Identifying Conifer Tree vs. Deciduous Shrub and Tree Regeneration Trajectories in a Space-for-Time Boreal Peatland Fire Chronosequence Using Multispectral Lidar

Wildland fires and anthropogenic disturbances can cause changes in vegetation species composition and structure in boreal peatlands. These could potentially alter regeneration trajectories following severe fire or through cumulative impacts of climate-mediated drying, fire, and/or anthropogenic disturbance. We used lidar-derived point cloud metrics, and site-specific locational attributes to assess trajectories of post-disturbance vegetation regeneration in boreal peatlands south of Fort McMurray, Alberta, Canada using a space-for-time-chronosequence. The objectives were to (a) develop methods to identify conifer trees vs. deciduous shrubs and trees using multi-spectral lidar data, (b) quantify the proportional coverage of shrubs and trees to determine environmental conditions driving shrub regeneration, and (c) determine the spatial variations in shrub and tree heights as an indicator of cumulative growth since the fire. The results show that the use of lidar-derived structural metrics predicted areas of deciduous shrub establishment (92% accuracy) and classification of deciduous and conifer trees (71% accuracy). Burned bogs and fens were more prone to shrub regeneration up to and including 38 years after the fire. The transition from deciduous to conifer trees occurred approximately 30 years post-fire. These results improve the understanding of environmental conditions that are sensitive to disturbance and impacts of disturbance on northern peatlands within a changing climate.

Morphological variation of Aceh Pinus (Pinus merkusii)

The genus Pinus is classified as one of the most widely distributed genera of conifer trees, that are majorly distributed in the Northern and Southern hemispheres. Pinus merkusii is the only member of the genus Pinus that is adapted in the tropics and grows naturally in south Equator. Its natural distribution found through-out Southeast Asia, e.g. in Indonesia; particularly on Sumatran Island. Three native strains are known on Sumatra: Aceh, Kerinci, and Tapanuli; with the first one is known as the largest population among the three and grows naturally on the high altitudes. The wood has been utilized in building construction, while the resin collected is classified as one of the most valuable Non Timber Forest Products (NTFP) worth up to US $ 50 million/year and applied in many industries. Planting of citron grass (Cymbopogon sp.) has been ’booming’ over the past seven years in the middle regions of Aceh due to its attractive selling price. As consequences, many Pinus trees have been logged and demanded as fire woods in the distillation process of citron grass. Thus, the citron grass’ plantation has been directly threatening the existence of Pinus forests. Therefore, in-situ conservation effort should be started from now on. Here, we would like to report the morphological variation (N= 15 traits) of natural Pinus (e.g., plant height, diameter of main stem, number of crowns per branch, etc.). The morphological data collected were then analysed with the Principal Component Analyses (PCA), in order to cluster the major agronomical parameters among them. This morphological data would be complemented and benefitted the efforts in the genetic study of Aceh Pinus.

RNA viral communities are structured by host plant phylogeny in oak and conifer leaves

Wild plants can suffer devastating diseases, experience asymptomatic, persistent infections, and serve as reservoirs for viruses of agricultural crops, yet we have a limited understanding of the natural plant virosphere. To access representatives of locally and globally distinct wild plants and investigate their viral diversity, we extracted and sequenced dsRNA from leaves from 16 healthy oak and conifer trees in the UC Davis Arboretum (Davis, California). From de novo assemblies, we recovered 389 RNA-dependent RNA polymerase (RdRp) gene sequences from 384 putative viral species, and a further 580 putative viral contigs were identified with virus prediction software followed by manual confirmation of virus annotation. Based on similarity to known viruses, most recovered viruses were predicted to infect plants or fungi, with the highest diversity and abundance observed in the Totiviridae and Mitoviridae families. Phyllosphere viral community composition differed significantly by host plant phylogeny, suggesting the potential for host-specific viromes. The phyllosphere viral community of one oak tree differed substantially from other oak viral communities and contained a greater proportion of putative mycoviral sequences, potentially due to the tree's more advanced senescence at the time of sampling. These results suggest that oaks and conifers harbor a vast diversity of viruses with as-yet unknown roles in plant health and phyllosphere microbial ecology.

Mercury accumulation in leaves of different plant types – the significance of tissue age and specific leaf area

Mercury, Hg, is one of the most problematic metals from an environmental perspective. To assess the problems caused by Hg in the environment, it is crucial to understand the processes of Hg biogeochemistry, but the exchange of Hg between the atmosphere and vegetation is not sufficiently well characterized. We explored the mercury concentration, [Hg], in foliage from a diverse set of plant types, locations and sampling periods to study whether there is a continuous accumulation of Hg in leaves and needles over time. Measurements of [Hg] were made for deciduous and conifer trees in Gothenburg, Sweden (botanical garden and city area), as well as for evergreen trees in Rwanda. In addition, data for wheat from an ozone experiment conducted at Östad, Sweden, were included. Conifer data were quantitatively compared with literature data. In every case where older foliage was directly compared with younger, [Hg] was higher in older tissue. Covering the range from the current year up to 4-year-old needles in the literature data, there was no sign of Hg saturation in conifer needles with age. Thus, over timescales of approximately 1 month to several years, the Hg uptake in foliage from the atmosphere always dominated over Hg evasion. Rwandan broadleaved trees had generally older leaves due to lack of seasonal abscission and higher [Hg] than Swedish broadleaved trees. The significance of atmospheric Hg uptake in plants was shown in a wheat experiment where charcoal-filtrated air led to significantly lower leaf [Hg]. To search for general patterns, the accumulation rates of Hg in the diverse set of tree species in the Gothenburg area were related to the specific leaf area (SLA). Leaf-area-based [Hg] was negatively and non-linearly correlated with SLA, while mass-based [Hg] had a somewhat weaker positive relationship with SLA. An elaborated understanding of the relationship behind [Hg] and SLA may have the potential to support large-scale modelling of Hg uptake by vegetation and Hg circulation.

Transitional genomes and nutritional role reversals identified for dual symbionts of adelgids (Aphidoidea: Adelgidae)

Many plant-sap-feeding insects have maintained a single, obligate, nutritional symbiont over the long history of their lineage. This senior symbiont may be joined by one or more junior symbionts that compensate for gaps in function incurred through genome-degradative forces. Adelgids are sap-sucking insects that feed solely on conifer trees and follow complex life cycles in which the diet fluctuates in nutrient levels. Adelgids are unusual in that both senior and junior symbionts appear to have been replaced repeatedly over their evolutionary history. Genomes can provide clues to understanding symbiont replacements, but only the dual symbionts of hemlock adelgids have been examined thus far. Here, we sequence and compare genomes of four additional dual-symbiont pairs in adelgids. We show that these symbionts are nutritional partners originating from diverse bacterial lineages and exhibiting wide variation in general genome characteristics. Although dual symbionts cooperate to produce nutrients, the balance of contributions varies widely across pairs, and total genome contents reflect a range of ages and degrees of degradation. Most symbionts appear to be in transitional states of genome reduction. Our findings support a hypothesis of periodic symbiont turnover driven by fluctuating selection for nutritional provisioning related to gains and losses of complex life cycles in their hosts.

Neuroprotective Potential of Caffeic Acid Phenethyl Ester (CAPE) in CNS Disorders: Mechanistic and Therapeutic Insights

: Neurological disorders like Alzheimer’s disease (AD), Parkinson’s disease (PD), stroke, amyotrophic lateral sclerosis, Huntington’s disease (HD), epilepsy, traumatic brain injury (TBI), depression and anxiety are responsible for thousands of deaths worldwide every year. With the increase in life expectancy, there has been a rise in the prevalence of these disorders. Age is one of the major risk factors for these neurological disorders and with the aged population is set to rise to 1.25 billion by 2050. There is a growing concern to look for new therapeutic molecules to treat age-related diseases. Caffeic acid phenethyl ester (CAPE) is a molecule obtained from a number of botanical sources such as the bark of conifer trees as well as propolis which is extracted from beehives. Though CAPE remains relatively unexplored in human trials, it possesses antioxidant, anti-inflammatory, antimitogenic and anti-cancer activities as shown by preclinical studies. Apart from this, it also exhibits tremendous potential for the treatment of neurological disorders through modulation of multiple molecular pathways and attenuation of behavioural deficits. In the present article, we have reviewed the therapeutic potential of CAPE and its mechanisms in the treatment of neurological disorders.

Mercury accumulation in leaves of different plant types – the significance of tissue age and specific leaf area

Mercury, Hg, is one of the most problematic metals from an environmental perspective. To assess the problems caused by Hg in the environment it is crucial to understand the processes of Hg biogeochemistry, but the exchange of Hg between the atmosphere and vegetation is not sufficiently well characterised. We explored the mercury concentration, [Hg], in foliage from a diverse set of plant types, locations and sampling periods to study whether there is a continuous accumulation of Hg in leaves/needles over time. Measurements of [Hg] were made in deciduous and conifer trees in Gothenburg, Sweden (Botanical Garden and city area) as well as of evergreen trees in Rwanda. In addition, data for wheat from an ozone experiment conducted at Östad, Sweden, were included. Conifer data were quantitatively compared with literature data. In every case where older foliage was directly compared with younger, [Hg] was higher in older tissue. Covering the range of current year up to four-year old needles, there was no sign of Hg saturation in conifer needles with age. Thus, over time scales of approximately one month to several years, the Hg uptake in foliage from the atmosphere always dominated over Hg evasion. Rwandan broadleaved trees had generally older leaves due to lack of seasonal abscission and higher [Hg] than Swedish broadleaved trees. The significance of atmospheric Hg uptake in plants was shown in a wheat experiment where charcoal filtrated air lead to significantly lower leaf [Hg]. To search for general patterns, the accumulation rates of Hg in the diverse set of tree species in the Gothenburg area were related to the specific leaf area (SLA). Leaf area based [Hg] was strongly negatively and non-linearly correlated with SLA, while mass-based [Hg] had a somewhat weaker positive relationship with SLA (both relationships with p < 0.001). An elaborated understanding of the relationship behind [Hg] and SLA would support large-scale modelling of Hg uptake by vegetation and Hg circulation in general.

Automatic Tree Crown Feature Extraction from UAS Multispectral Imagery for the Detection of Bark Beetle Disturbance in an Urban Forest

&lt;p&gt;Multispectral imaging using unmanned aerial systems (UAS) enables rapid and accurate detection of pest insect infestations, which are an increasing threat to midlatitude natural forests. Pest detection at the level of an individual tree is of particular importance in mixed forests, where it enables a sensible forest management approach. Moreover, urban forests may be affected more seriously because an urban environment produces additional stressors. The stressors include changes in forest soil properties, tree species diversity, higher temperatures, and carbon dioxide content. The stressed trees are then optimal material for a bark beetle feeding. Therefore, it is necessary to use an appropriate method for the detection of individual infested trees.&lt;/p&gt;&lt;p&gt;In this contribution, we present a novel method for individual tree crown delineation (ITCD) followed by feature extraction to detect a bark beetle disturbance in a mixed urban forest using a photogrammetric point cloud (PPC) and a multispectral orthomosaic. An excess green index (ExG) threshold mask was applied before the ITCD to separate targeted coniferous trees from deciduous trees and backgrounds. The individual crowns of conifer trees were automatically delineated as (i) a full tree crown using marker-controlled watershed segmentation (MCWS), Dalponte2016, and Li 2012 region growing algorithms or (ii) a buffer around a treetop from the masked PPC.&lt;/p&gt;&lt;p&gt;We statistically compared selected spectral and elevation features extracted from automatically delineated crowns of each method to reference tree crowns to distinguish between the forest disturbance classes and two tree species. Moreover, the effect of PPC density on the ITCD accuracy and feature extraction was investigated. The ExG threshold mask application resulted in the excellent separability of targeted conifer trees and the increasing shape similarity of automatically delineated crowns compared to reference tree crowns. The results revealed a strong effect of PPC density on treetop detection and ITCD. If the PPC density is sufficient (&gt; 10 points/m&lt;sup&gt;2&lt;/sup&gt;), the automatically delineated crowns produced by Dalponte2016, MCWS, and Li 2012 methods are comparable, and the extracted feature statistics insignificantly differ from reference tree crowns. The buffer method is less suitable for detecting a bark beetle disturbance in the mixed forest because of the simplicity of crown delineation. It caused significant differences in extracted feature statistics compared to reference tree crowns. Therefore, the point density was found to be more significant than the algorithm used.&lt;/p&gt;&lt;p&gt;We conclude that the automatic methods may constitute a reliable substitute for the time-consuming manual tree crown delineation in tree-based bark beetle disturbance detection and sanitation of individual infested trees using the suggested methodology and high-density (&gt;20 points/m&lt;sup&gt;2&lt;/sup&gt;, 10 points/m&lt;sup&gt;2&lt;/sup&gt; minimum) PPC.&lt;/p&gt;