October 



i88S,l 



Garden and horest. 



381 



rents of air are from the coast to the sen. These are charged 

 with dust, which gradually drops out of them, as they lose 

 force on leaving the land. This dust falls into the sea atmos- 

 phere, which is charged with moisture, and fog is the result. 

 Fog is irritating to those with weak or defective lungs. In 

 forests this dust, Avith moisture surrounding it, is sifted out 

 by the foliage, and fogs in forests are always modified, and if 

 the exposure be favorable, are entirely eliminated. Fogs do 

 not occur in dense forests. 



Trees all have some odor and many a balsamic and agree- 

 able one. Of such trees the Pines, Firs, Cedars, Eucalyptus 

 and Laurels, Bay and Camphor trees are the best known. 

 The emanations from these have, in general, a sedative effect 

 upon the nervous system, but a stimulating one on the vital 

 functions. These classes of trees are health-giving to the 

 human being, and, to an ecjual degree, the)' are fatal to germ 

 life. The importance of this effect will be recognized when 

 we reflect that many diseases are caused and transmitted by 

 germs. Insects will not congregate upon pitch, camphor, 

 myrrh, etc., and the burning of diese and many other tree 

 products, as the leaves of Pine or Eucalyptus, stupefies and 

 kills insects and germs. Some vegetable products, as pyre- 

 thrum, are more noted and deadly than others. 



The philosophy of the attraction that pleasing odors have 

 for man is well worthy of study. The taste or instinct for 

 them is as useful as its complement, the dislike for liad smells, 

 which enables us to avoid infected places. 



In the tree the sap mounts from the roots in a crude state, 

 composed of water (o.xygen and hvdrogen) and a slight admix- 

 ture of earthy salts; it is carried to the leaf, when it is elab- 

 orated by the chlorophyl or minute grains that .give the leaves 

 their green color, when carbonic acid is absorbed from the 

 air, and oxygen is liberated from the sap by the decomposition 

 of the carbonic acid. Carbonic acid has a debilitating effect 

 on man, this the tree al>sorbs; while oxygen is man's life, and 

 this the tree gives. 



Trees, while preservative of moisture in dry situations, have 

 a great drying power when moisture is excessive, as in 

 swamps and malarial lands. Few persons realize what an 

 extraordinary amount of moisture a tree is capalile of evap- 

 orating into the atmosphere. The evaporation takes place 

 through the stomata of the leaves. Of these mouths, 90,000 

 have been counted on the lower side of the Cherry Laurel 

 leaf, which is devoid of stomates on the upper side ; on the 

 leaf of the Lilac 160,000 have been counted. There is a great 

 diversity in this respect amongst plants. The only experiment 

 with which I am acquainted relating to the amount of evap- 

 oration which can take place through leaves of trees is that of 

 Marshall Yaillant quoted by J. C. Brown. He took a branch of 

 an Oak and placed it in a vase full of water. He measured 

 the water lost through its leaves and considered himself en- 

 abled to conclude that the tree from which this branch had 

 been detached would emit into the atmosphere in twenty- 

 four hours upwards of 2,000 kilogrammes of water, equal to a 

 little more than 5,000 pounds. The abnormal condition under 

 which this experiment was made must cause it to be consid- 

 ered as only an indication of what may take place under nor- 

 mal conditions. 



A flow of sap from wounds made in trees for commercial 

 purposes is another indication of this power of taking up 

 water. Pine trees tapped for resin. Camphor trees for cam- 

 phor Gum and Rubber trees for rubber, show a great flow of 

 sap, but I know of no measure having been taken of it. But 

 measures have been taken of the flow of the Sugar Maple {Acer 

 saccharinuiii) and the yellow Birch {Betiila exceha). Emerson 

 cites a Maple six feet in diameter that yielded thirty-one and 

 one-half gallons of sap in twenty-four hours, and Marsh cites 

 one in Warner, New Hampshire, two and one-half feet in 

 diameter, which yielded twenty gallons in eighteen hours; Dr. 

 William cites a large Birch tapped in Vermont, the flow of 

 which was measured from time to time for four or five weeks. 

 The sap ran at the rate of five gallons per hour, progressively 

 diminishing. The total yield was estimated at 1,890 gallons. 

 The flow from these trees was only from one or two auger 

 holes and was insufficient to immetliately injure the tree. 



When we consider the number of trees which thrive on a 

 single acre we may perceive how important their collective 

 action may become. Trees drain a soil in still another wa\-. 

 Their roots penetrate into the soil and make permeable strata 

 that would otherwise be impervious to water. The channels 

 made by the roots become a means by which surplus water 

 finds its way into substrata, from \yhich it appears later as 

 springs in lower situations. The life activity of plants pro- 

 duces on the oxygen of the air a condition known as ozone. 

 When in this condition oxygen is opposed to germ life, and, 



consequently, to all forms 

 points it can be vmderstood 

 forests than when it is clear 

 clearing, tlie more complete 

 beneficial influences of trees 

 discussed under another hea 

 electrical influence, their etju 

 temperature, and their maintai 

 wholesome water is secured. 



of putrefactioii. From these 

 why a district is healthier in 

 ■ed. The more complete the 

 the change. There are other 

 on health, some of which are 

 d, such, for instance, as their 

 alizing tendency on winds and 

 ni ng effect on springs, whereby 

 Ahbflf Kimiev. 



Correspondence. 



Ulmus effiisa. 

 To the Editor of Garden and Forest ; 



Sir. — I do not know whether you remember a tree which 

 particularly attracted your notice during your last visit to Ber- 

 lin. Large, fine and old, it was, nevertheless, no real giant 

 tree, but was attractive through the peculiar form of its head, 

 which, as I was aljle to tell you, was characteristic of the spe- 

 cies, and not merely of the individual. I refer to an Elm on the 

 Ijanks of Lake Tegel, opposite the island of Schaifenberg, 

 which rose tall and lonely from the edge of the wood. 



It seems best to retain for this kind of Elm the name 

 of U/?iiiis cffusa, wliich Wildenow gave it in the year 

 1787, and which appears as the oldest of published names, 

 although that of Li pcduniulata had been given it by Fouge- 

 roux three years previously, and had been read at a meeting 

 of the French Academy of Sciences, but never published. 

 Other synonyms are U. octandra and U. cilia/a. The species 

 belongs particularly to the province of Brandenburg. At least 

 I have never seen such enormous examples in any other partof 

 Germany, or the neighboring countries, as grow on the banks 

 of the Spree and the Havel. The trunk attains the size of 

 an Oak and a far greater height. Specimens seventy or eighty 

 feet in height are not uncommon, and there are someofatleast 

 100 feet. In old age it forms sharp, protruding ribs at the base 

 of the trunk, which have deep concave recesses between 

 them. These natural buttresses evidently greatly increase its 

 power of resisting storms and render eft'ectual help in the 

 struggle for existence. Higher up, the trunk becomes more 

 cylinclrical, although always inclined to be irregular, and shows 

 an abundance of yoinig shoots, especially where the tree 

 stands on the edge of a wood. Branching generally begins 

 only at a considerable height. But it is difficult to describe the 

 head, which is a wonder of picturesque beauty, easily sur- 

 passing in this respect all other trees in Germany. It must be 

 seen in winter to be fully appreciated, although even at other 

 times it makes a markecl impression. The branches l)endand 

 twist in the strangest curves, often even more fantastically 

 than those of the Oak. Sometimes they shoot outwards, some- 

 times bend back, and let the playing light penetrate to the very 

 ilepths of the head. The higher its crest, the more enchanting 

 is its shape, the more it combines grace with power, the more 

 the slender young shoots contrast with the robust forms of the 

 branches. At last it is a whorl of thin, flexilile ramifications 

 that droop and hang sornewhat like the branches of the Weep- 

 ing Willow, although not so low. High up over all, however, 

 tall leaders spring out, which add variety to the top. In short, 

 the sha].)e of the head is almost impossible to describe in 

 •words. It is quite dift'erent in effect from that of the much 

 more familiar U. cainpesiris. Its foliage is the least attractive 

 part of U. effiisa. It cannot be called beautiful, and if com- 

 pared, for example, with the glossy foliage of the Linden, has 

 a certain poverty of appearance. The rather large, one-sided 

 and unevenly-toothed leaves are rough to both eye and touch, 

 are not very closely placed, and form a surface of didl, dead 

 green. But seen from a distance these defects do not prevent 

 this Elm, wherever it stands, from being an ornament to the 

 landscape. As \\'\\\\ all other species of Elm, its blooming pe- 

 riod is very early. Its fruit ripens in the month of May, and is 

 ]iroduced in very great profusion, so that its first green in 

 spring is due to the fruit and not to the leaves. The effect is 

 extraordinary. Seen from a distance, the brown masses of 

 hanging blossoms give the illusion of autumn coloring. Then 

 followsthe transparent green of the unripe fruit, and the leaves 

 do not finally appear until the fruit begins to ripen and add its 

 shading of "brown, .■\lthough chickens and other poultry 

 greediiy de\-our the seeds of this Elm, its spontaneous distri- 

 bution is considerable. 



U. cffusa l:>elongs exclusively to Middle Europe, Germany 

 forming the centre of its area. In Sweden it is not to be 

 found, nor in Italy, except along the northernmost limits of 

 Lombardy. In its wild state, in the province of Brandenburg, 

 it likes the damp, decidvious woods and the swampy lianks of 



