Forest encroachment and forest ingrowth have negatively affected the distribution and health of interior grasslands. In the Cariboo-Chilcotin, it is estimated that 11% of the 188,400 ha of grassland have been encroached since 1965 (Cariboo-Chilcotin Grasslands Strategy Working Group 2001). Ingrowth has resulted in higher tree densities in open forests with significant impacts on shade intolerant species. The implications of encroachment and ingrowth in the Cariboo are far reaching, ranging from declines in biodiversity, rangeland size and quality of forage to increases in overall fire risk.

Grassland areas in which encroachment and ingrowth are currently extensive are disclimax (disturbance climax) ecosystems maintained by fire. In the absence of disturbance, these ecosystems have sufficient soil moisture to support trees and will convert to forested lands. Prior to European settlement, fires set by aboriginal peoples and lightening are believed to have maintained these ecosystems in an early seral stage. European settlement resulted in a reduction in fire frequency through disruption of historic fire management practiced by aboriginal peoples. The introduction of domestic animals and the advent of grazing also helped reduce fire frequency as overgrazing reduced the quantity and continuity of grassland fuels. Fire suppression activities since the 1960s resulted in a further reduction in fire frequency and facilitated encroachment of the grasslands.

Restoration of the grasslands is a priority for biodiversity conservation and rangeland management. The Ministry of Forests and Range (MOFR) retained B.A. Blackwell & Associates Ltd. to identify key areas where encroachment and ingrowth have occurred, and where ecosystem restoration treatments could be implemented to reduce tree density and restore grassland habitat.

The identification of areas suitable for treatment was based partially on encroachment mapping completed by Kristie Iverson and partially on work completed as part of the Fraser River/Cariboo Grassland Restoration Plan (Blackwell et. al. 2007).

The focus of this work was to identify and prioritize target treatment areas within the Fraser Grassland that will be the focus of detailed prescription development and treatments over the next three to five years.

2.0 Study Area

The 75,692 ha study area is located 50 km west of 100 Mile house, adjacent to the Fraser River (Map 1). It is located in principle grassland habitat of the Cariboo-Chilcotin. The area has been extensively used for cattle operations and over one third is privately owned land. First Nations live and practice cultural activities throughout the study area, and it is believed that historic burning by these peoples is a key factor behind the existence and distribution of the much of the grasslands.

Location Map.jpg

Map 1. Shows the location of the study area 50 km west of 100 Mile House.

Topography is varied in the study area. Rising from the steep scarps of the eastern shores of the Fraser River, it continues up rolling hills and drainages extending 18 km east of the river. Most proposed treatment areas are located on southwest to southeast facing slopes, although there are exceptions. The Study area covers mapsheets: 92I091, 92; 92O029.30, 39, 40, 49, 50, 59, 60, 69, 70, 79; and 92P.001, 002, 011, 021, 031.

The study area includes five Biogeoclimatic (BEC) Units:

· Bunchgrass - Very Dry Hot (BG xh3)

· Bunchgrass - Very Dry Warm (BGxw2)

· Interior Douglas-fir - Very Dry Mild (IDFxm)

· Interior Douglas-fir - Very Dry Warm (IDFxw)

· Interior Douglas-fir - Dry Cool (IDFdk3)

Precipitation in these subzones is generally low and summers are warm to hot. The BGxh3, xw2, and IDFxw are considered the BEC units that contain the principal grassland habitat in the study area. The BGxh3 is the driest and warmest, receiving the least amount of precipitation. Vegetation is dominated by grasses and sagebrush species (1997 Steen and Coupe). The BGxw2 occurs above the BGxh3 and below the IDF units. It is cooler and is distinguished by the scarcity of big sagebrush (1997 Steen and Coupe). The IDFxw occurs above the BGxw2 and is the driest and warmest of the IDF subzones and has ponderosa pine as a stand component on zonal sites (1997 Steen and Coupe). The IDFxm occurs above the IDFxw and is transitional to the IDFdk3. It is characterized by dominant Douglas-fir interspersed with parkland including grass species such as porcupine grass and pinegrass (1997 Steen and Coupe). The IDFdk3, a variant of the IDFdk subzone, extends to 1350 m, is cooler, and receives more precipitation than the other units (1997 Steen and Coupe). Grasslands in this unit are much less common as the climatic conditions are better suited to tree growth than the drier, warmer BEC units.

Map 2. Biogeoclimatic Units in the study area.

3.0 Invasive Species

Invasive species are a considerable concern in the Fraser Grasslands. Invasive species can displace native species and result in extirpation of local populations. The displacement of native species by often inedible invasive species can degrade forage and habitat for native wildlife and forage for cattle due to decreased palatability, nutritional value, and forage biomass.

Fifteen invasive species were recorded in the study area (Land Resource Data Warehouse Invasive Plant records) (Table 1). In total, 192 records exist for invasive species in the study area (Map 3). The full records for these invasive species occurrences are located in Appendix A - Invasive Species Records.

Of the polygons delineated for treatment, only polygon 25 had an invasive species record (Canada thistle) within its boundaries. However, records of invasive species are incomplete and it is expected that other invasive occurrences will be identified during prescription development. The Invasive Alien Plant Integrated Pest Management Plan for the Range Branch Ministry of Forests and Range Southern Interior (2008) should guide invasive species management during prescription development.

The following categories were taken from the Invasive Alien Plant Integrated Pest Management Plan for the Range Branch Ministry of Forests and Range Southern Interior (2008). These indicate the level of risk associated with each invasive species. Treatment prescriptions should prioritize invasive species according to the abundance in the treatment area and the risk associated with each species.

Category 1 - Invasive plants that pose extreme risk for invasion and spread into undisturbed sites. These species have the ability to become the most abundant plant across a site or area, often becoming the dominant species. The invasive may occur slowly or rapidly.

Category 2 - Invasive plants that pose a high risk of invasion and spread in undisturbed sites. These species may become very prevalent and abundant across some or all areas within a site, but may require some disturbance to become the dominant species.

Category 3 - Invasive plants that pose a moderate risk to invasion and spread into new areas and often requires disturbance to become significantly abundant in an area.

Category 4 - Invasive plants that pose a low to moderate risk of invasion and spread into undisturbed sites. Disturbance is required to allow these species to become abundant.

Table 1. Shows the species labels, english, and Latin names and risk category for invasive species recorded in the study area.

Map Label	English Name	Latin Name	Category
BU	Burdock spp	Arctium spp	3
BW	Blueweed / bluegrass	Echium vulgare	2
CB	Common burdock	Arctium minus	3
CT	Canada thistle	Cirsium arvense	2
DK	Diffuse knapweed	Centaurea diffusa	2
DT	Dalmatian toadflax	Linaria dalmatica	2
FS	Field scabious	Knautia arvensis	2
HA	Hoary alyssum	Berteroa incana	2
KS	Knapweed species	Centaurea spp.	3
LS	Leafy spurge	Euphorbia esula	1
NT	Nodding thistle	Carduus nutans	4
OD	Oxeye daisy	Leucanthemum vulgare	2
SK	Spotted knapweed	Centaurea biebersteinii	1
TC	Common tansy	Tanacetum vulgare	2
VL	Velvet leaf	Abutilon theophrasti	Not Listed

During treatment operations, soil disturbance and new trail or road development should be minimized to reduce the potential for invasive plants to become established and to ensure seed beds of native species remain intact. Where machinery has been working in the vicinity of invasive species, it should be carefully cleaned prior to relocation to reduce the potential introduction of invasive species to other areas. Where invasive species are noted in the field, control measures should be incorporated in the treatment prescriptions.

Map 3. Shows recorded invasive species codes and locations as per LRDW records.

4.0 Treatment Area Designation

Treatment areas were assigned using a combination of available GIS data, typing of areas on orthophotos in a GIS environment, and field visits conducted to ground truth photo and data interpretations. Preliminary treatment areas were identified using the data and orthophotos. After field reconnaissance, the areas were further refined and attributes inconsistent with observations and data were corrected.

GIS Methods

To identify areas where restoration treatments were appropriate and identify constraints, available GIS data was compiled and overlaid on orthophotos.

Layers included:

· Grassland encroachment (as mapped by Kristi Iverson)

· Priority polygons identified in the Fraser/Cariboo Grassland Restoration Plan

· Ownership

· Indian Reserves

· Biogeoclimatic Units

· Old Growth Management Areas

· Ungulate Winter Range

· Sensitive and Non-sensitive element occurrences

· Range Tenures

· Access

· Contours used to generate slope, aspect and elevation

· Crown Tenures

· Orthophotos

The grassland encroachment polygons and priority polygons from the Fraser/Cariboo Grassland Restoration Plan were used to identify areas where treatment was appropriate and should be considered. These areas were then reviewed on the orthophoto with other GIS layers to delineate and attribute polygons.

Ownership layers were used to exclude private lands from treatment consideration. Extensive private land ownership in the study area was one of the primary constraints in identifying areas for treatment. The total study area is 75,692 ha of which 20,415 (27%) are private lands and 5,378 (7%) are reserve lands. These lands comprise 34% of the total study area, however the ranchlands are primarily located in the key grassland ecosystems, so the actual percentage of private lands to grasslands is probably higher.

Biogeoclimatic units were used to help prioritize treatment areas with a focus on the three key grassland BEC Units: BGxh3, BGxw2, and the IDFxm.

Where treatment areas intersect Old Growth Management Areas, Ungulate Winter Ranges, Woodlots, or Masked Sensitive and Non-sensitive species at risk element occurrences, these were incorporated in the database to indicate whether a treatment area intersected one of these layers (7.0 Summary Table of Treatment Units).

Access was also a consideration and five classes were defined to help identify treatment areas that would be logistically easier to treat and involve lower costs:

1. Very High - Road through treatment area

2. High - <100 m to road

3. Moderate -100 to 300 m to road

4. Low – 300 to 500 m to road

5. Very Low >500 or access difficult due to topography

Contour data was used to derive average slope, aspect, and elevation for the treatment areas. Slopes >35% were used to determine operability constraints on machinery use where a harvest treatment was considered a possibility. Slope, aspect, and elevation were also used to aid interpretation of the orthophotographs.

Field Review

Field reconnaissance was conducted during the fall of 2008. The purpose of field work was to identify encroachment and as ground truthing of photo interpretation. This provided the framework for initial delineation and attributing of the polygon database. A field review of the proposed treatment areas was conducted in March 2009 by helicopter to confirm that delineated areas were correct and that appropriate treatments were assigned. Forty-seven of 106 sites (44%) were inspected and data regarding treatment type, priority, encroachment status, and access were recorded using a Trimble Nomad GPS unit and ESRI ArcPad 7.1. Photos of the treatment areas were also taken. This data was then used in to help interpret and assign final attributes to the treatment areas where photo interpreted attributes were incorrect or difficult to interpret on the photographs.

Map 4. Shows field inspection locations.

4.1 Treatment Priority Rationale

Treatments were assigned to five priority classes based upon their assessed attributes:

1. Very High

2. High

3. Moderate

4. Low

5. Very Low

Treatment priority was based upon a combination of characteristics:

· BEC Unit was considered with BG units and IDFxw identified as providing principal grassland habitat and therefore the most suitable areas to conduct restoration. However, this did not preclude treatment areas in other BEC units from being assigned Very High or High priorities based upon the combination of their other attributes.

· Degree of encroachment was a primary consideration, with more heavily encroached areas being given a greater weighting.

· Polygons that appeared to be associated with wetlands or open water within a closed forest matrix were rated low-moderate depending upon location, access and size.

· Size of the unit and continuity with adjacent grasslands was considered, with larger areas bordering grasslands given a higher priority over isolated, small openings.

· Access was considered, although unless access was considered ‘Very Low’ it was of less relative importance than other attributes.

· Slope was considered and areas with greater than 60% slopes were assigned to “Very Low” priority due to operability constraints.

5.0 Treatment Areas

In total, 106 polygons were identified for more detailed field assessment, prescription development, and treatment. The total area assessed was 4,171.3 ha. Map 5 shows the locations of the treatment areas and the mapsheets covering the study area. Table 2 shows the priority ratings of the treatment areas by BEC unit. Most of the High and Very High treatment areas are located in the IDFxm due to the greater size of this area when compared to the BGxw2. The Very Low areas identified in the IDFxw are on old scarps, have average slopes of 60% or greater, and are considered operationally constrained.

Table 2. Summary of areas by Treatment Priority and BEC Unit.

	BEC Unit
Priority Rating	BGxw2	IDFdk2	IDFdk3	IDFxm	IDFxw	Total Area (ha)
Very High	158.8	37.7	546.4	823.6		1566.5
High	102.2		334	146.3		582.5
Moderate		6.5	163.8	202.7		373
Low		9.3	166.5	62.8		238.6
Very low					1410.7	1410.7
Total Area (ha)	261	53.5	1210.7	1235.4	1410.7	4171.3

Map 5. Shows the location of the delineated treatment areas and corresponding mapsheets.

Treatment areas with Moderate to Very High priority ratings were assigned a treatment year from Year 1 to 3. This was done to help in scheduling treatments. Treatment years were assigned based upon spatial arrangement of the delineated polygons. Year 1 was assigned to areas in the north of the study area; Year 2 is the central region; and Year 3 is the most southern portion of the study area. If additional treatment area is desired, treatments designated as low priority can be reviewed for inclusion within this three year planning window.

Table 3. Summary of the areas by treatment year.

Treatment Year	Area (ha)
1	859.5
2	1088.4
3	574.1
Total	2522.0

5.1 Red and Blue Listed Species

All non-sensitive red and blue listed species and masked sensitive occurrences were downloaded from the Land Resource Data Warehouse (LRDW). Where occurrences intersect treatment areas, these were included in the Summary Tables for each treatment unit (shown in Section 7.0).

The Conservation Data Centre (CDC) was accessed to compare Masked Sensitive and Non-sensitive records with LRDW records as issues between data compatibility have been noted. One record missing from LRDW for Spea intermontana (Great Basin spadefoot toad) was noted and included in the relevant treatment unit in the Summary Tables in Section 7.0.

Only non-sensitive records for Great Basin spadefoot toad and Arnica chamissonis (meadow arnica) were recorded in treatment units. However, suitable habitat for other species exists in the treatment areas and treatment prescriptions will require a qualified biologist to identify species and habitat as well as recommendations to mitigate any adverse treatment impacts. A summary of all LRDW non-sensitive species and know locations is shown in Table 5 and Map 6.

Masked sensitive occurrences recorded in the study area are shown in Table 4. Masked areas are typically more difficult to use in planning as they highlight broad areas without specific species locations. The MOFR should work with MOE to provide the details of habitat occurrence prior to developing detailed prescriptions. Ministry officials should also review the species in question and identify species which may be impacted by treatment implementation.

Table 4. Feature identification numbers for LRDW recorded masked sensitive occurrences in the study area.

1468	3862	3878	6316	11322	25527
3860	3864	4484	11319	25456	32972

Table 5. Red and blue listed LRDW recorded species that occur within the greater study area.

Map 6. Non-sensitive occurrences in the study area.

Map 7. Masked sensitive occurrences in the study area.

5.2 Treatment Types and Objectives

Treatment objectives are to reduce tree cover densities to those similar to pre-settlement conditions and to restore grasslands to open or sparsely treed conditions.

Treatments will focus on the removal of smaller diameter trees and encroachment. The retention of veteran trees, where present, is important to maintaining structure that contributes to grassland and open forest biodiversity. However, in many cases, historic structure may no longer exist and diameter distributions will reflect encroachment pulses. In these areas, retention strategies are required to ensure sufficient structure is maintained such that large diameter tree recruitment is possible in the future. It is important that retention strategies consider ecological conditions where tree survival would be favoured, such as draws or depressions where edaphic conditions provide relatively moister soils. Groups and scattered individuals should be retained and the creation of homogenous retention patterns should be avoided. In terms of species preference, surviving ponderosa pine should be favoured with the consideration that they may be lost to beetle attack Douglas-fir should also be a preferred species. Most lodgepole pine should be removed. All treatment practices and implementation should follow the best management practices identified in the Cariboo-Chilcotin Grasslands Strategy – Best Management Practices for Harvesting Treatments on CCLUP Grassland Benchmark Sites (2007).

Most treatment areas will be a combination of treatment types including slashing, slashing/burning, and harvesting/slashing/burning. Identified treatment areas will need to be further divided into standards units based on tree density, size, species, and accessibility as these vary significantly within some units. Slashing is the predominant treatment type followed by Slash/Burn and Harvest/Slash/Burn (Table 6). There are 1,410.7 ha identified as being very low priority. No treatment type has been identified for these areas. The three basic treatment types are described below.

Table 6. Summary of area by treatment type.

Treatment Type	Area (ha)
Harvest/Slash/Burn	802.8
Slash/Burn	953.4
Slash	1004.4
None	1410.7

5.2.1 Slash

Slash treatments were identified in areas that have lower encroachment densities and smaller average tree size where residue is not anticipated to unduly raise fire severity or impact grassland functions. The combined fuel loading of grass and slashed trees is not considered high enough to carry a fire within these designated treatment areas.

Figure 1. Photo showing an area where treatment by slashing of widely spaced trees could occur.

5.2.2 Slash/Burn

Slash/burn treatment are best used in areas where harvesting is not economical due to tree size or density or where ecological values could be negatively impacted due activities required to remove merchantable trees. This treatment refers to tree thinning and then burning of the non-merchantable material. Typically these areas have a combination of tree and grass fuels that will support a surface fire and there is a good probability that prescribed fire can be used as a successful treatment.

Figure 2. Photo showing an area where treatment by a combination of slashing and burning of trees could occur.

5.2.3 Harvest/Slash/ Burn

Harvest/slash and burn treatments are best applied in areas where merchantable volume is recoverable to help offset treatment costs. Accessibility and the related impacts of tree removal are a key consideration. Treatments should be limited to winter conditions when snow pack and frozen soils will mitigate soil disturbance.

Figure 3. Photo showing an area where treatment by a combination of harvesting, slashing and burning of trees could occur.

5.3 Prescribed Burns

After encroachment and ingrowth treatments have occurred, it is recommended that prescribed burns be considered for the treated areas to help restore fire dependent species. However many of these areas are located in rangeland and fuel loading may be insufficient to carry a surface fire. Assessments of range and fuel conditions should be conducted to determine if surface fuels are adequate to implement a prescribed burn. Some areas may require a 1-3 year rest from grazing to allow sufficient grass fuels to accumulate before burning.

5.4 Using Treatment Maps and the Summary Tables.

The 106 treatment areas are shown in greater detail in the maps in Section 6.0. In the right hand corner of each treatment map is a key map, which shows abbreviated mapsheet numbers of adjacent mapsheets. The highlighted boxes in the key map refer to the mapsheet numbers of the treatment map. The treatments are colour coded according to priority and have unit numbers that cross reference with the Summary Tables in Section 7.0.

The Summary Tables in Section 7.0 list the attributes for each treatment unit. By using the columns Unit and Mapsheet, treatments can be located on the maps. Conversely, by identifying the mapsheet and treatment number on the maps, the correct row in the Summary Table can be located. Constraints such as OGMAs, UWR, species at risk, or Woodlot Tenures are noted in the Summary Table.

6.0 Treatment Maps

Starting next page.

Map 8. Mapsheets 92O069, 92O070 and 92O079 – treatment units.

Map 9. Mapsheets 92O059, 92O060 - treatment units.

Map 10. Mapsheets 92O049, 92O050 - treatment units.

Map 11. Mapsheets 92O039, 92O040 - treatment units.

Map 12. Mapsheets 92O029, 92O030 - treatment units.

Map 13. Mapsheets 92P020, 92P011 - treatment units.

Map 14. Mapsheets 92P001, 92I091 - treatment units.

7.0 Summary Table of Treatment Units

UNIT ID	MAPSHEET	YEAR	PRIORITY	TREATMENT	AREA (ha)	BEC UNIT	SLOPE	ASPECT	ELEVATION (m)	ENCROACH CLASS	ACCESS CLASS	UWR_UN_NO	OGMA	BIO_NS_SVW[1]	BIO_MS_SP[2]	WOOD LOT TENURE
0	92O.039	2	Very High	Slash/Burn	12.7	BGxw2	14	E	983	High	Very High	dmh_27	Yes		134919
1	92O.069		Low	Harvest/Slash/Burn	8.3	IDFxm	17	S	936	Very High	Moderate	dwl_4	Yes	Arnica chamissonis		ESKETEMC NATION
2	92O.069	1	Moderate	Slash/Burn	31.7	IDFxm	12	S	1082	Moderate	High	dwl_4	Yes
3	92O.069		Low	Slash	36.4	IDFxm	19	S	938	Moderate	High	dwl_4	Yes	Arnica chamissonis		ESKETEMC NATION
4	92O.079	1	High	Slash/Burn	102.2	BGxw2	16	SW	841	High	High	dwl_4	Yes	Arnica chamissonis		ESKETEMC NATION
5	92O.069	1	Very High	Slash/Burn	24.8	BGxw2	14	W	857	High	Very High	dwl_4	Yes	Arnica chamissonis		ESKETEMC NATION
6	92O.069	1	Moderate	Harvest/Slash/Burn	5.0	IDFxm	5	E	1110	High	High	dwl_4	Yes
7	92O.069	1	Very High	Harvest/Slash/Burn	145.8	IDFxm	16	SW	962	Very High	Very High	dwl_4	Yes
8	92O.069	1	Very High	Harvest/Slash/Burn	61.3	IDFxm	11	W	948	Very High	High	dwl_4	Yes
9	92O.069	1	Very High	Harvest/Slash/Burn	22.8	IDFxm	6	SE	1112	Very High	Very High	dwl_4	Yes
10	92O.069	1	Very High	Slash/Burn	10.1	BGxw2	14	W	831	Very High	Very High	dwl_4	Yes	Arnica chamissonis		ESKETEMC NATION
11	92O.070	1	Moderate	Slash	70.4	IDFxm	8	S	1089	Moderate	Very High	dwl_4	Yes
12	92O.070		Low	Slash/Burn	16.3	IDFxm	4	SW	1093	High	Moderate	dwl_4	Yes
13	92O.070	1	High	Slash/Burn	34.6	IDFxm	11	S	1096	High	Very High	dwl_4	Yes
14	92O.070		Low	Slash/Burn	9.9	IDFdk3	6	S	1119	Moderate	High	dwl_4	Yes
15	92O.070		Low	Slash/Burn	3.3	IDFdk3	7	S	1127	Moderate	Very High	dwl_4	Yes
16	92O.070	1	Very High	Harvest/Slash/Burn	13.9	IDFxm	13	S	1049	High	Very High	dwl_4	Yes
17	92O.070	1	High	Slash	8.4	IDFxm	16	S	1092	Moderate	High	dwl_4	Yes