United States

Department of

Agriculture

Forest Service

Northeastern

Research Station

Research Paper NE-713

Jerry T. Crews

Linton Wright

Temperature and Soil Moisture emperature and Soil Moisture

Regimes In and Adjacent to the Regimes In and Adjacent to the

Fernow Experimental Forest w Experimental Forest w Experimental Forest
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Manuscript received for publication 14 February 2000

Abstract Abstract

The effects of elevation, aspect, ambient air temperature, and soil moisture on

soil temperature were examined in and adjacent to the Fernow Experimental

Forest in West Virginia to determine the extent of frigid soils. The mean annual

temperature of frigid soils ranges from 1° to 7°C at a depth of 50 cm; the

difference between mean winter and mean summer temperatures exceeds 5°C.

Soil temperature and moisture were measured and data on air temperature were

collected at study sites on or near the Fernow from December l994 to December

l997. Readings were taken 6 times during the year (January, February, June,

July, August, and December) and the mean annual and seasonal soil

temperatures were calculated. The winter (December-February) and summer

(June-August) mean soil temperatures at each site were used to determine the

extent of frigid soils. One soil was classified as frigid for 2 consecutive years.

The Authors

JERRY T. CREWS is a soil scientist with Northeastern Research Station’s Timber

and Watershed Labortory at Parsons, West Virginia.

LINTON WRIGHT is a soil scientist with the Monongahela National Forest at

Elkins, West Virginia.
1

Introduction

On certain landscapes at higher elevations, average annual

soil temperatures may be within the range of frigid soiltemperature regimes. In Pennsylvania, Carter and Ciolkosz

(1980) found many soils at elevations of 460 m and

higher that could be classified as frigid. They also

proposed that at lower latitudes and elevations that

exceed 914 m, soils might fit the frigid classification on

central Appalachian mountain ridges as far south as

Pocahontas County, West Virginia.

The mean annual soil temperature (MAST) of frigid soils

ranges from 1° to 7°C. At 50 cm below ground, the

difference between summer and winter temperatures

exceeds 5°C. The variety of plant communities is greater

on frigid than on mesic soils. The latter support the

eastern and deciduous Appalachian forest types.

Predominant species in these forests are northern red oak

and yellow-poplar. Frigid soils are associated with northern

hardwood and northeastern conifer forest types. Species

that characterize these forests include sugar maple, black

cherry, gray birch, American beech, and eastern hemlock.

Soil temperature is an important variable in forest

management because it affects plant growth, species

diversity, nutrient cycling, rates of soil formation, and

other biotic activity (Flucker 1958; Munn et al. 1978;

Tajchman et al. 1986). Frigid soils dramatically reduce the

site index for most oak species (Kricher and Morrison

1988), and alter the relationship between certain plants

and wildlife (Tajchman et al. 1983; Werling et al. 1984).

The objective of this study was to determine the frigidmesic soil temperature zonal boundary in the Fernow

Experimental Forest and an adjacent study site in West

Virginia by measuring MAST at various elevations and

aspects.

Materials and Methods

The areas selected for study included Fork Mountain and

McGowan Mountain on the Fernow and Bearden Knob

near Davis, West Virginia. At these sites, MAST was

measured on the northeast (NE), northwest (NW), eastsoutheast (E/SE), and southwest (SW) aspects, and at the

summit (SU) where possible. The study sites had the

following elevations: Bearden Knob, 1,174 m (SU); Fork

Mountain, 768 (SU) and 762 m (NW, SW, E/SE);

McGowan Mountain, 908 m (SW) and 896 m (NW). The

site index for oak and soil series, respectively, were 60

and Mandy for Bearden, 70 and Dekalb (three aspects) or

Calvin (one aspect) for Fork Mountain, and 80 and

Cateache for McGowan Mountain. The landtype

association was M221Ba08 for Bearden and M221Ba10

for the Fork and McGowan Mountain sites.

Soils at the lower elevation sites were classified as Typic

Hapludults and those at higher elevations were classified

as Typic Dystrochrepts (Soil Survey Staff 1967). The soil

organic layer (Oi and Oa horizons) of the deciduous forest

was 3 to 5 cm thick.

Each year from December 1994 through December 1997,

soil temperatures were measured six times (January,

February, June, July, August, December). All but one Fork

Mountain site and one McGown Mountain site were

established in 1996. The time of measurement ranged

from 0800 to 2000 hours on the 15th to the 25th day of

the month. At each study site, three temperature-moisture

cells (model MC 301, Soiltest, Lake Bluff, IL)1 were

installed 50 cm below the ground. The cells were

positioned within 5 m of each other. The reference

junction of the thermocouple protruded from the soil

surface and was covered with a plactic bag. Soil

temperatures were measured with a Soiltest soil moisture

temperature meter (MC-300B). Accuracy of the sensors

during readings was 1°C at 22°C.

The mean winter soil temperature was derived from

readings taken in December, January, and February. The

mean summer temperature was derived from readings in

June, July, and August. MAST was calculated from the

mean seasonal soil temperatures (MSST) to determine the

soil-temperature regime at each study site. Because some

of our resistance data were invalid, the readings are used

only to indicate relative soil moisture (Table 1).

Results

The Bearden Knob summit was the only site classified as

having frigid soils for 2 consecutive years based on MAST

and MSST (Table 2, Figs. 1-2). Aspect influenced ambient

temperatures, which, in turn, influenced soil temperatures

(Table 3, Fig. 3). For example, the McGowan Mountain SW

site had the highest MSST for 2 consecutive years. As

expected, both SW sites (McGowan and Fork) had the

highest ambient air temperature in 1996 and 1997 (Table

3). In northern latitudes, soils on NW sites are cooler and

the MAST should be cooler. Although the soil on the Fork

Mountain NW site was mesic by definition, it was the

coldest of the Fernow sites. The likely reason for this

apparent anomaly was a “frost pocket” or cold air that

was trapped in a valley below the site. This cold air

probably influenced both the mean seasonal air temperature

at the site and the MSST in both summer and winter. The

1

The use of trade, firm, or corporation names in this paper is for

the information and convenience of the reader. Such use does not

constitute an official endorsement or approval by the U.S.

Department of Agriculture or the Forest Service of any product or

service to the exclusion of others that may be suitable.
2

McGowan NW site, with no frost pocket and at a

higher elevation, maintained a mesic soiltemperature regime.

The Bearden Knob summit had higher mean

seasonal soil electrical resistance than the mesic

study sites (Table 1). Higher resistance readings

indicate drier soils, which are influenced more by

ambient air temperatures than wetter soils

because of the higher specific heat of soil

moisture. Lower seasonal ambient air

temperatures at this drier site probably were

responsible for the frigid soils at Bearden Knob.

Seasonal ambient temperatures varied widely

with elevation (Table 3). The soil at Bearden

Knob was frigid but soils were mesic at the next

lower elevation (McGowan Mountain SW site).

Both sites were higher than the Fork Mountain

NW site, which has a cooler MAST than the

McGowan NW site.

Discussion

Soil moisture, ambient air temperature, and

aspect influence soil temperature and largely

determine the soil-temperature classification.

However, when evaluated individually, none of

these factors determined the MAST nor the

extent of frigid soils. Anomalies such as frost

pockets can influence soil temperatures. A

multivariate equation that includes ambient air

temperature, aspect, elevation, and moisture

could provide predictive information.

Soil temperature influences mineral and organic

matter content and microbial activity of the

soil. Warmer mesic soils contain less organic

matter and more iron and aluminum oxides

than cooler and frigid soils. Mesic soils

promote seed germination and rapid plant

growth, but the increased toxicity of harmful

ions such as Fe+++ and Al+++ in these soils

may slow or retard tree development. Leaf fall

and to a lesser extent decay and death of roots

increase the organic matter content of forest

soils. The accumulation of organic matter in

cooler soils leads to increased sequestration of carbon

as well as increased retention of beneficial nutrients

(e.g., phosphorus, nitrogen) available to plants.

Increased chelation by soil organic matter reactive groups

(e.g., carboxyl, phenolic hydroxyl, amine) not only

promotes the retention of beneficial nutrients but also

reduces the toxicity of harmful ions by lowering their

concentrations in soil solution. However, seed germination

and plant growth are slower in frigid soils.

We did not address the possible influence of forest

canopy on soil temperatures. The warmer temperatures at

the Fork and McGowan Mountain SW sites likely were

influenced by little or no forest canopy in addition to

aspect. A companion study on sites farther south and

eastward on the Monongahela and George Washington

National Forests will extend the scope of this investigation

by providing additional data on the effect of ambient air

temperature, soil moisture, aspect, and canopy on soil

temperatures at higher elevations.

Figure 1.—Effect of elevation on mean annual soil temperatures, 1996.

Figure 2.—Effect of elevation on mean annual soil temperatures, 1997.
3

Table 1.—Electrical resistance of soil at study sites, y sites, in ohmsa

Bearden (SU) Fork (SU) Fork (NW) Fork (E/SE) Fork (SW) McGow

Year Winter Summer Winter Summer Winter Summer Winter Summer Winter Summer Winter 

1995 4.4 5.3 3.7 5.4 5.6 1996 4.1 4.5 4.0 2.5 3.8 4.1 4.0 2.5 6.4 1.5 3.2 1997 4.1 4.3 1.2 2.4 3.4 3.8 1.2 2.4 1.0 4.2 0.9 

aAll measurements taken at a depth of 50 cm.

Table 2.—Mean annual (A) soil temperature and mean annual winter (W) and summer (S) temperatures (oC) at depth 

winter (December, January, February) and mean summer (June, July, August) measurements

Bearden (SU) Fork (SU) Fork (NW) Fork (E/SE) Fork (SW) McGow

Year W S A W S A W S A W S A W S A W S 1995 3.7 12.5 8.1 3.8 15.2 9.51996 3.0 8.8 5.9 4.3 13.8 9.0 4.0 13.1 8.6 4.5 14.3 9.4 3.9 14.2 9.0 4.7 141997 4.8 10.4 7.6 5.0 13.0 9.0 4.7 11.6 8.2 5.0 13.6 9.3 4.9 13.5 9.2 5.3 13

Table 3.—Mean seasonal ambient air temperatures (oC) at study sites

Bearden (SU) Fork (SU) Fork (NW) Fork (E/SE) Fork (SW) McGow

Year Winter Summer Winter Summer Winter Summer Winter Summer Winter Summer Winter 

1995 0.0 22.5 2.9 24.61996 -3.0 16.3 3.3 22.7 3.3 23.6 3.3 22.7 6.1 23.2 5.2 

1997 -2.2 16.2 4.4 22.6 5.0 22.9 5.0 22.9 6.4 24.7 6.1 
4

Literature Cited

Carter, Brian J.; Ciolkosz, E. J. 1980. Soil temperature

regimes of the central Appalachians. Soil Science

Society of America Journal. 44: 1052-1058.

Flucker, B. J. 1958. Soil temperatures. Soil temperatures. Soil Science. 86:

35-46.

Kricher, J. C.; Morrison, G. 1988. A field guide to eastern

forests in North America. th America. Boston: Houghton Mifflin:

75.

Munn, L. C.; Buchanan, B. A.; Nielsen, G. A. 1978. Soil

temperature in adjacent high elevation forests and

meadows of Montana. ws of Montana. Soil Science Society of America

Journal. 42: 982-983.

Figure 3.—Mean annual soil temperature vs. mean annual air temperature, 1996-97.

Soil Survey Staff. 1967. Soil survey of Tucker County,

WV. Washington, DC: U.S. Department of Agriculture,

Soil Conservation Service.

Tajchman, S. J.; Minton, C. M. 1986. Soil temperature

regime in a forested Appalachian watershed. Canadian

Journal of Forest Research. 16: 624-629.

Tajchman, S. J.; Wiant, H. V., Jr. 1983. Topography and

biomass characteristics of a forested catchment in the

northern Appalachians. Forest Ecology and

Management. 5: 55-69.

Werling, J. A., Jr.; Tajchman, S. J. 1984. Soil thermal and

moisture regimes on forested slopes of an Appalachian

watershed. Forest Ecology and Management. 7: 297-

310.
Printed on Recycled Paper

Crews, Jerry T.; Wright, Linton. 2000. Temperature and soil moisture regimes in

and adjacent to the Fernow Experimental Forest. w Experimental Forest. Res. Pap. NE-713.

Newtown Square, PA: U.S. Department of Agriculture, Forest Service,

Northeastern Research Station. 4 p.

The effects of elevation, aspect, ambient air temperature, and soil moisture on soil

temperature were examined in and adjacent to the Fernow Experimental Forest in

West Virginia to determine the extent of frigid soils. The mean annual temperature

of frigid soils ranges from 1° to 7°C at a depth of 50 cm; the difference between

mean winter and mean summer temperatures exceeds 5°C. Soil temperature and

moisture were measured and data on air temperature were collected at study sites

on or near the Fernow from December 1994 to December 1997. Readings were

taken 6 times during the year (January, February, June, July, August, and

December) and the mean annual and seasonal soil temperatures were calculated.

The winter (December-February) and summer (June-August) mean soil

temperatures at each site were used to determine the extent of frigid soils. One soil

was classified as frigid for 2 consecutive years.

Keywords: Forest soils; mesic soils; aspect; elevation
Headquarters of the Northeastern Research Station is in Newtown Square,

Pennsylvania. Field laboratories are maintained at: Field laboratories are maintained at:

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Durham, Durham, New Hampshire, in cooperation with the University of New Hampshire

Hamden, Hamden, Connecticut, Connecticut, in cooperation with in cooperation with Yale University

Morgantown, West Virginia, in cooperation with in cooperation with West Virginia University

Parsons, West Virginia

Princeton, Princeton, West Virginia

Syracuse, New York, in cooperation with the State University of New York,

College of Environmental Sciences and Forestry at Syracuse University

Warren, Pennsylvania

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