The grammar of 'kangaroo flatulence research'

The Guardian recently ran the following marvellous headline:

Kangaroo  flatulence research points to new climate change strategy for farmers (The Guardian, 5 November 2015)

What is the grammatical structure of kangaroo flatulence research?

Here we have three nouns in sequence, and the whole string is a noun phrase. That much is clear. But how do the three nouns relate to each other, since they are obviously not in a random sequence?

The first question to ask is : what is the head of this noun phrase? One way to identify the head of a phrase is to check what the phrase as a whole is a 'kind of'. Because kangaroo flatulence research is a kind of research, we identify research  as the head.

What about the other two nouns? They are clearly dependent on the head, but not in the same way. The noun flatulence modifies the head research directly, and in turn this noun is modified by kangaroo. In fact, kangaroo flatulence is a noun phrase in its own right which modifies the head.  And we can go further: within the noun phrase kangaroo flatulence we can analyse kangaroo as another noun phrase. So in fact we have three noun phrases: the overall sequence and two modifying noun phrases, slotted into each other like Russian dolls. We can represent the structure of the overall NP as follows:

[_NP [_NP [_NP kangaroo] flatulence] research]

Bear in mind, though, that the UK National Curriculum does not recognise kangaroo on its own as a phrase, because in the NC a phrase is defined as follows:

A phrase is a group of words that are grammatically connected so that they stay together, and that expand a single word, called the Head. The phrase is a noun phrase if its Head is a noun, a preposition phrase if its Head is a preposition, and so on; but if the Head is a verb, the phrase is called a clause. Phrases can be made up of other phrases.

This means that the NC analysis of our phrase is as follows:

[_NP [_NP [_N kangaroo] flatulence] research]