128 Principles of Plant Culture. 



ing period tends, therefore, to hasten wood maturity 

 and thus to reduce damage from cold (174). Tillage 

 should be early diseontitiued about trees liable to win- 

 ter injury, and in wet seasons, mulching should be re- 

 moved. Oats, buckwheat or clover sown in the nursery 

 or orchard in late summer promotes wood maturity by 

 increasing evaporation from the soil and is further 

 useful as a covering to the ground in winter (195). 

 Draining heavy or wet soils promotes wood maturity 

 by promptly removing surplus water. 



b — By Treatment of the Plant. 



200, Pinching the Terminal Buds (416 a) a few 

 weeks before the time for leaf fall favors wood matur- 

 ity by checking growth, as does the removal of the 

 younger leaves, in which food preparation is, most ac- 

 tive. These methods may be employed upon young 

 trees— especially nursery trees, which are very liable to 

 make late growth. Early gathering of the fruit from 

 trees of late varieties also tends to hasten wood maturity. 

 ■ 201. Protection with Non-Conducting Materials pre- 

 vents damage from cold in many herbaceous and 

 shrubby plants in climates where they are not fully 

 hardy. By covering such plants with straw or other 

 litter, or with soil, we lessen to some extent the in- 

 tensity of the cold, but— more important — we prevent 

 frequent freezing and thawing (189 d), and in a meas- 

 ure, the heaving of the ground, which on heavy or wet 

 soil is destructive to the roots of plants. A covering of 

 straw, leaves, or other litter is preferable for low, her- 

 baceous plants, such as strawberries. The covering 

 should not exceed an inch or two in thickness, otherwise 



