Ecosystem Unit Analysis

Transcription

1 Ecosystem Unit Analysis Background information provided for the Ecosystem Unit Analysis is largely from the Field Guide to the Native Plant Communities of Minnesota: The Laurentian Mixed Forest Province (MNDNR, 2003). Beltrami County has a diverse ecological base from which to manage its forests. Existing cover types, soils and wetlands/surface waters all combine to create a variety of conditions where certain types of vegetation can flourish. This section examines the ecology of Beltrami County forests in the context of the ecological categorization that make up the study area. Information provided here is taken from the Field Guide to the Native Plant Communities of Minnesota: The Laurentian Mixed Forest Province (MNDNR, 2003). At a broader level, Beltrami County is located in the Laurentian Mixed Forest Province, one of four provinces that are located in Minnesota. The Laurentian Mixed Forest is located in the northeast to northcentral areas of the state. This unit of analysis provides a major area with similar climate, vegetation and biomes. Provinces are further divided into Sections, which are units defined by the origin of glacial deposits, regional elevation, distribution of plants, and regional climate. Beltrami County s tax-forfeit forest land is largely located in the Northern Minnesota Drift and Lake Plains (MDL) Section, with a small northeast portion located in the Northern Minnesota and Ontario Peatlands (MOP) Section. Northern Minnesota Drift and Lake Plains (MDL) The Northern Minnesota Drift and Lake Plains and the Northern Minnesota and Ontario Peatlands Sections are larger planning units with consistent glacial deposits, elevation, distribution of plants and climate. The Northern Minnesota Drift and Lake Plains Section (MDL) covers the center of northern Minnesota. MDL has complex surface geology, formed over many episodes of glaciation. It is characterized by deep ( ft [ m]) glacial deposits in outwash plains, lake plains, till plains, outwash channels, moraines, and drumlin fields. The patterns of vegetation in MDL reflect the complex and patchy distribution of these glacial deposits. Mesic forests of sugar maple, basswood, paper birch, aspen and northern red oak are widespread. They occur mostly on moraines or till plains characterized by rough topography, fine-textured parent material, or soils with subhorizons that perch snowmelt and rainfall. Historically, forests and woodlands of jack pine and red pine were very common. These firedependent communities occur on the sandy out-wash plains formed by glacial meltwater. Sandy and gravely deposits that cap many of the major moraines in the western part of MDL provide habitat for mixed forests of pine and boreal hardwood species such as quaking aspen and paper birch. The eastern part of MDL is formed of deposits from Glacial Lakes Upham and Aitkin. These lake plains have expansive areas of acid peatland communities such as black spruce bogs and poor swamp forests, along with rich swamp forests of white cedar and black ash. Sedge meadows and alder and willow swamps occur along the Beltrami County Forestry Management Plan Assessment 45

2 sluggish streams draining the flat lake plains and along the Mississippi and Leech Lake Rivers. Northern Minnesota and Ontario Peatlands (MOP) The Northern Minnesota and Ontario Peatlands Section is flat and poorly drained. About half of the Section consists of clayey deposits from Glacial Lake Agassiz. The lake deposits are covered primarily by bogs, swamps, fens, and other peatland vegetation. At the eastern edge of the MOP, the peatlands are acidic, deep, and old (>4,000 years) and support extensive areas of acid peatland communities such as black spruce bogs and poor swamp forests. At the western edge of the Section, the peatlands are richer in minerals, shallower, and younger (~1,000 years). Tamarack swamps, rich fens, and other rich peatland communities tend to be common in this part of the Section. Some areas, especially along the eastern and southern borders of the MOP in the Littlefork Vermillion Uplands Subsection, have uplands formed by glacial till that was eroded and flattened by wave action from Glacial Lake Agassiz. Mesic and wet forests of aspen, paper birch, spruce, balsam fir, white cedar, and black ash are typical in these areas. Uplands formed of sandy shoreline deposits that mark recessional stages of Glacial Lake Agassiz are present across MOP. These low, sandy uplands are less extensive than either the peatlands or glacial till uplands. They are characterized by fire-dependent forests of jack pine or red pine. Field Guide to the Native Plant Communities of Minnesota: The Laurentian Mixed Forest Province (DNR, 2003) Within each section are several layers of further subdivision. For planning purposes, the staff team has determined that an appropriate level of study can be found at the landscape ecosystems level. The landscape ecosystems units of land identified in Map 1provide a way for managers to analyze the resource base across reasonably-sized areas of land that exhibit a fairly consistent set of characteristics. These units will follow the convention of being called Landscape Ecosystems. Beltrami County Forestry Management Plan Assessment 46

3 Beltrami County Forest Management Planning is providing ecological information in this format so that it can easily be understood and used by forest managers, partners and the public. This analysis is for long-range planning purposes only. Individual site-level determinations as to the ecological status of a particular stand will be made by the forester when investigating treatment needs and options. Map 3-9 Beltrami County Forestry Management Plan Assessment 47

4 Soils According to the MNDNR, soils and wetlands in Beltrami County can be grouped into two areas. The first, located in the north contiguous with the Northern Minnesota and Ontario Peat lands (MOP), is the Agassiz Lowlands subsection. The majority of the rest of the county falls into the Chippewa Plains subsection (analysis, Soils in the Agassiz Lowlands subsection are predominantly organic (Dept. of Soil Science, Univ. of Minnesota 1980c, 1981b). There are a greater percentage of organic soils in the center of the lake basin, with increased amounts of poorly drained mineral soils near the edges. About 75% of the soils are peats in this portion of the basin. Peat depths can exceed 15 feet (Heinselman 1963). Map 3-10 Beltrami County Forestry Management Plan Assessment 48

5 Soils are classified primarily as Hemists, Aqualfs, and Aquents (Anderson and Grigal 1984). Hemists occupy the center of the lake basin, whereas Aqualfs and Aquents are along the margins of the basin. Soils in the Chippewa plans range from sandy to clayey, depending on the parent material. Most fall in the Alfisol, Entisol, or Histosol orders. On moraines, most soils are loamy well to moderately well drained and are classified as Boralfs. Soils on the outwash plain are dominantly sandy and excessively well drained. They are classified as Psamments (young, undeveloped sandy soils). Landscape Ecosystem Boreal Hardwood Conifer Dry Mesic Pine Dry Mesic Pine/Oak Table 3-3 Acres of County Wetland 16,348 1,895 10,593 Dry Pine 1,865 Mesic 20 Northern Hardwoods White Cedar 3263 Swamp Total 33,983 [Above information provided by MNDNR Ecological Classification System website.] Wetland and Present Land Cover and Use The hydrology of the Agassiz lowlands is virtually level and the drainage network reflects that. Extensive ditching of the peatlands was done in the earlier part of this century in an effort to turn this land into an agricultural nirvana. These efforts were unsuccessful however. The Big Fork and Rainy Rivers are the largest rivers running through the subsection. The Rainy River forms part of the northern boundary of the subsection and the state. There are three large lakes that are remnants of the Glacial Lake Agassiz. They are Lower Red Lake, Upper Red Lake and Lake of the Woods. Currently, forestry and recreation are the major land uses. Black spruce, jack pine, and quaking aspen are the most common species utilized for paper making and sawlogs. Recreation and tourism are associated with the three large lakes, with dozens of other lakes in use throughout the area. In the Chippewa Plains subsection, the major river is the Mississippi River. The headwaters is just to the south in the Pine Moraines and Outwash Plains Subsection. Two large bodies of water are present they are Lake Winnibigoshish (a reservoir) and Cass Lake. The drainage network throughout the subsection is poorly developed due to the age and characteristics of the landform. Much of this subsection is presently forested and forestry is one of the most important land uses. Aspen is the most common tree Beltrami County Forestry Management Plan Assessment 49

6 species. It is found in both pure stands and mixed stands with birch, maple, oak, white spruce, jack pine, and red pine. Tourism and recreation is the other important land use. There are many lakes present and most are developed with summer homes. Agriculture is important locally, particularly in the western part. [Above information provided by MNDNR Ecological Classification System website.] Map 3-11 Beltrami County Forestry Management Plan Assessment 50

7 BOREAL HARDWOOD CONIFER LANDSCAPE ECOSYSTEM BOREAL HARDWOOD CONIFER LANDSCAPE ECOSYSTEM Description: Fire-sensitive, all-aged, brushy, aspen/fir/birch forests of somewhat poorly drained loamy soils over clayey soils, flat to moderately rolling habitats. This landscape comprises 30.8% of County-managed forest land. Composition and Structure Historically, this LE was dominated by mixed stands composed of aspen, paper birch, balsam fir, and northern white cedar. White pine, red pine, ash, basswood, bur oak, white spruce, and elm were also present with minor amounts of red maple, sugar maple, red pine and jack pine. Red maple, aspen, black ash and balsam fir are the most prevalent trees regenerating in the understory of mature stands. The aspen and black ash occurs where small pockets of several trees have blown down. Red maple and balsam fir can regenerate without a disturbance. This system occurs on nutrient rich, moisture transition areas between sugar maple dominated uplands and lowlands with saturated soils. Soils of this system are saturated during the spring and dryer during the summer months. On County lands, over half of this landscape is comprised of aspen cover type. Relatively significant numbers of acres Cover Acres Percentage Type Ash Lowland 1.21 Hardwoods 427 Aspen Birch Balm of.77 Gilead 270 Northern Hardwood 5942 Oak White Pine Red Pine Jack Pine White.13 Spruce 47 Balsam Fir Black 4.35 Spruce 1523 Tamarack White.87 Cedar 3058 COA Grand Total contain aged Northern Hardwoods, lowland Black Spruce and White Cedar. Beltrami County Forestry Management Plan Assessment 51

8 Ecology The following maps provide an overview of the basic soil types and wetland distribution in the subsection. Map 3-12 Function (from the U.S. Forest Service) Wind was the dominant disturbance in this ecosystem, with an estimated stand replacement return interval of years. Stand replacement fires occurred at intervals of years. Surface fires occurred, but they did not cause significant tree mortality or affect successional trajectory. Beltrami County Forestry Management Plan Assessment 52

9 Map 3-13 Outbreaks of the eastern spruce budworm caused mortality of balsam fir and white spruce stands, and stand replacement fires frequently followed these epidemics. This created conditions favorable to establishment of even-aged aspen, paper birch, and tamarack stands. Individual tree mortality and small groups of blown down trees provided release or regeneration opportunities for the mixture of species present. Without disturbance the stands tended toward a northern hardwood climax without sugar maple. These sites are too wet for sugar maple to competitively reach climax. Thus the climax stand would Beltrami County Forestry Management Plan Assessment 53

10 be a mixture of red maple, basswood, balsam fir, white spruce, white pine, black ash and bur oak. The trees requiring more light regenerate in small openings created by trees that have blown down. DRY MESIC PINE LANDSCAPE ECOSYSTEM DRY MESIC PINE LANDSCAPE ECOSYSTEM Description: Fire-dependent, multiple-storied, brushy, pine/spruce/fir/birch forests of well-drained sandy/gravelly over loamy soils, undulating to steeply rolling habitats. This landscape comprises 10.0% of County-managed forest land. Composition and Structure Historically, this LE had mature and older stands dominated by a supercanopy of red pine and white pine. The subcanopy is a mixed stand of red maple and paper birch. White spruce, balsam fir, aspen, northern red oak, bur oak and bigtooth aspen are also found in this mixed subcanopy in some of the stands at lower stocking levels. Jack pine, red pine and white pine can occasionally occur in pure stands. Beaked hazel is the dominant shrub, which is present on most sites. Almost one-half of the landscape was characterized as multi-aged, beyond 175 years old. Cover Acres Percentage Type Ash Lowland 1.81 Hardwoods 233 Aspen Birch Balm of.86 Gilead 110 Northern 7.40 Hardwood 949 Oak White Pine Red Pine Jack Pine White 2.18 Spruce 280 Balsam Fir Black 2.82 Spruce 362 Tamarack White.23 Cedar 29 COA Grand Total On County lands, nearly one half of this landscape is comprised of Aspen cover type. It also includes small but noticeable quantities of young Norway Pine and older Jack Pine cover type. Ecology The following maps provide an overview of the basic soil types and wetland distribution in the subsection. Beltrami County Forestry Management Plan Assessment 54

11 Map 3-14 Beltrami County Forestry Management Plan Assessment 55

12 Map 3-15 Function (from the U.S. Forest Service) Fire was the more common natural disturbance factor in this ecosystem, with an estimated stand replacement return interval of years. Surface fires are estimated to have occurred at 10 to 40 year intervals. Wind events leveled stands at an estimated interval of 500-1,000 years. Surface fires removed the smaller red and white pine and most of the other species, creating conditions suitable for a new generation of trees to become established. If a longer period occurred without a surface fire, more tree species became established and grew into the main canopy, adding to the age and species diversification. Beltrami County Forestry Management Plan Assessment 56

13 Surface fires slowed this succession, and ultimately a stand replacement event would reinitiate an even-aged stand. With surface fires occurring regularly, multi-aged red and white pine dominated the landscape. Aspen and jack pine trees would succeed to longer lived species by years of age. Paper birch and northern red oak would succeed slightly later. Oak species would experience mortality at earlier ages when exposed to drought conditions. Surface fires allowed these species to remain in the stands as regenerating trees. Without surface fires, a stand understory comprised of balsam fir, white spruce and red maple became dominant. As balsam fir and white spruce grew up to the main canopy, they provided ladders fuels, allowing a stand replacement crown fire. These understory species are thought to be the climax species when fire is absent for long periods. DRY MESIC PINE/OAK LANDSCAPE ECOSYSTEMS DRY MESIC PINE/OAK LANDSCAPE ECOSYSTEMS Description: Fire-dependent, multiple-storied, brushy, pine/oak/aspen forests of welldrained sandy/gravelly over loamy soils, undulating to steeply rolling habitats. This landscape comprises 25.7% of County-managed forest land. Composition and Structure Historically, this LE had a jack pine, red pine, and white pine supercanopy either alone or as mixed pines. Cover Acres Percentage Type Ash Lowland 1.36 Hardwoods 384 Aspen Birch Balm of.63 Gilead 177 Northern 7.08 Hardwood 1996 Oak White Pine Red Pine Jack Pine White 1.73 Spruce 487 Deciduous trees usually Balsam Fir occurred as a subcanopy Black 4.66 comprised of quaking aspen, Spruce 1314 paper birch, northern red oak, Tamarack bur oak, red maple, and White 2.01 bigtooth aspen. These Cedar 568 deciduous trees grow to merchantable size and in the absence of pines the COA Grand Total deciduous trees would form a cover type. Beltrami County Forestry Management Plan Assessment 57

14 These forests in a mature condition, typically were a mix of pines and deciduous trees, frequently with 2 pine species and a subordinate canopy of 3 deciduous species. The pine coverage would be 50% to 75%, with the deciduous species making up the balance. Vertical diversity is definitely a part of these mature and older forests in this system. Oak species and red maple are present at higher levels than aspen and birch in the seedling/sapling size class. This suggests the oak and maple will replace the shorterlived aspen/birch as the stand ages. Pine species are only a minor part of the understory stocking. Black cherry is a minor species on the Chippewa National Forest. This ecosystem is where it is present as a minor stand component. Beaked hazel is the dominant shrub. Large leaved aster is the most commonly found forb. On County lands, approximately 1/3 of this landscape is comprised of aspen cover type. Norway and Jack Pines also make up significant portions of this landscape, with a wide array of other cover types present. Ecology The following maps provide an overview of the basic soil types and wetland distribution in the subsection. Function (from the U.S. Forest Service) Fire was the more common natural disturbance factor in this ecosystem, with an estimated stand replacement return interval of years. Usually, stand replacement fire events ranged from 10s to 100s of acres. Surface fires are estimated to have occurred at 5 to 40 year intervals. Wind events leveled stands at an estimated interval of 1,000-2,000 years. Surface fires appear to be the most common process effecting species composition and structure. These fires removed the understory species, setting mature and older vegetation growth stages back one growth stage. A hardwood tree species age class was created, dominated by sprouting, creating a mixed aged stand. Eventually, a stand replacement event would reinitiate an evenaged stand dominated by aspen, jack pine, red pine, paper birch, northern red oak, bur oak or white pine. These stands were usually a mix of species, comprised of two or more pine species and 3 or more deciduous species. Beltrami County Forestry Management Plan Assessment 58

15 Map 3-16 Beltrami County Forestry Management Plan Assessment 59

16 Map 3-17 As the stands approach 60 years of age, the canopy separation between red pine/white pine and the other species becomes apparent. Surface fires may also create canopy separation, by removing the thinned barked hardwoods and jack pine, while retaining the thicker barked red pine/white pine. Pine species would regenerate in patches where surface fires burned hotter. Aspen and jack pine cover types would succeed to longer-lived species by years of age. Paper birch and northern red oak would succeed slightly later. Oak species would experience mortality at earlier ages when exposed to drought conditions. Surface fires allowed these species to remain in the stands as regenerating trees. Beltrami County Forestry Management Plan 60

17 In the absence of stand replacement events and surface fires, red maple appears to be the dominant climax species in this ecosystem. DRY PINE LANDSCAPE ECOSYSTEM DRY PINE LANDSCAPE ECOSYSTEM Description: Fire dependent, even-aged to multiple-aged, open to somewhat brushy, jack pine or jack-red pine forests or jack pine/bur oak woodlands of somewhat excessively or welldrained sandy/gravelly soils, flat to strongly rolling habitats This landscape comprises 8.0% of County-managed forest land. Composition and Structure Historically, jack pine and red pine were the dominant species in this LE; aspen, paper birch, white pine, oak, white spruce and balsam fir were also present. Mixed cohorts of all three native pines were common in the understory. Initially, stands were even-aged, but became multi-aged as stands matured. Cover Acres Percentage Type Ash 8.08 Lowland 0.00 Hardwoods 0 Aspen Birch Balm of.47 Gilead 47 Northern.04 Hardwood 4 Oak White Pine Red Pine Jack Pine White 1.64 Spruce 163 Balsam Fir Black 1.19 Spruce 118 Tamarack White 0 Cedar 0 COA Grand Total Jack pine succeeds to red pine when stand replacement fires do not occur, at approximately 75 years of age. A third to half of the landscape was characterized as multi-aged, beyond 75 years old. The deciduous species very rarely reach the main canopy level unless their roots can reach the water table. Beaked hazel is the dominant shrub and can achieve high coverage that prevents tree regeneration. Bracken fern is almost always present. A good potential for blueberries exists. Forests occurred primarily as large patches of jack pine, with red pine, aspen, paper birch, and white pine scattered as small pockets or as individual trees. Patch sizes ranged from 100s-1000s of acres through the multiaged pine growth stage, and from s of acres in the oldest multi-aged red-white pine growth stage (CNF Landtypes Paper and matrix, Shadis-see official record). Beltrami County Forestry Management Plan 61

18 On County lands in this landscape, 40% of the cover is comprised of Norway Pine cover type, with another third comprised of Jack Pine cover type. Aspen makes up 13.9% of this cover type. Ecology The following maps provide an overview of the basic soil types and wetland distribution in the subsection. Map 3-18 Beltrami County Forestry Management Plan 62

19 Map 3-19 Beltrami County Forestry Management Plan 63

20 Function (from the U.S. Forest Service) This ecosystem experienced frequent stand replacement fires large patches of forest regenerated every years from intense crown fires (Frelich, 2000). Moderate intensity surface fires occurred every years. This LE also experienced largescale wind events every years. Surface fires provided opportunities for periodic bursts of jack pine and red pine regeneration. These fires also reduced fuels before they reached a point where high-intensity fires resulted in significant main canopy tree mortality. The multi-aged red pine and white pine is considered climax as long as some surface fires occur to provide a seed bed for regeneration. Under natural conditions, fire probably kept this ecosystem from succeeding to spruce-fir. MESIC NORTHERN HARDWOODS LANDSCAPE ECOSYSTEMS MESIC NORTHERN HARDWOODS LANDSCAPE ECOSYSTEMS Description: Fire-sensitive, all-aged, open, maple/basswood/ironwood/bi rch to maple/basswood/ironwood/ye llow birch forests of well to moderately well-drained loamy over clayey/loamy soils or silty/loamy over clayey soils, undulating to moderately rolling habitats. Only 0.1% of County managed lands fall into this cover type. Composition and Structure This LE usually occurs on fine-textured, well-drained, gently rolling till plains or stagnation moraines. Historically, the canopy was dominated by sugar maple, basswood, and paper birch. Often listed as associated Cover Acres Percentage Type Ash Lowland 0.00 Hardwood 0 Aspen Birch Balm of 0.00 Gilead 0 Northern Hardwoods 23 Oak White Pine Red Pine Jack Pine White 0.00 Spruce 0 Balsam Fir Black 0.00 Spruce 0 Tamarack White 0.00 Cedar 0 COA Grand Total species present is minor amounts are yellow birch, bur oak and northern red oak. Beltrami County Forestry Management Plan 64

21 Rare were balsam fir, red pine, white pine and northern white cedar, which are never abundant. Sugar maple, basswood and ironwood are the major understory trees and would comprise the species present in the main canopy of any stand undisturbed for long periods. The majority of the cover type in this landscape type is aspen, with one third in other hardwoods and less than 3% in pine. Ecology The following maps provide an overview of the basic soil types and wetland distribution in the subsection. Map 3-20 Beltrami County Forestry Management Plan 65

22 Map 3-21 Beltrami County Forestry Management Plan 66

23 Function (from the U.S. Forest Service) This ecosystem experienced large-scale wind and stand replacement fire events every years. Moderate intensity ground fires were infrequent in this LE. Regeneration occurred primarily by gap-phase replacement so stands usually were allaged. Very infrequent stand replacement fires increased tree species diversity by killing the trees and preparing a seedbed suitable for seral species. This allowed invasion by aspen and paper birch, which in turn were replaced by a host of longer-lived species (including white pine and oak species). Eventually, without further disturbance, sugar maple and basswood again dominated the site. The more common wind disturbance events occurred at small gapphase opening sizes of ¼ acre to 10s of acres in size. These disturbances released the sugar maple seedlings/saplings that were present in the understory. This same replacement with sugar maple occurred in the larger scale wind disturbance events when stand replacement fires did not follow the wind event. WHITE CEDAR SWAMP LANDSCAPE ECOSYSTEMS WHITE CEDAR SWAMP LANDSCAPE ECOSYSTEMS Description: Wetlands, all-aged, brushy, black ash or white cedar or tamarack forests of poorly drained mineral soils with muck or moss peat deeper than 10cm; interstitial water ph>6.4; closed depressions, bases of slopes, or drains of any mineral-soil landform. Cover Type Acres Percentage This landscape comprises Ash % of County-managed Lowland 1.08 forest land. Hardwoods 70 Aspen Composition and Structure White Cedar Swamp is more common than Semiterrestrial White Cedar on the Chippewa lands within the Northern Minnesota Drift and Lake Plains Section. The White Cedar Swamp system is dominated by northern white cedar and balsam fir. The Semiterrestrial White Cedar system is dominated by northern white cedar and balsam fir with occasionally Birch Balm of Gilead 741 Northern.49 Hardwood 32 Oak 0 0 White Pine 0 0 Red Pine 0 0 Jack Pine 0 0 White Spruce 0 0 Balsam Fir Black Spruce Tamarack White Cedar COA Grand Total Beltrami County Forestry Management Plan 67

24 paper birch. The following descriptions pertain to the White Cedar Swamp system. In Beltrami County, two-thirds of County lands in this landscape are aspen cover type. Lowland firs, spruce and cedar cover type make up approximately 10%. Ecology The following maps provide an overview of the basic soil types and wetland distribution in the subsection. Map 3-22 Beltrami County Forestry Management Plan 68

25 Map 3-23 Beltrami County Forestry Management Plan 69

26 Function (from the U.S. Forest Service) Wind is the more common disturbance agent occurring at intervals of years. These wind events impact pole size and large stands, returning them to the seedling-sapling growth stages. Tree species dominating the post wind event stands would include northern white cedar and black spruce. Stand replacement fire is estimated to occur at intervals between years. These fires would return any growth stage back to the seedling-sapling tamarack stage. Fire creates an excellent seed bed for tamarack. Climax stand conditions after a long period without a disturbance is estimated to be a multi-aged, mixed stand of northern white cedar and black spruce. Climax stand conditions after a long period without a disturbance is estimated to be a multi-aged, mixed stand of northern white cedar and black spruce. Beltrami County Forestry Management Plan 70