344 THE BOOK OF THE LANDED ESTATE. 



abundant vegetation of any kind, than in barren and sterile districts. 

 In consequence of this, if a hot wind blow over a district in which there 

 are trees, it will be cooled down ; and therefore its power of holding 

 water in a state of vapour is diminished, in a geometrical ratio, with 

 every fall of temperature, and the consequence is a deposit of moisture 

 in the form of dew, mist, or rain. 



Again, Dr Brown states * that whatever moisture has been taken by 

 the tree from the soil is all, excepting what is required in the structure 

 of the plant, returned to the atmosphere by the stomates on the back of 

 the leaf. This operation is effected by different kinds of trees in various 

 degrees, and in this way the air around trees is saturated in a higher 

 degree with moisture than the air on an open treeless country. 



One thing is ce rtain, that where rains fall, that which lies in the soil 

 under trees is retained there for a length of time, as the shade of the 

 trees prevents evaporation ;- while, on the other hand, that which is 

 deposited on an arid plain is very soon evaporated by the heat of the 

 sun, and also by the heat of the soil itself. 



It must therefore be of great importance to those who are owners of 

 large estates, partly consisting of tracts of country without any plan- 

 tations, to know that they can improve their properties very much, 

 with benefit to themselves and to the occupiers of the land, by having 

 breadths of plantations formed on sites suitable for the growth of 

 timber. These plantations would not only be the means of retaining 

 the moisture in dry seasons, but would also give a large amount of 

 shelter to the farm-lands, and increase the value of the estates to a 

 considerable degree. Many intelligent farmers know the benefit derived 

 from the presence of plantations, and will always give a higher rent 

 for land judiciously sheltered by plantations than otherwise. Estates 

 with a proper outline of plantations have a rich warm look about them, 

 and this has a tendency to influence both purchasers of landed property 

 and tenants more than may at first be supposed. 



Experience has shown that estates studded with well- formed plan- 

 tations, extended to a certain point, but not more, have increased in 

 annual value very much. I know estates in the north of Scotland 

 which at one time were comparatively tracts of waste land, and thought 

 at the time unfit for anything but grazing a few head of sheep and 

 moor-birds. These tracts were laid out with plantations, by planting the 

 greater part of the hilly portions and the most exposed parts. The 

 lands left unplanted have gradually increased in value from the shelter 

 given by the plantations ; and estates which sixty years ago were worth 

 from Is. to 2s. per acre per annum on the average, are now let to 



* Report of Colonial Botanist, 1863 Cape of Good Hope. 



