The commercialization of biomass-derived pyrolysis liquids for use in heat and power applications is dependent on the ability to successfully provide a fuel of acceptable quality to an end user at a competitive price. One of the intentions of the European Union (EU) Altener 4.1030/C/00-015/2000 project was to derive standards for biomass-derived pyrolysis liquids, based on a consensus between providers of the equipment (boilers, engines, and turbines) and the producers of the liquids. Five basic properties (homogeneity, water content, solids content, stability, flash point) for the liquids are used as the primary criteria for pyrolysis liquid evaluation. Specific values are proposed to ensure that pyrolysis liquids meet a minimum grade that is acceptable for use as a fuel oil in boilers and engines. Data on emissions from boilers, engines and turbines are presented. Preliminary long-duration test data from boiler use are available to allow more-detailed specifications on secondary properties to be made. The purpose of this work is to ensure that a realistic set of specifications is determined, to allow the introduction of pyrolysis liquids into existing fuel infrastructures and markets.

We consider the mechanistic basis and functional significance of the pervasive influence of parasitic plants on productivity and diversity, synthesizing recent findings on their responses to drought, heat waves, and fire. Although parasites represent just 1% of all angiosperms, the ecophysiological traits associated with parasitism confer pronounced impacts on their hosts and disproportionate influence upon community structure, composition, and broader ecosystem function. New insights into the roles of their pollinators, seed dispersers, and litter-dependent detritivores have advanced our understanding of how parasitic plants modulate animal communities via their extended and complementary phenology. Direct and indirect impacts of climate change on parasitic plants and their ecological roles are already apparent. Trade-offs between maximizing efficiency at obtaining water from hosts and sensitivity to water stress underlie range shifts and host switching of parasitic plants and increased reliance on these plants by animal communities for food and shelter. Expected final online publication date for the Annual Review of Ecology, Evolution, and Systematics, Volume 53 is November 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Parasitic plants are mostly viewed as pests. This is caused by several species causing serious damage to agriculture and forestry. There is however much more to parasitic plants than presumed weeds. Many parasitic plans exert even positive effects on natural ecosystems and human society, which we review in this paper. Plant parasitism generally reduces the growth and fitness of the hosts. The network created by a parasitic plant attached to multiple host plant individuals may however trigger transferring systemic signals among these. Parasitic plants have repeatedly been documented to play the role of keystone species in the ecosystems. Harmful effects on community dominants, including invasive species, may facilitate species coexistence and thus increase biodiversity. Many parasitic plants enhance nutrient cycling and provide resources to other organisms like herbivores or pollinators, which contributes to facilitation cascades in the ecosystems. There is also a long tradition of human use of parasitic plants for medicinal and cultural purposes worldwide. Few species provide edible fruits. Several parasitic plants are even cultivated by agriculture/forestry for efficient harvesting of their products. Horticultural use of some parasitic plant species has also been considered. While providing multiple benefits, parasitic plants should always be used with care. In particular, parasitic plant species should not be cultivated outside their native geographical range to avoid the risk of their uncontrolled spread and the resulting damage to ecosystems.

Across its entire range in Australia's western and southern rangelands, Australian sandalwood (Santalum spicatum [R.Br.] A.DC.) is on a path towards 'extinction in the wild'--the International Union for the Conservation of Nature's penultimate category of conservation risk. Sandalwood populations have substantially diminished or become locally extinct, predominantly a consequence of land clearing for agriculture, introduced grazers, disruption of key ecological processes (e.g. seed dispersal, fire regimes) and 175 years of intensive commercial exploitation for its fragrant, high value timber. The status of the world's last wild-harvested species of sandalwood is significant to both conservation and rangeland management, and the implementation of a science-based sustainable yield approach to management of this species is vital. By highlighting the scale and precipitous rate of decline and identifying key drivers affecting mortality and recruitment, this review outlines the conservation and restoration needs of the species in situ to conserve remaining wild populations, and the need to transition to science-based resource management actions such as farm-based plantation production.

One-third of the world's trees are at risk of extinction, with large, old, long-lived trees among the most vulnerable. Long-lived trees in arid and semi-arid biomes are particularly at risk, including Australian sandalwood (Santalum spicatum, Santalaceae), which is experiencing substantial population decline due to a suite of natural and anthropogenic drivers, with no appreciable recruitment estimated for more than 80 years. To contextualize this range-wide collapse and quantify regional variation in population dynamics across Australia's western rangelands, we investigated the size-class profiles of 12 sandalwood populations in a 1,500-kilometre arc between Shark Bay and the Gibson Desert in central Western Australia including Indigenous Protected Areas, pastoral leases and public and private conservation parks and reserves. Stem diameters, indicative of age using known growth rates, were recorded for 1,355 sandalwood plants, along with a set of another plant structural and ecological parameters. Using size-class profiles and associated demographic data, we estimated the population age structure and trajectory to determine whether each population was increasing, stable or declining. Our surveys revealed sandalwood populations are declining and are composed almost entirely of very old trees in advanced states of senescence. Of 1,355 plants sampled, 1,198 (88.4%) individuals were large (old) trees. A total of 23 seedlings and 21 saplings were recorded across all sites, almost all of which (22 and 19, respectively) were in one population, and located under the canopies of parent trees where they would not be expected to survive to maturity. Our findings reinforce the urgent need to list Santalum spicatum as a threatened species in Western Australia (where wild plants are still being commercially harvested) and to initiate effective conservation actions to secure the species' continued existence across its natural range. K E Y W O R D S climate change, extinct, forest products, Hemiparasite, overexploitation, regeneration failure F I G U R E 1 Location of the 12 sandalwood populations surveyed in this study in the central and western rangelands of Western Australia. Inset: Schematic diagram showing a population (A), stand plot (B), stand transect (C) and haphazard transect (D).