Processes within pasture and crop ecosystems: Structure of vegetation in relation to energy exchange

[First paragraphs...]
New Zealand has a proud ecological history. Particularly as far as our vegetation is concerned, ecology has gone through phases similar to those in most countries of the world. The pioneers described the general patterns of the communities and set in perspective the picture for the country as a whole. Then came more detailed description of particular situations, and the introduction of quantitative measurement techniques. The latter allowed standardised definition of what is present at a site and measurement of differences between sites. The result has been a generally satisfactory answer to the question of "what species are present and what trends are occurring"?
Next came the question of why certain species are present and why the trends are occurring. It is with the treatment of these questions of "why" that vegetation ecology, and probably many other branches of ecology as well, has become notable for its imaginative speculation and for the low quota of hard facts on which those speculations are based. Remembering Kelvin's dictum that an issue does not become science until you can measure it, we have here a reason for the relative decline in the status of plant ecology, within the scientific community within the last 30 years.