FORESTRY. 339 



especially in the newest layers of peruiauent tissue, and affect corresponding 

 zones in the leaf stems. In most woods the thin-wulled parenchyma, contain- 

 ing crystals of oxalate of lime, is first affected. The first hreaks or ojienings in 

 Ihe vascular bundles occur either in the region of the hard l)ast fibers or in the 

 boundary region between I he cdnenchymatous tissues and the eiidodernus. 

 The spiral vessels are especially susceptible to injury. In the line veins of the 

 leaves these spiral vessels frequently showed a brown discoloration when the 

 surrounding mesoph.vll was uninjured. 



Frost, however, does not act uuiforndy. Some of the tissue in the leaf may 

 be brown while the remaining i>ai-ts are still green. 'I'lie dangci- from frost is 

 greatest where the bud is attached, because of the large amount of i)arenchynui 

 la proportion to the solid ring growth at this place. Frost injury is confined to 

 the region affected and does not spread to new tissue as does a fungus disease. 



In addition to discoloration, frost causes many mechanical injuries, and the 

 younger the twigs the greater the amount of such injury. Openings in the leaf 

 and bark surfaces caused by frost are most numerous where the soft parenchyma 

 tis.sue is united with more solid tissue. Injuries on the upper side of the leaf 

 are generally distinguished by the collenchymatous tissue being split ajjart from 

 the i)arenchyma lying underneath. 



Eruptions («f the vascular cylinder are generally manifested eitlicr in radial 

 clefts within the medullary rays or in tangential cracks within the cambium 

 region. In addition, many cavities appear in the pith and the bark i)arenchyma. 

 The separated tissue within the cambium region gradually heals over, often 

 presenting the appearance of a 2-years' ring growth. Sucli a])pearances are 

 most frequently found directly under a bud place. 



The permanent wilted appearance of frost-injured twigs is due to th(> uplifting 

 and splitting of the plant tissue. Leaves which when left on the branch show a 

 wilted condition because the water in the tissue is frozen or has been forced out 

 of the cells regain their normal turge.sence on placing the stems in waiter. 



English walnuts in New York, A. C. Pomeroy (Amcr. Afjr., 78 {1906), yo. 

 /-J. pp. 2S9, 297, pf/.<<. .?).— The author states that in 1876 English walnuts were 

 planted in Niagara County, New York, and that at the present time some of 

 the better trees give an average annual yield of about 20 bu. of nuts. Sugges- 

 tions are made on the culture of English w.ilnuts and illustrations of the 

 trees and nuts are given. 



The pecan and its culture, II. II. IIu.mk {I'ctcrshurti. \ ii.: Amer. Fruit and 

 Xut Jojir., 1!)06, pp. I'tO, pis;. 10, ihjx. .?,S). — A compact treatise on pecans, 

 treating of the botany, varieties, various cultural operations including harvest- 

 ing and marketing, and the diseases and insects, the uses of the luits, and a 

 hililiography of 23 papers on the suliject. 



Ornamental trees, shrubs, and herbaceous plants in Minnesota, S. B. 

 Grekn (M iinicsotd Sta. Hid. fXi. pp. 2,V.)-3')U fKjx. 1(1')). — Brief popular descrip- 

 tions are given of a large luunber of ornamental trees, shrubs, and herbaceous 

 plants which can be successfnll.y grown in INIimiesota, with some general rules 

 for i)lanting. making lawns, planting for special effects, and winter protection of 

 p(>rennial i)lants. .\ ])ronunent feature of the bulletin is the unusually large 

 number of illusti-atioiis of different ornamental plants showing their uses for 

 adornment. 



FORESTRY. 



Chestnut in Connecticut and the improvement of the woodlot, A. F. 



II.VWES ( Connect iciif Sidle ,sl(i. Bill. l-')'/. pp. Jfl, pis. 11, fujs. 3). — "The 



purpose of this bulletin is to s<>rve as a guide for the better management of 



(mr woodlots." Suggestions on making iuiiirovcnieiit thiiniing, and tables based 



13087— No. 4— OG M 1 



