288 FORESTRY INVESTIGATIONS U. S. DEPARTMENT OF AGRICULTURE. 



same reason, in the selection of the kinds that are to be left or to be taken out, we shall not only 

 consider their use value, but also their shading value, trying to bring about such a mixture of 

 shady and less shady kinds as will insure a continuously satisfactory crown cover, the shade 

 enduring kinds to occupy the lower stratum in the crown canopy, and to be more numerous than 

 the light needing. 



The forester, therefore, watches first the conditions of his soil cover, and his next care is for 

 the condition of the overhead shade, the "crown cover;" for a change in the condition of the 

 latter brings change into his soil conditions, and, inversely, from the olianges in the plant cover of 

 the soil he judges whether he mayor may not change the light conditions. The changes of the 

 soil cover toach him more often when "to let alone" than when to go on with his operations of 

 thinning out; that is to say, he can rarely stop short of that condition which is most favorable. 

 Hence the improvement cuttings must be made with caution and only very gradually, so that no 

 deterioration of the soil conditions be invited. We have repeated this injunction again and again, 

 because all success in the management of future wood crops depends upon the care bestowed upou 

 the maintenance of favorable soil conditions. 



As the object of this weeding is not only to remove the undesirable kinds from the present 

 crop, but to prevent as much as possible their reappearance in subsequent crops, it may be 

 advisable to cut such kinds as sprout readily from the stump in summer time June or July 

 when the stumps are likely to die without sprouting. 



It may take several years' cutting to bring the composition of the main crop into such a 

 condition as to satisfy us. 



METHODS OF REPRODUCING THE WOOD CROP. 



Then comes the period of utilizing the main crop. As we propose to keep the wood lot as 

 such, and desire to reproduce a satisfactory wood crop in place of the old one, this latter must be 

 cut always with a view to that reproduction. There are various methods pursued for this purpose 

 in large forestry operations which are not practicable on small areas, especially when these are 

 expected to yield only small amounts of timber, and these little by little as required. It is 

 possible, to be sure, to cut the entire crop and replant a new one, or else to use the ax skillfully 

 and briug about a natural reproduction in a few years; but we want in the present case to lengthen 

 out the period during which the old crop is cut, and hence must resort to other methods. There 

 are three methods practicable. 



We may clear narrow strips or bands entirely, expecting the neighboring growth to furnish 

 the seed for covering the strip with a new crop "the strip method;" or we cau take out single 

 trees here and there, relying again on an aftergrowth from seed shed by the surrounding trees 

 the "selection method;'' or, finally, instead of single trees, we may cut entire groups of trees 

 here and there in the same manner, the gaps to be filled, as in the other cases, with a young crop 

 from the seed of the surrounding trees, and this we may call the "group method." 



In the strip i/tethod, in order to secure sufficient seeding of the cleared strip, the latter must 

 not be so broad that the seed from the neighboring growth can not be carried over it by the wind. 

 In order to get the best results from the carrying power of the wind (as well as to avoid windfalls 

 when the old growth is suddenly opened on the windward side) the strips should be located on the 

 side opposite the prevailing winds. Oaks, beech, hickory, and nut trees in general with heavy 

 seeds will not seed over any considerable breadth of strip, while with maple and ash the breadth 

 may be made twice as great as the height of the timber, and the mother trees with lighter seeds, 

 like spruce and pine, or birch and elm, may be able to cover strips of a breadth of three or four 

 and even eight times their height. But such broad strips are hazardous, since with insufficient 

 seed fall, or fail years in the seed, the strip may remain exposed to sun and wind for several years 

 without a good cover and deteriorate. It is safer, therefore, to make the strips no broader than . 

 just the height of the neighboring timber, in which case not only has the seed better chance of 

 covering the ground, but the soil and seedlings have more protection from the mother crop. In 

 hilly country the strips must not be made in the direction of the slope, for the water would wash 

 out soil and seed. 



Every year, then, or from time to time, a new strip is to be cleared and " regeueratcd." But 



