THE NORTHERN HARDWOOD FOREST. 39 



right amount of light for the most rapid growth consistent with good 

 trunk development and the complete utilization of all sunlight by 

 the aggregate crown cover. In the selection forest, growth at this 

 rate can not be expected for all the trees all the time. Thinnings, 

 heavy enough to permit rapid growth of the younger trees, would 

 sacrifice a great deal of immediate volume increment per acre of the 

 larger timber. In fairly even-aged timber managed under the shelter- 

 wood system, however, the accelerated growth might be more nearly 

 maintained for all individuals by judicious thinning. 



Young growth under virgin stands must usually be sacrificed in 

 logging. There is little use in attempting to save it, since much of it 

 has been so suppressed by shade that it is less vigorous than a new 

 growth would be. If left exposed by the removal of much of the 

 large timber, it would probably suffer great damage from wind, 

 snow, and ice (PL XIV, fig. 1). Moreover the logging operations and 

 the subsequent hauling break down a large proportion of the smaller 

 trees, either killing them outright or causing them to lead a crippled 

 existence, occupying valuable space to the exclusion of better trees. 

 It is therefore advisable, in most virgin stands, to cut as cleanly and 

 utilize to as small sizes as possible, thus clearing the way for a vigor- 

 ous reproduction from the seed trees which are left. 



Culled forest. — By culled forest is here meant a forest which has 

 been culled of its best trees, but in which, usually, at least half of the 

 original stand remains (PL I). Among the trees commonly culled 

 from hardwood forests are white pine, red spruce, hemlock, bird's-eye 

 maple, curly birch, " whitewood" or yellow poplar, cucumber, cherry, 

 basswood, etc. Forests are often culled several times, a different 

 species being removed each time to fill a special demand. This tends 

 to simplify the composition of the forest, and also to decrease its 

 value, while the power of the more highly prized species to compete 

 with the others in the second growth is curtailed by the decrease in 

 their seed supply. 



The openings left by the removal of the scattered trees or groups of 

 trees admit sunlight to the soil, and the openings soon become filled 

 with young trees. These patches of young growth, when fairly 

 abundant, form the basis for the management of the stand. All 

 logging should be conducted with special reference to preserving and 

 extending the stand of young growth. The merchantable timber 

 should not all be removed at a single cutting, but enough of it should 

 be left to warrant a second cutting at a later date. The trees left 

 standing will serve to seed down the soil and fill up most of the gaps 

 between the already existing groups of reproduction. The increased 

 light which the remaining large trees receive will not only increase 

 their seed production, but will accelerate their growth. The second 

 cutting should be made after from 5 to 10 years, when the ground is 



