Treesearch

Increasing stringency of energy codes and the growing market demand for more energy efficient buildings gives structural insulated panel (SIP) construction an opportunity to increase its use in commercial and residential buildings. However, shear wall aspect ratio limitations and lack of knowledge on how to design SIPs with window and door openings are barriers to the wider adoption of SIP technology. An experimental study was conducted to evaluate the lateral resistance performance of high-aspect-ratio SIP shear wall segments and SIP shear walls with window and door openings. At most two...

Engelmann oaks (Quercus engelmannii) are restricted to extreme southern California and northern Baja, California. Their entire range falls within a landscape increasingly prone to human induced wildfires. The influence of fire on seedlings and saplings has been well studied, but there is less information available on its effects on mature trees. Two monitoring programs tracked Q. engelmannii for 13 years in areas experiencing fires and adjacent unburned areas. At the Santa Rosa Plateau Ecological Reserve, management fires were initiated in 1988. Management units have been subjected to...

Conventional accounting of agricultural income focuses on the commercial operating income from oak woodland ranches, omitting the value of amenities to the landowner and real capital gains, which includes land revaluation (appreciation). These accounting exercises also mix income earned through self-employed (landowner and household) labor with ranch operating income, making it difficult to estimate separately how capital investment and landowner labor time are remunerated. In this paper we estimate the total landowner income and profitability rates from six oak woodland case studies in...

The influence of enhanced nitrogen (N) deposition on key ecosystem services provided by oak woodlands was experimentally investigated. Fertilizer was applied for 2 years to paired plots in the oak understory and adjacent open grassland. Treatments simulated four N deposition levels and effects on forage productivity, biodiversity, and soil N supply were measured. At each treatment level, understory plots received twice the N fertilizer of paired open plots to simulate a deposition hotspot effect of the oak canopy. Soils in the open had lower inorganic N concentrations than the understory...

The exhibit Puerto Rico: Gateway to Landscape proposes to explore various ways in which citizens approach the landscape, or construct it – inside and outside the city – and considers city planning, the creation of parks and natural reserves, and their interpretation. From a perspective of citizen involvement, this thematic scaffolding related to landscape and the various ways we connect to is important, not just because it is relevant in the context of today’s Puerto Rico but also because it represents an opportunity to make a conscious effort to evaluate – from an interdisciplinary...

Multispectral satellite imagery, that is, remotely sensed imagery with discrete bands ranging from visible to shortwave infrared (SWIR) wavelengths, is the timeliest and most accessible remotely sensed data for monitoring tropical forests. Given this relevance, we summarize here how multispectral imagery can help characterize tropical forest attributes of widespread interest, particularly attributes that are relevant to GHG emission inventories and other forest C accounting: forest type, age, structure, and disturbance type or intensity; the storage, degradation, and accumulation of C in...

Biological knowledge about bird focal species may be used to inform planning, habitat management, and restoration efforts, with the assumption that the implementation of these species-based recommendations will maintain and enhance healthy functioning habitats and the ecosystems services they provide. Point Blue Conservation Science in collaboration with the Natural Resources Conservation Service (NRCS) state office in California recently formed the Rangeland Watershed Initiative (RWI) to restore ecosystem function by working with ranchers on privately held hardwood rangelands in the...

Fire frequency on a blue oak (Quercus douglasii) dominated rangeland in California's southern Sierra Nevada foothills was approximately every 10 years until 1965, followed by a 30 year period of fire exclusion. This resulted in a dense tree overstory with small diameters, high crown cover, poor acorn and forage production, and limited complexity in vertical habitat structure. Tree thinning was evaluated as a treatment to restore pre-fire stand structure to these rangeland areas. Three thinning treatments were evaluated: (1) thin one-third of the standing tree basal area (resulting in a...

During 1990 to 2013, the area planted with wine grapes increased nearly 4.5 times in San Luis Obispo County. Much of this development occurred on open oak savanna with scattered oak (Quercus spp.) trees. Remnant trees are retained in some vineyards, but their value to biodiversity retention has not been quantified. During April to September 2014, at six vineyards in San Luis Obispo County, we compared echolocation activity of bats and the abundance of insects at remnant trees to locations without trees in the vineyards. The mean number of insects per night was over two times greater at...

Turkey vultures (Cathartes aura) are a ubiquitous component of California’s oak woodland faunal assemblage. Though obvious, they are one of the least studied vertebrates found in our hardwood forests. This study attempts to define the role of oak trees as nesting sites for this large avian species. Verified nest trees are evaluated to determine tree structure and morphology, tree size, cavity size and cavity volumes. Nest trees need to be large and old to develop the nest characteristics being utilized by turkey vultures. Nest trees tend to be erect with large trunk cavities that extend to...