180 Transactions. 



Basin.* and these were recorded some years ago. The force of the wind 

 may be seen by records of the average daily force in miles for the year and 

 of the maximum velocity in miles on any day in the year. For the years 

 1874 to 1879, inclusive, the average daily force for the year was 127 miles ; 

 the maximum velocity for a day, 717-5 miles. The most frequent wind, 

 according to statistics, is the south-west, which is common in winter, and 

 is a cold, strong wind, blowing in gusts, and generally bringing rain. The 

 south side of the hills especially gets the full force of this wind. In summer 

 it usually follows a north-west wind, bringing a heavy storm, and greatly 

 lowering the temperature of the atmosphere. Though statistics show that 

 the south-west is the most frequent wind, the east wind is generally con- 

 sidered to be the most prevalent, and addition of figures of frequency of 

 the north-east, east, and south-east winds shows that the prevailing wind 

 is from the east, though not always blowing from due east. The east wind, 

 whether north-east, east, or south-east, is always steady, and often strong, 

 but never blowing in gusts. Neither side of the hills is protected from it. 

 A fairly frequent wind is the north-west, which is a great contrast to the 

 south-west, which in summer it often precedes. It is a strong, gusty wind, 

 laden with rain before it reaches the Southern Alps, but hot and dry after 

 it has deposited the moisture on the mountains and sweeps across the 

 plains to the east coast. The north-wester blows with force against the 

 north side of the hills, and has a very drying effect. The average daily 

 maximum relative humidity for the month before 1877 was in July, with 

 83, and minimum in October, with 72. 



Some idea of the amount of sunshine may be obtained from the number 

 of days with rain. New Zealand sees more of the sun than does Great 

 Britain. For example, during 1902 there weie 1 ,492-2 hours of sunshine in 

 Surrey, one of the sunniest parts of England, and 1,749-59 hours in Christ- 

 church. The light outside the bush, affecting the foliage of the trees, is 

 more intense than that reaching the lower leaves of the trees, the shrubs, 

 and the herbs but in most places the light in the interior of the forest on 

 the hills is not very diffuse. 



Another factor important in a study of plant-ecology is the altitude of 

 the habitat. The average height of the hills, as stated above, would be 

 between 460 and 530 metres above sea-level. 



(b.) Edaphic. 



The soil varies considerably in physical and chemical character in differ- 

 ent parts. Where there are no rocks near the surface the soil is a light 

 loam for about half a metre or so, varying slightly as to depth, and below 

 this there is clay. In some paits the substratum is composed mostly of 

 small rocks with some soil between. This unevenness seems to serve a 

 good purpose, or animals are not so fond of entering the " bush " and 

 destroying the undergrowth ; so that where the substratum is rocky ferns 

 seem to be more abundant than in other p^ces where animals are not kept 

 out. Most of the species seem able to grow on or between the rocks about 

 as well as in the deep soil. The clay would increase the water-capacity of 

 the soil, which, since it forms a sloping surface, would be inclined to allow 

 the water to run away. 



* Cockayne, L. : " Plant Geography of the Waimakariri River Basin. 1 ' Trans. N.Z. 

 Jnst,, vol. 32, p. 95. 



