But by the process I have recommended much more shade will be left than will ultimately be required, and I have found that it is impossible to clear down at once all the trees you wish to get rid of, as, if you did, you would be sure to require such a number of piles as would, when they were burnt, be sure to injure the trees to be preserved. It is therefore necessary to complete the clearing during the season following. Such trees, then, as you may wish further to remove may be thrown down between the rows of coffee, and others which may be likely to do much damage, either to the coffee or to the shade trees to be preserved, may be lopped and barked, and they should be barked as high up as a man can reach, as we have found that trees barked close to the ground die slowly. It sometimes, however, happens that the forest land is much cut up with narrow and deep ravines, and in that case the bottoms of such ravines should be cleared off entirely, and this can be done without injury to the standing trees above, as, when the wood in the bottom of the ravine is being burnt the flames will be too distant to inflict any injury to the trees left for shade higher up the slopes, but, as I have said, great care must be taken to prevent any running fire through the shaded land; and I can speak of the effect of such a fire from a melancholy experience. In the event of bottoms of ravines being thus cleared down, it may afterwards be found desirable to supply fresh shade on the southern and western slopes, and this can easily be done on the system recommended previously for lands which have been entirely cleared down. It is time now to turn our attention to the extremely complicated question of the quantity of shade required for the various aspects, gradients, and soils we have to deal with, and let us in the first place begin with some remarks on the effects of aspect as regards heat.