THE NEW FORESTRY. 1 87 



planting is resorted to, and two or three plants are put into 

 each hole, the crop suffers less from rabbits. Sheep bark some 

 kinds of trees very badly, and also eat the leaves and shoots 

 of many species indiscriminately. Cattle and horses also 

 browse on many kinds of trees, as may often be seen in parks 

 where the trees are usually cropped as high as the cattle can 

 reach. Cattle and sheep are not, however, expected to be 

 admitted into young plantations. 



SECTION III. — INSECTS AND DISEASES. 



In the following list the species are taken in the order in 

 which they are given in Chapter VII., and those species that 

 do not suffer seriously from disease and insects are grouped 

 together. 



THE Oak. — The foliage of the oak is often destroyed 

 about midsummer by the oak caterpillars — Tortrix viridana 

 and Liparismonacha. Whole tracts are frequently quite defo- 

 liated, not a tree escaping. The consequence is a severe check 

 to growth and a weak, ■ ill-matured second growth of leaves 

 after the caterpillars have gone. Caterpillars are always worst 

 on poor, slow-growing trees, the growth of which they quickly 

 overtake* They are always present in oak woods to a greater 

 or less extent, and are worse in some places than others. The 

 grubs also drop from the oaks upon the underwood beneath, 

 which they also defoliate, so that an oak wood, badly attacked, 

 presents a very miserable spectacle. Drought and poverty in 

 the soil seem to be the main predisposing causes. Flocks of 

 rooks, starlings, and other birds follow the caterpillars and 

 destroy immense numbers, the rooks gorging themselves to 

 such an extent that they can scarcely be made to rise. 



Ring-shake and Star-shake. — Whatever the cause of 

 this evil or disease may be, it affects the timber of the oak on 

 many estates and destroys its value. In a ring-shaken tree 

 the annual rings of the trunk and main limbs are shaken loose, 

 so to speak, become detached from each other round their 

 whole circumference, hence the word "ring-shake." There 

 may be several shakes in the trunk, but there are seldom two 

 close together. Ring-shake ruptures the timber, and when the 

 tree is sawn up it ; falls to pieces and is worthless. A badly 



* The geometer moth caterpillar, similar to the oak caterpillar, is also 

 invariably most destructive to pine plantations on poor, dry soils. (' ' Highland 

 Society's Transactions," 1897, p. 119.) 



