Location: Six miles east from Moscow to Pullman, WA on Highway 6; North on Highway 129 to Colfax, W.; 10 miles north on Highway 196

Date: 5/1/93             Time: 9:00 AM - 2:00 PM

Temperature: 72^o F Weather: partly cloudy, slight west wind

Purpose: To study the flora of the area in an effort to identify factors affecting the growth patterns on both the south and north aspects of Kamiah Butte in southeastern Washington.

Methods: Plant species were identified as we hiked along the trail. Air and soil temperature readings were taken and recorded for later comparisons.

Results: When one visits Kamiak Butte, hiking the loop from the northern exposure to the southern exposed portion gives a sense of changing from one vegetational world to another. The approach from the highway yields a southern face that is covered with bushes, grasses, and some conifers (see Figure 1), while the northern face is covered with conifers (see Figure 2). A closer inspection of the north and south aspects reveals operational factors in action, explaining some of the diversity and complexity of the vegetational patterns on the butte.
 

The southern face of Kamiak Butte is a complex system of Douglas fir, Ponderosa pine, chokecherry, two forms of wild cherry (tree and bush), snowberry, balsam, paintbrush, June grass, and several other vegetative forms representing both woodland and prairie species. Moisture is the most critical factor, with heat and soil ions playing important roles in determining the types of plants present in an area.
 
Moisture in the form of precipitation is wide-spread on the south side of the butte. The prevailing southwesterly winds bring rain and snow to the face, but also aid in evaporation. Soil depths vary with loess deposits covering the southwestern aspects of the butte as well as channels where water flows down the side of the face. The remainder of the southern side has thin soil with some talus present. Those areas with deeper soil host bushes that require continuous supplies of soil moisture. The thinner soils at the top of the ridge support growth of conifers, grasses, and forbes. Thinner soils on the steeper portions of the face support grasses and forbes. These thinner soils have less water holding capacity than deeper soils. The conifers have extended their roots to depths that correspond with the water table.

Heat is a critical factor on this and the other side of the butte. The southern exposure gets much more sunshine than does the northern portion of the butte, hence more infrared rays and more heat. Air and soil temperatures were higher on the south versus the north side (see Figure 3). More heat allows more grass and forb production as well as some bush production, including cherry and chokecherry. Because of this heat, some less heat tolerant species found on the north side of the butte will not be found on the south side.
 
Soil ions are more abundant and more readily available in deeper soils. For this reason the woody plants are usually found where deep soil conditions exist. Competition between Douglas fir and tree-type wild cherry occurs about mid-slope on the south face. It appears that the cherry is winning out, exhibiting more vigor in terms of growth and especially reproduction than the fir. This competition could be for soil ions as well as for water.

The north side of the butte presents a totally different complexion. Water, heat, soil ions and depth, as well as light are critical factors that determine the operational environment for Douglas fir, Ponderosa pine, larch, ferns, Grand fir, snow berry, orchids, wild strawberry, violets, and buttercups. The view from the road is much different approaching from the north than from the south.
 

The north side of Kamiak Butte supports primarily conifers, with cycling successions of Grand fir, Ponderosa pine, and larch occurring. The closed canopy associated with Grand fir inhibits growth of most vegetation. The open canopy associated with Ponderosa pine allows growth of bushes as well as Douglas fir. Between these areas and along the north face of the butte, shade and light tolerant forbes as well as ferns can be found. Light plays a greater role in operational conditions here as compared to the south side.

Water is more abundant here than on the south side as snow accumulations melt slowly, trickling through the thin soil, then settling near the bottom of the slopes where bushes are found as well as black cottonwoods. The growth of ferns also points to increased moisture in the air. Evaporation by sun and wind are not as common as on the south face, so more water is available for a longer time.

Soil ions are more plentiful here because of increased loess depths, but also due to the increased amount of duff and conifer needles present. The acidity of the soil is increased, breaking down organic material faster, and thereby releasing more ions into the soil. Vegetation on the north side is much more abundant with most species displaying vigorous growth and reproduction.

Heat is critical on this side of the butte. Air and soil temperatures are lower than on the south side, allowing the growth of ferns and not allowing the abundance of grasses. Larch are not at all present on the south side, nor is the alder as both are cooler temperature adapted trees. The chart below shows the relationships among temperatures taken at different points on the north and south side of the butte.

Conclusion: The differential vegetation patterns that are seen on Kamiak Butte may be explained by the interaction of the operational factors of water, heat, light, and soil ion concentration. Water and heat appear to be the causal factors for differences between the north and south face patterns. The south side of the butte, with less available soil moisture and more heat, shows woodland and prairie vegetation patterns, while the north side shows mostly woodland patterns, having less heat and more available moisture. Light appears to be a causal factor for differences in the patterns found on the north side while soil ion concentration levels can be causal factors for differences seen on both sides. Canopy conditions on the north side provide shaded areas with little undergrowth as well as open canopies where undergrowth is vigorous. Soil ion concentrations change with soil depth on both sides, woody plants being most abundant in deeper soils and grasses and forbes more abundant in thinner soils.