This is a public-interest archive. Personal data is pseudonymized and retained under GDPR Article 89.

Re: Gallery Forests vs. Savanna

It is quite possible that you are looking at a gallery savanna, 
especially if your site is on the west side of the stream, from which 
the prevailing winds come. It was often the case in the past that the 
west bank of a prairie stream would have scattered or open timber, 
while the more protected east bank would have a more fully developed 
forest, by virtue of fires stopping at the stream and not burning the 
vegetation on the east bank as often.

The difference between forest and savanna is structural. In the 
spectrum of openness from treeless grassland to closed-canopy 
multilayered forest, savannas fit in the middle. There are 
differences in details among authorities, but savannas have two 
charactereistics that everyone agrees on -- 1) the tree canopy 
layer is partly open, with the spaces between the trees letting in 
sufficient light to permit growth of some prairie plants, and 2) the 
vegetation is two-layered (canopy trees and ground-layer herbs, 
understory tree and shrub layer poorly or not at all developed). 

Trees in savannas generally grow far enough apart that many of them 
have broad, "open-grown" crowns of lateral limbs, which may be wider 
than the height of the tree. Forest trees are taller than they are 
wide, and have few braches on the lower half of the trunk. In 
degraded savannas, one can find obviously older, well-spaced,  
open-grown trees (typically members of the white oak group) in much 
more tightly-spaced forests of numerous, clearly younger trees 
(typically including many non-oaks).

James C. Trager
Shaw Arboretum
P.O. Box 38
Gray Summit MO 63039
PH# 314-451-3512
FAX 314-451-5583
---------------------------------------------------------------------
To sign-off this list, send email to majordomo@mallorn.com with the
message text UNSUBSCRIBE PRAIRIE
Other Mailing lists | Author Index | Date Index | Subject Index | Thread Index