.510 APPENDIX. 



No. VI. 



On the Advantages of planting Fruit-Trees on Declivities, 

 in a Letter from the Rev. Dr John Walker to Lord 

 Kames, dated Moffat, Feb. 18. 1773. 



(Referred to at p. 261.) 



Dodart first observed that trees pushed their branches in a 

 direction parallel to the surface of the earth. If a tree stands 

 on a steep, it pushes both towards the hill, and towards the 

 declivity ; but on both sides it still preserves its branches 

 parallel to the surface. As there is an attraction between 

 the upper surface of leaves and light, I am also persuaded, 

 though not equally certain of it from experiment, that there 

 U an attraction of the same nature between the under surface 

 of leaves and the surface of the earth. This I consider as the 

 cause of the phenomenon. 



I had long observed, that the most fruitful orchards, and 

 the most fertile trees, are those planted on a declivity, and 

 the steeper it is, though not quite a precipice, the more fer- 

 tile they prove. But I was never satisfied as to the cause of 

 it, till I called to mind the above observation of Dodart; 

 which occurred to me when I was in the town of Jedburgh. 

 There is more fruit about that place, and more fruit-bearing 

 wood upon the trees, than I have seen in any other part of 

 Scotland : But its orchards and fruit-gardens are mostly si- 

 tuated in very steep places. 



It is well known that the spreading of trees always renders 

 them fruitful. On a plain, however, they incline to shoot 

 upwards ; and therefore art is called in by skilful gardeners, 

 and applied in various ways to check their perpendicular, 

 and to promote their lateral growth. But this point, which 

 can odIv be gained upon a plain by art, is obtained upon a 

 declivity by nature. There a tree loses its tendency to shoot 

 upwards, and in order to preserve its branches parallel with 

 the surface, is constrained to put them in a lateral direction. 



Hence an important rule in the choice of orchards and 

 fruit-gardens. 



