Riparian Forest Buffer NEDC Conservation Buffers Course

1. United States Department of Agriculture Riparian Forest Buffer NEDC Conservation Buffers Course

2. Objective Participants will be able to understand the basic design components of riparian forest buffer. Participants will step through a demonstration of a possible layout for a given site.

3. What: An area of predominantly trees and/or shrubs located adjacent to and up-gradient from watercourses or water bodies. Where: On areas adjacent to permanent or intermittent streams, lakes, ponds, wetlands and areas with ground water recharge that are capable of supporting woody vegetation.

4. What are the Effects of Riparian Forest Buffers? Initial Setting: Former riparian forests and habitat used for forage, cropland, speculation property, or other non-forest use. Livestock are excluded from riparian areas. Includes cutover riparian zones within forested areas. Start Riparian Forest Buffer (391) 1. Wood fiber in established plants 2. Woody plant root systems of established plants 3. Canopy cover and vertical vegetative structure from established plants LEGEND Associated treatment #. Created by practice pathway (+) increase; (-) decrease

5. What are the Effects of Riparian Forest Buffers? Initial Setting: Former riparian forests and habitat used for forage, cropland, speculation property, or other non-forest use. Livestock are excluded from riparian areas. Includes cutover riparian zones within forested areas. Start Riparian Forest Buffer (391) 1. Wood fiber in established plants D.1 (+) Wood fiber growth rate 2. Woody plant root systems of established plants D.11 (-) Crop production (non-woody) D.10 (-) Non-woody agricultural land D.2 (+) Carbon storage 3. Canopy cover and vertical vegetative structure from established plants D.9 (+) Aesthetics D.8 (+) Arboreal and understory habitat D.7 (+) Leaf/debris fall and woody plant mortality D.6 (+) Shade D.3 (+) Infiltration of precipitation and soil storage D.5 (-) Streambank erosion and sedimentation D.4 (+) Uptake of soil nutrients during growing season LEGEND Associated treatment #. Created by practice D.# Direct effect pathway (+) increase; (-) decrease

6. What are the Effects of Riparian Forest Buffers? Initial Setting: Former riparian forests and habitat used for forage, cropland, speculation property, or other non-forest use. Livestock are excluded from riparian areas. Includes cutover riparian zones within forested areas. Start Riparian Forest Buffer (391) 1. Wood fiber in established plants D.1 (+) Wood fiber growth rate 2. Woody plant root systems of established plants D.11 (-) Crop production (non-woody) D.10 (-) Non-woody agricultural land D.2 (+) Carbon storage 3. Canopy cover and vertical vegetative structure from established plants I.1 (-) Later wood fiber growth rate D.9 (+) Aesthetics Periodic tree removal D.8 (+) Arboreal and understory habitat D.7 (+) Leaf/debris fall and woody plant mortality D.6 (+) Shade I.5 (+) Forest and forest edge wildlife 4. Harvested wood fiber (manufactured wood products) and other tree/understory-related products D.3 (+) Infiltration of precipitation and soil storage D.5 (-) Streambank erosion and sedimentation I.3 (+) Detritus and large woody debris in streams I.4 (+) Trapping of sediment and sediment-attached pollutants I.6 (+) Recreation opportunities I.2 (-) Stream water temperature D.4 (+) Uptake of soil nutrients during growing season D.12 (+) Landowner income; contractor income I.7(+) Stream fauna, e.g., fish, invertebrates LEGEND I.8 (+) Denitrification of soil nitrates Associated treatment #. Created by practice D.# Direct effect I.# Indirect effect pathway (+) increase; (-) decrease

7. What are the Effects of Riparian Forest Buffers? Initial Setting: Former riparian forests and habitat used for forage, cropland, speculation property, or other non-forest use. Livestock are excluded from riparian areas. Includes cutover riparian zones within forested areas. Start Riparian Forest Buffer (391) 1. Wood fiber in established plants D.1 (+) Wood fiber growth rate 2. Woody plant root systems of established plants D.11 (-) Crop production (non-woody) D.10 (-) Non-woody agricultural land D.2 (+) Carbon storage 3. Canopy cover and vertical vegetative structure from established plants I.1 (-) Later wood fiber growth rate D.9 (+) Aesthetics C.2 (-) Crop business and support infrastructure C.1 (-) Atmospheric CO2 and greenhouse effect Periodic tree removal D.8 (+) Arboreal and understory habitat D.7 (+) Leaf/debris fall and woody plant mortality D.6 (+) Shade I.5 (+) Forest and forest edge wildlife 4. Harvested wood fiber (manufactured wood products) and other tree/understory-related products C.3 (-) Income and income stability (individuals and community) D.3 (+) Infiltration of precipitation and soil storage D.5 (-) Streambank erosion and sedimentation I.3 (+) Detritus and large woody debris in streams I.4 (+) Trapping of sediment and sediment-attached pollutants I.6 (+) Recreation opportunities I.2 (-) Stream water temperature D.4 (+) Uptake of soil nutrients during growing season D.12 (+) Landowner income; contractor income LEGEND I.7(+) Stream fauna, e.g., fish, invertebrates Associated treatment I.8 (+) Denitrification of soil nitrates C.8 (+) Recreation business and support infrastructure #. Created by practice C.4 (+) Quality of receiving waters D.# Direct effect C.6 (+) Income and income stability (individuals and community) C.5 (+) Wood-forest business and support infrastructure C.7 (+) Aquatic health for humans, domestic and wild animals; reduced costs I.# Indirect effect C.# Cumulative effect pathway (+) increase; (-) decrease

8. Riparian Zones – What they do … Riparian Buffers VTS_08_1.VOB Stream Corridor Zones

10. Design Elements Criteria for elements vary by purpose • Configuration (location and layout) • Species • Height • Density • Width and zones • Length • Management • Operation and maintenance • Limitations What are the defined purposes for riparian forest buffer?

11. Practice Purposes* 1. Create shade to lower water temperatures to improve habitat for aquatic organisms. 2. Provide a source of detritus and large woodydebris for aquatic and terrestrial organisms. 3. Create wildlife habitat and establish wildlifecorridors. 4. Reduce excess amounts of sediment, organic material,nutrients and pesticides in surface runoff and reduce excess nutrients and other chemicals in shallow ground water flow. 5. Provide a harvestable crop of timber, fiber, forage, fruit, or other crops consistent with other intended purposes. 6. Provide protection against scour erosion within the floodplain. 7. Restore natural riparian plant communities. 8. Moderate winter temperatures to reduce freezing of aquatic over-wintering habitats. *Source: NRCS National Standard 391 9. To increase carbon storage.

12. Merging Design Elements and Purposes • The following table* displays some of the design highlights by practice purpose • An assumption is made that the designer has already identified desired conditions and functions … and determined primary purposes for the riparian forest buffer • “Reduce excess contaminants” will be used to demonstrate the design of a riparian forest buffer *handout

13. Table Purposes - Riparian Forest Buffer (Acre) Code 391 Design elements for Riparian Forest Buffer 1. Create shade to improve habitat for aquatic organisms 2. Provide detritus & large woody debris for aquatic and terrestrial organisms 3. Create wildlife habitat and establish wildlife corridors 4. Reduce excess contamin-ants in surface and subsurface runoff 5. Provide harvestable crops of timber, fiber, forage, fruit, other 6. Protection against scour erosion within the floodplain 7. Restore natural riparian plant communities 8. Moderate winter temps to reduce freezing of aquatic habitats 9. Increase carbon storage Configuration (location and layout) Nearest to water with south and west sides favored /15 Both sides of water courses /20 Both sides and continuous to connect fragmented corridors /26 Down-gradient from source /31 Generally the largest extent of the available riparian area /38 Strategically placed to intercept overbank flows /43 Match bounds of the original PNPC* /26 Generally the largest extent of the available riparian area /48 Generally the largest extent of the available riparian area /38 Species Most tree and shrub species work /16 Native species mix; favor fast grow trees with most durable wood /21 Native species chosen for desired wildlife or match PNPC* /27 Fast-growth deep-rooted plants; dense ground cover for trapping /32 Species with marketable products /39 Species with flexible stems when young and resprouting capability /44 Duplicate seral species that can succeed to the natural potential /27 Favor shade-tolerant conifers /49 Fastest growing trees suitable for wood products /39 Height Equal to twice water-course width if possible/16 Favor tallest species for woody debris; low shrubs near water /21 Match heights of vegetation in PNPC* /27 Depends on selected species and site /32 Depends on selected species and site /39 Depends on selected species and site /44 Depends on selected species and site /27 Depends on selected species and site /49 Depends on selected species and site /39 Density** 50-80% tree canopy /16 50-80% tree canopy /21 Depends on habitat objectives /27 50-80% tree canopy /32 20-60% tree canopy depending on product /39 50-80% tree canopy /44 Match densities of the selected seral stage /27 >70% canopy /49 20-60%; depends on product /39 Width and zones Zone 1 is a minimum of 15 feet /17 Zone 1 is a minimum of 15 feet; widen to equal tallest tree height /22 Target wildlife flourish if widths match PNPC conditions /28 Zone 1 (15') and zone 2 (20') at least 35 feet or 100 feet for wider flood plains /33-34 Widen zones to largest extent of the riparian area /40 Wide enough to slow overbank flows /45 Widen zones to largest extent of the riparian area /28 Widen zones to largest extent of the riparian area /48 Widen zones to largest extent of the riparian area /40 Length Match the dimension of the non-shaded condition /17 Match the dimension of where detritus and debris are lacking /22 Sufficient length to connect target wildlife habitats /28 Match the dimension of the contaminant source area /35 Increase length to the longest extent of the riparian area /40 Increase length to strategically intercept overbank flows /45 Increase length to the longest extent of the riparian area /28 Increase length to the longest extent of the riparian area /48 Increase length to the longest extent of the riparian area /40 *Potential natural plant community, **How is desired density achieved? … continued next page Example

14. Purposes - Riparian Forest Buffer (Acre) Code 391 Design elements for Riparian Forest Buffer 1. Create shade to improve habitat for aquatic organisms 2. Provide detritus & large woody debris for aquatic and terrestrial organisms 3. Create wildlife habitat and establish wildlife corridors 4. Reduce excess contamin-ants in surface and subsurface runoff 5. Provide harvestable crops of timber, fiber, forage, fruit, other 6. Protection against scour erosion within the floodplain 7. Restore natural riparian plant communities 8. Moderate winter temps to reduce freezing of aquatic habitats 9. Increase carbon storage Management Periodically thin trees to create dense crowns and understory /18 Periodically thin trees but do not remove; direct felling towards water /23-24 Match silviculture to needs of target species or to create species richness /29 Periodically thin trees to maintain fast plant growth and dense ground cover /36 Perform cultural operations based on need of species and product(s) /41 Periodically thin trees to maintain fast tree growth and dense ground cover /46 Perform cultural operations that mimic natural development /29 Little to no management to maintain a closed canopy /50 Perform cultural operations based on need of species and product(s) /41 Operation and maintenance Replace dead stock early on and control damaging agents /18 Replace dead stock early on and control damaging agents /23-24 Natural mortality can increase habitat diversity /29 Replace dead stock early on and control damaging agents /36 Replace dead stock and continue needed cultural operations /41 Replace dead stock early on and control damaging agents /46 Usually very limited but replace dead stock early on /29 Usually very limited but replace dead stock early on /50 Replace dead stock and continue needed cultural operations /41 Limitations Little effect on wide water courses; species may not reach needed heights /19 Detritus provided early but large woody debris may take decades /25 Wildlife needs of may ex-tend beyond hydrologic riparian areas; predation /30 Combine with upland treatment; intercepts only part of subsurface flow /37 Markets can be transitory; assess the risk of product supply-demand /42 Large woody debris may transport and accumulate to other sites /47 Development of potential communities will take decades /30 Results may be geographic-ally and seasonally variable /51 Markets can be transitory; assess the risk of product supply-demand /42 *Potential natural plant community Example

15. Purpose: Create Shade Element: Configuration(location and layout) Nearest to water with south and west sides favored Late morning to mid afternoon sun can warm waters significantly if not shaded. Sun angle varies by season, latitude and, of course, by time of day. Understand what is happening at the site and plan accordingly. In mountainous terrain, elevation and topographic shading can influence layout priorities. Natural color Infrared What’s happening upstream?

16. Purpose: Create Shade Element: Species, Height, Density Most tree and shrub species work; height equal to twice watercourse width; 50-80% canopy Most adapted trees* and shrubs* provide benefit. Evergreens provide year-round shade. Extra height compensates for daily and seasonal sun angle changes. Large crowned trees can provide shade on east and north sides. *Choose from a list of adapted species in the local Field Office Technical Guide.

17. Before Purpose: Create Shade N This is the beginning of a 303d ‘temperature’ listed stream reach. Will your design work? Element: Width and Zones; Length Zone 1 is a minimum of 15 feet; match the dimension of the non-shaded condition Increase the width to insure a high level of shade if the riparian area is managed. The length and connectivity of buffers are key to affecting a stream system. After? A forested, cold-water fish stream enters cropland at mile 21. A “cool” tributary joins at mile 12. What length is needed?

18. Purpose: Create Shade Element: Management and O&M Periodically thin trees to create dense crowns and understory. Replace dead stock early on and control damaging agents. Proper silviculture is closely tied to both tree and understory species and desired canopy cover. Cut trees can be left for large woody debris or marketed. Closely follow BMP’s or local regulations designed for riparian areas. Canopy densities of 50-80% should be sufficient to provide shade. Maintain highest densities for narrow buffers.

19. Purpose: Create Shade Element: Limitations Little effect on wide water courses; species may not reach needed heights. Obviously, a riparian forest buffer installed on a small ownership along a ‘too-warm’ wide river or large water body will have little effect overall. For a watershed, a stream system analysis can show hot spots tied to fragmentation and help prioritize where buffers are needed.

20. Purpose: Detritus and large woody debris Element: Configuration (location and layout) Both sides of water courses Close proximity to the stream or water body insures that some leaf drop, twigs, and other detritus (and eventually large woody debris) enters the aquatic system. Detritus and large debris are particularly important for lower order stream/riparian food chains and downstream effects on higher order streams.

21. Purpose: Detritus and large woody debris Element: Species, Height, Density Native species, fast growth, durable wood; tallest species for debris, low shrubs for detritus; 50-80% canopy Native fauna (e.g., aquatic macroinvertebrates and soil organisms) have evolved with native plant species and detritus. They form the base of the food chain in stream corridor and riparian systems. High canopy densities insure a continuous supply of small and large materials.

22. Purpose: Detritus and large woody debris Element: Width and zones; Length Zone 1 is at least 15 feet; widen to equal tallest tree height; match dimension where detritus and debris are lacking A good design protects as much of the stream system as possible with wide and long riparian forest buffers. Trees planted within one mature tree length of the water have potential to become large woody debris. Even wider zones and debris support terrestrial wildlife populations. Detritus? Large Woody debris?

23. Purpose: Detritus and large woody debris Element: Management and O&M Periodically thin trees but do not remove; direct felling towards water; replace dead stock and control damaging agents ‘Clean’ forestry in riparian areas can harm aquatic and terrestrial wildlife by removing snags and down materials that provide nesting, loafing and escape cover. As trees become older, thinning can stimulate understory species/detritus and, if directionally felled, artificially accelerate the creation of large woody debris in and near water.

24. Purpose: Detritus and large woody debris Element: Management and O&M Periodically thin trees but do not remove; direct felling towards water; replace dead stock and control damaging agents Don’t underestimate the value of large woody debris in the riparian zone for terrestrial wildlife.

25. Purpose: Detritus and large woody debris Element: Limitations Large woody debris may take decades to develop … or maybe a century or more. Designs may include alternatives such as bird boxes or introducing cull logs from nearby harvests. Accumulations of logs and large wood can pose a risk to life and safety if moved downstream by flooding.

26. A B What’s better? Purposes: Wildlife habitat and corridors Restore natural plant communities Element: Configuration (location and layout) Both sides and continuous to connect fragmented corridors; match bounds of the original PNPC Designs should look first towards connecting fragmented riparian forests. Isolated patches may be poorly utilized or act as a magnet in areas dominated by herbaceous or crop cover types such as on agricultural or range lands. What is the PNPC?

27. Purposes: Wildlife habitat and corridors Restore natural plant communities At a minimum, reference sites should be identified by stream order and geomorphic condition or status of the water course. Element: Species, Heights, Density Native species for desired wildlife or match PNPC/stage; match heights to PNPC; density depends on habitat objectives or match applicable seral stage of PNPC Sources of information are Ecological Site Descriptions, historical accounts, and remnant and ‘reference’ sites.

28. Purposes: Wildlife habitat and corridors Restore natural plant communities Element: Width and zones; Length Target wildlife flourish if widths match PNPC conditions; sufficient length to connect target wildlife habitats Design analysis should include the determination of stream geomorphic conditions and associated PNPC/seral stages. What has happened to the stream system in this landscape? Before agricultural use, what were the bounds of the riparian area? Are riparian buffers sufficiently wide and long?

29. Purposes: Wildlife habitat and corridors Restore natural plant communities Element: Management and O&M Match silviculture to needs of target species or to create species richness; natural mortality can increase habitat diversity; mimic natural development After buffers have established, perform only those cultural operations consistent with the development of PNPC. As a buffer matures to tall and full canopies, patches or openings can be added to increase edge effect and habitat variety.

30. Purposes: Wildlife habitat and corridors Restore natural plant communities Element: Limitations Needs of target species may extend beyond hydrologic riparian areas; development of potential communities will take decades; increased predation The value of riparian habitat is greatly increased if adjacent upland habitat is created and complementary. For some wildlife species, too narrow of a riparian/upland corridor may introduce nuisance or competitive wildlife. Full functionality takes time. Predator populations will increase also. Prescribed grazing and several years of use exclusion will initiate the slow recovery of this area’s natural woody vegetation.

31. Purpose: Reduce excess contaminants Element: Configuration (location and layout) Down-gradient from source Clearly understand the origin and boundaries of the source contaminants and locate the buffer down-gradient from them. Contaminants (sediment, chemicals, etc.) may be transported by surface sheet or concentrated flows or by subsurface flows. Consult with geologists for complex subsurface flows.

32. Purpose: Reduce excess contaminants Element: Species, Height, Density Fast-growth, deep rooted trees; dense ground cover for trapping; tallest trees; 50-80% canopy In general, adapted trees* with the fastest growth rates, deepest roots and tallest heights planted at densities to optimize growth are best for uptake of excess nutrients from upland sources. Canopy densities below 50% usually do not occupy the site fully; densities over 80% usually slow growth and vigor. For trapping of surface contaminants, dense close-to-ground species* should be favored. *Choose from a list of adapted species in the local Field Office Technical Guide.

33. Purpose: Reduce excess contaminants Note: This diagram is in Chapter 3h Element: Width and Zones Zone 1 (15') and zone 2 (20') at least 35 feet or up to 100 feet for wider flood plains These distances are established as national minimum criteria and come from available research*. Zone 1 is closest to the water; zone 2 is adjacent and up-gradient. *see next slide

34. Purpose: Reduce excess contaminants • Limited research • Indicates buffers of 10 meters in width or greater are significantly effective in reducing phosphorus and nitrates for many agricultural settings. • Inconsistencies/Gaps in Research • Subsurface flows in many settings bypass riparian buffer root systems • Early studies indicate buffers can remove pesticides, organics, metals • Very limited studies on pathogen removals are inconsistent Element: Width and Zones Phosphorus Removal from Surface Runoff (Wenger 1999*). *Wenger, S. 1999. A Review of the Scientific Literature on Riparian Buffer Width, Extent and Vegetation. Institute of Ecology, University of Georgia, Athens, GA. Subsurface Nitrate Removal (Wenger 1999*).

35. Purpose: Reduce excess contaminants Element: Length Match the dimension of the contaminant source area Length is measured parallel to the shoreline or bank and should match the dimension of the source or “problem” area Consider extending to the full length of the water body, water course, or ownership ... or beyond to connect forest-to-forest.

36. Purpose: Reduce excess contaminants • Element: Management and O&M • Periodically thin trees to maintain fast plant growth and dense ground cover. Replace dead stock early on and control damaging agents. • Proper silviculture is closely tied to both tree and understory species and desired canopy cover. Cut trees can be left for large woody debris or marketed. Closely follow BMP’s or local regulations designed for riparian areas.

37. Purpose: Reduce excess contaminants • Element: Limitations • Combine with upland treatment; intercepts only part of subsurface flow. • Study the pictures. Can a riparian forest buffer be fully effective and the sole practice to stop excess contaminants? • A variety of cropland practices (e.g., conservation crop rotation, conservation cover, nutrient and pest management, other kinds of buffers) are necessary for a complete Resource Management System.

38. Purposes: Provide harvestable cropsIncrease carbon storage • Potential products: • timber (sawlogs, post, poles, veneer) • fiber (pulp, firewood, energy biomass) • forage (livestock) • fruit (nuts, berries) • other crops (ginseng, mushrooms, herbs and floral greenery, etc.) Element: Configuration (location and layout) Generally the largest extent of the available riparian area Marketable products depend on current and future demand. A small acreage of products yields small profits unless a high-value, niche market is tapped. A riparian buffer’s wood growth, products and increased soil OM sequesters additional carbon.

39. Purposes: Provide harvestable cropsIncrease carbon storage Short-rotation, dense canopy poplar Element: Species, Height, Density Species with marketable products and fast growth; species-dependent heights; 20-60% canopy depending on products Choice of species, cultivars, their heights and canopy cover depend on adaptability to the site and moisture regime. The landowner needs to assess the risk of demand for the particular product(s). Faster growth generally reduces ‘opportunity’ costs. Understory ginseng Softwood sawlogs and forage Walnut veneer and nuts

40. Purposes: Provide harvestable cropsIncrease carbon storage A wide buffer Element: Width and zones; Length Widen zones to largest extent and length of the riparian area Product quantity is tied to using the greatest acreage available even though riparian buffers are relatively narrow. Consider extending the planting to adjacent upland areas if possible. High-value specialty products may not take as much area and may fit into narrower plantings. A narrow buffer A more complex situation with active streambank erosion, roads and a variety of soils

41. Purposes: Provide harvestable cropsIncrease carbon storage Element: Management and O&M Cultural operations based on species and products; replace dead stock and continue cultural activities as needed Management, operation and maintenance are closely tied to the particular products being grown. Consult technical guides and specialists for specific cultural operations that will be needed.

42. Purposes: Provide harvestable cropsIncrease carbon storage Element: Limitations Markets can be transitory; assess the risk of product supply/demand Assessing the supply and demand for a species/product under consideration cannot be overemphasized. Long-term product development must coincide with future demand. Producing certain products may not be compatible with other riparian buffer functions and purposes. Forest grazing (inset) diminishes understory diversity and vertical structure. This impacts local wildlife and trapping/uptake of contaminants by plants.

43. Purpose: Protect against floodplain scour • Element: Configuration (location and layout) • Strategically placed to intercept overbank flows • Where are the flood-prone areas? • Within these areas, what fields have evidence of scour? (e.g., landowner interview, concentrated flow erosion scars) • Are scour areas old overflow channels? • What is the feasibility of treatment? Can scour really be discouraged? Corn field scour in southwest Wisconsin

44. Purpose: Protect against floodplain scour Element: Species, Height, Density Species with flexible stems when young and resprouting capability; species-dependent heights; 50-80% canopy When young, the plants will have to withstand fast flows and mechanical damage from moving debris. When older, the plant community will function more effectively. (Will the potential debris buildup be tolerable?)

45. Purpose: Protect against floodplain scour Element: Width and zones; Length Wide and long enough to intercept and slow overbank flows In the lower figure, the red arrow is a scour area. If the objective includes keeping most of the field in cropland, where would a “scour” protection buffer be placed and how would it be dimensioned? What might happen over a 20 to 30 year period? Flood-prone area

46. Purpose: Protect against floodplain scour Element: Management and O&M Periodically thin trees to maintain fast tree growth and dense ground cover Spacing of trees depends on the species and amount of understory desired. Debris may or may not need to be removed. Determine if any trapped debris is detracting from the buffer’s function. Also consider wildlife use of debris.

47. Purpose: Protect against floodplain scour Element: Limitations Large woody debris may transport and accumulate to other sites Also, trees not adapted to long inundation may die or become weakened and prone to pest damage. Consider a land use change if scour areas are persistent. The meander of streams is a natural phenomenon of fine and coarse sediment movement. Trees were 3 miles from the Mississippi River. In most areas of the locale depicted and affected by the 1993 flood, vegetation was submerged too long and died.

48. Purpose: Moderate winter temps / freezing Element: Configuration (location and layout);Width and zones; Length Generally the largest extent of the availableriparian area; Widen zones and increaselength to the largest extent of the riparian area This purpose is probably most relevantin the northern latitudes and higher elevationsbut can be applicable wherever freezingconditions are a concern. Research tosupport design criteria specifically forreducing freezing of aquatic over-winteringhabitats is sketchy. Generally, deep streamsbordered by trees and shrubs are less likely tohave ice build-up than shallow, exposed streams.Conditions are most suitable for ice formation include cold clear nights with large heat loss by long-wave radiation and a strong wind accompanied by cold, dry air which produces large convective and evaporative heat losses. References?

49. Purpose: Moderate winter temps/freezing Element: Species, Height, Density Favor shade-tolerant conifers; species-dependent heights; >70% canopy Generalized classes of thermal cover effectiveness Wide shallow streams cool most rapidly A dense canopy reflects heat radiation back to the stream surface, especially at night

50. Purpose: Moderate winter temps / freezing Element: Management and O&M Little to no management to maintain a closed canopy; very limited O&M but replace dead stock early on Favor continuance of a dense, multi-storied evergreen canopy. Consider widening if adjacent land becomes available.