Treesearch

Rainfall interception by a tree's crown is one of the most important hydrological processes in an ecosystem, yet the mechanisms of interception are not well understood. A process-based experiment was conducted under five simulated rainfall intensities (from 10 to 150 mm h−1) to directly quantify tree crown interception and examine the effect of rainfall traits and crown structure characteristics on interception for broadleaf (Platycladus orientalis, Pinus tabulaeformis) and needle tree species (Quercus variabilis, Acer truncatum). Results indicated that (1) the interception process was...

Thinning with removal of whole trees in a plantation or natural forest stand raises two main concerns – soil compaction from the ground-based machinery and nutrient depletion particularly with whole tree harvest as is often practiced for attendant fuels reduction. To address these concerns, two sets of experimental treatments were imposed in young ponderosa pine plantations. In the first set, we applied four treatments to test the effects of thinning with biomass removal using progressively more soil manipulations: (I) control, (II) thinning only with all biomass removed, (III) same as...

Characterizing forest soil properties with high variability is challenging, sometimes requiring large numbers of soil samples. Soil bulk density is a standard variable needed along with element concentrations to calculate nutrient pools. This study aimed to determine the optimal sample size, the number of observation (n), for predicting the soil bulk density with a precision of ±10% at a 95% confidence level among different soil types. We determined soil bulk density samples at three depths at 186 points distributed over three different 1-ha forest sites. We calculated n needed for...

To determine the current range of water temperatures in the streams inhabited by California golden trout, Oncorhynchus mykiss aguabonita, I deployed and monitored water temperature recording probes from 2008 through 2013 in three meadows in the Golden Trout Wilderness (GTW). Ninety probes were placed in three meadow streams: Mulkey Creek in Mulkey Meadows (elevation 2838 m), South Fork Kern River in Ramshaw Meadows (2640 m), and Golden Trout Creek in Big Whitney Meadow (2963 m). Year-round water temperatures were successfully downloaded from 83 probes along with measurements of dissolved...

Many environmental challenges are exacerbated within the urban landscape, such as stormwater runoff and flood risk, chemical and particulate pollution of urban air, soil and water, the urban heat island, and summer heat waves. Urban trees, and the urban forest as a whole, can be managed to have an impact on the urban water, heat, carbon and pollution cycles. However, there is an increasing need for empirical evidence as to the magnitude of the impacts, both beneficial and adverse, that urban trees can provide and the role that climatic region and built landscape circumstance play in...

Urban forestry is an important green infrastructure strategy because healthy trees can intercept rainfall, reducing stormwater runoff and pollutant loading. Surface saturation storage capacity, defined as the thin film of water that must wet tree surfaces before flow begins, is the most important variable influencing rainfall interception processes. Surface storage capacity is known to vary widely among tree species, but it is little studied. This research measured surface storage capacities of 20 urban tree species in a rainfall simulator. The measurement system included a rainfall...

This chapter discusses the native ranges, histories of introduction, recent research efforts, and the potential impacts of some of 22 species of invasive scolytids in California’s Mediterranean forest ecosystems. The diversity of native and ornamental tree species, the varied climatic zones, and the widespread importation of nursery stock and packaged cargo have made California a fertile location for the introduction and establishment of bark and ambrosia beetles. Eight of the twenty two taxa are ambrosia beetles; four are spermophagous (e.g., Coccotrypes and Dactylotrypes sp.); six are...

In 2008, the goldspotted oak borer, Agrilus auroguttatus Schaeffer (Coleoptera: Buprestidae), was fi rst linked to elevated levels of oak mortality in southern California (CA), but it appears to have impacted oak woodlands and mixed conifer forests across all land ownerships in this region for nearly two decades. This unexpectedly damaging indigenous exotic phloem- and wood-boring pest is hypothesized to have been introduced in the late 1990s to early 2000s via infested fi rewood from southeastern Arizona to San Diego County, CA. The life history and impact of A. auroguttatus on oaks were...

Fire is a natural process and the dominant disturbance shaping plant and animal communities in many coniferous forests of the western US. Given that fire size and severity are predicted to increase in the future, it has become increasingly important to understand how wildlife responds to fire and post-fire management. The Angora Fire burned 1243 hectares of mixed conifer forest in South Lake Tahoe, California. We conducted avian point counts for the first 3 years following the fire in burned and unburned areas to investigate which habitat characteristics are most important for re-establishi...

The attrition of women from science with increasing career stage continues, suggesting that current strategies are unsuccessful. Research evaluation using unbiased metrics could be important for the retention of women, because other factors such as implicit bias are unlikely to quickly change. We compare the publishing patterns of men and women within the discipline of ecology and show sexual dimorphism in self-citation leading to higher h-index scores for men despite lower citations per paper, which is exacerbated by more career absences by women. However, if self-citations and non-researc...