Treesearch

Reforestation following timber harvests is an important topic throughout the coast redwood (Sequoia sempervirens (D. Don) Endl.) range. Furthermore, as drought-induced mortality spreads across many of California’s forests, it is important to understand how physiology and stand structure influence reforestation success. Finally, as climate throughout the West is projected to become hotter and drier, it is important to investigate seedling regeneration under hotter and drier conditions, particularly for species such as coast redwood that are generally restricted to mesic habitats. To study...

A perennial herb of the Campanulaceae (bellflower) family, swamp harebell (Campanula californica) is endemic to the north and central coast of California. The California Department of Fish and Wildlife (CDFW) considers the species to be moderately threatened, and is concerned with the severity of impacts from land use activities, and the effectiveness of mitigation measures proposed under California Environmental Quality Act compliance. A timber harvesting plan (THP) submitted during 2000 reported the species distributed in several clusters in the proposed Sonoma County logging area....

In the Pacific Northwest, there are discontinuities in the lineages of several plant and animal species in the northern California/Oregon region that are thought to have their origins in the separation of populations into refugia during the Pleistocene glacial periods. Redwood sorrel (Oxalis oregana Nutt.), a common understory species of the California redwood forests and other Pacific Northwest temperate rainforests, was found to have two distinct genetic lineages in California based on sequence analysis of two chloroplast intergenic loci (psbJ-petA and trnQ-5’rps16) and the nuclear rDNA...

The California drought of 2012 to 2014 was the most severe drought on record for the last century and likely millennium. Warm temperatures with below-average precipitation compounded over the three-year period, creating significant and sustained aridity over the course of three growing seasons throughout the coast redwood ecosystem. The citizen science project, Fern Watch, tracked the morphological response of Polystichum munitum (Western sword fern) in the coast redwood forest to the recent drought across a plot network spanning 10 sites and a latitudinal gradient of more than 800 km....

Poorly designed and unmaintained logging roads pose serious risks to aquatic ecosystems through sediment delivery from stream crossing failures and landslides. Redwood National Park (RNP) in northern coastal California has been implementing a restoration program for almost four decades, focused primarily on removing (decommissioning) abandoned logging roads on former commercial timberlands that were acquired by expansion of RNP onto large areas of cutover timberlands in 1978. Road decommissioning reduces sediment threats over the long term, however there are shorter-term impacts arising...

Using streamflow data from the U.S. Geological Survey, we assessed long-term (1953-2012) trends in streamflow on California’s North Coast including many sites in the redwood region. The study area spans from the Smith River to the Mattole River and includes the Eel and Klamath-Trinity basins. Antecedent Precipitation Index (API) is a time-weighted summary of precipitation which provides high weight to recent precipitation and low weight to precipitation that occurred many months ago. We used a regression model of the relationship between API and streamflow to calculate "precipitation-adjust...

Insight into genetic variation in trees may provide opportunities to select for genotypes that are better adapted to new locations and future climate conditions. We established a field test at two sites in Humboldt County, California to study the performance of coast redwood (Sequoia sempervirens (D. Don) Endl.) under assisted migration. Both test sites were near the eastern (inland) limit of coast redwood’s range and had no naturally occurring redwood. Seed were collected from redwood trees on dry, hot ridges and upper slopes from the southernmost populations, and combined with redwood...

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...