Enhancing the Ecological and Socioeconomic Benefits of Silvopasture Systems in Washington State through Participatory Research and Education

Socioeconomic research

Our research revealed that silvopasture systems have not been well researched for their socioeconomic and environmental impacts whether negative or positive and, in particular, have not been studied in the state. Exploration of the Web of Science and Scopus using the search terms: silvopasture, forest grazing, agroforestry and Washington determined the extant of published literature was limited. Research conducted by the Department of Natural and Washington State University employed a statewide survey on the awareness and perceptions of agroforestry (Lawrence and Hardesty, 1992). The result of this study determined that there was general awareness of agroforestry but a lack of technical knowledge and assistance. Further research conducted by Oregon State University examined silvopasture establishment and impacts on forage and soil quality and quantity (Sharrow, 1999, 2004, 2007). Investigation of Federal databases revealed the only funded research was through Western SARE titled “Silvopastoral Alternatives for Fruit Growers” which investigated the economic and ecological impacts of incorporating livestock using silvopasture methods. A freedom of information act request provided evidence that from 2012-2018, the National Resources Conservation Service processed 6 Environmental Quality Incentives Program grants for the purpose of establishing or supporting on going silvopasture systems on private property in four counties in Washington State.

From key informant interviews with partner organizations we learned that knowledge and perceptions of silvopasture are varied among organizations. Of the twenty conservation districts contacted, six are actively working with or aware of silvopasture practitioners. Among these six conservation districts, knowledge of best management practices (grazing density per acre, optimized overstory and understory composition) relied on multiple specialists (foresters and livestock specialists) for management input due to the integrated nature of silvopasture. All six districts noted that the lack of literature available to professionals and practitioners stemmed adoption. Among the interviewed conservation districts varied perceptions of silvopasture occur. The conservation district associated with the county that two NRCS EQIP grants for silvopasture in 2018 was unaware of any silvopasture systems in the county and said: “This is a practice we recommend against, mainly because the damage to the forest stand far out ways any benefits - there's little if any forage in western Washington forest stands. You would know far better than I, but I think grazing forest stands would have more benefits in eastern Washington.” Another conservation district was unsure if silvopasture was being practiced due the scale of the farm “We have a couple of folks who are grazing their forest land but it probably isn’t silvopasture as they are mostly hobby scale.” These perspectives likely serve as barriers to adoption (Orefice, et. al 2017).

Some NRCS staff members were aware of landowners using silvopasture, stating that  “we work with quite a few landowners who graze livestock in a silvopasture system and some we have funded via EQIP to do this type of work.” As the names and contact information of the landowners are protected by Federal law and cannot be disclosed, it is likely that this research project is an incomplete census of all silvopasture systems statewide. In addition to the wide range of perspectives and experiences, partner organizations noted that they relied on agroforestry literature that was not regionally or ecologically specific to Washington State.  The challenge with relying on literature from other regions is that silvopasture looks different in various parts of the U.S.  (Huntsinger, et. al.,  1999, Brodt, et. al 2019).  Finally, it was noted in discussions with partner organizations, that terminology and definitions of silvopasture varied greatly. The terms "forest grazing" and "silvopasture" were used interchangeably by many organizations even though  silvopasture incorporates the usage of managed grazing.  Other challenges arose as agencies have different goals for establishing silvopasture. The NRCS goals focus more on resource concerns such as reducing soil erosion, improving water quality, and enhancing wildlife habitat. The USDA National Agroforestry Center has goals that focus on diversifying incomes, forage production, and improved habitat for livestock.  While these are not mutually exclusive objectives, the interpretation of these goals by partner organizations greatly influenced the perceived understanding of what silvopasture is and how and why this management system should be funded and supported.

From the farmer/rancher interviews, Table 1 shows there is a bimodal split in the number of years farmers/ranchers had been the principal operator of a farm/ranch with 36% having less than 10 years of experience and 31% having more than 30 years of experience. In terms of utilizing silvopasture on their current farm/ranch, 42% have 1-10 years of experience using silvopasture on their current property which coincides with research conducted in other regions in the U.S. (Orefice et. al 2017). There are primarily two types of silvopasture systems that have been identified, the first is livestock integration with orchards and the second is the more common type of livestock integration into a managed forest in which pre-existing stand has been thinned and forage management occurs prior to livestock integration. Two of the landowners had both orchards and forests on the same property. In terms of acreage, 57% of farmers/ranchers operated on lands that were between 81-1100 acres and 42% operated on lands that were less than 80 acres.  Interview participants were asked about their investments in silvopasture infrastructure such as fencing and irrigation, however only four landowners were unsure as to specific costs as they were not keeping financial records.  Participants were asked to estimate yearly management costs and associated indirect costs.  Only four landowners were able to give estimates for yearly management costs ranging between $1500 and $10,000 per year. Only two landowners could estimate indirect costs ranging between $100 and $2000 per year. An estimate of direct economic benefits from livestock (meat or wool sales) and forest/orchard (timber, fruit, and nut sales) was unavailable with only two landowners able to estimate yearly income. These landowners estimated that total annual sales of meat and/or wool were between $50,000-$100,000.

Commodities comprised five main categories with a majority producing more than one type of commodity. All landowners produced either meat, wool, or dairy. Firewood was a common secondary product as a result of forest thinning particularly for landowners whose forest stands are composed of Ponderosa Pine, Red alder, Garry oak, Big Leaf maple, Pacific madrone. Timber was a commodity for landowners who had diverse forest stands of Douglas fir, Grand fir, Western larch, and Western cedar. Wood pulp was commodity for landowners who land was primary composed of Ponderosa Pine.  Asian pears, kiwis, chestnuts, cider apples, hazelnuts comprise the scope of fruit and nuts grown in silvopasture systems.

Table 1 Characteristics of silvopasture farms/ranches  (N = 19)

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Location

  Western Washington                                      10

  Eastern Washington                                       9

Silvopasture type

            Orchard                                                           5

            Forest                                                              17

Years farming/ranching

            1-10 years                                                       7

            11-20 years                                                     3

            21-30 years                                                     3

            31-60 years                                                     6

Years using silvopasture on current land                  

            1-10                                                                 8

            11-20                                                               2

            21-30                                                               3

            31-60                                                               6

Acres operated                                                          

1-10 acres                                                                  3

11-80 acres                                                                5 

81-800 acres                                                             5

800-1100 acres                                                        6

Commodities produced

Meat, Dairy, Wool                                                   19

Firewood                                                                   7

Timber                                                                       5

Wood pulp                                                                2

Fruit/Nut                                                                  6

Livestock species and composition fell into two main categories as seen in Table 2. Farms that utilized multiple species and farms using single species.  Multi-species farms follow a prescribed rotational grazing regime in which each species grazed in separately in specific paddocks or grazed paddocks asynchronously. Farms/Ranches using multi-species and single species determined the timing and duration of livestock rotation based on livestock species, herd size, forage residual height, vegetation status and yearly precipitation. The number of yearly grazing events per paddock range from 1-7 times with an average of two grazing events per paddock per year. Paddocks that were grazed more than 3 times in a year were irrigated. Paddock size varied and was dependent upon the number of livestock and farm size. The average number of paddocks on a given farm was 20 with an average paddock size of approximately 6.74 acres with range of 1.5 acres to 15 acres.

Concerns with livestock grazing in forest stands and orchards were driven primarily by tree species composition. For landowners who operated cow/calf operations and had forest stands with Ponderosa pine there was a concern about induced abortion caused by consummation of green pine needles. All landowners who have a cow/calf operation and Ponderosa pine reported that they had experienced this multiple times.  Pruning trees, grazing regimes and timing of paddock grazing could reduce abortion rates however wind or tree/branch fall is unpredictable. (Panter et.al. 2002;  Pfister et.al. 2002) Quantity and quality of forage were also a concern as decreased light availability decreases the lbs./per acre of available forage. (Sharrow, 1991; Mercier, et.al 2019;Lindgren and Sullivan, 2013). Forage quality is also a management issue as shade tolerant species occurring in forest stands may be low in nutrients (Buergler, 2006).

Table 2 Livestock Species and Grazing Management (N=19)

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Farms utilizing multi-species                                                              (n=5)

            Livestock groupings

            Katahdin Sheep, Kuni-Kuni and Berkshire pig                       1

            Finnish Sheep Heritage turkey, broilers, goats                       2         

            Cow/calf, Horse, goats                                                                 1                                             

            Cow/Calf, Stud, pigs                                                                     1

Farms utilizing single-species                                                             (n=14)

            Livestock type

            Cow/calf                                                                                         7

            Cheviot Sheep, Finn and Sally (wool)                                      1

            Katahdin Sheep                                                                            3

Herford, old spot, Berkshire pig                                                           1

Jersey (dairy)                                                                                            1

Suffolk sheep                                                                                            1

Paddock Size                                                                                    (acres)

            Average                                                                                   6.74

            Median                                                                                    2.0

            Range                                                                                      14.75

            Mode                                                                                      15

Herd size (number of head)

10-20                                                                                       2

21-50                                                                                       7

51-100                                                                                     2

101-200                                                                                   7

201-500                                                                                   1         

Concerns about animal health in forest/orchard grazing

Forage quality/quantity                                                          13

Pine needle abortion                                                              10

 Parasite loads                                                                         2

The amount of silvopasture on each farm/ranch ranged from 2 acres to 1000 acres with a median of 20 acres of silvopasture per site (Table 3).  Silvopasture conversion occurs through forest management practices such as pre-commercial or commercial thinning of existing stands resulting in a median of 3 unique forest stands per property. 11 of landowners worked with a forester or were foresters themselves. Only 2 landowners who worked with a forester stated the forester did not approve of livestock integration. In Eastern Washington silvopasture sites have even-age stand structure with primary species composition, Ponderosa pine, Douglas Fir and Grand fir. Outlier species include Western Cedar, Lodgepole, and Western hemlock. Western Washington sites are more varied in forest structure and composition with uneven and even age stand management being the most common systems. Most common forest species included Douglas Fir, Red Alder, Cottonwood, and Garry Oak. 11 of the 19 sites utilized natural stand regeneration with 4 sites using both natural regeneration and intentional planting.

Conversion of pastures to silvopasture only occurred at four sites and involved orchard establishment.  Landowner goals for forest stands were primarily ecosystem services that benefited the integration of livestock (shade, wildlife habitat, soil moisture retention for forage). Merchantable timber and other forest products including firewood production was a strong secondary goal for all landowners with forests.

Table 3 Forest/Orchard Composition and Management

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Acres composed of forest/orchard                            (N=19)

            1-10 acres                                                       5

            11-100 acres                                                   7

            101-800 acres                                                6

            800-1100 acres                                              1

Acres composed of pasture

            1-10 acres                                                       5

            11-100 acres                                                  6

            101-800 acres                                               7

            800-1100 acres                                            1

Number of forest/orchard stands                              (percent)

            Average                                                                  3.37

            Median                                                                   3.00

            Range                                                                     9.00

            Mode                                                                       4

Converted pasture to forest/orchard                        

            Yes                                                                  4

            No                                                                   15

Method of forest/orchard regeneration

            Natural regeneration                                      11

            Plant seedlings (orchard only)                     4

            Both                                                                   4

Worked with a forester

            Yes                                                                      11

            No                                                                        4

            NA (orchard establishment)                          4

Dominant tree species (Forest)

            Ponderosa Pine                                               6

            Red Alder                                                         4

            Douglas Fir                                                      2

            Grand Fir                                                         1

            Garry Oak                                                        1

            Cottonwood                                                    1

Primary Tree Species (Orchard)

            Hazelnuts                                                        2

            Asian pear                                                       1

            Chestnuts                                                        1

Understory forage species selection and management vary greatly between western and eastern Washington due to the delineation of soil types, temperature and precipitation regimes. Six eastern Washington landowners reported that they introduced preferred forages through broadcasting seed by hand or through the use of a no-till seed drill along the edges of forest stands or in recently thinned stands.  Using these methods, seeding typically occurred in October or November after the first Autumn rains and after a paddock had been grazed by livestock. An additional method involved broadcasting seed in areas where slash piles were burned or where bales placed during winter. Using this method, seeding occurred in late winter or early spring.  Four landowners in Eastern Washington who used this method determined that this was the only time that mineral soil was adequately available for successful forage propagation. Additional forage management includes removing undesirable plants. 4 of the 10 landowners named snowberry (Symphoricarpos albus), Common Mullein (Verbascum thapus) and Rose (Rosa multiflora)

In contrast, 5 out of the 9 western Washington landowners introduced preferred forages after discing, grazing, or herbicide application. Timing of seeding varied among landowners: those with irrigated pastures seeded in early spring, while those who rely on yearly precipitation seeded after the first Autumn rains.  Undesirable plants varied depending on livestock species.  Blackberry (Rubus armeniacus) is undesired by landowners who have cattle and poultry. Landowners who have goats, pigs and meat sheep prefer to have blackberry for forage. Scotch broom (Cytisus scoparius) was named by 6 out of 9 of the landowners as a undesirable plant.

Table 4 Common forage plants that are either planted or selectively managed for livestock

Grasses                                                                            Forbes                                    

Italian rye (Lolium spp.)                                              Trefoil (Lotus corniculatus)

Triticale (×Triticosecale)                                             Plantain (Plantago spp.)

Smooth Brome (Bromus inermis)                               Red Clover (Trifolium pratense)

Oatgrass (Danthonia spp.)                                          Chicory (Cichorium intybus)

Perennial ryegrass (Lolium spp.)                                White clover (Trifolium repens)

Annual ryegrass (Lolium spp.)                                    Small Burnet (Sanguisorba minor)

Timothy (Phleum pratense)                                        Sub clover (Trifolium subterraneum)

Orchard Grass (Dactylis spp.)                                     Alsike clover (Trifolium hybridum)

Meadow Brome (Bromus commutatus)                                

Mountain Brome (Bromus carinatus )

Alfalfa (Medicago sativa)

Kentucky blue grass (Poa pratensis)

Landowners utilize silvopasture for a few specific reasons (Table 5). All 19 landowners indicated that diversification of income streams, predictable revenue, shade and a perceived increase interaction with their farm/ranch and livestock were reasons for silvopasture adoption. 15 out of 19 landowners indicated that intentional integration of livestock and trees provided greater utilization of their existing forests.  The use of managed intensive grazing allowing flexibility was cited by most of the landowners. 12 landowners indicated that there was increase in ecosystem services (provisioning: raw materials of fuel, timber; regulation: climate regulation, controlling parasites; aesthetics: beauty and recreation; supporting services:  Perceived increase in biodiversity and nutrient cycling).

The time and cost of moving and managing rotationally grazed livestock as well as the costs of purchasing and maintaining permanent and portable electrical fences is the primary challenge associated with silvopasture. 9 landowners indicated that using rotational grazing requires consistent and constant time allocation. With the addition of trees comes a decrease in photosynthetically active radiation and thus less forage quantity  This is recognized as a specific challenge among landowners whose property is primarily composed of forest or woodlands. The impact of livestock on tree regeneration is additional complication that is specific to landowners.  Fire is a concern for landowners who live in arid zones or whose property is adjacent to unmanaged private or public forests.

Table 5 Reasons for silvopasture establishment (n=19)

Diverse income streams                                                                         19                                           

Predictable revenue                                                                                 19

Shade for livestock                                                                                   19

(Perceived) Increased interaction with landscape/livestock          19       

Adaptability of manage intensive grazing                                           15

Comprehensive utilization of existing forests                                     15

(Perceived) increase in ecosystem services                                          12       

Aesthetic values                                                                                         10

Challenges of silvopasture:     

Time and labor moving animals and electric fences                          14       

Less quality and quantity of forages                                                       12

Impact of grazing on tree regeneration                                                  6

(Perceived) threat of fire                                                                            6

Cost of permanent fencing                                                                        3

Of the 19 landowners who participated in this research project only one landowner knew of someone else practicing silvopasture. According to landowners this lack of awareness of other practitioners is in part due to a lack of forestry and agricultural agencies who understand silvopasture in Washington State. Conversely, the landowners acknowledged that they felt confident in their own management systems and thus do not seek out specialists unless they encounter a specific issue. Landowners also expressed that they have developed reliance on out-of-state resources including universities, professional organizations, conferences, or online resources to determine best management practices for their silvopasture systems.

Topics that landowners desired to know more were multidisciplinary (Table 6). When asked what research or information would support their operation a majority of the responses focused on site productivity. Ten landowners want to know more about which forages would be most productive on their land and which would have the most nutritional benefit for their livestock.  Half of the landowners would like workshops or research on ensuring tree survival and protection from livestock. Preventing soil compaction caused by forest and livestock management is a topic of concern for many landowners as reduction of invasive species.

Table 6 Information that landowners would like to access

­­­­­­­­Forage Management                                                                          10

Tree Protection/Regeneration                                                           8         

Preventing soil compaction                                                                6

Management of invasive/noxious weeds                                         5

Opportunities for funding                                                                   4

Discussion

Silvopasture in Washington State is unique in its design driven in part by a range of microclimates causing landowners to adapt their silvopasture systems to a mosaic of forest or afforested landscapes. In conjunction with ecological drivers the economic valuation of timber species, forest/orchard products and livestock act as primary motivators of landowner goals for their silvopasture systems.  The main components of silvopasture: livestock, trees and forage comprise heterogenous yet pragmatic site-specific applications that can be best defined by the intentional integration of intensively managed crops, forage and livestock into a system that relies upon interactions of the biotic components. Using the USDA definition of silvopasture which is the deliberate integration of trees and grazing livestock operations on the same land, this survey has identified 19 small to medium farms/ranches seeking social, economic, and ecological resiliency and adaptability through the use of silvopasture in Washington State. The challenge with this working definition is the relatively new utilization of this term. Research conducted in Washington State in the 1990s referred to forest grazing as an agroforestry practice (Lawrence and Hardesty, 1992). While of the 19 landowners surveyed all participants were familiar with the term agroforestry, only 12 landowners refered to their land management systems as silvopasture. Of the landowners interviewed, 7 olandowners use the term forest grazing when referring to their operation despite intentionally integrating livestock into a forest stand and utilizing managed intensive grazing practices in combination with managing the overstory and understory vegetation.  In discussions with key informant organizations, regardless of the intensive management design of silvopasture, the incorporation of livestock grazing into existing forest stands in regions is interpreted by professionals as forest grazing. This is a misperception that is repeated in other regions (Smith et. al 2022).  This may be in part due to the interdisciplinary nature of  silvopasture which requires the use of and knowledge of rotational grazing to prevent soil compaction and tree damage (Gabriel, S., 2018).  Skill in forage management under a treed canopy to ensure forage quality and quantity is also needed (Gabriel, S., 2018; Frey and Fike, 2018). Finally, knowledge of forest structure and composition is a prerequisite. Comprehension of site variability, potential natural vegetation, slope, aspect, elevation, soil types and precipitation regimes are necessary to ensure adequate tree growth, minimize disease and pathogens and maintain site productivity (Nyland, 2016; Pent et. al 2021).  As reported in the survey; in addition to foresters, landowners have consulted conservation districts to discuss resource concerns, NRCS staff to discuss forage management, and livestock specialists from UC Davis to request assistance in grazing management that reduces parasite loads.  Collectively the gaps in working knowledge of agroecosystems may inhibit professionals from seeking and/or recommending adoption; as well as limit funding opportunities available to farmers/ranchers.  Compounding this issue is a lack of regionally specific literature and knowledge of long term ecological, social, and economic research on silvopasture in Washington State.

Despite the complexity of silvopasture systems and a lack of relevant literature and resources; the landowners surveyed have designed and invested in robust management systems.  These early adopters rely on previous forest management and/or grazing and farming experience to inform their land management. As one respondent noted “you need to be hungry and be constantly looking for resources, look for passionate people who are interested in passing on their knowledge.”  A majority of landowners who have 10 years or more of experience have not defined their practices as silvopasture, but rather rely on their intuitive knowledge resulting from years of livestock and forage management to influence their land management decisions. For example, one respondent reflected that “ I have been doing this long before you all called this silvopasture, and I’ll keep doing it even after you change the name.”  Yet there is evidence that the lack of a clearly accepted definition of silvopasture has resulted in barriers faced by landowners. It is notable that 16 out of the 19 landowners stated that they experienced challenges caused by the lack of understanding by professionals who discourage them from integrating livestock into forest/orchards. One land owner lamented that “Any (professional) I talk to cannot tell me the number of trees I should have on my property to ensure I have good forage for my cows, the best they can do is point me to a rangeland specialist or an article written in another state.” 

Making progress on the identification and definition of silvopasture systems in Washington State could be a primary step to removing barriers, developing best management practices, securubg more resources, and addressing potential social, economic, and ecological challenges. There is an opportunity for foresters, livestock and agricultural specialists to learn from and mimic success of state and federal organizations and universities in other parts of the U.S.

Ecological Research 

The impacts of silvopasture practices on fuel loads, soil health metrics and forest structure and composition are still be analyzed. Preliminary analysis shows that silvopasture results in similar reduction of litter and vegetation as continuous grazing. continuous grazing was defined by  defined by Allen. et. al 2010.  However the rates of fuels reduction occurs much more rapidly using silvopasture primarily due to higher average stocking density of livestock at all silvopasture sites. Silvopasture achieved the same fuels loads (measured in tons/per acre) of litter and vegetation as continuous grazing in approximately 14 day.  Continuous grazing achieved the same fuels loads (measured in tons/per acre) in approximately 140 days.  

Preliminary results of fuels loads

For 1,10,100,1000 hour fuels loads (measured in tons per acre), there is no significant difference in silvopasture and continuous grazed sites. There was a significant difference between managed forests and unmanaged forests. This suggests that mechanistically managed forests (with or without grazing) reduces 1, 10,100, 1000 hour fuels by thinning forest stands thus removing a source of these types of fuels.  

In terms of litter and duff, silvopasture reduced litter amounts significantly more than continuous grazing and un-grazed sites.  Mechanistically, this due to the higher stocking density of silvopasture when compared to the lower stocking density of continuously grazed sites.  The reduction of litter is significant as litter helps "carry" fire across a landscape. 

It terms of surface fuels (defined as standing vegetation composed of grasses, forms and shrubs and new cohort of trees under 2 meter in height) silvopasture sites have an  alpha level of significance.  Silvopasture sites had the lowest surface fuels when compared to continuously grazed  and un-grazed sites.  Mechanistically this is due the higher stocking density of silvopasture sites.