2. The effect of redistribution of logging slash (unwanted portions) and 

 removal of all above-ground portions of trees on nutrient levels. 

 Weetman and Webber (1972) found that full-tree logging will not cause 

 any reduction in growth from nutrient removal during the second 

 rotation of trees. However, nutrient depletion due to full-tree 

 logging, particularly calcium, potassium, and nitrogen depletion, may 

 require correction in forest ecosystems of marginal fertility. These 

 sites are usually either dry, with low reserves of organic matter and 

 low exchange capacity, or wet, with excessive accumulations of 

 organic matter. No work with nutrient depletion has been done on 

 logging areas in the characterization area. 



3. The change in vegetation that occurs in an area is a result of 

 increased light and decreased soil moisture. Bird and mammal 

 populations are also affected when vegetation changes. See chapter 

 9, "The Forest System," for a discussion of these factors. 



4. Soil erosion and siltation of streams are dependent upon soil types, 

 slope, and the time of year the clearcutting operation is performed. 

 Usually, clearcutting should not cause serious erosion of sites or 

 siltation of streams if proper harvesting procedures are followed; 

 however, no relevant data on the characterization area are available 

 and it must be obtained if the extent of erosion and siltation due to 

 clearcutting is to be measured. 



5. The effects of spraying herbicides on the forest ecosystem are not 

 completely understood (see chapter 3, "Human Impacts on the 

 Ecosystem") . This topic is of national concern and has been the 

 subject of heated debate in recent months. The Environmental 

 Protection Agency (EPA) banned the use of 2,4,5-T (which had been 

 used in coastal Maine) on forest lands in March, 1979. 



Cubic foot yields per acre from fully stocked, even-aged stands of second- 

 growth red spruce in the northeast are given in table 19-5. Because yield 

 relationships between sites and for stands within sites are not distinct, 

 there is an overlapping of various sites and stand types for specific yield 

 values. The yield values in the table are given for four combinations of 

 sites and stand types. These yields are from so called normal unmanaged 

 stands. Yields from stands under a management scheme, including periodic 

 harvests or thinnings, would be substantially higher over a rotation. No 

 yield information on other species in even-aged stands is available. 



Management practices, including silvicultural manipulation, have a strong 

 influence on net annual growth. For example, experimental data have shown 

 that well-managed stands on reasonably productive sites can produce nearly 

 twice as much merchantable wood as unmanaged stands over the course of a 

 rotation age (Frank and Bjorkbom 1973). Net annual growth during the first 10 

 years after selective cutting in primary softwood stands ranged from 47 to 82 

 cu ft/acre annually in several experiments in northern Maine (Frank and 

 Bjorkbom 1973). Similar data for softwood sites in the characterization area 

 are not available. 



19-12 



