Logging in the headwaters of the Wilson River watershed.
Over the past year, I have been consulting for the Wild Salmon Center and Oregon Stream Protection Coalition, and providing guidance to the Oregon Department of Forestry (ODF) on the development of a 640,000 acre Western Oregon State Forests Habitat Conservation Plan (HCP). While the project has been intriguing and rewarding, I outline at the end of this post six opportunities that remain untapped.
With the protections provided by an HCP for their western Oregon state forestlands, the ODF seeks to obtain a federal incidental take permit for listed species such as coho, chinook, steelhead, spotted owls, voles, and torrent salamanders. The proposed permit term is 70-years, and covers the ODF activities of timber harvest, stand management, road system management, recreation infrastructure, and conservation actions. It is a huge undertaking in productive and charismatic landscapes that generations of Oregonians have both used and protected—often leading to significant conflicts, litigation, and distrust between stakeholders. In my role as a member of the Conservation Stakeholder Group, I provided reviews, analysis, and comments on the following subjects:
1. Stream buffer classification;
2. Landslide initiation and debris flow modeling to deliver large woody debris for fish habitat;
3. Habitat suitability indices for the listed, terrestrial species;
4. A linear program for forestry optimization called the “Policy Level Forest Management Model.”
Here I elaborate on the stream buffering system. The permit area contains over 8,500 miles of streams. The consulting firm TerrainWorks completed a spatial analysis to characterize both fish and non-fish bearing streams into 11 classes (Fig. 1, blue bars), which would receive various buffer widths called Riparian Conservation Areas (RCA). RCAs are designed to protect against logging-associated impacts to temperature, debris flows, and sedimentation, while delivering adequate large woody debris for aquatic habitat. The buffer widths attributed to the 11 stream classes range from 35 to 120 feet. I commend the quality of the analysis conducted by TerrainWorks, and the RCA buffering approach taken by ODF—buffers are known to protect stream temperatures, reduce sedimentation in certain cases, and achieve other ecologically-beneficial riparian management objectives.
Fig. 1: percentages of all stream types and buffer classes in the HCP Permit Area (in blue) as compared those streams without other encumbrances and only protected by Riparian Conservation Areas (in orange) (original data courtesy of TerrainWorks).
With my project partners, we analyzed the TerrainWorks data to more specifically describe and quantify the magnitude of conservation benefits from the HCP. Our question was: beyond existing planning restrictions and proposed non-aquatic restrictions (i.e. non-RCA policy encumbrances) that the ODF faces, what is the distribution and level of protection of the remaining streams? To answer it, under the given scenario, I determined how much of the Permit Area is protected only by RCAs. The encumbrance scenario includes areas already deemed inoperable for logging, an old method delineating landslide zones unavailable for harvest, public safety areas protecting infrastructure, off-limits river reaches in steep canyons (i.e. inner gorges), and the Habitat Conservation Areas (HCA) to be established by the HCP (Fig. 2). The resulting analysis clearly revealed the types of rivers receiving the least protection and for which I recommend Conservation Stakeholders seek additional protections: seasonal streams.
Fig. 2: Venn diagram of the Encumbrance scenario to isolate the streams protected only by Riparian Conservation Areas in the HCP Permit Area.
Seasonal streams represent over 1,300 miles and almost 16% of all river and stream miles in the Permit Area (Fig. 1, orange bars). Seasonal streams—often found in headwaters where active logging practices are widespread (as pictured above)—are protected simply by 35 ft. exclusion zone for harvest and some other activities. Not excluded are road building, culvert replacement, and cable yarding, which are known sources of erosion (Rashin et al. 2006). Even without these activities, an open question in the literature exists about the efficacy of 35-ft buffers to adequately mitigate up-slope erosion and hydrologic impacts from silvicultural practices (Rashin et al. 2006, Reid et al. 2010). If the HCP moves forward as currently planned, my conclusion from this analysis is that problems with chronic erosion and downstream sedimentation are likely over the 70-year permit term.
Due to the extent of RCA-only protected streams, I felt compelled to map seasonal streams for the watersheds intersecting the HCP permit area. I used the length of seasonal stream miles as an indicator of threat in HUC-12-level watersheds in Western Oregon (Fig. 3). Broadly speaking, the threatened watersheds (in red) are in remote areas with headwater streams near the crests of the coastal mountains. The impact of fine sediments on aquatic resources in the streams of the Pacific Northwest are an understudied issue (Gomi et al. 2005). From this exercise, in my mind, these threatened watersheds and their underlying processes deserve additional consideration during the up-coming National Environmental Policy Act (NEPA) review process.
Fig. 3: Seasonal stream miles used as a threat indicator in watersheds of Western Oregon. Inset map provides detail of the TerrainWorks stream classification analysis, and prevalence of seasonal streams along ridgelines (dashed blue line, “N-F seasonal”).
As I step back from the specifics of my four tasks outlined at the beginning of this Blogpost, during my year-long participation in the Conservation Stakeholder Group I saw six opportunities for improvement in the geoinformatics behind the negotiations and agreements of the HCP. The opportunities are as follows:
1. Address sedimentation delivered to headwater streams;
2. Similar to the terrestrial habitat suitability for listed species, construct a fish habitat suitability index for aquatic species;
3. Address the probability of fire, and its impact on erosion, the water balance, and persistence of habitat;
4. Improve understanding of landslide initiation zones with variables of vegetation, soil characteristics, precipitation;
5. Use the 275,000 acres of Habitat Conservation Areas for ecosystem service credits (i.e. carbon sequestration) to be sold on open markets;
6. Develop the Policy Level Forest Management Model into a full-blown decision support and adaptive management system.
Some of these issues are directly relevant to the process of environmental documentation for this HCP, some would be useful for development of future HCPs, and some are important things to do for state of science to inform forest resource management in the Pacific Northwest. I must admit—at times, I was frustrated by my inability to gain momentum on these issues. This month, the HCP has moved into NEPA review with NOAA as the lead agency. The review process is expected to continue until the Fall of 2022. Perhaps there’s time yet to address these opportunities? If you are interested in tackling them, please get in touch with me. I have deeper thoughts on each one.