308 JOURNAL OF FORESTRY 



Seven growing seasons have now passed since the estabhshment of 

 this experimental planting, and a careful survey of the three plots gives 

 the following results : 



1. The height growth of the white-pine trees has been best, and the mortality 

 lowest on the plot from which only a part of the existing growth was removed. 



2. The mortality was highest on the clear-cut plot, due to the unsheltered con- 

 dition during the first year and the subsequent dense shade produced by the low 

 and thick sprout growth which followed the original clearing. 



3. Partial cutting of existing growth, if properly done, reduces the origin and 

 development of subsequent sprout growth. 



4. Partially cleared plots are the safest from a protective point of view, except- 

 ing damage by deer. 



5. White-pine trees will not come through on any of the three plots unless as- 

 sistance is given to them. At the end of the 1918 growing season, when the trees 

 were 9 years old, their average total height on plots I, II, and III, respectively, 

 was only 16.5, 19.8, and 15.9 inches. Open-grown white-pine trees on a similar 

 site at this age would have attained a height of approximately 60 inches. 



The foregoing experiment is but one of a large number Avhich have 

 been established throughout the State for the purpose of ascertaining 

 "the best and most practical exterminative measures for overcoming 

 scrubby growth, such as scrub oak. In these experiments different 

 species of timber trees were given a trial, the principal ones being white 

 pine, red pine, pitch pine, bull pine, Scotch pine, European larch. Nor- 

 way spruce, Douglas fir, red oak, and sugar maple. 



The study not only embraced a large number of different species of 

 trees, but also covered a wide range of methods of treating the existing 

 growth on the planting sites. These methods may be classified as fol- 

 lows : 



A. Methods of Trcatuicnt Before Planting: 



1. Intentional burning over of planting site. 



2. Clear-cutting of existing growth, followed by piling or broadcasting of 



cut material. 



3. Clear-cutting and burning of existing growth, followed by: 



a. Grubbing out of stools and roots. 



b. Sculping ofif of stools. 



c. Covering of stools with ground. 



4. Partial — that is, selective — cutting of existing growth. 



B. Methods of Treatment After Planting: 



1. Clear-cutting of hindering growth. 



2. Partial — that is, selective — cutting of interfering growth. 



In the light of these experimental plantings, post-planting treatment 

 should be emphasized and preparatory or preplanting treatment min- 

 imized. Intentional burning of the site preparatory to planting is a 



