Size and age of plants impact their productivity more than climate

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in environment on (#3RE)
A study on plants using data from over 1000 forests has found that the size and age of the plant has more of an impact on their productivity than temperature and precipitation.
"A fundamental assumption of our models for understanding how climate influences the functioning of ecosystems is that temperature and precipitation directly influence how fast plants can take up and use carbon dioxide," said Enquist, a professor in the UA's Department of Ecology and Evolutionary Biology whose research lab led the study.

"Essentially, warm and wet environments are thought to allow plant metabolism to run fast, while cold and drier environments slow down metabolism and hence lower biomass production in ecosystems," he said. "This assumption makes sense, as we know from countless experiments that temperature and water control how fast plants can grow. However, when applied to a the scale of entire ecosystems, this assumption appears to not be correct."

To test the assumption on the scale of ecosystems, the team developed a new mathematical theory that assesses the relative importance of several hypothesized drivers of net primary productivity. That theory was then evaluated using a massive new dataset assembled from more than 1,000 different forest locations across the world.

The analysis revealed a new and general mathematical relationship that governs worldwide variation in terrestrial ecosystem net primary productivity. The team found that plant size and plant age control most of the variation in plant productivity, not temperature and precipitation as traditionally thought.
The abstract is available here.
Reply 4 comments

This is an interesting study, but... (Score: 2, Insightful)

by rocks@pipedot.org on 2014-07-22 15:20 (#2M7)

...while the basic conclusion is clear and presumably backed up by the analysis, the abstract leaves open the question of how climate indirectly influences the size and age of the plants... Perhaps this is/was beyond the scope of the given study.

Re: This is an interesting study, but... (Score: 1)

by zafiro17@pipedot.org on 2014-07-22 21:12 (#2MA)

Perhaps this is/was beyond the scope of the given study.
... and if so, it's yet another maddening example of a study only barely answering some questions while opening up so many other lines of inquiry that it fails to do much good at all, unless you consider "indefinite further research studies for interested scientists" a public good.

Re: This is an interesting study, but... (Score: 2, Insightful)

by rocks@pipedot.org on 2014-07-22 22:18 (#2MF)

well, I think it is an aspect of Cartesian philosphy that to know anything about one thing you have to know everything about its context (i.e., all of the boundary conditions). This idea strongly influences how our scientific culture tends to evaluate scientific results (since we owe a lot to Descartes). Basically, this idea makes incomplete results (almost always the case in science) "difficult to apply" to any practical decision making. In my opinion, it is one of the more subtle reasons why people can justify ignoring scientific results while claiming to respect the scientific method. As you say, this is all great for scientists who want to do more studies, but is pretty poor for students of life who want to know whether they should grow big plants or not :). I suggest we grow a lot of plants that grow large and see if we can effect the global contribution of primary productivity :).

Re: This is an interesting study, but... (Score: 2, Insightful)

by danieldvorkin@pipedot.org on 2014-07-24 03:32 (#2MQ)

unless you consider "indefinite further research studies for interested scientists" a public good
Considering that's pretty much how science has always worked, well, yes, it is. There will never come a time when science does not raise more questions than it answers, and given the results of that process so far, it's hard to see how it could be anything else.