|
|
UNITED STATES DEPARTMENT OF AGRICULTURE
NATURAL RESOURCES CONSERVATION SERVICE
ECOLOGICAL SITE DESCRIPTION
|
ECOLOGICAL SITE CHARACTERISTICS
|
|
Site Type: Forestland
Site Name: Pseudotsuga menziesii - Abies concolor / Quercus gambelii - Symphoricarpos albus / Festuca arizonica - Carex geyeri
(Douglas-fir - white fir / Gambel's oak - snowberry (common) / Arizona fescue - Geyer's sedge)
Site ID: F048AY014NM
Major Land Resource Area: 048A - Southern Rocky Mountains
|
 |
|
|
|
Physiographic Features
|
| Land Form: |
(1) |
Mountain slope |
|
(2) |
Ridge |
|
(3) |
Hill |
|
Minimum |
Maximum |
| Elevation (feet): |
8500 |
9000 |
| Slope (percent): |
5 |
75 |
| Water Table Depth (inches): |
|
|
| Flooding: |
|
|
| Frequency: |
None |
None |
| Duration: |
None |
None |
| Ponding: |
|
|
| Depth (inches): |
|
|
| Frequency: |
None |
None |
| Duration: |
None |
None |
| Runoff Class: |
Negligible |
Low |
| Aspect: |
No Influence on this site
|
|
|
Climatic Features
|
Precipitation in this zone of the subresource area is over 26 inches (water equiv.) annually. Approximately 60% comes as gentle rain or snow during the winter-spring (Oct-Apr) period, originates in the Pacific and Gulf of California and come as frontal storms with long duration and low intensity. The remaining 40% falls in summer (May-Sep), originats in the Gulf of Mexico and are convective, usually brief, intense thunderstorms. Snow is common Nov-Mar, averaging over 100 inches per year, and accumulates throughout the winter into spring. Apr, May and June are the driest months. Humidity is moderately low.
Temperatures are mild. Freezing temperatures are common at night Nov-May, but daytime temperatures are almost alwa;ys over 40 F. Below 0 F temperatures can occur Dec-Feb. Daytime summer highs rarely exceed 80 F.
Pine species grow mainly May-Oct. Cool season grasses grow mainly in the spring and summer. Warm season grasses grow mainly in the summer. The cones of pine species take two years to mature. They ripen in the fall. The cones of Douglas fir mature in one season and ripen in late summer. Minimum seed bearing age for pines is 20 years, optimum is 150 years. Minimum seed bearing age for Douglas fir is 9 years, optimum is 100-200 years.
|
|
Minimum |
Maximum |
| Frost-free period (days): |
0 |
0 |
| Freeze-free period (days): |
0 |
0 |
| Mean annual precipitation (inches): |
0.0 |
0.0 |
|
| Monthly precipitation (inches) and temperature (°F): |
|
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
| Precip. Min. |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
|
| Precip. Max. |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
|
| Temp. Min. |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
|
| Temp. Max. |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
0.0 |
|
|
|
|
|
Influencing Water Features
|
No water features are associated with this site.
|
| Wetland Description: |
System |
Subsystem |
Class |
|
|
|
|
Representative Soil Features
|
|
Predominant Parent Materials:
Kind:
Origin:
|
|
|
Subsurface Texture Group:
|
|
Minimum |
Maximum |
| Surface Fragments <=3" (% Cover): |
|
|
| Surface Fragments > 3" (% Cover): |
|
|
| Subsurface Fragments <=3" (% Volume): |
|
|
| Subsurface Fragments > 3" (% Volume): |
|
|
|
| Drainage Class:
|
| Permeability Class:
|
|
Minimum |
Maximum |
| Depth (inches): |
|
|
| Electrical Conductivity (mmhos/cm): |
|
|
| Sodium Absorption Ratio: |
|
|
| Calcium Carbonate Equivalent (percent): |
|
|
| Soil Reaction (1:1 Water): |
|
|
| Soil Reaction (0.01M CaCl2): |
|
|
| Available Water Capacity (inches): |
0.0 |
0.0 |
|
|
|
Plant Communities
|
| Ecological Dynamics of the Site |
The plant communities found on an ecological site are naturally variable. Composition and production will vary with yearly conditions, location, aspect, and the natural variability of the soils. The Historical Climax Plant Community represents the natural potential plant communities found on relict or relatively undisturbed sites. Other plant communities described here represent plant communities that are known to occur when the site is disturbed by factors such as fire, grazing, or drought.
Production data provided in this site description is standardized to air dry weight at the end of the summer growing season. The plant communities described in this site description are based on near normal rainfall years.
NRCS uses a Similarity Index to compare existing plant communities to the plant communities described here. Similarity index is determined by comparing the production and composition of a plant community to the production and composition of a plant community described in this site description. To determine Similarity index, compare the production (air dry weight) of each species to that shown in the plant community description. For each species, count no more than the maximum amount shown for the species, and for each group, count no more than the maximum amount shown for each group. Divide the resulting total by the total normal year production shown in the plant community description. If the rainfall has been significantly above or below normal, use the total production shown for above or below normal years. If field data is not collected at the end of the summer growing season, then the field data must be corrected to the end of the year production before comparing it to the site description. The growth curve can be used as a guide for estimating production at the end of the summer growing season.
|
| Historic Climax Plant Community |
The potential plant community on this site is a mixed stand of pine species and Douglas fir. Shrubs, perennial grasses and forbs are common in the understory. Canopy cover in mature stands range from 50-70%. Mature tree heights average 70 feet. The aspect is coniferous woodland.
The lower limit of these woodlands is controlled by drought and soil moisture regimes. These woodlands occur above the ponderosa pine belts and on steep, northern aspects at lower elevations. Pines are successional to Mixed conifer on this site.
Naturally occuring wildfires in the May-Aug lightening season are an important factor in shaping these woodlands. Natural fire-free intervals averages 10-20 years in drier areas up to 40 years in wetter areas. The natural fire regime consisted of low intensity surface fires. These tended to favor Ponderosa pine and Douglas fir over other conifer trees. Young fir trees growing in the shade of pine canopies and are more easily killed by surface fires because the bark is thinner and the foilage closer to the ground. The lack of fire in the last century on may areas of the site has led to a dominance of Douglas fir, white fir, other conifer trees, and unnaturally thick stands of trees. Fire prepares a mineral soil seedbed needed by both pine and fir species. In wetter soil areas on steep north exposures, quaking aspen is successional to Douglas fir, white fir and spruce. Aspens are easily top killed by fire, but the clones live 100s of years. In the infrequent stand where fires have killed fir and pine trees, these moist areas become dense stands of aspen sprouts. Densities as high as 2000 stems per acre are common. Aspen matures between 60-80 years of age and declines rapidly after 120 years. As these stands of aspen mature, Douglas fir and white fir saplings establish in the shade and grow to assume dominance in the next 40-50 years. On drier areas where aspen is not present, after stand replacing fires, shrubs like (Fendler buckbrush, New Mexico thimbleberry, mountain snowberry, manzanita, netleaf, oak, and New Mexico locust) can form into dense growth. The shrubby aspect yields in time to pine and finally to Douglas fir.
Dwarf mistletoe (Arceuthobium vaginatum var. cryptopodum) infects ponderosa pines. Another species (Arceuthobium Douglasii) infects Douglas fir. These mistletoes act to increase mortality, reduce growth and production, reduce seed yields and can predispose trees to attach by pine beetles. Mistletoe causes witches broom in branches, which increases crown flammability during wildfire. Snow breaks off branches with brooms, increasing fuel loading on the forest floor.
Pine beetles of the genus Dendroctonus attach both Douglas fir and pines. Infestations can kill healthy trees.
The spruce budworm (Choristonewra Douglas99) attacks immature stands of Douglas fir reducing growth, foilage volume, cone production and predisposes trees to attach by pine beetles. Outbreaks occur on average every 30-40 years. Uneven age, multi-story stands are more susceptable because more sunlight can penetrate to the forest floor, thus creating warmer, drier conditions conducive to budworms.
Exclusion of wildfires favor multi-story stands of shade tolerant species like Douglas fir, which spruce budworm prefers. Fire exclusion allows stands to thicken, making it easier for mistletoe to spread and suppressed growth weakens trees increasing attack by pine beetles. Allowing fires to burn naturally in open stands takes out damaged trees and favors one or two storied forests less conducive to spruce budworm outbreaks.
Tree stocking in these woodlands range from 50-200 trees per acre. Site index ranges from 60-70 for pines and 90-100 for Douglas fir. 100-yr old Douglas fir trees average 80 feet in height and 20 inches in diameter. Canopy cover in mature stands averages 60%.
Periodic severe drought can occur in this region. Stand replacing fires usually follow periods of severe drought. A drought in the 1950s caused large wildfires in these woodlands. A less severe drought in 1993-94 caused large wildfires in areas of this site as well
|
|
| Annual Production by Plant Type: |
|
Annual Production (lbs/AC) |
| Plant Type |
Low |
Representative Value |
High |
| Forb |
20 |
50 |
100 |
| Grass/Grasslike |
200 |
400 |
600 |
Total: |
220 |
450 |
700 |
|
Forest Overstory Composition:
|
|
|
Forest Understory Composition:
|
|
|
|
|
Ecological Site Interpretations
|
Animal Community:
|
Plant Preference by Animal Kind:
|
Hydrology Functions:
|
Recreational Uses:
|
Wood Products:
|
Other Products:
|
Other Information:
|
|
|
Supporting Information
|
Associated Sites:
| Site Name |
Site ID |
Site Narrative |
|
Similar Sites:
| Site Name |
Site ID |
Site Narrative |
|
State Correlation:
This site has been correlated with the following states:
|
Inventory Data References:
|
Type Locality:
|
Relationship to Other Established Classifications:
|
Other References:
Characteristic soils include Abreu, Bracos, Eody, Catlon, Lobat, Palon, Yata.
|
Site Description Approval:
|
| Author |
Date |
Approval |
Date |
| Christine Bishop |
5/10/2006 |
John Tunberg |
9/29/2008 |
|
|
|
|
Reference Sheet
Author(s)/participant(s):
Contact for lead author:
Date:
MLRA:
048A
Ecological Site:
Pseudotsuga menziesii - Abies concolor / Quercus gambelii - Symphoricarpos albus / Festuca arizonica - Carex geyeri
F048AY014NM
This must be verified based on soils and climate (see
Ecological Site Description). Current plant community cannot be used to
identify the ecological site.
Composition (indicators 10 and 12) based on:
Annual Production,
Foliar Cover,
Biomass
Indicators. For each indicator, describe the potential for the site. Where
possible, (1) use numbers, (2) include expected range of values for above- and below-average years
for each community and natural disturbance regimes within the reference state, when
appropriate and (3) cite data. Continue descriptions on separate sheet.
|
| 1. |
Number and extent of rills: |
|
| 2. |
Presence of water flow patterns: |
|
| 3. |
Number and height of erosional pedestals or terracettes: |
|
| 4. |
Bare ground from Ecological Site Description or other studies (rock, litter, standing dead,
lichen, moss, plant canopy are not bare ground): |
|
| 5. |
Number of gullies and erosion associated with gullies: |
|
| 6. |
Extent of wind scoured, blowouts and/or depositional areas: |
|
| 7. |
Amount of litter movement (describe size and distance expected to travel): |
|
| 8. |
Soil surface (top few mm) resistance to erosion (stability values are averages -
most sites will show a range of values): |
|
| 9. |
Soil surface structure and SOM content (include type and strength of structure, and A-horizon color
and thickness): |
|
| 10. |
Effect on plant community composition (relative proportion of different functional groups) and
spatial distribution on infiltration and runoff: |
|
| 11. |
Presence and thickness of compaction layer (usually none; describe soil profile features which
may be mistaken for compaction on this site): |
|
| 12. |
Functional/Structural Groups (list in order of descending dominance by above-ground weight using
symbols: >>, >, = to indicate much greater than, greater than, and equal to) with dominants and
sub-dominants and "others" on separate lines:
Dominant:
Sub-dominant:
Other:
Additional: |
|
| 13. |
Amount of plant mortality and decadence (include which functional groups are expected to show
mortality or decadence): |
|
| 14. |
Average percent litter cover (%) and depth (
inches): |
|
| 15. |
Expected annual production (this is TOTAL above-ground production, not just forage production:
|
|
| 16. |
Potential invasive (including noxious) species (native and non-native). List Species
which BOTH characterize degraded states and have the potential to become a dominant or co-dominant species
on the ecological site if their future establishment and growth is not actively controlled by
management interventions. Species that become dominant for only one to several years (e.g., short-term
response to drought or wildfire) are not invasive plants. Note that unlike other indicator, we are
describing what in NOT expected in the reference state for the ecological site: |
|
| 17. |
Perennial plant reproductive capability: |
|
| |
|
|
|
|
|
Ecological Site Description
Back to Top