32 COVERING AND GERMINATION OF TREE-SEEDS. 



seeding, so that taking everything into account, the advantage is 

 altogether on the side of pUmting. Be it far from us, however, to think, 

 that we should never have recourse to direct seeding. In sylvicul- 

 ture there are no absolute and universal rules. Thus, for example, wo 

 would never advise planting timber on the light sands of La Manche or 

 Basse-Lusace, as we would always blame sowing on the strong-sodded 

 but thin soils of Saxony. All we have to say as to this is, that as a gen- 

 eral rule, and except in certain well-defined cases, such as those above 

 mentioned, 2J?aw<i«(; should be the rule ; sowing, the exception. 



THE CONDITIONS MOST FAVORABLE FOR GROWING OF FOREST-SEEDS. 



That seeds may germinate, they must have a certain amount of 

 contact with the air, and a proper degree of warmth and moisture. 

 In tlie natural process of seeding but a very small number of the seeds 

 so bountifully produced, ever find these due proportions of congenial 

 influences so as to take root and grow. It is only here and there that a 

 seed gets lodged among the dead leaves and the mosses or gets covered 

 by the detritus, so as to secure the needed protection and a successful 

 growth. If seeds are left too lightly covered they may be eaten by 

 birds, or washed out by rains. If too deep, the young shoot will be 

 entirely smothered, or will come slowly to the surface in too feeble con- 

 dition for vigorous growth. 



With the view of determining fixed rules from careful trial, a series 

 of observations was made by Dr. Baur, director of the experimental 

 station for forestal researches at Hohenheim, in Wiirtemberg, iu 1873, 

 1874, and 1875, the principal results of which are given in the Eevue dcs 

 Eaux et Forets for June, 1876. The soil selected for these experiments 

 was of average density. We can only state the general results : 



Dcech. — Seeds should be but slightly coTered. The best results were found when the 

 covering was from 0.39 to 1.57 inches, and the best depth 0.79. This agrees quite nearly 

 with the rule laid down by Burckhard, Heyer, and Lorentz and Parade. 



Quercus peduiiculata. — The acorns should be planted shallow, but a little deeper than 

 beech-nuts. The depth should be more in light soils. Heyer recommends 1 to 2 inches, 

 and advises that they be sometimes covered by a plow. 



Jeer cawpestre (English maple). — The seeds should be but slightly covered, but a 

 little deeper than with beech. From 0.39 to 0.78 is unquestionably best, and beyond 

 2.75 inches they will not grow. The observer noticed the following appearances in 

 the germination of the maple: They issue with very long cotyledons, and if deeply 

 covered, or if the surface ot the soil is too hard, these cannot easily break through the 

 obsracle, yet continue to grow, and at length break, and thus the germ is lost. We 

 may thus see why many vacant places often occur in seed-beds of the maple. 



Jcacia. — The results'here obseived were quite interesting, and agreed perfectly iu 

 the two years observed. When Stumpf ( TValdbau, 2d ed., p. ^76) laid down the general 

 rule that " large and heavy seeds should be more deeply covered," he should have ex- 

 cepted this kind. The results teud to show that depth has but very little iniiuence, 

 but that these seeds, however light, should be planted at least as deep as acorns. The 

 result appears to lead to the concluf-ion that the acacia might be used with advantage 

 in planting arid soils and southern slopes, where seeds thinly covered would scarcely 

 grow from want of moisture. 



Black alder.— This should be but very slightly covered, a third of an inch being 

 enough. Burckhard advises that it should be very slightly covered, or even simply 

 8 rown upon the surface, and Heyer remarks that it should be mingled with the most 

 superficial parts of the soil. The experiments of Dr. Baur gave the best results at 0.39 

 inch. From 0.59 to 0.98 the shoots were but few, and from greater depths but one seed 

 came up. 



Comvion pine. — The results of two years showed that a covering of 0.39 to 0.59 inch 

 is the most advantageous. At greater depths the plants were scattered, and none grew 

 from a depth of over 1.18 inches. 



ir(,.._\vith this, as with the iiino, the deeper seeds were slower in coming to the sur- 

 face, and the general average for best results was the same. 



St/rcr-yir.— The best depth ranges between 0.39 and 0.77 inch, or a little more than iu 

 the case of the pine and fir. None appeared which had been covered 1.18 or more 

 inches. 



