After reading an extract from a book by Chris Yates, describing in detail the writer's great love for a river that he's fished in all his life, students were asked to write a detailed description about a different natural feature.  This is one of my favourites ( I especially love the phrase "yearning for affection from the sun" ):

The tree is majestic in size, towering above the clouds and overseeing the plain greenness  below; but to know its beginnings can be a humbling experience.  Its starts off as a helpless shoot, yawning, stretching and yearning for affection from the sun.  Steadily growing and enduring winter's strangling whips as it eagerly awaits spring's tender touch once again.  Over the years, it spreads out its foliage like a magnificent peacock, only to recoil at the start of every winter.  After many springs and winters, and with its roots grasped deep within the soil's richness, it finally reaches its maturity.  However, it continues to grow, wrinkles forming as rings deep in its aged heart, until finally it touches the clouds and wisdom fills its leaves.
Yet century after century its growth seems to diminish, and at the end, after seeing generation after generation grow alike, it sighs a breath of approval and returns back to mother nature, providing nutrients to newborns that will eventually repeat the never-ending process of the cycle of trees.