FOREST MANAGEMENT. 61 



the sulphur leaf-roller moth (Dichelia sulphureana Clem.), Teras ferrttgana S. V., and Amorbia 

 hnmerosanaC\em. An interesting species is the pine tube-builder (Lophoderns politana Haw.), 

 which, in its larval stage, lives within a tube formed by webbing together a number of pine needles 

 as shown in fig. 14. 



A number of species of adult Coleoptera, whose larval habits are imperfectly understood, sub- 

 sist upon the leaves of White Pine. Of these are the Scarabceid, Dichelonycha albicollis Burm., 

 and the Chrysomelid, Glyptoscelis pubesccns Fab. 



The best remedy for the sawfly larvae, caterpillars, and beetles is a spray of Paris green, 

 applied upon tbe first appearance of these insects on the trees. 



The consideration of the insect enemies of the White Pine may conclude with the mention of 

 the pine-leaf scale insect (Chionaspis pinifoliie Fitch), which forms its scales upon the leaves, 

 exhausting them of their juices and causing them to turn yellow. This species is illustrated at 

 fig. 15. 



A strong spray of kerosene emulsion will be found an efficient remedy against these scale 

 insects. >/^ 



FOREST MANAGEMENT. 



As regards forest management, we have, unfortunately, in this country no experiences which 

 would permit us to form very positive opinions based on actual observation regarding this species 

 or any other. The study of the natural history of the species in its native occurrence permits us, 

 nevertheless, to draw conclusions which may at least serve as a basis for its future sylvicultural 

 treatment. 



In the first place, it may be declared that the White Pine is the most important and promising 

 species upon which to expend attention in our coming forestry operations within the limits of its 

 natural occurrence. Its adaptation to a variety of soils and situations within these limits, its rapid 

 growth, its excellent form, its remarkable mass development per acre, its shade endurance, its 

 all-round useful wood product, and its propagation, both by natural and artificial reproduction, 

 give it a position among our timber trees hardly approached by any other. 



There are certain general principles which are the result of experience in forest management 

 in Europe arid elsewhere^applying to this as to most species. The first is, that mixed growth is in 

 every respect superior to pure growth; it will therefore be proper policy to grow White Pine pref- 

 erably, if not altogether, in mixture with other species. This advice is given in spite of the fact 

 that the White Pine grows rather well in pure stand, and that, owing to its shady crown during a 

 long period of its life and the density of stand in which it can develop, and the large quantity of 

 foliage which it sheds, the soil conditions are not in danger of deteriorating, as would be the case 

 with more light-needing species. But, as has been observed in its natural occurrence, its develop- 

 ment is more favorable in compa'niouship, and especially is this tlie case with regard to the 

 cleaning of the bole of its branches, which are peculiarly persistent. W r hether it would pay to 

 substitute an artificial cleaning by pruning the young growths is still doubtful; meanwhile the 

 self-pruning performed by mixture with shady companions will have to be encouraged, especially 

 as thereby other valuable advantages are secured which attach to the mixed forest in general. 



Unfortunately, our irrational exploitation has reduced the White Pine in the natural forest areas 

 often to such an extent that its reestablishment is possible only by artificial means. Wherever 

 the culling has not been too severe, and either young growth has developed or seedling trees have 

 been left, the natural reproduction should be encouraged by favoring the young growth and by 

 removing or thinning out other species which interfere with the starting of a young growth. 

 Fortunately, the White Pine, owing to its shade endurance, is specially fitted for natural repro- 

 duction from the seed of mother trees, more so than most other pines, and the rapidity of its 

 growth, in which it excels most other shade-enduring species, is also favorable in this respect. 



We are not yet prepared to determine the most profitable rotation in which the species is to 

 be managed under varying conditions. The fact that it is not only a very rapid but one of the 

 most persistent growers, trees making wood at the rate of 1| to 2 cubic feet per year up to the 

 one hundred and fortieth year, permits a wide range of choice for -rotations, and since its wood, 

 being rapidly changed into heartwood, becomes serviceable very early, the rotations may be either 

 low or high, varying from fifty to one hundred and fifty years, according to local economic and 

 soil conditions. 



