Thursday, January 20, 2011

How Range Maps Get Drawn

** Updated proof read version, this time in actual English for your reading pleasure **

I'm feeling vindicated and gypped at the same time.

Every range map I have seen for chinkapin oak (Q. muhlenbergii Engelm.) shows it just barely reaching into the southeastern corner of Minnesota.  From time to time I have joked that we have six native oaks in Minnesota (white, swamp white, bur, red, black and northern pin), seven if you count "those two chinkapins growing in Houston County."

I didn't realize how correct I was!

I was reading Welby R. Smith's amazing and gorgeous Tree and Shrubs of Minnesota (guess which section I went to first - my two favorite words both start with Q, Quercus and quixotic).  Under 'Natural History' for chinkapin oak:

Native chinkapin oak has been found only once in Minnesota.  The discovery was made by the early botanist W. A. Wheeler on July 15, 1899, in Section 19, Crooked Creek Township, Houston County.  Wheeler described two small trees in some detail:  one was 9ft (2.8m) tall, the other 10ft (3.1m) tall.  He documented the discovery with authenticated herbarium samples.

The site is on a dry southwest-facing hillside at an elevation of 850ft... At the time of the discovery the habitat was apparently open and prairie like... The site has since grown into a substantial forest, a common fate for savannas deprived of wildfire.  It is now dominated by several species of oak (only chinkapin is missing)...

No one knows for sure what happened to the chinkapin oaks, but they have not been seen since the original discovery.  Some say they were cut for fence posts or trampled by cattle, but more likely they were overgrown or crowded out when the habitat succeeded from savanna to forest.

In the general description under fruit (acorn) it says: "Maturing August-September of the first year (dates imperfectly known for Minnesota)."

Imperfectly known?  I should say so, considering the entire documented presence of chinkapin oak in Minnesota consists of two small trees which were probably too young to bear acorns and haven't been seen since July of 1899.

I feel vindicated in that my little joke was more accurate than I ever could have thought; not only are there officially two chinkapin oaks in Minnesota, those two chinkapins no longer exist.  But they seem to have earned Minnesota a permanent spot on the range map for chinkapin oak.

I feel gypped because despite my joke about 2 trees I always assumed there was a least a viable small population of chinkapin oaks in SE Minnesota to justify the shading of the range maps, and that someday on a hike or bike ride in Houston County (which is a beautiful area by the way - Mississippi River bluff country) I would see some.  The cool thing now is that if I do it will be big botanical news - first sighting in more than a century - and I'll probably get a mention in the next edition of Smith's book!

1 comment:

  1. "The site has since grown into a substantial forest, a common fate for savannas deprived of wildfire."

    The oak savanna restoration community would probably want that to read "frequent low intensity burning" rather than wildfire.

    They would give him credit, though, for understanding the role of fire in maintaining "the open parklike" landscape noted by all the early explorers.

    I hope you do find those Chinkapin Oaks, Chris, and in a completely place. Then you could be the reason for the entry in the next 100 years of guidebooks, accurate or not.