From Little Acorns

Why would an otherwise normal senior citizens like us spend hours collecting acorns from oak trees?  As food on a fixed income?  Actually, it is part of a research project described fully below.

It was also quite educational for me.  To reach fresh acorns before they were on the ground and potentially moldy, we had to toss a rope over branches and pull them down within reach.  I learned to look carefully first as I pulled one down and found it was supporting a large partially broken limb above which came crashing down.  It took me to the ground but the limb absorbed the momentum so I only had a few scratches.  I guess that is what is meant by the phrase "life and limb."

Leaf Press

We needed to send a branch of the leaves from each tree that we collected from.  The leaves need to be kept in a leaf press until they are dried and flattened.  Our home leaf press was quite sophisticated while the one we used at the creek was electrical, consisting of two books weighted down by a 12 volt automotive jumper battery.

I will let our friend Matt Kaproth describe below his PhD research project.

Acorn Study Harvest

Starting this winter, a team of plant ecologists at the University of Minnesota and the National University of Mexico are starting experimental common gardens to test drought tolerance in oaks. The researchers asked for collections from across the continent. Half the acorns will be cleaned and sent to Morelia, Mexico to be grown outdoors while the other half will be grown under different watering treatments in a greenhouse in St. Paul, MN.

Why you ask?  Oaks, (Quercus species) are critical components to our forests. They have the highest species richness and biomass across the US and Mexico (see the figure), but for years researchers avoided studies involving different oak species because they hybridize frequently and it was hard to find a “true” species. Recent molecular work now lets us identify species compositions, which will let us dig into pressing evolutionary and ancestral questions.

For example, 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.