http://www.ucsusa.org/ |
Fire Ecology
Tuesday, June 7, 2016
Bark Beetles and Wildland Fire Behavior
With all the science surrounding bark beetles in western states, I have come to learn that bark beetles can cause serious mortality in western forest and some urban environments. All though bark beetles are a natural part of a functioning ecosystem, under undesirable conditions, bark beetles may actually come in conflict with land management objectives. Many interactions between bark beetles and fire suggest that these relationships are not good. Bark beetles can change the forest environment by influencing forest structure and transforming fuels. If beetles are linked to tree mortality, it's no secret that disturbed stands will likely burn threw hotter and faster. The magnitude of recent outbreaks and large wildfires has resulted in a flurry of research attempting to quantify bark beetle/fire/fuel/ interactions. Conventional science is pointing to the fact that large scale beetle outbreaks are altogether altering fuel complexes resulting in an increased potential for high-intensity, high-severity fires. Conversely, some scientist believe fire damaged trees may predispose western stands to initial bark beetle attacks in the first place. These phenomena together present land mangers with formidable challenges in regards to bark beetles, fuels, and future fire hazards.
Sunday, June 5, 2016
Invasive Medushead in Western States
http://www.sagegrouseinitiative.com/wp |
deseretnews.com |
It's no secret that extensive stands of pinyon juniper and sagebrusg steppe exist across the American West. In semiarid big sagebrush steppe and woodlands, medusahead acts as a fire promoter. Like other annual grasses, medusahead fills in between the native vegetation, creating a continuous fuel corridor that accelerates the fire cycle, posing a risk of fire during any season. Because of these the mean fire return interval on disturbed sites is greatly reduced.
http://bugwoodcloud.org/ |
It can be difficult to selectively remove an invasive grass such as medusahead from a grassland, steppe, or woodland community. For this reason, medusa is often burned during late spring at high temperatures when the seeds are still present on the plant to promote mortality.Following a burn, other control techniques such as grazing, revegetation, and preemergence herbicides are often used as appropriate land managment tools for medusahead in areas with high annual grass biomass production.
George MR (1992) Ecology and Management of Medusahead. Davis, CA: University of California Range Science Report 31:1-3
Hilken TO, Miller RF (1980) Medusahead (Taeniatherum asperum Nevski): A review and annotated bibliography. Oregon State University Agricultural Experiment Station Bulletin 644, Corvallis, Oregon, USA
Howell TJ (1903) A Flora of Northwest America. Self-published. Portland, Oregon.
Richardson DM, Pysek P, Rejmanek M, Barbour MG, Panetta FD, West CJ (2000) Naturalization and invasion of alien plants: concepts and definitions. Divers Distrib 6:93-107
Bark Beetles: What Role Do They Play In Fire Ecology?
After reading into bark beetles I see why they can be a big
factor on how detrimental fire is to an area. Bark beetles feed mostly on dead
or dying trees but have been known to eat living trees as well.
There are two main
reasons that bark beetles can increase risk and severity of fire. For one bark
beetle brake down timber leaving gabs that aerate the logs and make them dry
more quickly. This leaves tinder that can catch much more easily allowing crown
fires to destroy huge amounts of forest.
The second reason that they can lead to higher rates of fire
is they can feed off of and kill living tree. This also increases tinder for
fires to use as accelerant.
With climate change effecting forests everywhere and dry hot
weather increasing the risk of fire, bark beetles give one more risk to forest
in warmer climates.
https://www.google.com/search?q=bark+beetle+damage&espv
Saturday, June 4, 2016
Future of Grasslands
Global change defines how every abiotic and biotic factor along with ecological process's on our planet can or is changing, some of these changes may include increasing CO2 levels, wildlife and vegetation migration, transitioning of ecosystems into new alternate stable states and phases, and many more factors. Basically its how all of our planets systems can or are changing. I think global changes biggest affect on grasslands will be increasing temperatures or changes in the precipitation regime. Basically any type of change that is going to alter a site and possibly better support other vegetation. For example, say the precipitation regime changes and the grasslands are getting more rain than average, decreasing the fire frequency. The change in fire regime could allow woody encroachment or provide a habitat for non-native species, causing the ecosystem to start to shift to a tree, shrub, or non-native dominated ecosystem. Another impact on global change is that land managers cannot do anything about a changing temperature or precipitation regime, so the change would not be preventable in that case. Temp and precip are just two of the many examples that come with global change and its possible affects on grassland ecosystems. Feel free to comment down below if you guys think of other examples!
Bark Beetles and Wildfire
Bark beetles feed off of living trees.
Once the tree is infested, it dies,
leaving it dry and susceptible to fire. Bark beetles and trees have had
a symbiotic relationship in the past where the beetles would feed off a
few trees and those trees would release seed for regrowth. That
relationship is no longer the same as the climate is getting warmer, the
bark beetle have been spreading to higher elevations and attacking
trees that have not had a symbiotic relationship with them, leaving them
vulnerable.
In any case, once
the trees are dead, they become fuel for fire.
If the bark beetle just left the remnants (saw dust) on the forest
floor, the forest may be able to survive as the fuel would be just enough for a
low-severity ground fire.
However, the bark
beetle can kill a tree, and the tree will still be standing, getting drier as
it dies. If there were a fire with many
standing dead trees, these trees will ignite and cause high-severity crown
fires, killing the entire forest.
Managing Invasive Species with Fire
Non native spices can cause stressful conditions to native
species in an environment. There are many ways to remove invasive species from an
ecosystem. One technique that works well in some situations is prescribed burns.
This can be effective when native plants are resilient to fire and non native
are not.
Although fire management works well in some situations it is
not always the best way to rid invasive species depending on the fire regimes
you may have to continue to set prescribed burns every several years.
Other methods such as pulling non-native species and using
chemicals and herbicides work better in some ecosystems with invasive species
such as cheatgrass actually thrive after burns. In cases like this fire is not
a good option when it comes to ways of managing invasive species.
When using fire as a management against non-native and
invasive species it is important to make sure you know what effects fire will
have on the ecosystem it can be a very effective tool yet it also can cause
more problems then you had to begin with.
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