IMPROVEMENT CUTTINGS 75 



valuable species, or often worthless shrubs. In any case, they 

 need to be removed in order that the stand may eventually be 

 of the highest possible character. This type of cutting is called 

 a cleaning, and always takes place in young stands, usually when 

 they are from three to ten years of age. Frequently one cleaning 

 is not suificient and another must be made three to five years 

 after the first. 



The trees removed differ but little in age from those left and 

 oftentimes are the same age but of more rapid growth. When 

 a few years older they are usually of the type termed "advance 

 growth," by which is meant trees that seeded in first and obtained 

 a few years start of the rest of the stand. Because of their com- 

 parative freedom from side crowding they have rather branchy 

 crowns and will not develop into high-grade trees. 



The expense of the cleaning can often be reduced and the 

 purpose as well accomphshed by lopping off the tops of the trees 

 instead of cutting them at the base. They should be lopped back 

 far enough so that the tops of the trees to be freed are above them. 



One is tempted in making a cleaning to remove all trees of 

 inferior species, all shrubs, and all poor individuals from the 

 stand. But from both the financial and silvicultural standpoints 

 only the material should be cut which is actually hindering the 

 development of better trees. If all inferior species were to be 

 cut, great gaps might be left in the stand, since there may be no 

 valuable trees in mixture with the poor ones. In such a place 

 a cleaning need not be made. 



A small hatchet or a brush hook is an excellent tool with which 

 to make cleanings where the material is small or the tops are to 

 be lopped, but often in stands five to ten years of age an axe 

 is needed. 



Inasmuch as a cleaning is in such young stands that no mer- 

 chantable material is secured from the cutting it results in a 

 present financial loss. Cleanings should only be made where a 

 small expenditure will be justified by the improved development 

 of the stand. A stand of white pine overtopped by gray birch 

 is an example of where they are justifiable. The forest of 



