Tuesday, January 29, 2013

Forest Fires versus Forest Restoration

At ESA this year, one discussion turned to the elephant in the room of forest restoration thinning projects: the certainty that thinning will have some deleterious effects versus the probability that a thinned area would actually encounter a forest fire during the approximately 25-year window of restoration effectiveness.  Forest restoration typically involves thinning forests to lower stand densities to discourage the spread of stand-replacement crown fires in historically low-intensity fire regimes.  Yet,  absent the return to presettlement semi-annual burn patterns (i.e. an end to the total suppression paradigm), tree seedlings will recruit and form high density stands within a couple decades.  

What are the odds that a given patch of forest will encounter a mega-fire over a 25-year time span?  According to some participants in the discussion, the odds are quite low.  But that may depend on the forest.  Take, for example, the fire-prone semi-arid mountains of the southwest:

Representative map of burned areas in SE Arizona and SW New Mexico over the last decade.  The Wallow Fire (538,000 acres in the White Mtns) and the Horseshoe Two (223,000 acres in the Chiricahua Mtns) fire, are visible as large yellow areas.

Shaded areas indicate official MTBS 2000-2009 burned area polygons.  Yellow areas are provisional "fire detection" areas from MODIS.  This map was generated using the U.S. Forest Change Assessment Viewer (FCAV), which can map a large number of forest disturbance types, utilizing historical to contemporary GIS layers and current satellite imagery.

Perhaps the ESA discussion participants should read:

Rhodes, J.J. and Baker, W.L., 2008. Fire probability, fuel treatment effectiveness and ecological
tradeoffs in western U.S. public forests. Open Forest Science Journal, 1: 1-7.

Monday, January 28, 2013

Current data shows biosphere carbon uptake holding steady

One of the biggest questions for ecosystem scientists is the degree to which terrestrial and marine ecosystems  can continue to sequester carbon in the face of continuing human emissions of CO2 and accompanying global climate change.
This is one of the best (i.e. easiest to interpret) graphs to show that the fraction of emitted CO2 remaining in the atmosphere (i.e. not sequestered) has held steady at around 50% for the last 40+ years (purple line, "Airborne Fraction").  Data Sources: Fossil fuel CO2 emissions - Land use CO2 emissions -  Airborne CO2 levels Graph by Willis Eschenbach.

Similar conclusions were reached by the National Oceanic and Atmospheric Administration’s Earth System Research Laboratory in Boulder, Colorado last year.

Wednesday, January 23, 2013

Best Map of Tucson and Mexico

Check out species lists and maps for flora and fauna.  Data portal is powered by Symbiota, which also has fungi and South American biota.

Wednesday, January 16, 2013

Piedmont Streams

Typical NC stream, fresh off the Piedmont, meandering through Triassic basin sediments.  These finer sediments build good point bars, and will hold a slope; geomorphologic indicators for bankfull, are not hard to find.  Relatively recent erosion is undercutting veg on the outside of the meanderbend.  The point bar is under-sized for the depth of the undercut, meaning that this is a gully.  The fine substrate can support tighter bends then if the substrate were sand.

Tuesday, January 08, 2013


from Regolith Geology and Regolith Geomorphology by Taylor and Eggleton:

Saprock indicates some color change, but no volume/texture/hardness, while saprolite retains original rock volume but is more "rotten" and may flake off easily (reduced strength).

Mottled zone is splotches of red and white showing variable iron movement.
Pallid zone may indicate leaching of iron.
Plasmic zone indicates accumulation of clay particles from the dissolution of feldspar and recrystalization of various clays.  Shrink/swell clay particles like may displace grains of quartz, causing accumulations.

Dark reduced zones around plant roots contrast with light oxidized zones along cracks and channels that communicate with above-ground atmosphere.

 In the French literature, saprock is the zone where the fabric of the parent rock is conserved, contrasted to the zone above where the fabric has been lost (pedolith).

Saturday, January 05, 2013

NC Stream Watch - New Hope Creek

NC Stream Watch volunteers take monthly samples along an elevational transect of New Hope Creek as it flows from Duke Forest slate belt down through Triassic basic sediments and bottomlands into the northernmost lobe of Jordan Reservoir 

Samples include wetted-width cross-sections to estimate total flow.

Water chemistry including Dissolved Oxygen, Total N and Total P.

Inspection of the macroinvertebrate fauna.  At Old Chapel Hill Rd and New Hope Creek, and at Erwin Road and New Hope Creek, we observed:

Female copepod
Snow Leopard leach
Dragonfly larva
& Asiatic Clam

Friday, January 04, 2013

Air Ions and Indoor Air Quality

     Having researched air ions before, I can attest that the subject is extremely technical and, worse, often prone to contradiction and obscurity depending on who is writing (and who is selling) various ideas.  It is another of those interdisciplinary areas with different and competing claims, in this case, from fields as divergent as air chemistry, ecology, and human health.  The following article, from Townsend Letters, does an admirable job of introducing most of the major competing health claims and sifting the evidence:

Static Electricity and Respiratory Infections
More times than not, shaking out a blanket on a cold night generates the crackle and sting of static electricity and a flurry of sparks. Synthetic materials, low humidity, and ungrounded electrical equipment are producing an unprecedented amount of electrostatic charge indoors, and these electrical fields may be contributing to increased risk of respiratory illness and other infections, according to a 2007 article in Atmospheric Environment. Indoors, most particles, including microbes and allergens, are so small (less than 1 microgram) that they could float in the air indefinitely; but electrical charges cause these miniscule particles to settle on surfaces and stick. These surfaces include skin and lungs. High electrostatic levels and increased deposition of airborne particles on skin have been linked to facial rashes, especially when humidity is low. Charged particles in the lungs increase the risk of infection and asthma. 

Keith S. Jamieson, H. M. ApSimon, and J. N. B. Bell advocate several ways to decrease indoor static electricity and the accompanying health effects. One recommendation is to reduce electrical charges by grounding laptop computers and other electrical equipment. They also recommend unplugging equipment when it's not in use. 

Another option is bipolar air ionization. (Long-term unipolar air ionization with negative ions has shortened lifespan of laboratory animals.) Air ionizers produce varying amounts of ozone, which damages the lungs, according to the EPA. Jamieson et al. urge people to use passive air ionization measures, such as grounding electrical equipment and choosing materials and furniture finishes that do not conduct electrical charges.

Another way to combat electrostatic is to use humidifiers. Indoor heating and cooling systems often reduce humidity levels. Low humidity encourages high electrostatic levels and decreases beneficial small air ion levels. (Small air ions kill microbes and reduce employee fatigue in the office workplace.) Humidifiers are often used to make breathing easier during respiratory infections; but humidifying indoor air, especially in winter months when furnaces are running, may prevent illness as well. 

Jamieson KS, ApSimon HM, Bell JNB. Electrostatics in the environment: how they may affect health and productivity. Electrostatics 2007 Journal of Physics: Conference Series. doi:10.1088/1742-6596/142/1/012052. Available athttp://iopscience.iop.org/1742-6596/142/1/012052. Accessed September 18, 2012.
Jamieson KS, ApSimon HM, Jamieson SS, Bell JNB, Yost MG. The effects of electric fields on charged molecules and particles in individual microenvironments [abstract]. Atmosph Environ. August 2007;41(25):5224–5235. Available at www.sciencedirect.com. Accessed April 27, 2011.
Reeves D. Electrical fields from everyday equipment and materials could increase infection risk [press release]. Imperial College London. July 20, 2007. Available atwww3.imperial.ac.uk. Accessed September 18, 2012.