Friday, July 26, 2013

Missouri Oaks in Minnesota

Mighty Missouri oaks growing in Minnesota- Matt Kaproth
Missouri oaks are growing in a lab in Minnesota in a study of Relative Growth Rate and drought tolerance between species.  We described the collection process in last fall's blog so I won't repeat all the science behind it here, but will quote from that blog to explain the why of the study.
"We can look into which oak species withstand stresses better than others. With the recent droughts (and more predicted to come), we can identify which lineages have drought-tolerance, which can pass on this trait, and which species stand a better chance to survive with changing climates. You can’t get anything for free in nature though, and it’s hypothesized that lineages that can handle water stress have slower growth rates. Identifying this trade-off will let researchers predict species range limits and guide managers about how to care for their oaks."
The research is headed by our friend Dr Matt Kaproth.  Matt is a PhD in botany.  In the description by the child of a friend with a PhD, "Dad is a doctor, but not the kind that helps people."  He sent me some pictures of his research as well as more information on the process.

Forest under development- Matt Kaproth
In Matt's own words:
"I ended up planting over 5,000 acorns of 41 species. They've been growing on the Saint Paul campus of UMN for 5 months and I have currently transplanted 1000 plants.  I'm setting up irrigation supplies to start changing the watering treatments for the big plants soon - watering to saturation every other day, every other week and monthly. We'll see which species can handle drought and which fizzle out. We think there is a tradeoff between Relative Growth Rate (RGR) and drought tolerance, meaning that a plant that can handle drought has a lower RGR, thus there's a cost to being able to withstand drought - you put on less weight than ones that can not (but you stay alive)."
While the methodology of measuring the RGR is complex, the concept is understandable to us simple naturalists.  The RGR quantifies the speed of plant growth.  It is the mass increase per above ground biomass per day.  Over time as the plant grows, the RGR usually decreases as the plant biomass increases.  This is probably because as the biomass (roots and stems) increase, the top leaves start to shade the lower leaves, limiting photosynthesis while the plant's respiration (yes they "breathe") continues at a rate proportional to the biomass.  Also, with time, the soil nutrients can start to be depleted.

Matt's study may eventually contribute to our knowledge of which trees are best to survive our changing climate and still grow larger to help suck the increasing CO2 from our atmosphere.   Maybe he is the kind of doctor that helps people after all.

Coming soon to the blog.  
What is it?

1 comment:

  1. Looks great Bob! Thanks for posting this!

    We just had a conference call between all the investigators on the NSF grant... We may need more acorns again this winter! I'll be in touch...