Time management difficulties

Classes and a full time job have made it hard to keep this blog updated. I'll hopefully add more current postings soon!

Fires on the Front Range

Lots of coverage of the fires in Colorado in local media, with one really big fire above Golden, and a few down on the Arkansas Valley. Last night on my way to work, there was a lot of smoke from a small fire on the Air Force Academy. That one was put out in a few hours.

Conditions have been good for fires in the lower elevations in Colorado. The wind has been pretty strong along the Front Range and the temperatures warm. We haven't had much precipitation lately to boot. No surprise we're seeing a lot of fires.

I made a quick map to show some of the fire activity for this year. I added a layer to show drought conditions to see if they are making fire conditions worse.

The drought data is current to March 15 and the fire data is current to this morning. The fire data comes from satellites and remote sensing processing at RSAC. The satellite made a pass over Colorado just before 6 yesterday and around 10 this morning, the 22nd.

(click to enlarge)

The fire near Golden is the only one of these displayed that seems to be larger than 300 acres (still looking for the data on size). It is the only fire to show up on the Forest Service's large fire incident map,and it blew up last night to more than 1200 acres, according to the Denver Post.

As expected, most of the fires are in the driest areas of the region. What surprised me is that most of the fires are along the river corridors. My hunch is that these fires might be caused by farmers burning their fields. I thought it was more common to do this in the fall, but something is going on, especially along the Arkansas, but also along the South Platte, Gunnison and San Juan rivers.

I've been wondering about the seasonality of the fire regime where the shortgrass prairie meets Gambel oak and Ponderosa pine along the mountain front. Most of the research on fire regimes has been done, for obvious reasons, on higher elevation, forested areas. Big forest fires often happen in Colorado during the summer and early fall after the snow melts. Most of the fires this year to date, into the spring, have been small grassland fires. This seemed to be true last year as well.  Is the early spring always a busy time for grassland fires around the Southern Rockies?

GIS and ecology

I've had three classes so far in my semester of GIS at PPCC. It struck me, looking at my last post, that re-doing Ahlefeldt's dissertation with GIS is a needed update, and could be done after I've had a few more semesters. I need a little programming to write the algorithms (or maybe ArcGIS will do this already) and the statistics to look for correlations between geology, geomorphology, soils, and climate in the Palmer Divide. In 1992, ESRI software was very expensive (not cheap now, however), and I'm not sure if students at CSU then had access to it at all. Now, at PPCC GIS students get a one year license for ArcGIS desktop as part of their tuition. It seems like this type of analysis is really the only way of doing things now.

Landscape Ecology of the Palmer Divide

The other day I finished reading Judy von Ahlefeldt's Ph.D. thesis on the ecology of the Palmer Divide. Judy is now the owner and publisher of the Black Forest News. Written in 1992 while she was at Colorado State, it focuses on answering the question of why does the Black Forest (of Colorado) exist? Why do we have a ponderosa pine forest extending out onto the Great Plains at the base of the Rocky Mountains?

Black Forest is at a four-way crossroads of the plains and the mountains, as well as the northern and southern Great Plains. The Black Forest is a mix of species such as Douglas fir, white fir, ponderosa pine, pinon pine, junipers, gambel oak, and relict tallgrass prairie. In her thesis, she looks at the geology, geomorphology, climate, soils and vegetation of the area to build a landscape ecology of the Palmer Divide.

She also throws in some ordination graphs, and uses computer programs like DECORANA and CANOCO, which at this point are beyond me. However, I got some good information I could take away.

Soil parent material and particle size (and their water holding capabilities) follow vegetation communities pretty closely.

• Northern mixed grass prairie is linked with eolian (wind blown) sand dunes and sandy alluvium
• Shortgrass prairie likes warm, clayey, alkaline (high Ca++ and Mg++ levels) soils
• Coniferous forest seems to be found more on weathered Pikes Peak granite and arkosic (high feldspar content, eroded sandstone) residuum of the the Dawson formation, in areas of higher moisture
• Douglas fir is found on steep (>20%), north-facing slopes where snow lingers longer
• Pinyon-juniper shows up in south or southeast facing slopes in soils with high clay content
• Gambel oak which grows by itself in grassland experiences less frequent and less intense fires than oak that grow in ponderosa pine.
• Grazing has altered the fire regime of the region
• Tallgrass prairie appears on arkosic alluvium and clay-silt soils. Little bluestem and prairie dropseed are found in cooler areas as opposed to mountain mahogany shrubland, which appears in warmer areas with sandy clay.
• Areas a few miles apart have different moisture seasonality. The south side of the divide and the highest elevation have a late summer moisture pulse, or monsoon, while the area north all the way to Castle Rock gets an earlier spring pulse of moisture, and not much a late summer monsoon.
  

Of further interest to me is that she mentions how no one alive has seen what the Black Forest looked like before it was logged extensively, grazed, farmed, and then built over with more and more houses, which altered the fire regime to be virtually non-existent.

I wonder if it would be possible to recreate 1. a pre-1860 fire regime, and 2. a description of the structure and age class of the forest at that time. Are there records of the timber volume extracted from the forest in the 1860s? Could one go backwards and recreate a forest based on this information, if it exists?

What would it take to reactivate the eolian dunes? How does thinning change the ecology of the forest, now that the fires are completely suppressed?