174 Forestry Quarterly. 



The black spruce, likewise, is very prolific. Often it has the 

 peculiarity of bearing at its very top a dark, oblong object from 

 one to two or more feet in height. This is found to be a Hterally 

 solid mass of cones and twigs, the former sometimes numbering 

 many hundreds. 



The entire forest is divided into even-aged stands, distributed 

 in time and place according to the vagaries of the fire. Some- 

 times two or three ages of pine occur mixed in pure stand, prob- 

 ably due to lighter surface fires. But on much the larger area a 

 single age class is found in pure, or practically pure stand. These 

 classes naturally occur at irregular intervals in point of age, and 

 with variously drawn boundaries, yet in their evenness of height, 

 sharpness of boundary, and occupancy of all available ground 

 space suggest a forest managed by man under the clear cutting 

 system. Some such stands, with the road cut cleanly thru them, 

 presented a picture not unlike German spruce forests in their 

 great density of tall and straight boles. 



One of the most striking facts to be observed on .some of these 

 northern jack pine plains is the natural thinning produced by 

 great numbers of the common rabbit (Lepus canadensis). On 

 considerable areas of dense reproduction a part of the pine sap- 

 lings had been cut off while at a diameter of one-half to one inch. 

 This cutting was done at an almost exactly even height above 

 ground of i8 to 24 inches, according to location. In many cases 

 the stumps had been stripped of a part of their bark. It is prob- 

 able that the living saplings had also been stripped of a portion 

 of their bark, but being now of greater girth than the stumps, had 

 recovered so that no injury was noticeable. The cutting evi- 

 dently took place on top of the snow during one of the recent 

 winters. The date of cutting, had time permitted, might have 

 been ascertained from an inspection of the annual rings, while the 

 depth of the snow at the time was self-evident. VxHiile a varying 

 proportion, usually from 25 to 75 per cent, had been cut, no area 

 was entirely denuded. This had produced a most effective thin- 

 ning, as the trees remaining are now free to grow at a much faster 

 rate than would otherwise have been possible. For the original 

 stand, as once seen in .some similar lodgepole pine flats in Idaho, 

 is exceedingly dense and of even age and size, and the process of 

 natural thinning by competition could be accomplished only at 

 the expense of much growth increment in the survivors, possibly 



