Best year ever for spring burns at Pleasant Valley Conservancy
We have been doing burns at PVC for 22 years and we burned
more acreage this year than ever.
We always have ambitious burn plans but conditions are not
always cooperative. This year things
just worked out, and we burned 131 acres of the 140 acre Conservancy. These
were all dormant-season burns. Because of the long period of degradation before
restoration began, we are always fighting the legacy of invasive woody plants,
and the best way to deal with them in our Conservancy is with fire.
The table and ArcMap summarize the burns.
Date of burn
2019
|
Habitat type(s)
burned
|
Acres
|
Crew size
|
March 21
|
South-facing slope; prairie and savanna
|
19
|
13
|
March 22
|
Restored prairies
|
11
|
12
|
March 26
|
Mainly savanna; Pocket Prairie; read narrative
|
39
|
12
|
March 27
|
Oak woodland & prairie
|
10
|
6
|
April 9
|
Wetland
|
25
|
10
|
April 19
|
North-facing oak woods
|
27
|
9
|
|
Total acreage
|
131
|
|
Not all the wetland acres burned, since there is standing
water in a number of areas. Also, the coverage in the North Woods was not 100%
either, but fire passed across >90% of the area.
The March 22 and 27 burns were fairly routine, involving mostly
planted prairies. The present post focuses on the March 26 burn, which was predominantly oak savannas. Although a large and complicated burn, we had a crew with lots of
savanna burn experience and everything went off quickly.
It is important to do lots of prep work for a savanna burn, especially
clearing around standing dead snags to eliminate lots of time-consuming mop-up
work. On a burn of this size, that takes most of a day. The work must be done
ahead of the burn, but not too many days ahead.
We have two types of savannas, and both were burned the same
day.
- Ridge-top savanna, predominantly bur oak with a significant hickory component. This is the top area, on the dolomite, and mostly on both sides of the gravel service road. It includes Unit 19 and Units 11A, B, and C.
- Basin savanna, predominantly white oak with some hickory. This is on the sandstone, and surrounds the Pocket Prairie. It includes Unit 11D, 12A and B, Unit 18 and Units 20 A-C.
And then there is the
Pocket Prairie. Although not savanna, the Pocket Prairie is always burned
at the same time the Basin Savanna is burned.
Ridge-top units 8 and 10 had already been burned during the March
21 burn and provided a solid black line uphill and downwind. Also, the Unit 7/Unit
18 boundary was secure because Unit 7 had been burned on March 21.
Running the burn Drip
torches moved east and south in Unit 11A from the anchor point along the two
roads. As soon as the starting area was solidly black, other drip torches moved
into the burn units for interior lighting. This is essential because a savanna
fire almost never backburns through a whole unit without “help”. The Unit 19
crew joined the main crew for extensive interior lighting of the Basin Savanna.
Two-way radios Each
crew member had a two-way radio, and it was vital that the burn boss and line
bosses monitor progress. Most crew were out of sight of each other. It is
especially important to monitor for potential head fires due to wind shifts or
changes in topography. As the map shows, there are several ATV trails that
follow the contours of the units, which interior lighters can use as
guidelines.
Mop-up There was
very little mop-up. After the burn, I drove one of the UTVs through the upper trail, which gave
a good view of both the ridge-top and basin savannas. There were no standing
smokers, and few smokers on the ground. The latter is not surprising,
since we have been burning these savannas annually for many years.
Pocket Prairie burn After
the basin savanna is completely black, the Pocket Prairie is usually burned as
a head fire. Given reasonable wind and R.H., it generally takes about 10-15 minutes
to burn. By this time, all of the crew are out of the savanna units (which are
totally black) and are watching from the road.
We started lighting at 9:57 AM and finished the Pocket
Prairie at 11:39 AM. So the whole burn took 1 hour and 42 minutes (102 minutes)
Amanda ran the burn. Here she is doing crew assignments |
Initial lighting |
The fire has reached the corner of Unit 12B. It is now off the Ridge |
Interior lighting just before the fire moves into the Basin Savanna |
Waiting for the final interior lighters to finish and leave the burn |
Watching the Pocket Prairie burn |