Vol. XVI. No. 397. 



THE AGKICULTURAL NEWS 



221 



PRUNING. 



Pruning, according to Bulletin 2JfS of the Ontario 

 Department of Agriculture, is primarily a special operation 

 performed on the tree regularly or irregularly to make it 

 produce fruit abundantly, by modifying the growth of the 

 tree in reducing the amount of branches and leaves and in 

 giving the tree a more regular form in order to obtain a 

 higher yield. First of all, therefore, the removal of all 

 useless branches is necessary, and then it has to be con- 

 sidered whether, by reducing the number of branches, those 

 remaining will be so strengthened as to produce more fruit 

 than if all the branches were allowed to grow. On the latter 

 point opinions vary and, in fact, pruning, though one of 

 the oldest of horticultural practices, has received but little 

 scientific attention, so that definite rules cannot be laid down. 

 The planter must investigate and ascertain for himself 

 whether pruning increases the bearing power to an appre- 

 ciable extent. The suggestions offered by Dr van Hall 

 in his work on cacao are valuable. After the removal of weak 

 and diseased twigs, he advises regular treatment, once a year 

 or if possible twice a year, always in tlie dry season when the 

 tree is resting, when the wound drie? quickly and parasites 

 do not penetrate easily. A more regular reaction follows at 

 this season than at other times when all the buds in the 

 heighbourhood are ready to develop at once as soon as a twig 

 has been cut. The cleaning of the tree by cutting away the 

 suckers and diseased twigs needs care but no special 

 skill, but trained pruners should be employed in the dry 

 season to look after the clean trees and to remove superfluous 

 twigs when the foliage system is considered too dense. In 

 cleaning, the dead and diseased twigs and branches, as well 

 as the water-shoots, must be cut quite close to the branch 

 or stem to which they are attached so as to leave no stump. 

 Both cleaners and pruners must, also, carefully cover the 

 wounds with coal-tar in order to close them against parasites 

 such as fungi and borers. 



Theie is a coiiniion Iclicf in I he West Irjdies that, should 

 a tree like the cacao be pruned, say three days after the new 

 tnoon, for every twig cut the upward circulation of the sap 

 will cause many more to appear, whereas if the tree be pruned 

 after the full moon or when the sap is ascending no shoots, 

 or very few, will be seen to appear after the operation. How 

 inuch truth underlies this belief has never been scientifically 

 ascertained. 



In respect of orange trees, the general principle of 

 pruning is to remove growth to such a degree as to aliow 

 anyone standing at the bottom of the tree to see the sky 

 through the branches. The leaves, which are the greatp.st 

 chemists in the world, cannot perfurm their work except 

 under the direct influence of the sunlight and develop into 

 growths for the extension of the tree or into blossoms 

 furnished with protective and essential organs for producing 

 fruit. 



In Pamphlet No. 72 of the Imperial Department of 

 Agriculture it is stated that limes for the most part require 

 but little pruning. Dead wood should be promptly removed 

 and suckers kept trimmed to such a number that they will 

 not choke out the main growth of the tree. From the habit of 

 growth of the lime it will be seen that it is natural for a few 

 suckers to be continuously developed and these take the 

 place of the older branches which die from one cause or 

 another. In fact, it is often necessary to develop one or 

 more suckers when the top of the tree has suffered an injury 

 in order to preserve the tree and save the time that would be 

 lost if a new tree had to be grown from the seed supplied. 



CLOUDS. 



Among the readily accessible means at hand for ascer- 

 taining the approach of hurricanes, provided intelligent use 

 is made of ordinary powers of observation, clouds are so 

 invaluable in affording information as to atmospheric changes 

 and disturbances that it is almost a matter of necessity that 

 an elementary knowledge of different cloud formations be 

 acquired to supplement the information as to Hurricane 

 Warnings contained in the issue of the Agricultural News of 

 •luneSO, 1917. 



There are four primary forms of clouds: — 

 Cirrus 

 Cumulus 

 Stratus 

 Nimbus. 



Cirrus Clouds, which take their name from their 

 resemblance to a lock or curl of hair and are commonly 

 called mare's tails or cat's tails or Pele's Hair, are composed 

 of isolated feathery masses of cloud particles from 1.5,000 to 

 30 000 feet in the higher regions of the atmosphere, so far 

 above the surface of the earth that these particles are gener- 

 ally in the condition of ice crystals. It is chiefly to do with 

 Cirrus clouds that haloes appear round the sun and moon. 

 There are two distinct forms of Cirrus clouds The first form, 

 like feathery shafts, commence to appear when a cyclone is 

 300 to 400 miles away and spread out like a fan from 

 a spot on the horizon, indicating the centre of the 

 disturbance and giving warning of a storm of small 

 diameter but of considerable force, while the second kind 

 are of zone shape and of large diameter forecasting a storm 

 of moderate strength. The upper currents of Cirrus 

 clouds afford more information as to its situation and 

 force while the storm is still at some distance, but, when 

 the vortex is near at hand the movements of the lower clouds 

 are more reliable guides in determining the position and 

 direction of the centre. 



Cumulus or Heap Clouds consist of dense masses of 

 cloud formation collected in the lower regions of the atmos- 

 phere (4,.500 to 7,.i00 feet) where the amount of water vapour 

 IS greatest, and are humpback on the top with flat bases. 

 They are, as a rule, produced by the ascending daily air 

 currents carrying the warm moisture to the upper regions, where 

 the clouds are chilled by the cold of elevation and expansion. 



Stratus or Layer Clouds occur in the form of horizontal 

 bands or layers^ and are due to the gradual settling of the 

 other clouds, for which reason they are common in the 

 early morning and late evening, when the ascending currents 

 of air are weak. This form of cloud is the least elevated of 

 all, being under 3,000 feet, and often becoming fog by falling 

 to the surface of the earth. 



Nimbus, yr Rain Clouds, are dense masses of formless 

 clouds with ragged edges, through which are often .seen 

 CirroStratus clouds. When the mass of nimbus is broken 

 up into small fragments, or if portions float below the cloud, 

 they are called 'scud'. 



The chief secondary forms of clouds are: — 



Cirro Stratus 



Cirro-Cumulus 



Cumulo-Stratus 



C irro- Stratus Clotids are whitish layers, usually forming 

 a diaphanous veil and often giving the sky appearance of 

 a mackerel's back; hence such a sky which indicates approach- 

 ing rain, is known as a mackerel sky. 



Cirro-Cumuliis Cloxids, known as 'Wool Sacks', are 

 Cirrus clouds arranged in little round masses like small 

 cumulus and point to dry weather. 



Cumulo-Stratus Clouds resemble mountain masses with 

 a stratus base. 



