchers mounted on the tool bar of a Uni-carrier pulled 

 by a tractor. This device assures absolutely uniform row spacing and 

 permits multiple-row cultivation, which cannot be done readily when 

 rows are lined out with a single row trencher. 



Transplanting is also used as a method of saving medium-sized 

 trees which are not cull stock. Sometimes adverse growing condi- 

 tions will prevent a block of seedlings from attaining normal size by 

 the end of the first year. In case of stock shortage, it is often neces- 

 sary to take the best 20 or 30 percent of such a block for use in field 

 planting and to grade out the remainder into liners, or medium-sized 

 trees for transplanting, and culls. 



Even though careful grading is practiced to avoid including the 

 inherently weak plants, planting stock produced from liners is gen- 

 erally regarded as being less desirable than seedlings which have 

 attained usable size during their planned nursery cycle, and is only 

 justified as being less expensive than a new crop of seedlings. The 

 nurseryman determines the selection of species to be lined out by one 

 or more of the following guides: (1) If seed is unusually expensive, as 

 that of bur oak, or if no seed is available owing to crop failure ; (2) if 

 the species is difficult to bring through the germination period, as 

 mulberry or Russian-olive; (3) if growth rate of the species is so slow 

 as to require that seedling stock remain in the nursery 2 years to 

 attain usable size. Lilac and honeysuckle are outstanding examples 

 of this class. Transplanting lilac liners, which can be expected to 

 attain usable size in one additional season will save a year's time. A 

 notable exception to the last group is green ash, which is so easily 

 propagated from seed that the saving of liners is not generally feasible. 



In the nurseries located in the Dakotas the growing season is so 

 short that American plum is one of the few species grown from seed 

 that will consistently produce a high percent of plantable seedlings 

 in 1 year. In these nurseries the practice of growing 2-year-old stock 

 is being adopted for almost all species. Green ash, hackberry, 

 Siberian pea-tree, American elm, bur oak, and chokecherry are planned 

 for 2-0 production. Lilac and honeysuckle are invariably grown for 

 1-1 stock. With Russian-olive, Chinese elm, boxelder, and cotton- 

 wood there is a choice of growing the stock either as 2-0 or 1-1 age 

 classes. There is an indication that with use of the four-row trencher 

 and refinements in transplanting technique there will be some trend 

 toward growing some of these species in fairly dense beds for the first 

 year to a height of 6 to 10 inches and lining them out the second year 

 for 1-1 production. 



Propagation by Cuttings 



Some deciduous stock, such as poplars, willow, and certain strains 

 of tamarix, has been grown from cuttings (fig. 34). This method of 

 propagation is ordinarily limited to those species which root readily 

 from cuttings and are difficult to propagate by seed. For most 

 species, planting stock propagated from seed is generally considered 

 less expensive and the quality superior to that grown from cuttings. 



