Bark Beetles

Bark beetles can affect wildfire fuels by adding decomposing or dead litter to the forest floor, potentially aiding in more fuels during a fire. However, there are debates whether or not bark beetles can actually influence the intensity of fires or not. Black et al. (2010) state that bark beetle outbreaks do not substantially increase the risk of crown fires in lodgepole pine or spruce forests under normal conditions. Instead, other conditions such as climate may act as more prominent factors. Interestingly, climate change is also the reason bark beetle outbreaks are becoming a serious concern (Black et al. 2010).



Source:
Black, S.H., D. Kulakowski, B.R. Noon, D.A. DellaSala. Do bark beetle outbreaks increase wildfire risks in the central U.S. Rocky Mountains? Implications from recent research. Natural Areas Journal 33(1):59-65.

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Prepare for attack of the bark beetle!!!

 www.readyforwildfire.org

In many areas where the bark beetle is prominent there are advertisements just like this one, that shows the dangers of bark beetles and wild fire. Bark beetles may seem like a completely different entity since they do not start fires obviously but they do provide an important part of fire in the fire triangle, and that is fuels. Bark beetles have the ability to kill large amounts of trees creating a large stock pile of fuels.Once ignited, this is where we end up with high intensity/severity f

Bark Beetle Outbreak

A bark beetle outbreak may change the stand characteristics and the accumulation of surface fuels. For example, the tree mortality caused by the outbreak will change the live to dead fuel ratio in an ecosystem. This increases the amount of dry fuel that is ready to burn in an area. Another factor is the loss of canopy cover. Dead trees lose their canopies, which create changes in microclimates such as relative humidity, temperature, wind exposure, and evaporation/evapotranspiration. All of these changes can lead to lower moisture contents in fuels and altered fire behavior.

(Image From: http://www.fs.fed.us/rmrs/projects/bark-beetles-natural-and-dramatic-forest-disturbance)

Fire and the Management of Invasive Species - Yellow Starthistle

Within the Deschutes National Forest (which is where I live), there are over 395 invasive plant species as of 2015. Yellow starthistle (Centaurea solstitialis) is one such invasive plant (FS 2015). It out-competes native vegetation, is unpalatable to livestock and wild life (within the US), and prefers the Mediterranean climate in which it grows world wide (ODA 2016). Luckily, yellow starthistle dies quite quickly as it is an annual weed. Generally it dies after it has reproduced, shortly after summer. What this means for fire managers is huge. They have discovered a way to combat this weed with fire. This thistles' seed only has a 3 year longevity, so if land/fire managers know the longevity of the seedbank for both the invasive thistle and whatever local native vegetation was there, they can ultimately eliminate the thistle with fire as long as the native plant that is being restored has a longer longevity than that of the thistle (Fire Science 2009). It is also beneficial that this plant dies right after summer, allowing for the risk of fire damage in the area greatly decreases as well (ODS 2016). 


                                                             Yellow Star Thistle

                                                             Photo Source: USU.edu



                                     Fire Fighters attacking Yellow Star Thistle in California

           Photo Source: http://www.blm.gov/ca/st/en/info/newsbytes/2009/389xtra_fire_v_weeds.html


Sources:

Fire Science. 2009. [Internet] Using Fire to Manage Invasive Species. [Cited 27 May 2016) Available at: https://www.firescience.gov/projects/briefs/06-S-01_FSBrief37.pdf

FS. 2015. [Internet] Invasive Plant Treatments. [Cited 27 May 2016] Available at: http://www.fs.usda.gov/detail/deschutes/landmanagement/planning/?cid=stelprdb5302243


ODA. 2016. [Internet] Early Detection and Rapid Response. [Cited 27 May 2016] Available at: http://www.oregon.gov/ODA/programs/Weeds/Pages/EDRR.aspx

Using Fire as an Invasive Killer

 Fire can effectively control invasive species if the invasive species lack fire adaptations or do well in undisturbed areas. Fire can remove unwanted invasive species and enable the establishment of natives with fire adaptations. Conditions where fire can be used are when there is an invasive species that is intolerant to fire in an area that is adapted to fire. In these areas fire is apart of the natural process and can reduce invasive species while promoting natural successional processes in the ecosystem. Also areas with high resilience can re-establish after fire and beat the invasive species to establishing in the area and out-compete the invasive species for space and resources.    

According to the forestry service website Houndstongue (Cynoglossum officinale) is an invasive plant species that can be introduced into areas that lack fire disturbance. In order to prevent disturbance, fire should be a maintained part of the selection processes. The website also states that post-fire conditions can create ideal habitat for the invasive species as well, which thrives in the current fire regime. They mentioned that the historic fire regime might be a better repellent of this invasive species. So it’s possible that restoring a historic fire regime can remove invasive species from an area. Houndstongue has a very wide distribution and across many different ecosystems such as chaparral, ponderosa pine, Douglas fir, and many more (for the full list check out the url at the bottom of this page). The species spreads through barbed seeds dispersed by animals and can travel well using this method. The plant also has low growing points and can survive a low intensity fire due to the nutrients in its taproots. I think the best fire management approach is going to be prevention. The best way to protect areas is to monitor them and keep native diversity high with prescribed burning when necessary.

(Houndstongue, retrived from: http://www.fs.fed.us/database/feis/plants/forb/cynoff/all.html)

Source: http://www.fs.fed.us/database/feis/plants/forb/cynoff/all.html

Invasive Species

Fire can be used to control some invasive species, but not all.  Fire is good for managing an ecosystem and helping to create the environment we are looking for, but sometimes this needs to be coupled with herbicides or pulling root systems.  

For instance, in the Willamette Valley of Oregon, we have an issue with scotch broom.  Scotch broom is a dark green bush with bright yellow flowers.

Although pretty to look at, it is considered an invasive species and will compete for water with other vegetation and destroy animal habitat.Once it has established itself in soil, the only way to get rid of it is to dig up its root system.  Burning it only encourages growth.  

 

However, controlled burning is not an entirely bad idea since it will burn them.  The seeds will reestablish, just as well as the other native seeds.  This is where range management comes in.    

Once scotch broom is recognized in its early stages, it is easier to pull out of the ground to get rid of it.  This will assist in eliminating the return of scotch broom and encourage regrowth of native grasses and other desirable vegetation.