Unravelling the functions of biogenic volatiles in boreal and temperate forest ecosystems

Abstract

Living trees are the main source of biogenic volatile organic compounds (BVOCs) in forest ecosystems, but substantial emissions originate from leaf and wood litter, the rhizosphere and from microorganisms. This review focuses on temperate and boreal forest ecosystems and the roles of BVOCs in ecosystem function, from the leaf to the forest canopy and from the forest soil to the atmosphere level. Moreover, emphasis is given to the question of how BVOCs will help forests adapt to environmental stress, particularly biotic stress related to climate change. Trees use their vascular system and emissions of BVOCs in internal communication, but emitted BVOCs have extended the communication to tree population and whole community levels and beyond. Future forestry practices should consider the importance of BVOCs in attraction and repulsion of attacking bark beetles, but also take an advantage of herbivore-induced BVOCs to improve the efficiency of natural enemies of herbivores. BVOCs are extensively involved in ecosystem services provided by forests including the positive effects on human health. BVOCs have a key role in ozone formation but also in ozone quenching. Oxidation products form secondary organic aerosols that disperse sunlight deeper into the forest canopy, and affect cloud formation and ultimately the climate. We also discuss the technical side of reliable BVOC sampling of forest trees for future interdisciplinary studies that should bridge the gaps between the forest sciences, health sciences, chemical ecology, conservation biology, tree physiology and atmospheric science.

Forest Volatile Organic Compounds and Their Effects on Human Health: A State-of-the-Art Review

“…HIPVs comprise isoprenoids, products of the lipoxygenase (LOX) pathway, such as GLVs, some carotenoid derivatives, indoles and phenolics, and phytohormones such as ethylene, jasmonic acid, and others [17,18]. It is hypothesized that forest VOCs are not only involved in some plant-related physiological functions (biogenic stress response, adaptation to climate changes), but they also have a central role in forest ecosystems (interplant communication, antimicrobial and insecticidal activity against parasites, influence on animals' feeding behaviors as well as on underwood environmental conditions) [19]. Thus, forest VOCs can have several functions for plant physiology [18]; the most important of them are summarized in Table 1 and Figure 1.…”

Amazonian biogenic volatile organic compounds under global change

“…These emissions may represent a substantial loss of carbon previously assimilated by photosynthesis (up to 2% of carbon fixed for tropical forests; Kesselmeier, Ciccioli, et al, 2002). Isoprene is the most common de novo biosynthesized compound, with isopreneemitting plants found as a typical component in tropical forests (Harley et al, 2004;Šimpraga et al, 2019;Taylor et al, 2018).…”

“…Protection against pathogens and sealing wounds are also drivers for BVOC emissions (Laothawornkitkul et al, 2009;Ninkovic et al, 2019;Šimpraga et al, 2019). For example, the biosynthesis of natural rubber by Hevea brasiliensis is stimulated by wounding, releasing methyl jasmonate and ethylene (Duan et al, 2010), which is then oxidized during latex coagulation, sealing the wound (Piva et al, 2018 (Bloem, Haneklaus, Kesselmeier, & Schnug, 2012) rather than sinks as generally seen (Whelan et al, 2018).…”

Functional Role of Extrafloral Nectar in Boreal Forest Ecosystems under Climate Change

“…Provisioning services include material products such as food, fibers and timber; regulating services include environmental controls such as maintenance of hydrological and carbon cycles, water purification, control of soil erosion, and biological pest control; cultural services include recreational activities such as hiking and berry picking and spiritual experiences such as artistic representations of nature [89]. In ES assessment of specific groups of phytochemicals produced by forest plants, such as plant volatiles [90] or flower nectar [91], the services of the plant product can be classified into the provisioning (e.g., perfumes and honey) [91] and regulating (e.g., ozone removal and pollination) [90] ES categories. In the case of EFN in forest plants, mutualism with ants and the regulatory ES provided by ant communities, such as control of forest pests [7,92] and maintenance of the carbon cycle in forest ecosystems [56,57,93], are probably the major ES related to EFN production in boreal forest plants.…”