THE INFLUENCE OF SHELTER ON THE DEVELOPMENT OF PIT. 31 



The tree selected in the Burnley Horticultural Gardens was Strathden, an obsolete variety, 

 on account of one limb having been left unpruned and spreading out somewhat horizontally. This 

 limb bore 22 apples, and a canvas hammock arranged beneath it was kept daily full of water, so that 

 the growing apples were constantly surrounded by a moist atmosphere. This particular branch 

 shed its leaves before the other portions of the tree, and the fruit reached a normal size. 



There were eight windfalls, and the remaining 14 apples were picked on 4th February when 

 ripe. Every apple was pitted and some of them very badly. 



The rest of the tree bore 14 apples, of which 11 were pitted or 79 per cent. In order to pro- 

 perly appreciate this result, it is necessary to remember that while humidity of the air lessens trans- 

 piration, this effect is modified by the degree of heat which increases transpiration up to a maximum 

 varying in different plants. The horizontal branch was fully exposed to the sun's rays, and the early 

 fall of the leaves left the fruit unprotected. 



The temperature of the air has therefore to be taken into account, and it is found that the action 

 of insolation or exposure to the sun's rays is stronger when the air contains much water vapour than 

 when it contains but little. 



The exceptional season through which we have passed was noted for its high temperature, and 

 Mr. Hunt, Commonwealth Meteorologist, remarks on the weather experienced in Victoria : " These 

 results have established no fewer than five new records, the highest maximum temperature on any 

 one day, the highest mean daily maximum for the month, the highest mean temperature, the highest 

 mean barometric pressure, and the lowest rainfall." So that before any definite conclusions could be 

 drawn, the experiment would require to be repeated in a normal season. 



VIII. THE INFLUENCE OF SHELTER ON THE DEVELOPMENT OF PIT. 



Four healthy Cleopatra trees growing in a row in rather an exposed situation were selected in 

 North and Brady's orchard, on the Tamar (Figs. 9, 10). Two in the middle were surrounded by a 

 screen of waterproof white duck cloth on 12th October, 1914, when the trees were in bud, but not 

 in blossom. The other two on the outside were retained as a check. 



As might have been expected, the sheltered trees grew towards the light, and the new growth 

 for the season measured 39 inches. When the screen was removed the two trees were conspicuous 

 by their height all over the orchard (Figs. 11, 12). 



As compared with the adjoining trees, the leaves were of a pale green, but this was partly due 

 to " Red Spider." Both " Red Spider" and Woolly Aphis were very bad on the screened trees, and 

 the young wood looked as if sprinkled with snow. When examined in February the crop was lighter 

 than on neighbouring trees, but the apples were quite as large, only still green and not coloured. 



The apples were picked on 17th March, with the following result : 



Yield. Clean. Pitted. Pitted. 



Ibs. Ibs. Ibs. % 



Sheltered JTrees ..34 26 8 23 



Unsheltered Trees 45 32 13 29 



There was not a great difference in the relative amount of Pit, still the sheltered trees were 

 least affected. 



It is always an advantage to have the trees well sheltered from the prevailing winds, but in 

 practice this is done by means of wind-breaks, which while breaking the force of the wind, allow a 

 free circulation of air and sunlight. At the same tune the transpiration is reduced, when the drying 

 effects of the wind are moderated. 



