Modification of Climate by Plant Communities
Authors:   , Henderson Charles 
Published: February 2023

A six-months microclimatic investigation (November, 1957 to April, 1958) of the various climatic factors (temperature, light intensity, wind velocity, and humidity) was conducted at seven different stations. The area selected for this study was a relict area of approximately 36 acres located in the mixed prairie association. The relict area was located approximately 1.5 miles southwest of Hays, Kansas, in Ellis county. Observations were made six days each month under two sets of time tables; three days each month readings were taken at sunrise, noon, and sunset and three days each month at mid-morning, mid-afternoon, and at midnight. Temperature (degrees centigrade) measurements at each station were made at five levels: six inches below soil surface, soil surface, six inches above soil surface, 12 inches above soil surface, and above vegetation. 1he temperature below the soil surface was obtained by placing the thermometers in holes bored to the desired depth in the ground, with the holes being covered with a lid when the thermometers were not being checked. Air temperatures for the various heights were obtained by fastening the thermometers to a stake at the desired heights. Light intensity, wind velocity, and relative humidity measurements were taken at four levels: soil surface, six inches above soil surface, 12 inches above soil surface, and above vegetation. A Weston illumination meter (model 756) was used to record the light intensities (foot candles). Wind velocity (mph) was taken with a hand type ventimeter. Relative humidity was determined with a cog type, wet-dry bulb psychrometer. Two methods were applied in gathering the data used in determining the basal composition and per cent composition of the vegetation surrounding the study stations. The point transect method (Clarke, et al., 1942) was employed in determining the basal cover and composition of the grassy vegetation. In each study area the relative abundance and importance of the non-grassy species, forbs and weeds, were rated according to the method described by Weaver and Fitzpatrick (1934). Station one was located on a north-facing, partly protected slope within a big bluestem (Andropogon gerardi) habitat. Station two was located in a weedy lowland area. Located on a north-facing, unprotected slope in a mixed midgrass habitat was station three. Station four was located on a fairly level area in a little bluestem (Andropogon scoparius) habitat. Station five was located approximately halfway between stations two and four in a mixed grass habitat on a west-facing slope. Station six was located across the draw from station five on an east-facing slope in a mixed grass habitat. Station seven was located across the draw from station one on a south-facing, partly protected slope in a mixed grass habitat. The data gathered from the present investigation are summarized in Tables I through XXVIII. It was found that the vegetation of the area effected the air climate in varying degrees, depending upon the characteristics of the vegetation and also upon the topography of the area, as per cent slope and direction of slope were found to play an important role in the modification of the macroclimate. It was found that the microclimate for the study stations also varied according to the time of day. Although, the present investigation was limited in time and scope, it is the opinion of the author that a more extensive study would merit much valuable information regarding microclimates in the mixed grass prairie.