Treesearch

In conducting oak restoration, it is common to plant at least two acorns per location to increase the probability that at least one will germinate and produce a seedling. If both seedlings successfully establish, one is generally removed to reduce possible competition. To test the assumption that the near neighbors are competing, we examined several cohorts of valley oak (Quercus lobata) seedlings established from acorns planted at the University of California Sedgwick Reserve in Santa Barbara County. We assessed correlations between presence/absence of neighbors and individual performance,...

California oaks exhibit tremendous phenotypic variation throughout their range. This variation reflects phenotypic plasticity in tree response to local environmental conditions as well as genetic differences underlying those phenotypes. In this study, we analyze phenotypic variation in leaf traits for valley oak adults sampled along three elevational transects and in young seedlings grown from their acorns in greenhouse conditions. This project represents the early phase of a long-term provenance study of valley oak (see Delfino Mix and others, Establishing a range-wide provenance test in...

The Sacramento Tree Foundation (Tree Foundation), a nonprofit organization operating in the greater Sacramento California region, has been engaged in planting native oak trees in urban and suburban areas since 1998. Through an effort to provide efficient access to tree mitigation services and support compliance with local tree protection ordinances, more than 20,038 trees have been planted, monitored and cared for. Through developing the program and building hyper-local best practices, Tree Foundation staff has achieved a very high rate of success, growing the program to include a broad...

Over the past decade, the use of wood for thermal energy in Alaska has grown significantly. Since 2000, nearly 30 new thermal wood-energy installations in Alaska have been established. Cordwood units, burning primarily firewood and other forms of roundwood, have played an integral part in this success and are well suited to many rural communities in Alaska. In this case study, we evaluate cordwood installations located in three geographic regions of Alaska. Included are systems at Coffman Cove (southeast Alaska), Ionia (Kenai Peninsula, Alaska), and Gulkana (south-central Alaska). We...

The invasive goldspotted oak borer, Agrilus auroguttatus (Coleoptera: Buprestidae), is threatening the health and survival of oak trees in San Diego County, California (Flint and others 2013). The primary oak species colonized and killed in this area include coast live oak (Quercus agrifolia), California black oak (Quercus kelloggii), and canyon live oak (Quercus chrysolepis). The high amount of damage recorded on these hosts suggests that the association between A. auroguttatus and these oaks is recent. Damage by A. auroguttatus in its native range in Arizona to Emory oak (Quercus emoryi)...

The goldspotted oak borer (GSOB) Agrilus auroguttatus (Coleoptera: Buprestidae), has killed over 80,000 oaks across all land ownerships, costing over $8 million in public and private funds for mitigation and response. Linked to oak mortality in San Diego County in 2008, this exotic beetle likely arrived in California through infested firewood from Arizona and attacks three native oak species found through California and southern Oregon: coast live oak (Quercus agrifolia), California black oak (Q. kelloggi), and canyon live oak (Q. chrysolepis). The University of California Division of...

In 2012, the goldspotted oak borer (Agrilus auroguttatus, GSOB) was discovered in the mountain community of Idyllwild, 56.3 km north of its known area of infestation. This was the third time that a point of outbreak was discovered >32.2 km from the GSOB infestation area, suggesting that human transport of GSOB has substantially expanded the halo of California communities at imminent risk of GSOB-associated oak mortality. Even though this pattern of dispersal puts more communities at risk, the isolated nature of these new points of infestation offer some hope that their damage could be...

We counted seedlings and assessed crown characteristics and abundance of fire-induced stump sprout regeneration in California black oak (Quercus kelloggii) 11 to 12 years after wildfire. Regeneration was examined across three levels of burn severity (low, moderate, and high) according to the Composite Burn Index. Fire severity affected crown width of oak sprout clumps; clumps of a given width were taller in areas of high severity fire. Multi-stemmed, sprouting black oak genets were more common than black oak seedlings. The data illustrate a positive sprout clump density association with...

The goldspotted oak borer, Agrilus auroguttatus (Coleoptera: Buprestidae), was first associated with oak mortality in San Diego County, California in May of 2008. Since that time, a research and survey program has outlined the biology of this flatheaded borer in the invaded and native habitats; delimited the invaded range; and developed the components of an integrated pest management (IPM) program. Significant advances have been made in the understanding of its host range, feeding habits, life cycle, and natural enemies in Arizona and California. Some research progress has also been made...

The earliest signs of goldspotted oak borer (Agrilus auroguttatus, GSOB)-associated oak declines can be found in 1996 aerial photo images from the Descanso area of San Diego County. By 2014, GSOB had spread over a 4000 km2 area, with a patchy distribution similar to the early spread of the emerald ash borer (Agrilus planipennis). The GSOB occurs over about 26,250 ha (60 percent) of the oak woodlands in its primary range of infestation; with heaviest damage near rural housing and communities. Three GSOB diaspora have occurred 30, 40, and 55 km from closest known infestation areas, implicatin...