Countable or Uncountable?

[kyobancha]

I believe you are familiar with the following poem by Robert Louis Stevenson.

Rain

The rain is raining all around,
It falls on field and tree,
It rains on the umbrellas here,
And on the ships at sea.

This is one of my favorite poems and I have read it over and over again. Yet I have always had a question about the usage. Why isn't the second line like:

It falls on the field and the trees,

Both "field" and "tree" are countable nouns, yet "field" is used without "a" or "the", and "tree" is not pluralized.

Even if we say "It falls on the field and the trees," it seems to me that it won't damage the rhythm of the poem.

I hope you can help me with this. Thank you.

[Alan]

This is an example of what is known as 'poetic licence', whereby normal grammatical rules are suspended for the sake of the poetical meter.

Normally, you are quite right: both 'field' and 'tree' are indeed countable nouns, and, as such, must be prefixed by a determiner when used in the singular.