OCTOBftR l8, 1893.] 



Garden and Forest. 



439 



than on the Concord and Worden. The cultivated forms of 

 Vitis riparia are quite free from this mildew. The Worden 

 and Concord both show it in considerable quantity every year, 

 but, as a rule, it is not so general over the vineyard. 



Iowa Agricultural College, Ames. • L- H. Patnmel. 



Tecoma Mackenii. 

 To the Editor of Garden and Forest : 



Sir, I note Mr. W. Watson's remarks in a recent number of 



Garden and Forest regarding the tiowreringof Tecoma Mac- 

 kenii at Kew, and perhaps our experience with this plant in 

 southern California may not be without interest. It was in- 

 troduced here about five years ago, but was little known until 

 recently, and even now it is not common by any means ; with 

 us it requires a great deal of room, and the hottest and sunniest 

 position possible, otherwise it appears to be a shy bloomer. I 

 know it in some gardens where it is slightly shaded by trees, 

 and yet after three years' growth, with rambling branches fif- 

 teen feet long, it still fails to flower. Against sidings, or on 

 the tops of arbors where the refracted heat in summer is al- 

 most intolerable, it flowers freely enough in midsummer, and 

 is certainly a beautiful and desirable plant. <-. ^ zj 



Los Angeles, Calif. 7- C. Harvey. 



Recent Publications. 



The Protection of Woodlands Against Dangers Resulting 

 from Organic and Inorganic Causes. By Hermann Fiirst. 

 New York : Wm. R. Jenkins. 



This book is a translation by Dr. John Nesbit, of the In- 

 dian Forest Service, of a work written by Dr. Hermann 

 Fiirst, director of a Bavarian forest-institute. Its title 

 shows the scope of the book, which embraces a most 

 essentia] part of forestry, and it is well worth the study of 

 American readers, although, from the nature of things, the 

 dangers which threaten the forests in this country are many 

 of them quite different from those which need to be guarded 

 ao-ainst in Europe. The book was translated primarily for 

 the readers in Great Britain ; but, although American forest- 

 owners are not likely to take the precautions here suggested 

 ao-ainst injuries by frost or damage by heat, it is, neverthe- 

 less, instructive for any one to read how such dangers are 

 regarded, and how they are met in the countries where 

 wood is valuable and where forest-property is looked upon 

 as a permanent investment, and where there has grown up 

 under these conditions a systematic forest-practice. The 

 chapter on Forest Weeds, a term made to include herba- 

 ceous or shrubby plants which may become noxious by over- 

 topping and interfering with the growth of young trees, 

 contains much instruction that can be adapted to our own 

 latitude, and in a general way the elaborate account of the 

 fungal parasites which grow on or in trees and endanger 

 their health can be made immediately useful, although the 

 parasitic plants here differ widely from those in the Old 

 World. Most interesting is the chapter on animals which 

 are injurious to forests. It will require some severe school- 

 ing before our people will take note of the damage inflicted 

 upon standing timber by small rodents like mice and squir- 

 rels, or, indeed, by animals of the chase like the deer and 

 rabbit. ' But our woods, both public and private, are every 

 day suffering from domestic animals which are turned out 

 in them to graze on grass and weeds and the fruits of the 

 trees. In Europe goats do the most injury, because they 

 prefer the leaves, buds and young shoots of woody plants 

 to grass weeds, even when this forage is more abun- 

 dant. The destruction of the forests in many of the moun- 

 tains of Tyrol, Switzerland, and Greece is attributable mainly 

 to the grazing of goats, which has made it impossible to 

 recover areas once cleared of forests. The destructive 

 habits of these animals have lately been noted by our corre- 

 spondent. Dr. Franceschi, who relates in Zoe how they are 

 destroying the vegetation on Guadeloupe Island, off the 

 coast of Lower California. Horses rank next to goats in 

 destructiveness, for, although they prefer to graze on sward 

 along wood-roads, they are yet fond of the young shoots 

 of saplings and their leaves, and they can strip these to a 

 considerable height. Young horses also love to gnaw 

 bark, while their weight and their iron-shod hoofs increase 



their power to damage superficial roots by trampling. 

 Sheep are ranked third in destructiveness, and cattle, 

 although they do less damage comparatively, accom- 

 plish much harm in the long run, for although they 

 decidedly prefer soil-grazing, and only attack fibrous 

 growth when there is a dearth of grass, still they 

 will browse on leaves and shoots when they are suc- 

 culent, bend down strong saplings under their chests to 

 get at the crown and injure trees by rubbing themselves 

 against them. Besides this, they loosen by their weight 

 and with their sharp feet the soil on slopes until it is easily 

 dislodged and washed away, and stamp down the earth 

 wherever they gather for the night. 



The paragraphs relating to the injuries by birds, squirrels, 

 tree-mice and game will be relished by any one who has a 

 taste for natural history and is interested in the relation 

 between plants and animals. Nearly half the book is taken 

 up with descriptions of injurious insects and the remedies 

 used against them. Of course, the most destructive forest- 

 insects in Europe are not those which now give the most 

 trouble in this country, and yet the general discussion on 

 the life-history of various classes of insects, and of the 

 influences which favor their increase, of the improved 

 methods of general prevention and extermination, the 

 different forms of injury which are inflicted on timber- 

 crops and the proper way to treat such crops when dam- 

 aged, all make instructive reading for forest-owners in any 

 country. While the book cannot be commended as a prac- 

 tical treatise in all details for American foresters, it is, never- 

 theless, a thorough and conscientious work, one that arouses 

 reflection, and is, therefore, worthy of careful reading by 

 all who are interested in forest-practice. We quote a section 

 on frost-shakes, which is of popular interest and will give 

 an idea of the quality of the work : 



In certain species of trees longitudinal fissures often appear 

 on the older sterns as the effect of hard frost. Beginning near 

 the ground, these frost-shakes are sometimes only a yard or 

 two long, but olten extend into the crown and peneti^ate from 

 the circumference sometimes to the very core of the stem. 

 Although they do not interfere with the vital energy or growth 

 of the tree, they decrease the value of the timber and some- 

 times afford a chance for the entrance of fungus spores into 

 the stem, which bring on disease. These fissures are caused 

 by the contraction of the wood which takes place during great 

 cold, much in the way that timber contracts as water is 

 withdrawn when it becomes seasoned. During severe cold, 

 not only water in the elementary parts of the wood, but the 

 water in the cell-walls, freezes and at the same time this is 

 drawn into the interior of the cells, so that the substance of 

 the walls is diminished and contracts, the contraction being 

 greater tangentially than radially, and greater on the outside 

 zones with their larger quantities of water than in the drier 

 heart-wood. Whenever this shrinkage exceeds a given limit a 

 sudden division of the woody tissue takes place in the direc- 

 tion of the medullary rays, and the formation of this frost-shake 

 is accompanied by a loud noise.* As soon as the thaw 

 follows the frost-shake the expansion begins, the fissure closes 

 and is overgrown by a new annual zone the next summer, but 

 it is usually opened again during the next winter even by a 

 moderate degree of cold. If several mild winters pass with- 

 out causing the fissure to re-open, the stem may assume the 

 external appearance of being healed and may remain perma- 

 nently closed. Along the edges of the cleft the formation of 

 the new annual zone is always somewhat thicker than on the 

 rest of the stem, and as these two cicatrized edges are close 

 together they gradually form ridges or frost-scars standing 

 about a hand-breadth from the normal outline of the stem. 



Hardwoods with strongly developed medullary rays, like 

 Oak, Elm and Sweet Chestnut, are chiefly exposed to the 

 danger of forming frost-shakes, but they are formed less 

 frequently in the Beech, in the Willow, the Poplar, the Lime 

 and Conifers. They are usually found on the east and north- 

 east side of the stems, as the harder frosts only set in when the 

 wind comes from that direction. Preventive measures can 

 hardly be used to mitigate this evil, but the.early utilization of 

 the trees with bad fissures is recommendable in view of their 

 liability to fungoid disease and consequent depreciation in value. 



* A similar noise is heard in the Bamboo forests of Burmah, where the wood 

 splits in the hot months of March and April, on account of shrinkage from heat, 

 and the halms burst with a report as loud as that from a pistol. 



