The occurrence of large and recurring forest fires has long been associated with fire-prone environments, but this perception has been shifted rapidly in recent decades as Earths' landscapes have ...become increasingly threatened by severe and unpredictable fires as a result of climate changes. In this regard, the flammability of trees is a topic of great interest for ecology, management, and the development of sustainable restoration and rehabilitation plans. Tree species differ in regard to flammability, and many plant functional traits contribute to flammability at species, community and vegetation level. The relationship between plant traits and flammability at species level is important for a broader understanding of the vegetation-fire dynamic at the local and landscape scales. This review summarizes the current state of knowledge regarding the impact of individual plant traits of tree species on flammability components. By keywords-based searching of academic databases, 85 research papers were collected and analyzed. The literature synthesis shows: i) main issues addressed in studies on plant trait-based tree flammability, ii) general research output and biogeographic regions studied, iii) inventory of tree taxa investigated, iv) relationships between plant traits and flammability components, v) the most relevant plant traits that determine the flammability-related differences between species.
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•Trait-based flammability studies yield scientific knowledge with wide applicability.•Relevant plant traits determine the flammability-related differences between species.•Environment-traits-flammability linkage by collecting more empirical data is needed.
Population variability of n-alkanes in the cuticular waxes of Serbian spruce needles from Bosnia and Herzegovina was investigated for the first time. n-Alkanes exhibited composition variability ...ranging from C18 to C35.
The divergence of populations from Bosnia and Herzegovina and previously investigated Serbian populations was statistically confirmed by PCA, DA, and CA (Cluster analysis), which could support the fact that there are two possible spruce chemotypes: one relating to the Bosnian-Herzegovinian and the other to the Serbian populations. Climate parameters (precipitation, temperature, wind, and solar radiation) approved this conclusion.
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•n-Alkanes of Serbian spruce from Bosnia and Herzegovina were investigated for the first time.•Among them, C29, C23, C27, and C25 were the most abundant.•PCA and especially DA showed the greatest distance of population Viogor.•There are two possible chemotypes: Bosnian-Herzegovinian and Serbian populations.•Precipitation, temperature, wind, and solar radiation approved this conclusion.
In this study we have reported the chemical composition of the essential oils obtained from the needles of twelve Pinus taxa, belonging to the subgenera Pinus (sections Pinus and Trifoliae) and ...Strobus (sect. Quinquefoliae). Monoterpenes dominated over sesquiterpenes in most of the investigated taxa of both subgenera, except in representatives of the subsection Pinaster, subgenus Pinus. ?-Pinene was the most abundant terpene in eight pines, but other dominant terpenes were found in some taxa - trans-caryophyllene, germacrene D, abietadiene and ?-pinene. In the subsect. Pinaster, the most dominant compounds varied from species to species. In addition, P. halepensis and P. pinaster had the highest percentage of diterpenes, while P. heldreichii was the richest in germacrene D. In the PCA and cluster analyses, three species from the subsect. Pinaster emerged as the most distant: P. halepensis, P. pinaster, and P. heldreichii. In addition, the possible taxonomic implications of the terpene profile in the analysed Pinus taxa were also discussed.
Diarylheptanoids are a group of secondary metabolites widely distributed in the Betulaceae family and characteristic for
species. In this study, the chemotaxonomic power of diarylheptanoids, such as ...hirsutanonol-5-
-glucopyranoside, rubranoside A, oregonin, platyphylloside, alnuside A and hirsutanonol, has been investigated in combination with principal component analysis (PCA) for differentiation of
species. Concentrations of six diarylheptanoids in the bark extracts of two natural populations of
(black alder) and
(gray alder) were determined by ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). PCA clearly shows the separation of three groups. Populations I (
) and II (
) both consisted of individuals of the corresponding species. Four individuals from both sampled populations formed a separate group (population III), which possibly represents a hybrid group. Accordingly, diarylheptanoids may serve in combination with PCA as chemotaxonomic markers at the species level, which may also reveal hybrid species.
Comparative analysis of terpene diversity and differentiation of relict pines Pinus heldreichii, P. nigra, and P. peuce from the central Balkans was performed at the population level. Multivariate ...statistical analyses showed that the composition of needle terpenes reflects clear divergence among the pine species from different subgenera: P. peuce (subgenus Strobus) vs. P. nigra and P. heldreichii (subgenus Pinus). In addition, despite the described morphological similarities and the fact that P. nigra and P. heldreichii may spontaneously hybridize, our results indicated differentiation of their populations naturally growing in the same area. In accordance with recently proposed concept of ‘flavonic evolution’ in the genus Pinus, we assumed that the terpene profile of soft pine P. peuce, defined by high amounts of six monoterpenes, is more basal than those of hard pines P. nigra and P. heldreichii, which were characterized by high content levels of mainly sesquiterpenes. In order to establish precise positions of P. heldreichii, P. nigra and P. peuce within the taxonomic and phylogenetic tree, as well as develop suitable conservation strategies and future breeding efforts, it is necessary to perform additional morphological, biochemical, and genetic studies.
The variability of n-alkanes in the needle cuticular wax of Pinus heldreichii and P. peuce in two natural populations from the Scardo-Pindic mountains was investigated for the first time. Gas ...chromatography (GC) and gas chromatography/mass spectrometry (GC–MS) analyses of two-year-old needles were performed using an Agilent 7890A GC equipped with an inert 5975C XL EI/CI mass spectrometer detector (MSD) and a flame ionization detector (FID) connected by a capillary flow technology 2-way splitter with make-up. An HP-5MS capillary column was used. n-Alkanes ranged from C19 to C33. In P. heldreichii the most abundant were C23, C25 and C27 (16.3, 15.6 and 12.8% on average, respectively), while in P. peuce they were C29, C25, and C27 (16.5, 15.3 and 13.5% on average, resp.). Mid-chain and long-chain n-alkanes prevailed in both species. Principle component analysis (PCA) and Cluster analyses of five and six n-alkanes, respectively, showed divergence of the Scardo-Pindic populations from the Dinaric ones.
The reliability of diarylheptanoids as chemotaxonomic markers at inter- and intraspecific levels has been investigated. Six diarylheptanoids were quantified in bark ethanol extracts of four
spp. ...populations by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The populations described here as
(I) and
(III) are clearly differentiated. Compared to population I, individuals in population III have higher extract yields and hirsutanonol-5-
-D-glucopyranoside content and lower contents of hirsutanonol, rubranoside A and oregonin. Individuals from neighboring populations of
(II) and
(IV) share similar contents of hirsutanonol. All the studied populations exhibit a high intrapopulation variability of the selected diarylheptanoids; they have a heterogeneous chemotype and they partially overlap. The geographical proximity of populations II and IV increases their chemical similarity. Principal component analysis (PCA) clearly shows that the biggest dispersion of individuals lies within population IV. The reason for its heterogeneity might be its physical proximity to population II, i.e. the appearance of hybrids. Also, geometric morphometrics of leaves was performed as a screening criterion for spontaneous hybrids.
This is the first report on the composition and variability of the needle‐wax n‐alkanes in natural populations of Pinus nigra in Serbia. Samples of 195 trees from seven populations belonging to ...several infraspecific taxa (ssp. nigra, var. gocensis, ssp. pallasiana, and var. banatica) were analyzed. In general, the size of the n‐alkanes ranged from C16 to C33, with the exception of ssp. nigra, for which it ranged from C18 to C33. The most abundant were C23‐, C25‐, C27‐, and C29‐alkanes. The needle waxes of Populations I–III and V were characterized by a higher content of C23‐, C25‐, and C27‐alkanes and a lower content of C24‐, C26‐, C28‐, and C30‐alkanes, compared to the other populations, and the trees of these populations could be assigned to ssp. nigra. The samples of Population VI were characterized by higher amounts of C22‐, C24‐, C30‐, and C32‐alkanes and lower amounts of C25‐ and C27‐alkanes, and the trees could be considered as ssp. pallasiana. The samples of Population VII, consisting of trees belonging to var. banatica, were richer in C29‐, C31‐, and C33‐alkanes. The wax compositions of Populations IV and V, both composed of trees previously determined as P. nigra var. gocensis, showed a tendency of splitting. Indeed, the alkane composition of Population IV was closer to that of ssp. pallasiana pines, while that of Population V was more similar to that of ssp. nigra pines. From the results presented here, it is obvious that in the central part of the Balkan Peninsula, significant diversification and differentiation of the populations of black pine exists, and these populations could be defined as different intraspecific taxa. Our results also indicate the validity of n‐alkanes as chemotaxonomic characters within this aggregate.
The n‐alkane composition in the leaf cuticular waxes of natural populations of Bosnian pine (Pinus heldreichii), Austrian pine (P. nigra), and Macedonian pine (P. peuce) was compared for the first ...time. The range of n‐alkanes was wider in P. nigra (C16 – C33) than in P. heldreichii and P. peuce (C18 – C33). Species also diverged in abundance and range of dominant n‐alkanes (P. heldreichii: C23, C27, and C25; P. nigra: C25, C27, C29, and C23; P. peuce: C29, C25, C27, and C23). Multivariate statistical analyses (PCA, DA, and CA) generally pointed out separation of populations of P. nigra from populations of P. heldreichii and P. peuce (which were, to a greater or lesser extent, separated too). However, position of these species on the basis of n‐alkane composition was in accordance neither with infrageneric classification nor with recent molecular and terpene investigations.
The content of nonacosan-10-ol and n-alkanes in needle waxes of 12 Pinus taxa (P. halepensis, P. heldreichii, P. mugo, P. nigra ssp. nigra, P. nigra ssp. dalmatica, P. peuce, P. pinaster, P. pinea, ...P. ponderosa, P. strobus, P. sylvestris and P. wallichiana) were examined. In eight Pinus taxa (except of P. halepensis, P. pinaster, P. heldreichii and P. peuce) nonacosan-10-ol contents were examined for the first time. In all examined pines C29, C27 or C25 were the main n-alkane compounds. C range was mainly 18--33. In six Pinus taxa (P. mugo, P. nigra ssp. dalmatica, P. sylvestris, P. pinea, P. strobus and P. wallichiana) carbon preference index and average chain length values were examined for the first time. In the plane of Axis 1 (PCA), P. strobus, P. mugo and P. wallichiana were strongly separated from P. heldreichii and P. pinea. In the plane of Axis 2, P. peuce, P. strobus and P. wallichiana as well as P. heldreichii and P. pinea diverged from other examined species. In DA, P. heldreichii, P. strobus, P. peuce and P. wallichiana diversed. CA divided sections Pinus and Pinaster from the section Strobi.
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