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- Artaxo, Paulo, et al.
(författare)
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Tropical and Boreal Forest – Atmosphere Interactions : A Review
- 2022
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Ingår i: Tellus. Series B, Chemical and physical meteorology. - : Stockholm University Press. - 0280-6509 .- 1600-0889. ; 74:1, s. 24-163
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Forskningsöversikt (refereegranskat)abstract
- This review presents how the boreal and the tropical forests affect the atmosphere, its chemical composition, its function, and further how that affects the climate and, in return, the ecosystems through feedback processes. Observations from key tower sites standing out due to their long-term comprehensive observations: The Amazon Tall Tower Observatory in Central Amazonia, the Zotino Tall Tower Observatory in Siberia, and the Station to Measure Ecosystem-Atmosphere Relations at Hyytiäla in Finland. The review is complemented by short-term observations from networks and large experiments.The review discusses atmospheric chemistry observations, aerosol formation and processing, physiochemical aerosol, and cloud condensation nuclei properties and finds surprising similarities and important differences in the two ecosystems. The aerosol concentrations and chemistry are similar, particularly concerning the main chemical components, both dominated by an organic fraction, while the boreal ecosystem has generally higher concentrations of inorganics, due to higher influence of long-range transported air pollution. The emissions of biogenic volatile organic compounds are dominated by isoprene and monoterpene in the tropical and boreal regions, respectively, being the main precursors of the organic aerosol fraction.Observations and modeling studies show that climate change and deforestation affect the ecosystems such that the carbon and hydrological cycles in Amazonia are changing to carbon neutrality and affect precipitation downwind. In Africa, the tropical forests are so far maintaining their carbon sink.It is urgent to better understand the interaction between these major ecosystems, the atmosphere, and climate, which calls for more observation sites, providing long-term data on water, carbon, and other biogeochemical cycles. This is essential in finding a sustainable balance between forest preservation and reforestation versus a potential increase in food production and biofuels, which are critical in maintaining ecosystem services and global climate stability. Reducing global warming and deforestation is vital for tropical forests.
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| 2. |
- Lehmanski, Linda M.A., et al.
(författare)
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Addressing a century-old hypothesis – do pioneer beetles of Ips typographus use volatile cues to find suitable host trees?
- 2023
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Ingår i: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 238:5, s. 1762-1770
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Tidskriftsartikel (refereegranskat)abstract
- Global warming and more frequent climate extremes have caused bark beetle outbreaks of unprecedented scale of these insects in many conifer forests world-wide. Conifers that have been weakened by drought and heat or damaged by storms are highly susceptible to bark beetle infestation. A large proportion of trees with impaired defences provides good conditions for beetle population build-up of beetles, but mechanisms driving host search of pioneer beetles are still uncertain in several species, including the Eurasian spruce bark beetle Ips typographus. Despite a two-century-long history of bark beetle research, we still lack a sufficient understanding of interactions between I. typographus and its host Norway spruce (Picea abies) to forecast future disturbance regimes and forest dynamics. Depending on the scale (habitat or patch) and beetle population state (endemic or epidemic), host selection is likely driven by a combination of pre and postlanding cues, including visual selection or olfactory detection (kairomones). Here, we discuss primary attraction mechanisms and how volatile emission profiles of Norway spruce may provide cues on tree vitality and suitability for attacks by I. typographus, in particular during the endemic phase. We identify several crucial knowledge gaps and provide a research agenda addressing the experimental challenges of such investigations.
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