I need your help!

The National Science Foundation has asked me to write an abstract of one segment of my Ph.D. research.  In 350 words or less, I need to describe a project I'm working on back home, also using Douglas-fir, but with fungi from its native range.  Because the National Science Foundation is funded through our tax dollars, they -- and I -- want this abstract to be really readable.

Unfortunately, having buried my head in science for the past four years (and having been nose-deep in it for four years before that), I'm not the best at catching all my technical jargon.  Have a look at what I've written below, and let me know what you think.  What don't you understand?  What's missing?  What's unnecessary?

Thanks!

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Metabolic Bet Hedging as an Explanation for Maintenance of Diverse Tree-Ectomycorrhizal Mutualisms*

Trees are a critical part of many terrestrial ecosystems, providing both physical structure and chemical energy through the process of photosynthesis.  In order to conduct photosynthesis efficiently, many trees rely on mutually-beneficial interactions with below-ground fungi called mycorrhizae, which gather nutrients, supply water, and defend against pests in exchange for energy provided by the tree.  One group of these fungi, the ectomycorrhizae, is particularly diverse, having a large number of species, each with its own suite of metabolic abilities which determine its value as a trading partner to its host tree.

Intriguingly, an individual tree may host dozens of different species of ectomycorrhizae simultaneously, including species which appear to be of little to no benefit, or may even be harmful to the tree.  Presumably, rather than limiting its interactions to the subset of most useful fungi, the tree is incurring fitness costs by supporting a larger fungal community. Why hasn't natural selection produced a tree that can perfectly control its suite of fungal partners, so that it maintains only those that are most beneficial to it at any given time?

One possible explanation is metabolic bet hedging.  Trees are long-lived organisms that experience seasonal and interannual environmental variation. Therefore, their nutrient requirements also vary over time, potentially altering the relative value of each fungal partner. So, much as human investors maintain a portfolio of stocks to compensate for economic variation, trees may passively maintain a range of ectomycorrhizae in response to changing environments. 

This project tests the metabolic bet hedging hypothesis using laboratory (greenhouse experiments that control trees, fungi, and environmental conditions) and mathematical (economic models that test tree fitness as a function of fungal mutualisms) approaches. Results, in addition to their broader theoretical value to scientific understanding of mutualisms, will be of specific value to the management of Douglas-fir (the tree model used in this study), which is both a commercially important forestry species, and an aggressive invader in some foreign locales.


*Sorry, I can't do anything about the title.  Otherwise, I'd have tried to think of something more witty, like this week's ozone hole column, "All that's holey".