372 SEEDING AND PLANTING 



Freedom of the stock from fungous diseases and insect enemies 

 is also a mark of quality. All stock should be carefully inspected, 

 and under no conditions should non-inspected stock be used in 

 forest planting. ' 



15. THE PLANTING SEASON 



Even with the utmost care planting is always accompanied by 

 damage to the root system and the checking of growth for a more 

 or less extended period. The lifting of a plant in the nursery or 

 field, the storing for any length of time, and the final planting are 

 severe checks on its vitality. The greatest danger arises from 

 the root system becoming overdry, either during the period of 

 lifting, storing, or planting or during the first few weeks after 

 planting. The danger from overdrying during and after planting 

 can be best overcome by planting during the most favorable sea- 

 son and by selecting days when the weather conditions are best 

 for field operations. Trees can be lifted and planted with the 

 least danger on damp, overcast days. Ordinarily planting should 

 not be attempted on hot, dry days during high winds, particu- 

 larly if the soil is dry. It is far safer to hold the stock in storage 

 until the weather conditions are more favorable. 



From extended studies by Engler l on the periodicity of root 

 growth in silver fir, white and Scotch pine, beech, oak, birch, and 

 maple, it was ascertained that the development and production 

 of roots are not continuous. Root growth is interrupted by periods 

 of repose which do not exactly correspond with those when the 

 shoots are at rest. The growth of the roots of coniferous species 

 was entirely suspended from November to March or April, while 

 root growth in the deciduous trees did not appear to undergo 

 complete arrest in growth even in mid-winter. However, the 

 period from February to the beginning of March is the least favor- 

 able for root growth, due to the low temperature of the soil. In 

 general, root growth begins its rapid development from a few 

 days to several weeks before the buds start. For this reason spring 

 planting is most successful when conducted at least one or two weeks 

 before the buds begin to swell. The new root growth will not be in- 

 jured or broken off in setting the plants. 



1 Engler, Arnold: Untersuchungen xiber das Wurzelwachstum der Holzarten. 

 (Mitteilungen der schweizerischen Centralanstalt f. d. forstliche Versuchwe- 

 sen, VII. Bd., S. 247-317. 1903;) 



