Photo of the Week – November 5, 2015

As I was looking at some of my recent photos from our Niobrara Valley Preserve, I realized that I have a series of photos from approximately the same vantage point that illustrates the site’s recovery from the major wildfire back in 2012.  If you’ve followed this blog for several years, you’re probably aware that we have a significant timelapse project going on at the Niobrara Valley Preserve that is documenting that recovery as well.  Those images will provide a very comprehensive look at change over time, but those cameras weren’t installed until after the fire.  The three photos below are interesting because they represent shots taken before, immediately after the fire, and a few years later.

October 1, 2011

October 1, 2011

The above photo was taken in the fall before the big 2012 wildfire.  The big pine tree on the right is a good landmark to watch as you compare this photo to the next two.  The following photo was taken just a few days after the wildfire.

July 25, 2012

July 25, 2012

The last photo (below) was taken just a few weeks ago.  The grass and other vegetation has clearly recovered nicely from the fire.  That’s not really a surprise to any of us who are familiar with grassland fires.  Even a very hot summer fire in the midst of severe drought is not typically fatal to most prairie plants.  In fact, the drought was harder on prairie plants than the fire was, but even so, those plant species are well adapted to both.

TNC Niobrara Valley Preserve, Nebraska.

October 23, 2015

More interesting than the recovery of grasses and wildflowers is the recovery of woody plants.  The two small pine trees on the left side of the image look happy and healthy, despite the fact that young ponderosa pines tend to be vulnerable to fire.  If you look closely at the image taken immediately after the fire, you can see both of those trees.  The one on the right, especially, had the majority of its needles burned by the fire, but both appear to have come out of that stressful period just fine.  Why were those two trees able to survive (along with the big tree) here when just across the river, almost every single pine on the south-facing slope died?  Most likely, there are multiple reasons, including slope, fire intensity, and the fact that these trees were surrounded mostly by grasses instead of lots of other pine trees (and eastern red cedars).  The point of showing these photos isn’t to answer these kinds of questions as much as it is to stimulate them.

It’s also interesting to note that most of the oaks and other big deciduous trees seem to have survived.  That is the case across most of the Preserve, although many of the bur oak trees that were growing close to pine and eastern red cedar trees were top-killed by the fire and are now regrowing from the base.  A few oaks and other deciduous trees (especially cottonwoods) did die from the fire, but most didn’t.

I’m hoping to put together some timelapse sequences this winter that will help tell the story of recovery from multiple locations across the Preserve.  For the most part, those stories will show that the natural communities along the Niobrara River are well-adapted to major disturbances such as the drought and fire that occurred in 2012.  The big exception is the pine woodland that was nearly completely wiped out across big swaths of the landscape. The density of pine and cedar trees led to fire intensity that caused 100% mortality in many stands, and while those areas will recover, they will be grassland and/or shrubland for a very long time, and their long-range future as pine woodlands is far from assured.

Aside from those pine woodlands, however, the natural communities across the Preserve did what natural communities usually do in response to fire, drought, and other major events – they continued to thrive.

A Day in the Bluffs

We spent a long day at our Rulo Bluffs property last week.  The site is at the very southeast corner of Nebraska, and includes about 450 acres of mostly oak/hickory woodland with prairie and savanna habitat on steep ridge tops.  I’ve written before about our work to burn and thin the woodlands to open up the understory layer as a way to encourage higher plant diversity and better wildlife habitat.  Last week, Nelson, our land manager, spent the entire day in a rubber-tracked skidsteer, shredding brush along ridges because we didn’t manage to get a fire  done last fall or this spring.  I got a few overhead photos of his work with our drone.

Nelso Winkel shredding brush with a skidsteer at The Nature Conservancy's Rulo Bluffs Preserve, Nebraska.  Using fire, thinning, and shredding, we are trying to allow more light to hit the ground in the woodland, which enhances oak tree regeneration, increases plant diversity, and improves habitat quality for many wildlife species.

Nelso Winkel shredding brush with a skidsteer at The Nature Conservancy’s Rulo Bluffs Preserve, Nebraska. Using fire, thinning, and shredding, we are trying to allow more light to hit the ground in the woodland, which enhances oak tree regeneration, increases plant diversity, and improves habitat quality for many wildlife species.

This photo shows a ridge where we've been working for more at least 15 years to beat back brush with fire and mechanical treatments.  Nelson didn't have to shred this area this year because the brush is finally starting to give way to more herbaceous plants.

This photo shows a ridge where we’ve been working for more at least 15 years to beat back brush with fire and mechanical treatments. Nelson didn’t have to shred this area this year because the brush is finally starting to give way to more herbaceous plants.

The second image above, taken with our drone, was interesting because it and others from the day showed a surprising number of large dead trees scattered across the property.  We knew we were reducing the number of smaller diameter trees with our thinning and fire work, and that a few bigger trees were also dying, but couldn’t see the real scope of that without being in the air.  (Couldn’t see the forest for the trees…)  While we’re not trying to kill off a large number of big trees, losing some provides space for new oak trees to get started, and provides a number of other benefits – including habitat for the many species that live in standing dead timber.  So, it wasn’t a shock or disappointment to see all the dead trees, it was just an interesting observation we couldn’t have gotten without the ability to get eyes up in the air.

My main job last week was to be on site in case Nelson ran into trouble with the skidsteer.  (That makes it sound like I was there to help fix the skidsteer – nothing could be further from the truth.  Nelson has more mechanical ability in his little finger than I could dream of.  I was just there to go for help in case he rolled the thing down the hill or something.)  While he was doing the real work, I tried to stay productive by pulling garlic mustard, scouting for invasive honeysuckle, and killing small trees with herbicide.  I also managed to find a little time for some photography.  Here are a few of the photos I took.

This is

This is starting to look more like what we want the site to be.  A strong herbaceous (non-woody) plant community, including sedges, grasses, and wildflowers, supports better wildlife diversity and also helps facilitate fire to maintain that open woodland character.

 

These paw paw trees were top-killed in our 2014 prescribed fire. they are regrowing from the base, but aren’t yet tall enough to suppress growth of other plants beneath them.

 

A small bur oak is fighting to establish itself on a prairie ridge as older oaks near the end of their lives.  Both in the woodland and savanna portions of the site, this replacement process is critically important.

A small bur oak is fighting to establish itself on a prairie ridge as older oaks near the end of their lives. Both in the woodland and savanna portions of the site, this replacement process is critically important.

 

These beautiful metallic-looking flies were pretty abundant the day were at the site.  I saw several in the clutches of spiders, but didn't manage to photograph any of those.

These beautiful metallic-looking flies were pretty abundant the day were at the site. I saw several in the clutches of spiders, but didn’t manage to photograph any of those.

A close-up photo of bur oak leaves.

A close-up photo of bur oak leaves.

I'm not sure what species of bug (and it is a true bug) this nymph is, but it sure was striking against the green leaves it was feeding on.  I watched it repeatedly stick its long proboscis into this leaf as it moved across it.

I’m not sure what species of bug (and it is a true bug) this nymph is, but it sure was striking against the green leaves it was feeding on. I watched it repeatedly stick its long proboscis into this leaf as it moved across it.

Eastern redbud (Cercis canadensis) is a beautiful tree.  Both its pink flower and leaves are very attractive.  However, it is also one of the species we are trying to reduce the density of in the understory of the Rulo Bluffs woodland.

Eastern redbud (Cercis canadensis) is a beautiful tree. Both its pink flower and leaves are very attractive. However, it is also one of the species we are trying to reduce the density of in the understory of the Rulo Bluffs woodland.

This beautiful little brown snake was about 10 inches long.  I spotted it  as it was making its way through one of the areas Nelson had just shredded.

This beautiful little brown snake was about 10 inches long. I spotted it as it was making its way through one of the areas Nelson had just shredded.

There are a couple species of raspberries, or close relatives, at Rulo Bluffs, but I don't know what species they are.  This one was particularly beautiful the day we were there.

There are a couple species of raspberries, or close relatives, at Rulo Bluffs, but I don’t know what species they are. This one was particularly beautiful the day we were there.

Because of its long distance from our shop and field headquarters, we never feel like we spend enough time working at Rulo Bluffs.  It’s a beautiful site, and one of the best examples of oak woodland remaining in Nebraska.  As with other oak/hickory woodlands, however, it requires active management in order to survive and regenerate.  Without frequent fire, or substitutes such as thinning and shredding, the understory at Rulo Bluffs would become choked with small trees and shrubs, such as ironwood, dogwood, paw paw, and others.  Those woody understory species block light from hitting the ground, prevent the establishment of new oaks, and choke out most grasses, sedges, and wildflowers.  Eventually, if older oaks die without being replaced, these woodlands change into new communities, dominated by trees such as ash, hackberry, and others that don’t create leaf litter that can carry fire.  At that point, restoring the oak/hickory woodland community, which supports a much larger diversity of plant and animal life, is nearly impossible.

…and that is why we keep trying to find time to head down to Rulo Bluffs.  That, and it’s such a beautiful place.