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?