These trees create a continuous deep shade at ground level which inhibits the growth of shrubs and herbs. The needleleaf forest is associated with the boreal forest climate and the high elevations of mountainous areas. The schlerophyll forest develops in the Mediterranean climate. The trees have adapted to the dry, hot summers by producing small, hard, thick leaves that minimize water loss. The Savanna Biome is a product of the tropical wet-dry climate.
Vegetation changes from woodland to thorntree grassland with increasing dryness.
The adaptation to dryness includes deciduous habit and small leaves or thorns. The Grassland Biome is found in the midlatitude and subtropical zones which have well developed winter and summer seasons. The biome includes both tall-grass prairie and steppe. Steppe vegetation grows in the semi-arid subtype of the dry continental climate. The desert biome includes both desert and semi-desert subtypes.