Treesearch

Ecological boundaries have been of interest to naturalists since the time of Darwin and Wallace because they are transitional zones on the landscape across which distinct changes occur in constitution of plant and animal communities. In the xeric landscapes of the central Baja California Peninsula, fan palm (Erythea armata and Washingtonia robusta) oases are small (usually ,1 ha) mesophilic islands of structurally complex habitats. We report new records of mesophilic reptiles and amphibians from the adjacent Californian biome in palm groves of the Sonoran region; these highly philopatric...

Phytophthora ramorum, an introduced invasive plant pathogen that causes sudden oak death, has killed over a million tanoak, coast live oak, Shreve oak, and California black oak trees along the California coastal region from Monterey through Humboldt Counties. Most trees infected with P. ramorum will eventually die, including prized landscape trees. Be aware that P. ramorum can infect California bay laurel trees in advance of oak and tanoak infection and that the symptoms of bay laurel infection are not obvious. This publication provides advice to landowners, land managers, arborists,...

Agathosma species, which are indigenous to South Africa, are also cultivated for commercial use. Recently growers experienced severe plant loss, and symptoms shown by affected plants suggested that a soilborne disease could be the cause of death. A number of Phytophthora taxa were isolated from diseased plants, and this paper reports their identity, mating type, and pathogenicity to young Agathosma plants. Using morphological and sequence data seven Phytophthora taxa were identified: the A1 mating type of P. cinnamomi var. cinnamomi, P. cinnamomi var. parvispora and P. cryptogea, the A2...

Following stand-replacing wildfire, post-fire (salvage) logging of fire-killed trees is a widely implemented management practice in many forest types. A common hypothesis is that removal of fire-killed trees increases surface temperatures due to loss of shade and increased solar radiation, thereby influencing vegetation establishment and possibly stand development. Six years after a wildfire in a Mediterranean-climate mixed-conifer forest in southwest Oregon, USA, we measured the effects of post-fire logging (>90% dead tree (snag) removal) on growing season surface air temperatures....

Partitioning of gross primary production (GPP) to aboveground versus belowground, to growth versus respiration, and to short versus long‐lived tissues exerts a strong influence on ecosystem structure and function, with potentially large implications for the global carbon budget. A recent meta‐analysis of forest ecosystems suggests that carbon partitioning to leaves, stems, and roots varies consistently with GPP and that the ratio of net primary production (NPP) to GPP is conservative across environmental gradients. To examine influences of carbon partitioning schemes employed by global...

Urban environments have been compared to the global environment predicted at the end of the twenty-first century, in that urban areas are currently experiencing elevated atmospheric C02 concentrations, warmer temperatures, increased nitrogen loads, and elevated concentrations of pollutants (Grimm et al. 2000). It is extremely difficult to predict ecosystem responses to multiple atmospheric and climatic perturbations (Norby and Luo 2004), yet such predictions are critical, both for understanding global change as well as for quantifying critical ecosystem processes in urban areas in which...