The Blodgett Forest Plan is designed to provide a variety of habitat conditions for wildlife in the context of an actively and intensively managed forest. Many of the ideas for this plan are derived from observations and findings of the recently completed Coastal Oregon Productivity Enhancement (COPE) program. The plan attempts to provide adequate habitat for the diversity of species using forest habitats ranging from early seral, open habitats to mature forest conditions. This approach hinges on two fundamental strategies: 1) a landscape plan that provides a significant proportion (> 20%) of the landscape in older forest habitat with one large contiguous block of habitat (> 200 acres) in this condition at any point in time; and 2) maintenance of snags and fallen logs throughout the landscape, with an emphasis on larger structures in the older forest habitat. Other activities, such as management of riparian and upland hardwood patches, will complement these strategies. Limiting the amount of habitat in densely stocked stands that are in the competitive exclusion stage (the stage which has the smallest number of wildlife species associated with it) is implicit to this approach.
Information from the COPE program suggests that thinning can be used to promote development of structural characteristics that are found in older forests (Barbour et al. 1997, Hayes et al. 1997). In addition, while the numbers of a few wildlife species decrease following thinning, COPE studies have not found any species that are extirpated from stands following thinning, and the short-term influences of thinning are negligible or positive for many species (Hayes et al. 1998). Although the long-term effects of thinning on wildlife are less clear, current information suggests that the influences will be positive for species associated with older forest stands (Hayes et al. 1997). These findings were integral to the management plan developed for the Blodgett Tract. Blodgett will be used to demonstrate these findings and may be used to test some of the underlying assumptions and questions behind them.
Dedicating a significant proportion of the Blodgett Forest to the development of older forest conditions will provide habitat for species that use large diameter trees, snags and logs. By allocating a portion of this habitat to a large contiguous block, two functions are served. First, the block should provide better habitat for species using mature forest habitat with large home ranges (e.g., forest carnivores, pileated woodpeckers). In addition, given the relatively short period of time that stands will occur in an older forest condition (as short as 20 years), there is concern that the older forest habitat may not be fully functional prior to its harvest. This is especially a concern for species with limited vagility, such as some species of amphibians and lichens. After the initial acreage goals are achieved for mature forest habitat, the contiguous block of mature forest will move across the landscape as forest management activities proceed. As a consequence, this design should provide relatively short dispersal distances through favorable habitat for species and individuals occupying mature forest habitat that is lost by logging.
Dead wood, in the form of snags and fallen logs, is one of the most critical factors influencing the presence and abundance of wildlife species in coniferous forests of Oregon. Snags are used extensively by many species of birds for nesting, foraging, and roosting, by bats for roosting, and by several other species of mammals, including flying squirrels, martens, and others for den sites. Downed wood is a critical habitat component for a diversity of wildlife species, especially for mammals and amphibians. Wildlife use downed wood for a number of functions, including sites for feeding, reproduction, resting, and cover.
Despite the existing empirical data (see page 30), assessment of the number of logs that should be retained, created, or managed for in stands on the Blodgett tract is problematic for a number of reasons. 1) Response to logs is a multivariate problem and noise resulting from other factors (e.g., previous disturbance history, differences in moisture regimes, processes occurring at larger spatial scales such as the landscape level) have made it difficult to separate the “signal” from the “noise.” 2) It is possible to gather a large amount of data on some species that use logs, such as deer mice, but many of these species are of minimal management concern. It is difficult to gather large amounts of data for many of the species of greater management concern because these species may be difficult to study (e.g., salamanders occurring in the interior of decaying logs) or are relatively rare (e.g., some species of forest carnivores). 3) It is difficult to distinguish between use, preference, strong association, and dependence, complicating interpretation of implications of the data that do exist. One function of the OSU Research Forests is to contribute to resolving forest management issues. As a result, rather than establishing a policy of managing for a fixed amount of downed wood in the Blodgett Tract, an adaptive approach will be pursued. This approach will involve active manipulation of levels of downed wood in the forest, and monitoring key biotic responses over time. The intent of this approach is to gain information that can be used to determine future guidelines for management of downed wood on the Blodgett Tract as well as other forest lands in western Oregon.
Hardwoods play a variety of ecological roles in our conifer dominated landscape. COPE found that although the Coast Range is dominated by coniferous forests, deciduous vegetation has been a long-standing source of diversity and productivity that exerts control over succession (Hobbs, in press). As is true for any tree species, each of our hardwood species plays a critical role in the life cycle of a variety of insect and wildlife species. The abundance and diversity of birds is positively correlated with hardwood abundance in landscapes dominated by conifers (Carey et al. 1991, McGarigal and McComb 1992, Hagar et al. 1996).
Alder is best known in this capacity; as a nitrogen-fixing species, it can contribute up to 200 kg/ha/yr. Having scattered alder patches and occasional alder trees within young stands can make very significant contributions to the soil nitrogen pool and so improve general tree growth. Bigleaf maple and other hardwoods have been implicated in improved nutrient cycling in conifer forests. The easily decomposed litter of these species mixes with and hastens the decomposition of the conifer litter, thus increasing the rate of nutrient cycling. Hardwood stands support a very different understory community compared to conifer stands, with a higher number of species that are in an assemblage rarely found in conifer stands.
Riparian management philosophy
Riparian areas are a special part of the Blodgett Tract landscape. COPE found that riparian forests differ from upland forests in their dynamics and ecosystem patterns and require different approaches to ecosystem management (Hobbs, in press). They support a greater diversity of plant species and communities than the uplands. Their hardwood stands and aquatic environments provide habitat to wildlife found infrequently in the uplands. The aquatic system provides habitat for fish and a connectivity for organisms, organic material and sediment beyond the bounds of the Tract itself. For all of these reasons, the riparian area is a focus of attention and special management guidelines. At the same time, many riparian processes and functions are poorly understood so recommendations for management guidelines are based on current knowledge and need to be re-examined as our knowledge base changes.
Planning team discussing riparian management strategy above Fishhawk Creek.
size to create high quality aquatic habitat sooner in actively and intensely managed riparian zones (Emmingham and Maas, 1994). The Blodgett plan includes active management of riparian areas to establish and grow riparian overstory trees, both conifer and hardwood, to act as a supply of large woody debris to the streams of the Blodgett Tract.
In developing riparian guidelines, we have recognized several principles. 1) Maintenance of in-stream dead wood is essential. In contrast to most existing dead wood guidelines today, our guidelines set standards for dead wood input levels rather than in-stream loading levels or on-bank tree stocking levels. This distinction makes it clear what amount of the trees growing on the bank are needed to meet dead wood goals and how much is in excess of this need and so available to meet other goals. We believe that this approach will result in higher and more consistent dead wood loading through time compared to unmanaged riparian systems or those managed under current ODF regulations. 2) Hardwood types are important riparian forest types. Historically, the streams of the Blodgett Tract had more hardwood forest than conifer. We are reducing this hardwood domination (to a 50/50 hardwood/conifer mix) to increase the production of longer lasting dead wood. 3) In the absence of fire or other large disturbances in riparian areas, natural tree regeneration is usually inadequate to maintain forest cover and stocking in the long run. Therefore, active management for regeneration is required where natural advance regeneration is inadequate. 4) Many riparian goals (e.g., dead wood, wildlife habitat, timber) involve the presence of large trees. Active management of these stands will promote these goals.
Research, demonstration and extension
The plan for the Blodgett Tract provides an opportunity for the College of Forestry to demonstrate the findings from the Coastal Oregon Productivity Enhancement (COPE) project and other research efforts through the use of active riparian management and the development of complex forest structures in both the upland and riparian areas. These demonstrations will be used by the College’s extension program. Formal research studies currently installed on the tract will help us better understand the growth and development of actively managed conifer and hardwood forests with different treatments. Over time the College hopes to attract more research on some of the fundamental habitat issues that the management strategies in this plan attempt to address.
The College of Forestry needs a high and dependable flow of revenue to support forest operations, research, demonstration and other college programs. A moderate amount of period to period fluctuation has been permitted in Blodgett harvest schedules since the Blodgett Tract represents only a portion of total revenue, and operations will not necessarily be conducted at the Blodgett Tract for each year of the five year planning period. The 8000 thinning and regeneration harvest planning prescriptions used in the analysis were selected to control the rate at which stands can be moved towards the large tree goal by moderate to heavy thinning regimes and to provide thinning revenue during time spans when final harvest rate is low. Special prescriptions were developed for stands with windthrow concerns. The regenerated stand prescription uses precommercial thinning to quickly achieve large tree goals in the second rotation facilitating harvest of current stands.
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