Monthly Archives: July 2013
By far the biggest burns we participated in this past year were a pair carried out on the Massachusetts Military Reservation (MMR). Over two full days the prescribed burns on the MMR covered~330 acres. Both days we had highly active fire behavior, culminating with flame lengths somewhere around 100 feet high and a smoke column that (apparently) was visible from across the bay in Provincetown (35-40 miles). A few days ago I posted pictures from Day 1 of these burns, today is Day 2’s turn.
Again, during the second day our primary job was to hold one of the flanks of the burn. Unlike the first Rx at MMR however, this time we were tasked with keeping our flank burning in lockstep with the far side. Another team was on the true internal ignitions, but we still got plenty of torch time over the course of the day.
The second day’s total hovered somewhere around 230 acres, finishing in a spectacular 100+ foot display that was burning deep inside the unit. We had an easy time on our flank, in part because the vegetation was quite forgiving — A mix of tightly packed dog-hair pitch pines and fuel heavy (but otherwise clear) forest floor. The picture below is a good example of one of the “roughest” areas we were responsible for, the tightly packed pines in the lower portion of the picture acted like ladders, which allowed the flames to reach the upper reaches of their neighbors easily.
There wasn’t much we could realistically do to prevent those trees from torching, instead we mitigated the hazard (of having a tree torch on the perimeter) by having an engine on scene and ready to dowse spots. In large part because of the wind direction that day (note the direction of the flames in the picture below) spotting wasn’t nearly as much of a worry on our flank as it was the first day.
Like the first burn at MMR we participated in, the prescription for this day allowed for full-stand replacement. We kept the pace of the advancing flame front moving slowly in an effort to keep things “cool,” but some torching still occurred. Again, this really wasn’t a concern, just something for us to be aware of all day.
That just about covers the two MMR burns, unfortunately it was around this time that the camera on my phone decided it had had enough life and quit on me. I’m still hoping (somewhat unrealistically) that I can save the pictures I’d already taken, but I haven’t actually “tried” to extricate them from the apparently broken SD card yet. I’ll figure that out “eventually.” Probably.
Next I’ll be covering our year-end (ish) trip to Baker Island in Acadia National Park.
By far the biggest burns we participated in this past year were a pair carried out on the Massachusetts Military Reservation (MMR). A base that now goes by at least three names depending on who you talk to about it. Over two full days the prescribed burns on the MMR burned ~330 acres, both days we had highly active fire behavior, culminating with flame lengths somewhere around 100 feet high and a smoke column that (apparently) was visible from across the bay in Provincetown (35-40 miles). This entry is going to focus on the first of the two Rx Burns.
During the first of the two burns we were primarily a holding group, our job was to watch one flank of the burn unit and ensure that burning embers in the smoke didn’t light spot fires outside of the unit. What we were able to do if and when those embers did cross the line depended heavily on what the fuel type behind us consisted of. When we had our backs to a large grassy field, we were generally able to stomp out the fires before they grew much larger than a campfire. When we had thick brush or trees to our backs we instead called out for help and focused on staying out of the way of the brush-breakers as they barreled through the underbrush to put out the spot.
Luckily for us, the smoke was mostly heading in the other direction, which meant that for a large portion of the day we really didn’t have much to do except watch the fire work its way through the burn unit.
Fire behavior on the first burn was largely mild to moderate. There were a few instances of multi-tree torching, but complete stand replacement (when all of the trees in a clump burn and die in the same event) was within the bounds of the burn’s prescription. There are decent ecological reasons for allowing stand replacement, and since this burn was at least partially “for the bunnies,” the burn bosses were happy to let stands that were well within the perimeter ignite.
This first burn covered around 100 acres, a bit over half of what we’d hoped to do that day, shifting winds and caution kept us from hitting our mark. Day two, which occurred a few weeks later, would more than make up for the day’s potential shortfalls, though. I’ll get to that story next.
More pictures. This set comes from our first “larger” prescribed burn, carried out at Pilgrim Heights in Truro.
We were blessed with good, consistent weather all Spring. It was cool and dry, and over the course of the last few months we managed to get in over thirty (30) days of prescribed burning. I’m not exactly sure, but I think that the actual number is getting close to forty at this point.
Much like the pile burning over the winter, the mechanics of broadcast burning quickly became business as usual. Our standard operating procedure relied heavily on setting up looping hose-lays around the burn area before even lighting a test fire. While this strategy takes a little while to set up, it also greatly increases the safety of the whole operation. And in the long run I’m sure it made our lives a great deal easier.
To set up those crucial loops we used inch-and-a-half hose as our trunk line and every 100 feet we split off a 50 foot length of 3/4 inch hose. Optimally, that meant that we had complete coverage of the burn perimeter. In actual practice that wasn’t always true, but adding more 3/4 inch hose to the end of existing lines was a trivial fix to a generally non-pressing problem.
After the hose lay was in place we’d light a test fire and hold a briefing while watching it burn. Running the test fire simultaneously with the briefing is (apparently) somewhat atypical, but it did give us the advantage of being able to directly observe what the fire-behavior was likely to be before we began proper ignitions. It also sped up the day by getting two crucial steps in the burn process over with at once.
Test fire completed we’d go about the actual burn — using drip torches to lay down lines of fire, then using the 3/4 inch hose to extinguish one “edge” of the thickening line. The other edge was allowed to (hopefully slowly) burn across the unit until until it hit another line of fire coming from the other direction and went out from lack of fuel to burn.
Once there was no more active flame in the unit we’d use the hose ringing the area to soak everything still smoking, spending extra time making sure that rotting logs and other areas where embers could be smoldering were well and truly saturated.
After the last smoking embers were drowned we’d break up the hose-lay, roll everything up, pull our warning signs off the sides of the road, and head home.
Almost every prescribed fire we lit all year followed that same basic formula. Therefore, I’m going to just skip describing most of them and move on to posting the pictures and talking about the few times when things were — for one reason or another — different.
For instance, all of the pictures in this update were taken at a burn we carried out at an old Boy-Scout camp. The Boy Scouts sold the campsites to the Cape Cod National Seashore a few years back and our burn was step two in preparing the site to be used as a special group campground in the future. We also spent the better part of a day dismantling most of the old camp’s decrepit structures.
This burn was a little bit different since there were already defined paths all around the burn unit. Those paths were free of fuel (needles and brush in this case) and provided a secure enough fire-line that we didn’t need to surround the burn area with a hose lay. Instead we carried in 5-gallon backpack pumps and used them to discourage the flames from crossing the paths.