YALE AGRICULTURAL LECTURES. 69 



the level. This is the operation called trenching, and without 

 it no garden is in condition for giving best results. For grow 

 ing strawberries, raspberries, and blackberries, it is equally 

 advantageous, but with this difference, that the fruits last 

 named are expected to continue perhaps only from six to twice 

 six years on the same ground, while vines properly planted and 

 managed have no limit to their duration, and the fruit for many 

 years will constantly improve in quality and earliness of matu 

 rity. If the trenching is performed one season in advance, the 

 subsoil may be put upon the top of the mold, and enriched by 

 having manure thoroughly incorporated by a second or third 

 spading, or by plowing, according to extent of ground. If 

 ground is prepared in early autumn, it will be ready for vines 

 in the spring ; but if in spring, it will not be in the best condi 

 tion for vines before fall, without a renewal of subsoil. 



The subjects of pruning and planting were also fully discuss 

 ed, but my space is already exhausted, and I must leave them 

 undescribed. 



In the evening, Mr. GEORGE B. EMERSON, of Boston, gave a 

 lecture upon " The character of the various forest trees of 

 Europe and America." He alluded, in commencing, to the 

 differences observed in the tree of the plain and the forest : 

 the one tall and bare, the other full of limbs, and short. He 

 then went on to speak of the great uses of the forest in creat 

 ing soils. Described the lava-covered sides of Vesuvius, where 

 the lichen first, the moss, the grass, the low shrub, small trees, 

 and finally larger ones, added to and made the soil upon which 

 grows the tree of 400 or 500 years. One oifice of the forest 

 is thus to prepare a soil for the use of man. As forests have 

 disappeared here, we have an unfavorable change of climate, 

 becoming colder in winter and hotter in summer, and the 

 streams become dried up. Many places, in valleys once pro 

 tected, are now open to the cold blasts, and nothing will grow 

 well. A row of trees planted across the valley would mitigate 

 the result in one generation. He considered the more exten- 



