THE AGRICULTURAL NEWS. 



January 7, 191L 



ent wind-breaks, the protecting crop f^rows up with the 

 main one, and the period of its existence is more or less 

 that of the pbints which it is designed to shelter. The 

 advantage of wind-breaks of this kind is that they can 

 be removed when the principal crop is harvested, leav- 

 ing the ground entirely clear for such cultural opera- 

 tions as may be necessary. They possess disadvan- 

 tages on account of the fact that their sheltering 

 action extends to a short distance, only, to leeward of 

 them, necessitating the taking up of valuable space, 

 where the area of cultivation is large, bv suheessive 

 rows (jf shelter belts; and because they are of litfcl^ or 

 no use in storms or in very high winds. 



It will be well to consider, at this stage, the gen- 

 eral effects of wind-breaks. Reference has been made 

 alreadv to their directly protective quality, by which 

 they prevent mechanical injury by wind. Among such 

 damage is the breaking off of branches, and the removal 

 of flowers and fruits, by which the pi'oductive ca]iacity 

 of the trees is lessened, and in the first instance, oppor- 

 tunities are given for invasion by disease. The chances 

 of serious loss of flowers and fruits in this way are not 

 visually great in cacao orchai-ds; it is in citrus cultiva- 

 tions that greater harm is likely to accrue from this 

 cause. In any case, the presence of a shelter belt, 

 where this is reipiired. lessens the stunting action of 

 the wind, and thus removes one of the largesthandicaps 

 that have to be met by the plants, in their struggle for 

 existence. 



The ways in whi('h wind-bi-eaks are of use to plants 

 are, however, generally secondary, 'i'hey often serve to 

 ameliorate the conditions under which the plants are 

 existing, to such an extent as to enable them td attain 

 a state of energetic healthfulness in which they resist 

 successfully all attacks of diseases and pests; while much 

 of the effort that would be otherwise required in com- 

 bating untoward conditions is employed in producing 

 good crops, of a useful (piality. The agriculturist can- 

 not afford to igiKii'c these two most important aspects 

 of the employment of shelter lor ]ilants against the 

 wind. 



The presence of belts of plants of a kind other than 

 those which form the jirincipal cultivations is of much 

 use in the chocking of epidemics of disease. These 

 start in a certain i)lace or places, and, often tra\elling 

 with the wind, s])read easily, because they can pass 

 through an uninterrupted area of the very plant th.at 

 is the object of tln-ir attack. If, however, a wind-break 

 composed of a plant m- jilants on which a disease has 

 little or no effect, occurs in it-< path, its course is inter- 



ru]ited, and the chances of safety of the plantations on 

 the other side of the shelter belt are increased to a use- 

 ful degree. This circumstance mikes it important that 

 wind-breaks should be chosen in consideration of their 

 power to resist dise;ise, and of the diseases to which 

 they are most subject — a matter to which further refer- 

 ence will be made below. 



( )ne of the subsidiary results of the presence of 

 the plants which form ;i permanent wind-break is that 

 the existence of these in the soil lessens the washing that 

 takes place at times of heavy rain, so that they posse.ss 

 a useful forest effect. The importance of this cannot 

 be over-estimated, particularly where permanent crops 

 are being grown on stee]) slopes, in regions of heavy 

 rainfall. 



Not the least among the advantages of the exist- 

 ence of wind-breaks is the assistance that this gives in 

 conserving the water in the soil, and in decreasing 

 transpiration fi-om the leaves of ])lants. Whei'e shelter 

 belts are foimd. the force of the air currents is lessened, 

 so that the rate at whiah moisture is carried away 

 from the areas over which they tr.ivel is diminished to 

 a useful degree. Wind-breaks serve also to temper the 

 chilling effect of cool winds: this reside is, however, of 

 no great importance in the West Indies, except in the 

 more mountainous islands. A minor matter, but one 

 worthy of mention, is that tiiey are said to encourage 

 the presence of birds; though whether this is of advan- 

 tage, or not, will depend im the circumstances of the 

 special case. 



Reverting to suitable wind-breaks for crops of one 

 season, it seems that more attention may well be given 

 to the feasibility of providing those which are of a per- 

 manent nature. Where s'u^h jirovision can be made, 

 as will have been seen from what is said above, special 

 advantages will ai:crue, in that the pi'otective effect of 

 belts of this kind will extend over a far larger area than 

 that which can be sheltered by a temporary wind-break, 

 and that such protective etie'jt will be available during 

 storms, in which the teuipor.iry belts, from their very 

 nature, woidd cease to do the work that is required of 

 them. It is recognized that there is little incentive, 

 when ground is being opened for the growing of one- 

 season crops, to plant permanent wind-breaks. Never- 

 theless, this course is followed in some districts, in the 

 French West Indian islands, and the suggestion is 

 madi: that its further atloption would be of advantage, 

 and would make for its justification. 



A final matter is to jioini out that care is required 

 in the choice and planting of wind-breaks. The plants 



