16 



ant tree, such as the cottonwood, for planting in the rows taken out 

 during the second cutting. For example, if Norway spruce were 

 planted in rows 1, 3, 5, 7, and 9 (see fig. 17), and cottonwood in rows 

 2, 4, 6 and 8, ten years after the Norway spruce had been planted, 

 there is little question but what the cottonwood, in a few years, would 

 overtop the adjoining Norway spruce, since the former is much more 

 rapid in growth. 



REGENERATION BY UNDERPLANTING 



The object of the method of underplanting is to provide for a new 

 growth of trees under the shade of the existing stand, without the 

 removal of any except diseased or suppressed trees for a period of 

 years. This method can only be used profitably in plantations where 

 the original spacing was rather wide, or at least only in plantations 

 where there is some direct light preaching the ground. 



It is evident that in planting new trees between the old rows with- 

 out the removal of any of the old stand, only the most shade enduring 

 species can be used. This point should be thoroughly kept in mind, 

 since a considerable loss and much delay might result in underplant- 

 ing with the wrong species. Aside from this the greatest disad- 

 vantage is in the removal of the old stand of trees after the young 

 growth has developed for 5 to 10 years in the shade. It is impossible 

 to cut and remove the large trees without breaking and damaging the 

 young growth to a greater or less extent. (See cover page figure.) 



The system would be most applicable to relatively young stands of 

 trees in which a reinforcement of evergreens is desired, as, for ex- 

 ample, a young open stand of cottonwood trees might very well be 

 underplanted with such a tolerant tree as the Norway spruce. 



The proper time for cutting out the old trees must depend entirely 

 upon conditions, and it is impossible to specify any definite time. The 

 removal of the large trees might either be gradual or be done at one 

 operation. In any event, the overtopping trees should be taken out 

 when the new growth is being crowded or is suffering from lack of 

 light. In certain stands of a very open nature, the trees making up 

 the underplanting might be permitted to grow to a large size without 

 cutting out any of the overtopping trees. However, this would be an 

 exceptional case. 



The application of this method to groves of different species de- 

 pends more on the openness of the stand than on the species itself, 

 since the system could be applied to any grove if the old trees were 

 widely spaced. The system, as a rule, will more generally apply to 

 cottonwood and willow plantations than to soft maple and boxelder 

 groves, since the two former are never found in as dense a stand as 

 the last two. 



SPECIES FOR UNDERPLANTING 



As previously stated, only tolerant trees should be used in this 

 method of regeneration. The following trees are suitable within their 

 range and under proper soil conditions, for use under this method: 



Norway spruce Bass wood 



White spruce Hard maple 



White cedar Soft maple 



Red cedar Boxelder 



The above list of trees might be used in various combinations suc- 

 cessfully. 



