Chapter 2. Vegetation of the Upper Gunnison Basin In the Upper Gunnison Basin, as in many other Daubenmire (1943-1944), although some scientists parts of the Rocky Mountains, vegetation appears have called them “belts” (Löve 1970). The different at different elevations. These are called vegetation zones that are usually used are shown in vegetation zones by Rydberg (1917) and Figure 2-1 and Table 2-1. 13,000 3,920 12,500 3,770 12,000 3,620 11,500 A 3,470 11,000 3,320 10,500 3,170 10,000 S 3,020 9,500 2,870 t f 9,000 2,720 m n, n, o 8,500 2,570 i o i at 8,000 2,420 at v v e l 7,500 2,270 e MS l E 7,000 2,120 E 6,500 M 1,970 6,000 1,820 5,500 1,670 5,000 F 1,520 4,500 1,370 4,000 1,220 3,500 F 1,070 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Latitude, °N Fig. 2-1. Elevational boundaries between zones in the Rocky Mountains (after Daubenmire 1944, Gregg 1963, Marr 1964, Cronquist and others 1972). A = Alpine Zone, S = Subalpine Zone, M = Montane Zone, F = Foothills Zone. MS = Mountain Shrub. The double arrows show the elevational range of piñon-juniper. Table 2-1. Life zones and vegetation used by various workers (adapted from a table in Gregg 1963). Plant species names are explained in Appendix A. Rydberg Daubenmire Harrington Vegetation in the Merriam 1898 1916 1943a 1954 Marr 1967 This Classification Upper Gunnison Basin Vegetation Vegetation Life Zones Zones Plant Zones Zones Zones Zones tundra meadows, grasses, Arctic- Alpine Alpine Alpine Alpine Alpine sedges, cushion plants Alpine Engelmann spruce, subalpine fir, limber pine, Thurber fescue, Hudsonian Subalpine Spruce-fir Spruce-fir Subalpine Subalpine meadows, fens, planeleaf & Wolf willows Douglas-fir, lodgepole pine, ponderosa pine, Arizona fescue (south) – Idaho fescue (north), Canadian Montane Douglas-fir Douglas-fir Saskatoon serviceberry, and Upper Montane serviceberry & blue willows Ponderosa Montane ponderosa pine, Pine Ponderosa Pine blue spruce (uplands) canyon forest, oak, Saskatoon- Transition Submontane Oak - Mountain- Lower Utah serviceberries, Mountain Mountain Mahogany Montane mountain-mahogany, Shrub yellow-Geyer-Bebb willows Piñon- Shrub Rocky Mtn. juniper, Juniper Piñon- short grasses, yucca, Upper Upper Piñon- Juniper Foothills- Wyoming big sagebrush, Sonoran Sonoran Juniper plains or shrub Plains Semidesert bottomland forest saltbush, greasewood Lower Lower steppe Plains and Shrub (very little in UGB) Sonoran Sonoran Semi-Desert 4 13,500 4,080 13,000 Alpine Zone 3,930 12,500 3,780 12,000 A 3,630 11,500 3,480 11,000 3,330 t Subalpine Zone f m n, 10,500 3,180 n, io io at at v 10,000 3,030 v Ele B Ele Montane Zone 9,500 2,880 9,000 2,730 C Mountain Shrub 8,500 D 2,580 8,000 2,430 Foothills- 7,500 Desert Shrub 2,280 7,000 2,130 1 2 4 9 7 5 6 3 9 0 8 7 5 3 2 6 1 5 6 3 1 4 4 2 24 27 11 28 18 25 13 29 12 19 10 14 30 31 21 32 26 20 15 22 17 16 23 L0 L1 L0 L0 L0 L1 L0 L1 L0 L1 L0 L0 L1 L1 L0 L1 08A 08B A A A A A A A A A A A A A A A A Fig. 2-2. Distribution of the Ecological Series by elevation and Zone. The zonal ecotones are shown by rectangles: A. Alpine – Subalpine ecotone, B. Subalpine – Montane ecotone, C. Montane – Mountain Shrub ecotone, D. Mountain Shrub – Foothills-Semidesert Shrub ecotone. Series 13. Yellow Willow 27. Wyoming Big Sagebrush A7. Pyrenees sedge-cloud sedge-black alpine 1. Rocky Mountain Juniper 14. Blue Willow-Serviceberry Willow-Booth 28. Black Sagebrush sedge 2. Ponderosa Pine Willow 29. Big Sagebrush-Bitterbrush A8. Cliff sedge 3. Bristlecone Pine 15. Planeleaf Willow-Wolf Willow-Bog Birch 30. Mountain Big Sagebrush A9. Dwarf bilberry/varileaf cinquefoil 4. Douglas-Fir 16. Grayleaf Willow-Barrenground Willow 31. Low Sagebrush A10. Whiproot clover/alpine sandwort 5. Blue Spruce Uplands 17. Water Sedge 32. Silver Sagebrush A11. Parry clover/tufted hairgrass-bistort 6. Lodgepole Pine 18. Indian Ricegrass-Needle-and-thread A12. Dwarf clover/alpine sandwort 7. Subalpine Fir-Douglas-Fir 19. Arizona Fescue Alpine Ecological Types A13. Mountain dryad/curly sedge-alpine 8a. Subalpine Fir-Engelmann Spruce, Tall 20. Thurber Fescue A1. Alpine Rocky Forblands fescue Forests 21. Osha A2. Kobresia/curly sedge-club-moss A14. Snow willow 8b. Fir-Spruce Series, Krummholz 22. Idaho Fescue A3. Kobresia-like sedge/alpine sandwort- A15. Arctic willow 9. Limber Pine 23. Timber Oatgrass alpine sagebrush A16. Marsh-marigold-king’s crown riparian 10. Aspen 24. Purple Pinegrass A4. Curly sedge/Greenland bluegrass forblands 11. Narrowleaf Cottonwood 25. Utah-Saskatoon Serviceberry A5. Tufted hairgrass/alpine avens 12. Spruces-Subalpine Fir Riparian 26. Rocky Tall-Shrublands A6. Sibbaldia/alpine avens 5 Table 2-2. Vegetation zones in the Upper Gunnison Basin. Plant species names are explained in Appendix A. Elevation on Elevation on Soil Soil north and east south and west Temperature Moisture Zone Dominants slopes, ft slopes, ft Regime(s) Regime(s) Gravity and freeze-thaw processes, mostly very low Pergelic, Alpine herbaceous plants such as curly sedge, alpine >11,800 >12,200 ft Udic Cryic avens, tufted hairgrass Subalpine fir, Engelmann spruce, aspen, lodgepole pine, Douglas-fir, bristlecone pine, mountain big Mostly Udic, Subalpine 9,700-11,800 10,100-12,300 Cryic sagebrush, Thurber fescue, planeleaf and Wolf some Ustic willows, Idaho fescue Douglas-fir, ponderosa pine, lodgepole pine, aspen, Udic above to Montane Arizona fescue, big sagebrush, Saskatoon 9,100-10,700 9,400-11,100 Frigid Ustic lower serviceberry, blue and serviceberry willows Douglas-fir, big sagebrush, muttongrass, Utah Ustic above Mountain Shrub serviceberry, Gambel oak, yellow-Geyer-Bebb 7,600-10,100 Frigid to Aridic willows, narrowleaf cottonwood lower Aridic Piñon-Juniper* Missing Missing Mesic (Torric) Wyoming big sagebrush, Indian ricegrass, Needle- Foothills- Aridic and-thread, Rocky Mountain juniper, narrowleaf <8,400 Mesic Semidesert Shrub (Torric) cottonwood *. Piñon-Juniper is sparsely represented in the Upper Gunnison Basin. Table 2-2 shows the five elevational zones that alpine types, dominated by very short are apparent in the Upper Gunnison Basin, based vegetation. on the elevational distribution of ecological series 3. The upper extent of short-willow series 15, 16, (Fig. 2-2). All the ecotones (shown as dashed and 17. These short willow ecological types, rectangles in Fig. 2-2) are broad and poorly dominated by such species as planeleaf willow, barrenground willow, Wolf willow, and bog defined. Most zones overlap considerably, except birch, are fundamentally subalpine types. In for the well-defined Alpine. some places, these willow bottoms are located It is difficult to delineate zones accurately on a above upper treeline, where they represent an map of any scale, because the zones overlap upper extension of the Subalpine Zone. broadly, and the ecotones between them are wide 4. The upper extent of forested series 3 and influenced by small changes in microsite and (bristlecone pine) and 8a (fir-spruce tall forests). These are characteristic subalpine microclimate. In fact, it is probably improper to types. delineate zones on a map, based on these data. SUBALPINE ZONE ALPINE ZONE In the northern part of the Basin, away from The Alpine Zone is the best defined in the UGB, deep rainshadows, the lower line of continuous in part because upper treeline provides such a forest is often formed by a narrow or broad sharp boundary between different climates. The transitional belt of mixed aspen, Douglas-fir, and Alpine Zone is not dominated by vegetation, but subalpine fir. There may also be stands dominated primarily by the processes of gravity and freeze- by aspen to the exclusion of conifer trees. thaw. Most of the landscape in the Alpine Zone is dominated by rocks of various kinds on various In the southern part of the Basin where slopes. Sometimes large slopes of rock will be rainshadow climates are dominant, the lower forest moving downward, forming a rock glacier (White edge is often formed by a narrow to broad 1965). Vegetation in the Alpine Zone is all short to transitional belt of mixed-conifer forest, with blue very short, mostly below 8 cm (3 in) tall. spruce, Douglas-fir, and aspen, sometimes mixed Vegetation growth and soil formation are slow to with bristlecone pine on rocky slopes at the forest very slow processes. edge. Across the whole Upper Gunnison Basin, the ALPINE–SUBALPINE ECOTONE belt between the transitional belt below and the upper treeline is usually a broad expanse of conifer We have defined the Alpine – Subalpine forest, of subalpine fir and Engelmann spruce. ecotone (A in Fig. 2-2) by: Within the Subalpine Zone in the Upper 1. The distribution of Series 8b (Krummholz). Gunnison Basin, there are openings in the forest of This belt of wind-formed short trees, which forms the Alpine – Subalpine boundary is various kinds. There are several large parks – broad in some places. Taylor Park and Waunita Park, for example – 2. The lower extent of Alpine ecological types A3, where cold air drainage eliminates trees. These A5, A7, A13, and A16. These are characteristic parks are dominated by mountain big sagebrush or 6 fescue grasslands. Within the grasslands, Thurber • Series 2. Ponderosa Pine fescue is often prominent, sometimes with Arizona • Series 4.