Wednesday, April 8, 2015

Two more major burns done!

Due to Amanda's initiative and the skilled help of Integrated Restorations, Monday 6 Apr 2015 we managed to carry out two more major and complicated burns.


At Pleasant Valley Conservancy (PVC) we burned 10 acres of oak woods, 3 acres of Hill's oak savanna, and 5 acres of prairie. The woods are on a north-facing hill just downhill from the prairie (see air photo/map). Most of this woods had never been burned, and was the last piece of unburned property at PVC. This woods, which we call Unit 17, consists of a ridge between two shallow gullies. According to our tree database, the principal trees are species of oak: black oak, 93 (20 over 20" in diameter); red oak, 77 (3>20"); and white oak 164 (19>20"). Also 63 cherry plus scattered trees of other species. This woods is shady enough so that invasive species such as buckthorn have never become established and has never been logged.

The woods to the east of Toby's Prairie, which we call Unit 13, consists mostly of white oak with a small area of Hill's oak, all mostly less than 80 years old. This area had probably been logged because at the time of the 1937 air photo it was mostly open land, except for one large open-grown white oak. 

A fire break had been blown around the periphery of the woods. The fuel in both of these wooded areas is almost exclusively oak leaves. Because of the relatively dry conditions, the fire carried fairly well. 

Toby's Prairie has been burned annually since it was planted in 1998 and always burns well.

Area of  the Monday burn at Pleasant Valley Conservancy.
This is at the far eastern end of the Preserve.
We had a short lunch after completing this burn and then moved on to Black Earth Rettenmund Prairie, about 3 miles away. As the map below shows, we did two separate burns, leaving the Saddle area unburned. The fire breaks separating the burn units from the Saddle were wide tractor-mowed strips. Because of the strange boundaries of the South Unit, this unit is burned together with the adjacent Pasture, which is not part of the Preserve. The whole Preserve is surrounded by crop fields, all of which had been harvested so that there was no danger of spot fires. The wind was out of the east and northeast and was fairly light, thus reducing the danger of spot fires. Lots of wetlining was done with the pumper unit on our Kawasaki Mule, so that the boundaries of the burn units could be well maintained.


Burn plan for Black Earth Rettenmund Prairie State Natural Area; spring 2015
View of the entrance area and the North Unit just after the burn

Note regarding the Pasture

In the early years a few cows were pastured in this field, but by the time Kathie and I started managing this area it had been fallow for about 10 years. The vegetation then consisted of non-native grasses and sweet clover. We received permission to burn this field together with the South Unit, and this has been done now for at least 12 years. About three years after this Pasture was first burned, little bluestem became established on the east-facing slope, and has remained dominant since then. Later, other prairie plants started to move in, especially butterfly milkweed, which is prominent in the Saddle area. Recently, a wood lily became established and has flowered. 

This Pasture provides a good example of what can happen in a highly degraded remnant just from frequent burning.

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