350 



ON THE PRACTICAL USE OF LEAVES. 



per cent, of mineral matter than the wood of 

 the trunk. The dried leaves of the Elm 

 contain more than eleven per cent, of ashes, 

 (earthy matter,) while the wood contains 

 less than two per cent.; those of the Wil- 

 low, more than eight per cent., while the 

 wood has only 0.45 ; those of the Beech 

 6.69, the wood only 0.36 ; those of the (Eu- 

 ropean) Oak 4.05, the wood only 0.21; those 

 of the Pitch Pine 3.15, the wood only 0.25 

 per cent.* 



It is very plain from these facts that, in 

 forests, the mineral ingredients of the soil 

 perform a sort oi circulation ; entering the 

 root, they are deposited in the leaf; then, 

 with it, fall to the earth, and by its decay, 

 they are restored to the soil, again to travel 

 their circuit. Forest soils, therefore, in- 

 stead of being impoverished by the growth 

 of trees, receive back annually the greatest 

 proportion of those mineral elements neces- 

 sary to the tree, and besides, much organ- 

 ized matter received into the plant from 

 the atmosphere ; soils therefore are gaining 

 instead of losing. If the owner of parks or 

 groves, for neatness sake, or to obtain leaves 

 for other purposes, gathers the annual har- 

 vest of leaves, he will, in time, take away 

 great quantities of mineral matter, by which 

 the soil, ultimately, will be impoverished, 

 unless it is restored by manures. 



Leaf manure has always been held in 

 high esteem by gardeners. But many re- 

 gard it as a purely vegetable substance; 

 whereas, it is the best mineral manure that 

 can be applied to the soil. What are call- 

 ed vegetable loams, (not peat soils, made 

 up principally of decomposed roots,) contain 

 large quantities of earthy matter, being 

 mineral-vegetable," rather than vegetable 

 soils. 



Every gardener should know, that the 



* See Dr. Gray's Botanic Text Book, an admirable work, 

 which every liorliculturisi sliould own and study. 



best manure for any plant, is the decomposed 

 leaves and substance of its own species. 

 This fact will suggest the proper course 

 with reference to the leaves, tops, vines, 

 haulm, and other vegetable refuse of the 

 garden. 



The other fact connected with the Leaf, 

 is its function of exhalation. The greatest 

 proportion of crude sap which ascends the 

 trunk, upon reaching the leaf, is given forth 

 again to the atmosphere, by means of a 

 particularly beautiful economy. The quan- 

 tity of moisture produced by a plant is hard- 

 ly dreamed of by those who have not special- 

 ly informed themselves. The experiments 

 of Hales have been often quoted. A sun- 

 flower, three and a half feet high, present- 

 ing a surface of 5.616 square inches expos- 

 ed to the sun, was found to perspire at the 

 rate of twenty to thirty ounces avoirdupois, 

 every twelve hours, or seventeen times more 

 than a man. A vine with 12 square feet, 

 exhaled at the rate of five or six ounces 

 a day. A seedling apple tree, with twelve 

 square feet of foliage, lost nine ounces a 

 day.* 



These are experiments upon very small 

 plants. The vast amount of surface pre- 

 sented by a large tree must give off im- 

 mense quantities of moisture. The practi- 

 cal bearings of this fact of vegetable exha- 

 lation are not a few. Wet forest-lands, by 

 being cleared of timber, become dry; and 

 streams, fed from sxich sources, become al- 

 most extinct, as civilization encroaches on 

 wild woods. The excessive dampness of 

 crowded gardens is not singular, and still 

 less is it strange that dwellings covered 

 with vines, whose windows are choked 

 with shrubs, and whose roof is overhung 

 with branches of trees, should be intolera- 

 bly damp ; and when the good housewife is 

 scrubbing, scouring and brushing, and, ne- 



* I<indley's Horticulture, p. 42-44. Gray's Botany, p. 131. 



