Key message Studied organic molecules in Pinus sylvestris L. seem to have acted as a safety net for metal transport, chelation and sequestration, allowing adaptation and growth under highly polluted conditions. Abstract Pinus sylvestris L. is known for its ability to survive in areas of highly elevated metal pollution, such as flotation tailings. The aim of the study was to estimate the content of

Key Message Short-term exposure to high temperatures modulates the aromatic cytokinin profile of radiata pine embryonal masses when measured 8 weeks after initiation. Abstract Recent research has demonstrated that cytokinins could be involved in abiotic stress responses. However, little research has been published about the role of endogenous aromatic cytokinins during these processes. Therefore, in

Key message Some species synthesize larger amounts of polyprenols, which probably increase the plant’s ability to mitigate salt stress. Salt stress does not cause macronutrient deficiency in the leaves of urban trees. Ionic imbalance in the leaves caused by soil salinity worsens the health status of sensitive species. Abstract Street trees are exposed to relatively high stress levels, and the average

Key message Whereas cold temperatures and artificial smoke pollution (during World War II) cause negative pointer years in northern Fennoscandian downy birches, mass outbreaks of Epirrita autumnata L. and Operophtera brumata Bkh. are the strongest growth-influencing and -synchronizing factor. Abstract Variations in radial tree growth of downy birch can be affected by short-term environmental changes

Key message Pathogen-induced defoliation resulted in a reduction in transpiration, an upregulation of photosynthesis in the early growing season, and no change in NSC reserves across stem, root, and foliar tissues. Abstract The defoliation of eastern white pine (Pinus strobus L.) by native fungi associated with white pine needle damage (WPND) can substantially reduce foliar area for much of the growing

Key message Twelve HbPHT1s were identified in Hevea and most of them were induced by phosphate starvation. HbPHT1;5 complemented the defective yeast mutant strain EY917 and HbPHT1;7 only partly complemented it. Abstract Phosphorus is an important element of the latex of rubber tree, and its content affects the quality and yield of latex. However, with the outflow of latex, a large amount of phosphorus

Does mistletoe infestation influence the position of the dry range limit of oaks? We explored this question and our results contrast most earlier findings on host-mistletoe interaction. The study was located in the SE Himalayas in an environment with 200–360 mm annual precipitation falling mainly during the short monsoon season (hardly any rain during 9–10 month). The hemi-parasite species (HPs) Loranthus

Key message Low number of pistillate flowers in the tung tree is a major factor causing the low yield of tung fruits. Abstract The tung tree (Vernicia fordii Hemsl.), an economically important woody oil plant, produces excellent fast-drying oil from the seeds which has been used as a protective finish on projects and surfaces for centuries. Knowledge of sex determination and flower development of tung

Key message This study investigates efficient strategies for fine tree root sampling, in terms of estimating root trait parameters with desired confidence intervals for least effort and cost. Abstract Sampling tree roots is difficult and costly with high variation among samples and wide confidence intervals for parameter estimates. Efficient strategies for fine tree root sampling will estimate root

Key message Branch sizes and their vertical orientation increase progressively further up the lower stem to support a newly developing crown. Abstract Diameter at base, orientation, and height up the stem of live branches on the lower 5 m of tree stems were measured several times over 2.5–5.7 years of age in an experimental plantation of blackbutt (Eucalyptus pilularis) in sub-tropical eastern Australia

Key message Soil pH, EC, and salinity explain the leaf nutrient concentrations of Prosopis pallida despite the high amount of soil nutrients near the trees. Abstract Dryland forests constantly face extreme abiotic conditions, and this affects plant growth and nutrition. We have determined the effects of soil chemical attributes and soil nutrients on the leaf nutrient concentrations of eight Prosopis

Key Message Needle anatomic plasticity enables fast-growing maritime pine trees to cope with water limitations by enhancing both water-use efficiency and embolism resistance. Abstract Maritime pine is a major forest tree grown for wood production in Southern Europe. A breeding program for the selection of fast-growing varieties was established in the 1960s, in France. In the context of climate change

Key message Tree species differ in their functioning at the scale of an individual tree which will result in differences in ecosystem service provision. Replacement trees for diseased trees should take account of functional differences. Abstract Globally tree species composition is changing due to species loss from pests and pathogens. The impact of this change on ecological functioning is rarely tested

Key message Seasonal variations in the leaf photosynthetic traits of an urban tree, Ginkgo biloba, were almost synchronized with the photoperiod. Non-stomatal limitations were a cue for photosynthesis in Ginkgo biloba. Photosynthetic functions, which are key traits in determining the carbon uptake of urban trees, exhibit significant seasonal variations in temperate zones. It is essential to clarify

Key message Fine root and litterfall are major contributor of NPP and fine root production may reflect forest productivity in a warm-temperate forest in Japan. Abstract Forest ecosystems play an important role as the major carbon sink on land, with fine root dynamics and litterfall representing major carbon fluxes. The objectives of this research were to estimate NPP including annual fine root production

Key message Extreme growth reaction analysis shows that larches in the Sudetes are more vulnerable to climate changes, but negative extreme responses will also be observed in the Carpathians in the near future. Abstract Pointer year analysis provides information on extreme tree-ring growth reactions, which can significantly improve the interpretation of tree growth response to climate. Similarities

Key message Mimosa luisana seeds germinate after 7 years of storage, suggesting that they have a long span life; an interesting characteristic for environmental restoration of semi-arid zones. Abstract Mimosa luisana is endemic to Mexico, provides ecosystem services and is economically and culturally important. This species exhibits morphological, anatomical and physiological qualities that make it

Key message Vitrified shoots of strawberry tree propagated in vitro showed poor lignification when analysed by FTIR-ATR and by the acetyl bromide method, as well as marked disturbances on leaf tissues organization. Abstract Arbutus unedo (Ericaceae), commonly known as strawberry tree, is a bush or small tree grown mainly for the production of edible fruits that can be eaten fresh, processed or used

Key message The origin of xylem cells, intracellular variation, and gall position relative to the host plant organ are related to mechanisms that positively compensate hydraulic conductivity in galls. Abstract Gall position in its host organ may be determinant for the new patterns of xylem differentiation. Leaf galls may be attached to the host leaf by a peduncle, as the extralaminar galls, or may

Key Message First study of mepiquat chloride as a growth regulator in Eucalyptus. Application of mepiquat chloride in Eucalyptus clones at planting may promote drought resistance. Abstract The reduction of available areas has pushed Eucalyptus away to marginal areas with low water availability. Management practices such as the application of growth retardants may have potential to modify plant morphological

Key Message Earlywood and latewood widths differently respond to the climate in boreal and Mediterranean Scots pine forests. The response is constrained by allometric relationships. Abstract Measurements of earlywood (EW) and latewood (LW) width can be used to assess how tree growth responds to the climate in different biomes. Through tree-ring analyses, we quantified and analysed EW and LW width in

Key message Expression analysis of Larix kaempferi mature miR171s and their primary transcripts and target gene LaSCL6 during somatic embryogenesis revealed the transcriptional and post-transcriptional regulation of the miR171-LaSCL6 module. Abstract Somatic embryogenesis provides a useful experimental system for studying the regulatory mechanisms of plant development. The level and activity of microRNA171

Many forests restoration programs and efforts depend on seeds. Particularly in the Andes, further information regarding seed germination requirements and seed storage behavior is necessary. The aim of this study was to evaluate the effects of storage conditions on the germination percentage, the viability and the coefficient of velocity of germination for seeds of three native tree species (Cedrela

Key message The epiphyte Tillandsia recurvata modifies the anatomy of the xylem, phloem and periderm of its host Prosopis laevigata, these modifications affect water flux and photosynthetic activity in this host. Abstract The relationships between epiphytes and host plants are commensal interactions, where epiphytes obtain support to growth without damaging their hosts. However, some epiphytes may

Key message SSRs related to parent selection of D. kaki were validated by transcriptome sequencing, and genetic diversity of these markers among 76 persimmon germplasm resources was additionally investigated. The selection of hybrid parents is critical in cross-breeding plants for germplasm innovation and cultivating improved varieties. This study used a published RNA-Seq database of a persimmon cultivar

Key message Effect of drought during 2017 and 2018 resulted in radial stem increment reduction to 78% and 61%, respectively, of the levels occurring in normal year 2016 in Central Europe. Abstract Norway spruce (Picea abies (L.) Karst.) is currently the most threatened commercial tree species in Central Europe. This is due to increased drought stress from advancing climate change as well as the species’

Key message National and regional climate-sensitive biomass equations were developed for poplar plantations in China, with mean annual temperature and precipitation significantly affecting predicted biomass. Abstract In the context of global climate change, information on forest biomass becomes more and more important, and the impact of climate change on biomass estimation is also receiving increasing

Key message The proteomic analysis of vascular tissues in rubber tree reveals differentially expressed proteins related to laticifer differentiation in mature phloem and secondary cell wall formation in mature xylem for latex/wood-yield improvement. Abstract Rubber tree (Hevea brasiliensis) is a latex-producing plant that has worldwide economic importance for the rubber and wood industries. Natural

Key message Models for quantifying tree biometric properties, imperative for forest management decision-making, including height, diameter, bark thickness and volume were developed, and wood basic density was documented for dry Afromontane forests of south-central Ethiopia. Abstract Tree biometric properties such as height (ht), diameter at breast height (dbh), bark thickness (bt), volume and wood

Key message Higher solar radiation leads to higher crown temperatures, sap flow, and airborne volatile concentrations as well as altered bark chemical composition in trees at fresh forest edge. Abstract Spruce bark beetles are likely to attack trees that are at newly opened forest edges after wind disturbance due to higher temperatures and higher emission of primary attractants. The mechanisms behind

Key message Drivers of the abundance and richness of tree-related microhabitats are similar in mountain forests of Europe and North America and their occurrence may be explained by tree functional groups. Abstract A common approach to support forest-dwelling species in managed forests is to preserve valuable habitat trees. To assess the quality of habitat trees, a hierarchical typology of tree-related

Key message When Populus wutunensis seedlings are salt stressed, many genes involved in cellular metabolism, signal transduction, transport, osmotic regulation, and reactive oxygen species scavenging show elevated expression levels. Abstract Populus wutunensis, a natural hybrid individual resulting from a cross between Populus × xiaozhuanica W. Y. Hsu et Liang, shows salt and drought tolerance and

Key message Resilience to xylem embolism and the accumulation of cyclitols are promising criteria for the selection of drought-resilient Eucalyptus species. Abstract Due to the aridity of the climate in the southern Mediterranean region, the choice of suitable species for afforestation projects is crucial. The present study aims to compare resilience mechanisms against drought in two frequently used

Key message Our results from iTRAQ-based proteomics extend the understanding of the mechanisms employed by AMF to defend against drought stress in blueberry. Abstract Arbuscular mycorrhizal fungi (AMF) can substantially contribute to plant drought tolerance. In this work, south highbush blueberry (Vaccinium corymbosum) ‘O’Neal’ cultivated with or without Funneliformis mosseae inoculation under well-watered

The impact of plants on soil enzymatic activity and their potential for remediation of oil-contaminated soil has been widely studied but information about tree species is scarce. Here, we used seedlings of four tree species (Ailanthus altissima Mill, Fraxinus rotundifolia Mill, Melia azedarach L. and Robinia pseudoacacia L.) to investigate rhizosphere effects on key soil enzymes (dehydrogenase, urease

Key message The dioecious Idesia polycarpa all that males and females do not invest in the same way in growth and branching in quantity, type of axes and in time (annual growth and sequence of these events over time). Abstract The annual growth of plants is an important indicator for growth and development, especially for younger trees. The aim of this study was to decide the physiological basis for

Key message Local adaptation largely segregates between traits affecting light responses and water relations, but population-level differences in stomatal conductance when growth is unconstrained converge among populations under water stress. Abstract Warming temperatures and altered precipitation patterns threaten plant populations worldwide. European beech (Fagus sylvatica) is a species that expresses

Key message A flexible stem respiration chamber was developed and successfully employed in a feasibility study in a tropical forest. Abstract We present a flexible chamber to measure the CO2 efflux from tree bark. The easy-to-use chamber is made of stainless steel and is clamped around an individual tree stem section; it uses a portable gas analyzer to retrieve the stem respiration value. Using the

Key message The extreme hydroclimatic events in the Conchos River Basin, are strongly associated with ocean–atmospheric phenomena such as the El Niño Southern Oscillation, Pacific Decadal Oscillation, and Atlantic Multidecadal Oscillation, the streamflow reconstruction showed the occurrence of up to 10-year droughts. Abstract Dendrochronology is a modern science used to study hydroclimatic events through

Key message The optimization of plant hormone application to achieve better rhizogenesis in eucalypt cuttings has been demonstrated using a machine learning approach. Abstract This study focuses on reducing the human bias in treatment selection in case of adventitious rhizogenesis in eucalypts. The effect of different concentrations of indole-3-butyric acid (IBA) on rhizogenesis was studied and differential

Key message Juveniles and canopy trees may not exhibit similar nitrogen acquisition responses to soil temperature change caused by variation in snow cover over winter. Abstract The use of 15N tracer is a powerful tool for tracking the effects of variation in soil frost on plant nitrogen acquisition. While the responses of juvenile trees to environmental change are often used to infer the responses

Key message Juniperus communis males are better adapted than females to changing, seasonal environmental conditions due to their higher photosynthetic capacity and the higher concentration of photosynthetic pigments in their needles. Males cope with ROS more efficiently than females having greater carotenoids concentration in needles. Abstract In dioecious woody plants, females often exhibit greater

Key message A random sampling between 30 and 50 trees is sufficient for forest-level wood density estimates. Abstract Wood density (WD) is a key trait used to determine forest biomass and carbon stocks, but determining WD accurately is logistically demanding and expensive. These challenges also hamper comparisons across studies and different forest types, because sampling intensity within forests and

Key message Crown variables and height can improve biomass predictions and may help to quantify how tree biomass is influenced by inter-tree competition (stand density, species composition), climate, edaphic conditions, and age. Abstract Tree biomass is influenced by tree age, stand structural characteristics, and climatic and edaphic site factors. However, most allometric equations for predicting

Key message Leaf area index and species composition influence red-to-near-infrared and red-to-shortwave-infrared transmittance ratios of boreal and temperate forest canopies. In this short communication paper, we present how the spectral composition of transmitted shortwave radiation (350–2200 nm) varies in boreal and temperate forests based on a detailed set of measurements conducted in Finland and

Key message Geography and tree diameter were the major factors in determining oleoresin yield in Sindora glabra. The tangential diameter and area of secretory canals are reliable indicators of the oleoresin amount. Abstract Sindora glabra is a native tropical plant of China that exudes copious amounts of oleoresin from wounds on the stem. Elucidation of the mechanism affecting the oleoresin yield is

Some studies suggest that tapping sugar maple (Acer saccharum Marshall) trees can cause their growth to decline, particularly on poor and acidic soils. We tested this hypothesis in seven sugar bushes located in the Quebec Appalachians by comparing the growth of tapped trees with nearby untapped trees. The sites represented a range of soil fertility, from very good for sugar maple to strongly deficient

Key message Black spruce ecotypes exhibit temperature-adapted bud burst, while bud set is independent of temperature. Warmer conditions could advance bud burst, but no direct effect is expected for bud set Abstract Phenological adjustment is a key adaptive trait closely associated with the environment. Species spreading over a wide geographical range can evolve ecotypes that are able to grow and reproduce

Key message Functional stomata can be generated by in vitro ABA applications. This mitigates the desiccation responses of Persian walnut leaves in their early stage of ex vitro exposure. This finding paves the way for discovering a solution for the uncontrollable water loss problem of in vitro-generated walnut plantlets. Abstract Most in vitro-generated plants are susceptible to wilting when they are

Key message We identified 15 genes encoding enzymes for phenylpropanoid biosynthesis in the genome of birch by combining phylogenetic analysis and tissue-specific expression data. Abstract Lignin is one of the most abundant terrestrial biopolymers and is essential for plant structure and defense. An essential step in lignin formation is phenylpropanoid synthesis, we identified 120 gene models in 10

Key message Canopy tree species with a large mean xylem vessel diameter has a high sensitivity of stomatal conductance to vapor pressure deficit in a wet tropical rainforest in Malaysia. Abstract We investigated the diurnal variation of stomatal conductance to water vapor (gs) and leaf water relations in nine tropical rainforest canopy tree species in Malaysia to investigate the sensitivity of stomatal

Key message Phloem cell production was less influenced by environmental factors than xylem cell production. The moment of maximum number of conducting phloem cells occurred at the end of the growing season. Abstract The understanding of the seasonality of phloem production, its dependence on climatic factors and potential trade-offs with xylem cell production is still limited. This study determined

SUMOylation in plants is associated with biotic and abiotic stress responses, flowering, and other aspects of development. ICE1 protein SUMOylation by the SUMO E3 ligase SIZ1 plays important roles in plant cold tolerance. Here, we reported the subcellular localization of EcaICE1 and its interaction with EcaSIZ1 in Eucalyptus camaldulensis. The genes EcaICE1 and EcaSIZ1 were isolated by homologous cloning

Key message This study proposed the combination of PR26S and PP1 as a good choice for RT-qPCR normalization in pecan under abiotic stress, developing kernels, grafting, and various tissues. Abstract Reference gene selection is an essential pre-requisite to generate reliable results in real-time quantitative polymerase chain reaction (RT-qPCR) analysis. However, studies regarding systematic validation

Key message We developed and identified a new set of polymorphic EST-SSR markers in Sophora japonica Linn. and analyzed their genetic diversity. Abstract Sophora japonica is a native species in China with ornamental and medicinal value. To explore the genetic diversity and the genetic differentiation of this species, expressed sequence tag-simple sequence repeat (EST-SSR) markers were developed based

The net photosynthetic rate (A), stomatal conductance (gs), and transpiration rate (E), chlorophyll content, and midday xylem water potential (Ψmd) of Pinus nigra Arn. subsp. pallasiana (Lamb.) Holmboe trees were studied in a natural stand (Burdur-Aziziye, Turkey) for the first (2015), second (2016) and third (2017) years after precommercial thinning (PCT) to better understand the physiological and

Key message We performed a comparative transcriptome combined with morpho-physiological analyses between two differential cold tolerance in two contrasting apricot cultivars. The revealed candidate genes potentially were identified by differential expression analysis. Apricot (Prunus armeniaca L.) is a major (non-wood product) forest tree species that is adversely affected by spring frost. However

Key message Flow within internal secretory systems derived from autolyzing epithelia in kino-producing angiosperms may have lower metabolic energy costs. This presents physiological advantages and possibly constitutes an evolutionary step of these species compared to resin flow in conifers in using internal secretory systems in plant defence mechanisms. Abstract Kino is a plant exudate, rich in polyphenols

Black walnut (Juglans nigra L.) is a light-demanding, competition-intolerant, and tall forest tree species, introduced in Europe from North America at the beginning of the seventeenth century. It has an important economic role in Europe for producing wood and fruits, in agroforestry systems, as an ornamental tree for parks and avenues, for rehabilitation/restoration of degraded lands. The best sites