Key message The Larix leptolepis SPL-like gene LaSPL9 was identified. Additionally, premiR156b and LaSPL9 expression patterns during somatic embryogenesis and the effects of gibberellin and salicylic acid on their transcription revealed the post-transcriptional regulatory functions of the miR156–LaSPL9 module. Abstract A full-length cDNA sequence of a SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE (SPL) gene

Key message A lack of snow cover and increased soil freezing may not only have short-term impacts on trees but longer-lasting lagged effects on radial growth. Abstract Soil temperature and soil frost intensity are affected by the depth of insulating snow cover and the timing of snowmelt which are predicted to change by climate warming. This may increase tree growth if there is less soil freezing or

Key message Environmental stress resulting from rapid climate changes leads to the initiation of the seed aging process in mitochondria and peroxisomes. Seed storage methods limiting germinability loss are fundamental for forest future. Abstract Seed aging is a natural process. It decreases the seed germination rate, i.e. the process is essential for the plant’s life cycle. Aging involves a progressive

Key message While providing either NH4+ or NO3− to Cyclocarya paliurus, a mixture of NO3− and NH4+ at a ratio of 7/3 results in the best combination of plant growth and leaf secondary compound production. Abstract Cyclocarya paliurus is a well-known multiple function tree species with leaves that have been used as medicine and nutraceutical foods based on their high content of polyphenolic secondary

Key message In some circumstances vessel elements, both broad and narrow, enlarge only symplastically in tangential direction. Rays play a special role in regulating intrusive enlargement of vessel elements. Abstract The aim of this study was to analyse relations occurring between vessel elements and surrounding cells, i.e. susceptibility to separation of walls of cells occurring in the vicinity of

Key message Minimum wood density is a proxy of soil moisture during the early growing season. Maximum wood density responds to late growing-season drought. Abstract Seasonally dry areas are ideal settings to refine our understanding of tree growth proxies of water availability. Despite recent methodological advances in quantitative wood anatomy and wood density, our knowledge of wood density responses

Key message Exogenous ABA increased the flowering rate and advanced the flower formation of “Fuji” apple cv. “Nagafu No.2” by promoting the accumulation of soluble sugar, glucose and sucrose, and also increased the activities of α-AMY and SPS. Abstract “Fuji” apple (Malus domestica Borkh) has a long vegetative growth phase and difficulty in flower induction, which seriously affects apple production

Key message Growth sensitivity to climate varies with soil moisture regime in spruce–fir forests in central British Columbia. Stands growing at their dry edaphic limits displayed especially strong and unique climatic sensitivities. Abstract Soil moisture regime is an important influence of productivity, process, and structure in forested ecosystems. In western North America, projected warming trends

Key Message Nutrient uptake in the biomass of healthy and root (wilt) disease affected coconut palms are different. Abstract Root (wilt) is a predominant phytoplasmal disease affecting coconut (Cocos nucifera L.) palms and to sustain the palm health and productivity, better nutrient management practices are required. The objective of this research was to understand the uptake pattern and the partitioning

Key message Evidence supporting hydraulic limitation hypothesis was found using foliar δ13C in combination with nitrogen content per unit leaf area and statistical partitioning for three conifer species. Abstract One theory behind the productivity decline of mature forests is the hydraulic limitation hypothesis (HLH); leaf-level gas exchange is reduced with increasing forest canopy height via increased

Key message Stump-to-tip trends in basic wood density complicate the conversion of tree volume into aboveground biomass. We use 3D tree models from terrestrial laser scanning to obtain tree-level volume-weighted wood density. Abstract Terrestrial laser scanning (TLS) is used to generate realistic 3D tree models that enable a non-destructive way of quantifying tree volume. An accurate value for basic

Key message A fixed sequence existed in the timing of critical stages between apical and radial growth. Radial growth was highly correlated with apical growth during the onset stage but not during the peak or cessation stages. Abstract The temporal relationships between the apical and radial growth of conifers may vary with species and site, and the varied responses of growth to climate change have

Key message Distributions of water- and air-filled conduits can be distinguished by observing a xylem cross-section of frozen conifer stem. This method is applicable to field observation in cold winter. Abstract Xylem embolism resulting from summer drought and frost drought is one of the critical stresses responsible for the dieback of stems and individuals of subalpine evergreen conifers. The occurrence

Key message Using more than 10,000 bamboo leaves, we found that the scaling between leaf surface area and length follows a uniform power law relationship mainly relying on the degree of variation in leaf shape (reflected by the ratio of leaf width to length). Abstract A recent study based on leaf data of different plant taxa showed that the scaling of leaf surface area (A) with linear leaf dimensions

Key message Our manuscript discussed salt tolerance mechanisms in trees, genes associated with salt stress tolerance, methods to improve the salt tolerance of trees, and research frontiers. Abstract Soil salinization is a global problem that seriously affects plant growth and development. Improving the salt tolerance of trees is an import economic and ecological aim in forestry. Recent studies have

Key message This study utilized dendrochronology and long-term (2003–2017) eddy covariance (EC) carbon flux data to investigate the relationships between tree growth and gross ecosystem productivity (GEPEC) in different-age (15-, 42- and 78-year old) pine plantation forests in the Great Lakes region in eastern North America and found that tree-ring growth in these different-age pine forests was significantly

Key message The results showed a significant relationship between the potential evapotranspiration of the provenance collection site and the leaf turgor loss point and significant positive differences in drought tolerance between provenances and subspecies of B. pendula. Abstract The ecosystem services provided by urban trees make substantial contributions to the quality of urban living and securing

Key message Tree roots hold soil that is dramatically heavier than the tree biomass, wet or dried. This soil might compensate for the imbalance between above- and belowground mass. Abstract Root–soil plates are recognized to play an important role in root anchorage of plate-like root system, however, actual measurements of their mass have rarely been reported. Even though the root–soil plate mass is

Key message Exogenous MJ does not alter the resin duct structure of pines in the cortex, but increases the number, density and mean size of resin ducts in the secondary xylem, particularly in Pinus sylvestris and P. radiata. Abstract Methyl jasmonate (MJ) is an organic compound capable of modulating defence responses in plants. Exogenous application of MJ has been shown to modify the structure of the

Key message A systematic review (1950–2018) summarizes the research on woody lianas and their interaction with trees in the Neotropics. We identify knowledge gaps, propose new directions for future studies and discuss the control, management, and conservation of lianas. Abstract Lianas are key components of species composition, structure and dynamics of tropical forests. Current global warming scenario

Most of the plantations were planted with single species for economic reasons. Continuous planting of such single tree species over a longer period has led to a series of ecological problems including soil degradation, low stand productivity and ecosystem stability. Studies have suggested that mixed-species plantations have greater levels of ecosystem functions and services such as higher nutrient

Key message Near upper forest line, values of conifer wood anatomical traits are species-specific, but relationships among traits are common. Growing season temperature significantly impacts wood anatomy only in its extremes. Abstract Quantitative wood anatomy can provide detailed insight into adaptation of trees to changing environment, especially on the borders of species distribution ranges. This

The jaborandi is a natural source of alkaloids used in the treatment of important diseases and, therefore, relevant for the pharmaceutical industry. However, the lack of information on the jaborandi ecophysiological responses under different climatic conditions is the major limitation for its expansion in Brazil. Thus, we investigated the effects of different environmental conditions on the ecophysiology

The different genotype response to fertilization varies greatly for tree growth. Therefore, the selection of superior genotypes and the optimal fertilization formula are important measures for cultivation of high-yielding forest. In this study, 30 hybrid clones of Betula platyphylla with supply different doses of formulated fertilization were used. Height, DBH (or ground diameter), and volume were

Key message Temporary immersion bioreactors can improve hybrid sweetgum somatic embryo conversion and somatic seedling growth rates compared to semisolid medium, significantly improving somatic seedling production efficiency for hybrid sweetgum, an emerging woody biomass crop. Abstract Fast-growing hybrid southern hardwood trees should make excellent material for woody biomass production in the Southeastern

Key message A clear carryover effect of tree-ring formation was not detected based on a pulse-labelling experiment conducted on Juniperus communis in South Germany. Abstract The inherent linkage between photosynthesis and the formation of wood is important for the understanding of relationships between tree-ring series and climate/environmental data in dendroclimatology studies. However, it is impossible

Alpine treelines are thought to be controlled by low temperature, which affects tree physiology and limits growth. Irrespective of carbon and nutrient limitations are physiological mechanisms affecting the formation of alpine treelines still needs to be defined. We measured the rates of tree growth (basal area increment, BAI), nutrient concentrations in leaves and roots, foliar concentration of nonstructural

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