The bracing weather of Canadian winters is followed by the warmth and humidity of genial summers, under which crops grow in almost tropical luxuriance, while the cool evenings and nights give the plants a robustness of quality which are not to be found in tropical regions, and also make life for the various domestic animals wholesome and comfortable.
This arrangement is adopted in order to prevent excessive luxuriance in the grass.
(6) The tropical forest, which represents the maximum of plant luxuriance, stimulated by the heaviest rainfall, greatest heat and strongest light.
The relative luxuriance of the vegetation on the upper part of the mountain, compared with that of its lower slopes, is due not only to the rainfall, but to the large additional moisture condensed from clouds.
The Samoan forests are remarkable for the size and variety of their trees, and the luxuriance and beauty of tree-ferns, creepers and parasites.