538 



NA TURE 



[April 9, 1896 



injurious to the Scotch pine, and likewise feeds upon the 

 leaves of the beech and other broad-leaved trees. From 

 1888 to 1 89 1 this caterpillar appeared in such enormous 

 numbers in the spruce woods of South Germany, par- 

 ticularly of Bavaria, that over large areas the trees 

 became entirely denuded of their leaves, and were killed. 

 In the Ebersberg Park, a densely stocked forest, spruce 

 with a small proportion of beech and Scotch pine, form- 

 ing a compact area of 16,510 acres, 4700 acres were 

 completely bare, while on 7400 acres the trees were 

 severely damaged. The timber that had to be cut on 

 this area, in consequence, amounted to 53,000,000 cubic 

 feet, more than half the normal annual yield of the State 

 forests in the kingdom of Bavaria. Timber-cutters were 

 brought from all parts of the country, and lodged in 

 temporary barracks built in the forest. A railway seven 

 miles long was constructed into the heart of the devas- 

 tated area ; tramways were laid upon the rides separating 

 the compartments, and portable lines were used to bring 

 out the logs. At the same time the Nun had devastated 

 other extensive areas in Bavaria and the adjoining dis- 

 tricts of Wiirttemberg, necessitating the cutting of large 

 quantities of timber. The news of these events created 

 great uneasiness among timber traders, and a dis- 

 astrous fall in timber prices was anticipated. This, 

 however, was to a great extent guarded against by the 

 prompt and carefully-planned measures taken by the 

 Bavarian Government. The annual cuttings in the 

 Bavarian State forests were at once considerably reduced, 

 and the action thus taken was aided by the circumstance, 

 that the timber of the Ebersberg Park has a very good 

 name, and justly so, for the stems are well-shaped, clean, 

 without knots, and the wood is even-grained. Most of 

 the large timber was sent across the Alps by the Brenner 

 line, and found a ready market in Italy, The smaller 

 pieces were sold to paper factories to be converted into 

 wood pulp, and what was only fit for fuel was collected 

 at the great depot that supplies the town of Munich 

 with firewood. The cleared areas have since been 

 planted up, and except that the working plan of the 

 forest was completely upset, no permanent damage was 

 done by the calamity. 



If the timber of Conifers killed by caterpillars is not 

 cut at once, it is apt to be much injured by bark beetles. 

 In the present instance this was avoided ; but formerly, 

 with the means of communications less developed, and 

 the plan of action less prompt and less comprehensive, 

 the ravages of Tomiciis typographus and other bark 

 beetles have greatly intensified the mischief. In North 

 Germany and in Russia the principal devastations by 

 the Nun, and by the bark beetles in its wake, have been 

 recorded in 1688 (Altmark), 1794 to 1797 (Southern 

 Thuringia), 1837 to 1840 (the greater part of Germany, 

 from the North German Plain to the lake of Constance), 

 1845 to 1867 (Western Russia and Eastern Prussia, 

 extending over forest areas aggregating 32,000 EngHsh 

 square miles). 



The moth lays about 150 eggs, and, as is the case with 

 other species (for instance, Orgyia a?ifiqua), the male 

 and female insects of one brood attain the perfect stage 

 on different dates, necessitating the inter-breeding of 

 different broods, and thus insuring a vigorous develop- 

 ment of the pest. A succession of warm dry springs, 

 with weather otherwise favourable to the life of the insect, 

 brings about the rapid multiplication of the Nun, and, 

 unfortunately, the protective measures are difficult, and 

 their success uncertain. 



Fortunately, the Nun has formidable enemies. A 

 number of birds eat the eggs — up to 200,000 eggs have 

 been found on one tree ; but only the starling eats the 

 hairy caterpillars on a large scale. Of insects, parasitic 

 Diptcra i^Tac hint dee) are exceedingly useful in destroying 

 the caterpillar wholesale. The most powerful ally of the 

 forester, however, has in most cases been an epidemic 



NO. 1380, VOL. 53] 



disease, which breaks out among the caterpillars when 

 the rnultiplication has attained its climax. They congre- 

 gate in large masses at the tops of trees and branches, 

 where they die without making any attempt at feeding. 

 In the diseased caterpillars several species of bacteria 

 have been found in large numbers ; attempts have also 

 been made to inoculate healthy caterpillars with these 

 bacteria ; the success, however, has not been sufficient 

 for practical purposes. 



Equally mischievous, not, however, in spruce woods, 

 but in those of the Scotch pine, is the Pine Moth {Gastro- 

 pacha Pint), a species, Mr. Fisher states, not found in 

 Great Britain. Formerly the Pine Moth was dreaded as 

 the greatest enemy of the extensive pine forests of 

 Northern and Middle Germany. Fortunately, however, 

 when its life-history became better know«, a simple and 

 most effective remedy was devised. The eggs are laid 

 early in August ; the caterpillars, which come out about 

 the end of that month, proceed at once to feed on the 

 needles; but, being small, the damage done at this season 

 is not considerable. When night frosts commence, they 

 descend from the trees, and spend the winter months 

 ensconced in moss or dry needles near the foot of the 

 stem. In spring, aroused by the warmth, they ascend 

 the trees and eat them bare in no time. The average 

 consumption by one caterpillar is estimated at 1000 

 needles. What is done by way of protection against 

 this pest, is to prevent their ascending the trees in spring, 

 and this is effected by putting broad bands of tar, grease 

 and glue, mixed, round the stems, the outer rough bark 

 having first been scraped off to present a smooth surface. 

 These sticky bands the caterpillar cannot get over, and 

 in this manner nearly the whole of the pine forests in 

 the plains and broader valleys of Germany are now 

 protected against the ravages of this insect. The pine 

 woods on the hills, having generally a mixture of other 

 trees, are safe from the attacks of the Pine Moth. 



The Scotch pine has many enemies besides the Pine 

 Moth. During the summer of 1895 the Pine Noctua 

 ( Noctiia piniperda) and the Pine Looper Moth {Geometra 

 piniarid) have appeared in immense numbers, the 

 former between Darmstadt and the Main River, and 

 the latter in the forests near Nuremberg, as well as in the 

 Rhine Valley. 



Among insects which attack young plants, the Pine 

 Weevil {Hylobius abietis) is one of the most mischievous. 

 The larva does not do much damage, but the beetle is 

 found in large numbers in plantations of spruce and 

 Scotch pine up to six years of age, killing the plants by 

 gnawing the bark all round the stem, down to the root. 

 It lays its eggs on stumps and roots, and the best pro- 

 tection is to give him as little opportunity as possible for 

 breeding in the vicinity of young plantations. Small 

 felling areas and intermittent fellings ought to be the 

 rule ; when a clearance has been made, the adjoining 

 area should not be cut until after the lapse of three to five 

 years. 



Of the Cockchafer {Melolo7itha vulgaris) the beetle 

 does some damage by eating the foliage of broad-leaved 

 trees, particularly of the oak ; but the chief mischief is 

 done iDy the larva, which eats the roots of plants. A 

 fungus {Botrytis tenelld) some years ago in France was 

 found to infest the larvae, and at one time it was hoped 

 that it might be possible, by inoculating larvae with the 

 spores, to spread the infection, and thus to destroy a large 

 portion of the brood. Experiments have been made with 

 great care in France, in Switzerland, and at Berlin, but 

 hitherto without practical success. 



Part iii. discusses protection against plants, forest 

 weeds, climbers, parasitic and epiphytic phanerogams 

 and fungi. In tropical and sub-tropical forests huge 

 woody climbers play an important part, and are often 

 very mischievous. They bend and twist the trees on 

 which they have found their support, and finally, by their 



