Shelter 65 



normally succeed to woody vegetation. When enough of the land is 

 covered with a sprinkling of bushes, saplings, briars and vines to 

 attract grouse to use it regularly, it becomes overgrown land. This 

 point of change between open land and brush is sharpest when 

 about forty to fifty per cent of the ground is covered with woody 

 plants of significant size, bush size or bigger. The land remains in 

 this cover type until it develops into a pole-stage woodland, or is set 

 back in its development by some external action. 



The species that compose the overgrown land-plant association 

 depends upon many factors: the type of soil, fertility and moisture 

 characteristics of the site, the land use in recent years, presence of 

 seed-producing plants near by, as well as climate and geographical 

 location. Often a group of short-lived, light-demanding pioneers 

 take over the area first— raspberries, poplars, "old field" pine, pin 

 cheiTy, hardback, and gray birch are examples. These are displaced 

 in relatively few years by longer-lived shrubs and trees. On fields of 

 good fertility, a good seeding of subclimax species will often result 

 with the virtual elimination of the pioneer association stage. I recall 

 an instance of a complete establishment of red pine the year follow- 

 ing abandonment of a potato field. Many times one may observe 

 similar stands of maple, ash, and other long-lived species. 



The type of overgrown land is of considerable importance to 

 grouse. For convenience it may be divided into three subtypes (see 

 Plate 9). The first varies immensely but in each case is made up 

 largely of a single species, usually a short-lived one. If the species 

 is quaking aspen it is a high quality grouse cover type; if pin cherry, 

 scmb oak, or alder it makes rather good cover too, but if it is gray 

 birch or hardback it is definitely inferior. The second type may be 

 described as a mixture of hardwood shrubs and tree saplings, with 

 few if any conifers. The last important subtype is the same as the 

 second except that it contains considerable conifers in the mixture, 

 one third or more of the total. 



Among the more important plants found in the last two subtypes 

 are: thomapples, hazelnut, sumacs, rose, brambles, blueberries, 

 viburnums, grape, bayberry, huckleberry, and elder among the 

 shrubs. White pine, red pine, and hemlock are best among the coni- 

 fers while oaks, apple, cherry, and poplar are among the more useful 

 trees— all, except the tree oaks, being useful as saphngs. Among the 

 more useful herbaceous plants found in these types are sedges 



