Treesearch

We now report 22 years of new data and observations from the third of three small projects evaluating the effects of inbreeding in coast redwood (Sequoia sempervirens (D. Don) Endl.). We also briefly summarize previously-reported effects of inbreeding on redwood’s cone production, seed set, germination percentage, nursery growth and survival, rooting of juvenile cuttings, and their growth and survival in field plantings. Offspring resulting from self-pollinations were compared to offspring from controlled outcrosses of the same seed-parents. Milder forms of inbreeding, likely among...

During this century, climate warming and altered precipitation patterns will lead to habitat changes that may be beneficial to some long-lived tree species and detrimental to others. Paleoendemics, with limited and disjunct distributions will face the greatest challenges, as migration rates will be too slow to keep pace with rapid environmental change and populations at the receding edges are eroded through mal-adaption. Giant sequoia (Sequoiadendron giganteum (Lindl.) Buchholz) is an iconic Sierra Nevada tree species with populations that tend to be small and highly fragmented (particularl...

The effects of selective-harvest on forest composition and structure in the southern range of the coast redwood (Sequoia sempervirens (D. Don) Endl.) forest have not been well documented. This case study focused on the Byrne-Milliron Forest in Santa Cruz County, California where selective-harvest is currently the primary method of timber extraction. The purpose of this research was to determine how forest structure and composition varied in regard to harvest intensity and management goals. We sampled 100 plots in the Byrne-Milliron Forest across five harvest sites. All sites had been...

Interest in the restoration of second-growth forests has continued to increase in the redwood region, which has further increased the importance of evaluating restoration-based silvicultural strategies. This study assessed the short-term effectiveness of four silvicultural treatments (two silvicultural thinning methods, low thinning and crown thinning, and two basal area retentions, 80 percent and 45 percent) as forest restoration tools via analysis of relative basal area growth at Redwood National Park. Prior to treatment, the second-growth stand had more than 1,600 trees ha-1 and 70.0 m2...

Precommercial or early thinning of regenerating redwood forests can support management objectives including maximizing yield, forest structure restoration, and promoting carbon sequestration. We present data collected over 30 years following a precommercial thinning (PCT) in a 19 year-old naturally regenerated and planted coast redwood (Sequoia sempervirens(D. Don) Endl.) and coast Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) stand. The study site is typical of most regenerating redwood forests with spatial variation in tree distribution from stump sprouting (coppice)...

The ongoing, severe drought in the redwood ecosystem has many ramifications, including loss of summer rearing habitat for juvenile salmonids. Many ‘perennial’ streams now cease to flow during parts of the summer and fall, either drying up completely or disconnecting pools as riffles go dry, subjecting fish to increased predation, high water temperatures, and desiccation. Numerous factors have contributed to this hydrologic impairment, including natural hydrologic cycles, legacy land use effects, human consumptive uses, and climate change. The search for solutions is now in full swing, and...

After decades of intensive timber harvest and land use change that removed forests from the landscape, recent satellite data show that forest cover has increased in North America (Liu et al. 2015). However, these regenerating forests differ greatly in structure and composition than the forests that preceded them (McIntyre et al. 2015). This has been especially evident on the Pacific coast, where only 3 to 5 percent of old-growth coast redwood (Sequoia sempervirens (D. Don) Endl.) forest remains (Russell 2009). To address this, land managers are actively thinning second-growth forests to...

Large landslides can exert a lasting influence on hillslope and channel form and can continue to contribute to high in-stream sediment loads long after the event. We used discharge and suspended sediment concentration data from the Caspar Creek Experimental Watersheds to evaluate the temporal distribution of sediment inputs from 11 landslides of 100 to 5500 m3. Slide-related suspended sediment loads were estimated as deviations from expected loads referenced to nearby control watersheds. For the two largest slides, suspended sediment export during the year of the slide accounted for 5 and...

Shallow streamside landslides are a principle source of sediment on managed timberlands in northern California. Using an adaptive management process, LiDAR, and a detailed field-based landslide inventory, Green Diamond Resource Company (GDRCo) has redefined the interim preventative landslide tree-retention buffers it applies to steep streamside slopes along fish bearing (Class I) and non-fish bearing (Class II) watercourses. The application of these buffers are dependent on slope gradients and when applied, enhance and in some cases, expand upon the customary riparian buffers associated...

A number of watersheds on the North Coast of California have been designated as sediment impaired under the Clean Water Act, including the 112 km2 upper Elk River watershed that flows into Humboldt Bay just south of Eureka. The objectives of this paper are to: 1) briefly explain the geomorphic context and anthropogenic uses of the Elk River watershed; 2) develop a process-based sediment budget for the upper watershed, including an explicit assessment of the uncertainties in each component; and 3) use the results to help guide future management and restoration. Natural (background) sediment...