Picea engelmannii Forest Alliance
Engelmann spruce forest
Engelmann spruce forest
USDA Ecological Section Map
Summary Information
- Primary Life FormTree
- Elevation1200-2100 m
- State RarityS2
- Global RarityG5
- DistributionCAN: AB, BC, YT. USA: AZ, CA, CO, ID, MT, NM, NV, OR, UT, WA, WY (NatureServe)
- Endemic to CaliforniaNo
- Endemic to California Floristic Province and DesertsNo
- Date Added1995/11/01
Characteristic Species
Picea engelmannii is dominant in the tree canopy with Abies concolor, Abies ×shastensis, Calocedrus decurrens, Picea breweriana, Pinus contorta ssp. murrayana, Pinus lambertiana, Pinus monticola, Pinus ponderosa, Pseudotsuga menziesii, Taxus brevifolia and Tsuga mertensiana.
Vegetation Layers
Trees < 55 m; canopy is continuous. Shrubs are common or infrequent. Herbaceous layer is sparse or abundant.
Membership Rules
- Picea engelmannii > 50% cover in the tree canopy (NatureServe 2007).
Habitats
Stream terraces, seasonally saturated depressions. The USFWS Wetland Inventory (1996 national list) recognizes Picea engelmannii as a FAC plant.
Other Habitat, Alliance and Community Groupings
| MCV (1995) | Engelmann spruce series |
| NVCS (2009) | Picea engelmannii forest alliance |
| Calveg | Engelmann spruce-Subalpine fir |
| Holland | Salmon-Scott enriched coniferous forest |
| Munz | Red fir forest |
| WHR | Klamath mixed conifer, Subalpine conifer |
| CDFW CA Code | 83.100.00 |
National Vegetation Classification Hierarchy
| Formation Class | Mesomorphic Tree Vegetation (Forest and Woodland) |
| Formation Subclass | Temperate Forest |
| Formation | Cool Temperate Forest |
| Division | Western North America Cool Temperate Forest |
| Macro Group | Rocky Mountain Subalpine and High Montane Conifer Forest |
| Group | Rocky Mountain mesic subalpine forest and woodland |
Remarks
Picea engelmannii is a conifer that attains a height of 50 m and an age of 600 years. Plants begin producing cones at 15 years; seed crops are large every 2-5 years. Seeds are dispersed up to 90 m from source trees in the fall. Seed viability is high, averaging 70%. Seedlings grow best in mineral soil but can establish on shady, cool, moist duff. Plants are shade tolerant, and individuals can layer (Alexander and Shepperd 1990, Uchytil 1991c). P. engelmannii forms extensive stands in western mountains in the Cascades and Rocky Mountains (Uchytil 1991c), in areas with long, cold winters, heavy snowpacks, and short, cool summers.
In California, stands exist along glaciated valley bottoms in areas with mature A. concolor or Abies x shastensis stands at montane and subalpine elevations. The stands occur in only six isolated occurrences and, like A. lasiocarpa, may represent recent migrants to the state (Sawyer 2006, 2007). P. engelmannii is a rare CNPS list 2.2 plant in California.
In California, stands exist along glaciated valley bottoms in areas with mature A. concolor or Abies x shastensis stands at montane and subalpine elevations. The stands occur in only six isolated occurrences and, like A. lasiocarpa, may represent recent migrants to the state (Sawyer 2006, 2007). P. engelmannii is a rare CNPS list 2.2 plant in California.
Life History Traits of the Principal Species
| Picea engelmannii | |
|---|---|
| Life forms | Tree; evergreen |
| Seed storage | Transient |
| Seed longevity | Short |
| Mode of dispersal | Wind |
| Germination agents | Stratification—winter |
| Mode of sprouting | None |
| Survivability after fire/disturbance | Fire-sensitive; thin epidermis; canopy architecture susceptible; high flammability |
| Disturbance-stimulated flowering | No |
| Reproductive range | 15-600 years |
| Recruitment | High |
| Regional variation | Low |
Fire Characteristics
Even a low-intensity fire easily kills most Picea engelmannii trees. Large trees occasionally survive fires. Those that survive are often killed later by wood-rot-ting fungi that enter through fire scars (Alexander and Shepperd 1990, Uchytil 1991c).
This and related forests usually develop in moist locations and experience fire-free intervals averaging 150+ years. High fuel loads in old stands promote stand-replacing fires. In addition, stands often appear even-aged, suggesting that they usually develop after stand-replacing fire. Post-fire establishment is by wind-dispersed seeds that readily germinate on fire-prepared seedbeds. In general, seedling establishment is very slow in areas burned by large, continuous crown fires that destroy all seed sources. However, regional studies elsewhere throughout its broad range indicate that on small burns or near pockets of surviving trees within large burns, P. engelmannii usually establishes numerous seedlings within 5-10 years (Uchytil 1991c).
| Fire return interval | Long |
| Seasonality | Late summer (short) |
| Size/extent | Small up to stand size |
| Complexity | Low |
| Intensity | Multiple |
| Severity | High to very high |
| Type | Multiple |
| Regional knowledge | Klamath, Cascade ranges |
Regional Status
- Klamath Mountains (M261Af-g, Ap, At). Unlogged stands occur along Blake’s Fork and along South Russian, Duck Lake, Horse Range, Music, and Sugar creeks in the Salmon Mountains. Only the Duck Lakes Botanical Area and Sugar Creek cRNA (Keeler-Wolf 1989k, see Cheng 2004) have special recognition, although others occur within wilderness areas. The Sugar Creek stands fall within some of the bestknown, high-diversity enriched conifer stands of the Klamath Mountains (Sawyer 1986, 2006, 2007), where ten or more species of conifers occur in a single stand.
- Southern Cascades (M261Dj). The stream terrace stands along Clark and Hat creeks have been logged and are very close to the northeastern margin of the Klamath Mountains. These stands are at lower elevations than most of the Klamath stands.
Management Considerations
Picea engelmannii grows at the range limits of the alliance in California, which would make it an excellent indicator of climatic shifts if we establish monitoring plots. The Cascade stands are privately owned.
Associations
- Picea engelmannii / Clintonia uniflora [1]
- Picea engelmannii / Senecio triangularis [1]
References
- [1] Sawyer, J.O.;Thornburgh, D.A. 1971
- Alexander, R.R.;Shepperd, W.D. 1990
- DeJager, W.R. 1991
- Griffin, J.R.;Critchfield, W.B. 1972
- Sawyer, J.O. 2006
- Sawyer, J.O. 2007
- Sawyer, J.O.;Thornburgh, D.A. 1977
- Uchytil, R.J. 1991c