Stages Of Tree Development Research Articles

Influence of Mulching on Replantation Disease in Sour Cherry Orchard

Increasingly, in orchards around the world that are planted one after another, disturbances are observed, and these issues with growth and development are called replantation disease. It is manifested mainly by poor tree growth after planting and poor ripening. One way to reduce replantation disease is to improve soil fertility after many years of fruit tree cultivation. The aim of the work was to evaluate the growth and yield of cherries after replantation and to compare this with a site where fruit trees had not grown before. The trees were planted at two sites: after the replantation of the cherry orchard (OR1) and in a site where fruit trees had not been cultivated before (OR2). Two combinations were used in each orchard: boiler without mulching (C), mulch—after planting mulching with a substrate after growing mushrooms (M). The trees at the site after replantation grew and bore less fruit than in the position where fruit trees had not grown before. The disease also affected some of the quality characteristics of the fruit. This resulted in an increase in fruit weight and a darker color (L*) and a higher value of hue fruit color. Mulching, which is often recommended in orchards planted after previous cultivation, did not provide the expected improvement. It did not significantly affect tree growth and yield. Only an effect on the content of components in the soil was observed, but it affected the condition of the trees. In addition, we analyzed how experimental combinations responded to climatic conditions by calculating the correlations between the SAT (sum of active temperatures) and the stages of tree development.

Experimental analysis of spray droplet deposition behaviour for centrifugal assisted spinning disc sprayer

The biological effectiveness of insecticides is influenced both by the amount of sprayed material that is left behind on the canopies and by the physicochemical characteristics of the spray solutions. The type of sprayer and its settings, the type of canopy and its density, the stage of tree development, and the variables in the surrounding environment all have an impact on where and how much spray is deposited within canopies. PIV is used in this study to investigate the behaviour of droplet deposition on a three-dimensional prototype of a centrifugally assisted spinning disc sprayer. A variety of rotational velocities are represented here by the aerosol distribution from the exit of the nozzle to −1.5 m and 4 m, respectively. If the mass flow rate is slowed down, the droplet diameter can be increased while maintaining the same rotational speed. This is accomplished by reducing the amount of friction that exists between the spinning disc and the liquid that is being sprayed. This impact is caused by not only an increase in the droplet deposition rate in the direction of downward movement, but also an increase in the mass flow rate. Some droplet particles actually travel upward for certain mass flow rates because they are unable to overcome resistance and have a low density.

Using stable water isotopes to understand ecohydrological partitioning under contrasting land uses in a drought‐sensitive rural, lowland catchment

AbstractVegetation plays an essential role in water partitioning, as it strongly influences evapotranspiration, infiltration and water retention. To analyse the influence of vegetation on water partitioning under innovative land management strategies, we used stable water isotopes as natural tracers to monitor precipitation, soil water and groundwater fluxes over the growing season of 2021 (March–October). We selected eight plot sites with four contrasting land covers and soil types in the drought‐sensitive Demnitzer Millcreek Catchment (DMC) in NE Germany. The land use types include forest, grassland, and arable with the latter being subdivided into conventional (e.g., crops) and innovative (e.g., agroforestry) sites. Two weather stations, a flux tower, and in situ soil moisture monitoring complemented our isotopic data with a hydroclimatic context. The year of 2021 had near‐normal precipitation totals compared to the prolonged drought of 2018–20. Soil water storage was highest at the agricultural sites, while lowest at the forest, though this reflected both the influence of soil properties (as forests dominated sand soils while crops loam soils) and the greater evapotranspiration from forests. We also estimated soil water ages and found the greatest isotopic variability and fastest turnover of water in the upper soils of arable sites. The forest soil water had the most limited variability in isotopic composition and tended to be older, revealing lower levels of groundwater recharge. Conventional and innovative cropping sites were similar to each other, likely due to the early tree development stage in agroforestry schemes under the latter. Our investigation revealed the forest sites are potentially most vulnerable to limited water availability in the DMC and land use changes in agricultural land lacked major differences in ecohydrological fluxes over the study year. The study further underlines the need for long‐term observations of recent adaptive land use changes and drought‐sensitive vegetation to improve our understanding and evolve drought resilient land management strategies considering time lags in impacts and non‐stationarity.

Tracking Individual Scots Pine (Pinus sylvestris L.) Height Growth Using Multi-Temporal ALS Data from North-Eastern Poland

In this study, we analyzed the change in tree height of 2594 Scots pine (Pinus sylvestris L.) trees with respect to the distribution among different forest sites: HCfs—hydrogenic coniferous forest site; MCfs—mineral coniferous forest site; MMfs—mineral mixed forest site. We obtained tree height information from three independent airborne laser scanning (ALS) point clouds acquired in north-eastern Poland over a 5-year interval in 2007, 2012, and 2017 using verified tree crown segments. We performed a comparative analysis of digital terrain models (DTMs) calculated from analyzed point clouds, indicating that the highest elevation differences were observed in the case of data from 2007. The analyses showed that tree growth varies significantly depending on the forest site productivity and the stage of tree development, which was described as initial tree height instead of age—commonly used in such studies. In conclusion, it is possible to indicate the significant information potential of using multitemporal ALS data to track individual tree height changes. These field data, combined with meteorological data, can be successfully used to predict changes in the abundance of stands depending on the forest site productivity. We have built Scots pine growth models for each forest site, which indicates that it is possible to predict the change in the tree stand height.

Cover cropping and chemical fertilizer seasonally mediate microbial carbon and phosphorus metabolisms in an apple orchard: Evidence from the enzymatic stoichiometry method

The extracellular enzymatic stoichiometry in soil in terms of the ratios of soil enzyme activities related to the acquisition of nutrients such as carbon (C), nitrogen (N), and phosphorus (P) can reflect the demand for resources by microorganisms. However, it is not clear how cover cropping and chemical fertilization might shift nutrient limitations for microbes in terms of the soil enzymatic stoichiometry in an apple orchard. Thus, we determined the metabolic limitations for microbes in soil based on enzymatic stoichiometry and clarified their effects on the carbon use efficiency (CUE) for soil microbes. The experiment was conducted in two main orchard plots under cover cropping and no cover cropping, where two subplots received no fertilizer or N, P, and K fertilizer application. The activities of C, N, and P acquiring enzymes (β-1,4-glucosidase, leucine aminopeptidase, β-1,4-N-acetylglucosaminidase, and acid or alkaline phosphatase), soil nutrient contents, plant nutrient contents, and microbial biomass were determined. We found that cover crop and fertilization significantly influenced the soil properties, microbial biomass, and soil enzyme activities and stoichiometry in the apple orchard, and the effects varied at different developmental stages (bud breaking, fruit swelling, and fruit maturity stages) and distances (soil samples were collected at 30, 60, 90, 120, and 150 cm from the trunks of apple trees). Soil extracellular enzymatic stoichiometry analysis showed that microbial metabolism was affected by relative P limitation in the soil throughout the growth of apple trees, but it varied among different treatments, stages, and sampling distances. Microbial carbon limitation was affected by the cover crop and fertilization at different stages and distances. Random forest analysis suggested that the soil available P and available N contents were the two most important factors that affected microbial C metabolism in the germination, fruit swelling, and mature stages. Microbial CUE was also significantly correlated with microbial P and C limitation. However, microbial C metabolism was affected by the soil available P as well as the soil C. An increase in the soil available P could have made more P available for microbial energy production and increased microbial C metabolism. Overall, our results indicate that the soil available P and available N regulated microbial C and P metabolism at different tree development stages, thereby providing insights into how microbial C and P metabolism and microbial C turnover are affected by the soil enzymatic stoichiometry in an apple orchard under cover crop and fertilization.

Biomass Allocation and Leaf Morphology of Saplings Grown under Various Conditions of Light Availability and Competition Types.

Plant growth is almost always limited by light availability and competition. However, plants are generally plastic and can change their morphology and biomass allocation to optimize growth under suboptimal conditions. We set up a controlled pot experiment with three light availability levels (10%, 20%, and 50%) to study the effect of light and competition on the biomass allocation and leaf morphology in monospecific and mixed pots of recently planted European beech (Fagus sylvatica L.), Norway spruce (Picea abies (L.) Karst.), and Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) saplings using a quantile regression model. Specific leaf area (SLA) showed the strongest reaction and increased with decreasing light availability. Woody aboveground mass fraction (AMF) increased with decreasing light availability, but the effect of light on biomass allocation was less pronounced than on SLA. The SLA, woody AMF, and root mass fraction (RMF) of the two conifer species and European beech varied greatly, with European beech having a higher SLA and RMF than the two conifer species. The associated effect of plant size on biomass allocation was small, and the strength of the association was not meaningful on a practical level. The competitor’s effect on biomass allocation was minor overall and only present for some species, suggesting that species’ functional dissimilarity does not greatly affect allocational patterns in early tree development stages.

Functional evaluation of height–diameter relationships and tree development in an Australian subtropical rainforest

Context Allometric equations describing the relationships between tree height (H) and breast height diameter (D) should be both statistically efficient and biologically relevant. Aims To determine whether selected allometric equations can meet established criteria for both efficiency and relevance. Methods Nine equations were compared to define the H–D relationships of 1122 individuals and 18 species from an Australian subtropical rainforest. Key results Three-parameter asymptotic equations described initial slope (a), curvature (b), and asymptotic height (Ha). Each equation was evaluated for precision (root mean square error, RMSE) and bias in H estimates, and ease of interpretation of function parameters. For both individual species and all stems, a non-rectangular hyperbola (NRH) provided almost equally high precision and low bias as did the statistically most parsimonious generalised Michaelis–Menten function, plus linear parameter values easily relatable to tree structural and functional attributes. The value of NRH a increased linearly with wood density for canopy species, but not for understorey and subdominant species, whereas the value of NRH b decreased as Ha increased from understorey to canopy species. Conclusions Species within understorey, subdominant, and canopy structural groups shared similar ranges of parameter values within groups that reflect both intrinsic architectural and developmental patterns, and environmental limitations to Ha. Implications The NRH can be used to visualise both early and later tree development stages and differences among the growth patterns of species occupying different positions within a forest.

Shifts on archaeal community structure in pure and mixed Eucalyptus grandis and Acacia mangium plantations

Archaeal community has important contributors to nutrient cycling in the forest ecosystems. However, how soil-litter attributes shift their community structure remains poorly understood. To date, the structure of the archaeal community has never been reported either in pure or in mixed eucalypt and acacia plantations, especially in tropical soils. Here, we analyzed the archaeal community and performed correlations with C, N and P attributes in soil-litter layers of pure Eucalyptus grandis without (E) and with N fertilization (E + N), a mixed system of E. grandis and Acacia mangium (E + A), and a pure A. mangium (A) plantation. We extracted DNA from soil (0–20 cm) and litter samples at 27 and 39 months after planting and sequenced the archaeal 16S rRNA gene. We also analyzed the abundance of 16S rRNA and amoA genes by quantitative PCR and assessed the correlations between molecular data with soil-litter attributes (i.e., microbial and enzyme activities, and C, N and P contents). The high-throughput sequencing of the archaeal 16S rRNA gene revealed that the treatments influenced the archaeal community structure. However, the litter layer showed more significant modifications, since archaeal richness, diversity, and the relative abundance of Thaumarchaeota increased in the litter of pure acacia and mixed treatments at both, 27 and 39 months after planting. There was no clear pattern regarding the abundance of functional genes in the soil, but archaeal structure responded to treatments in the litter layer, in which NH4+, total-N and the C/N ratio were the most important attributes for community group differentiation. Our study provides novel insights into the structure and function of archaea in pure and mixed forest systems, but highlights that young mixed plantations exert a low effect on soil community structure. Archaeal community may have an important role in nutrient cycling in the litter interface, especially related to the N cycle in the initial stages of tree development.

Orchard Planting Density and Tree Development Stage Affects Physiological Processes of Apple (Malus domestica Borkh.) Tree

One of the most important factors affecting photosynthesis and metabolism is light absorbance by leaves and penetration through the canopy. The aim of this study was to evaluate the influence of planting density and tree development stages on photosynthetic activity, photosynthetic pigments, and carbohydrates in apple (Malus domestica Borkh.) trees in a combined way. The apple tree, Auksis, was grafted on dwarfing rootstock P 22. Space between rows was 3 m, trees were planted in 2001 in four distances: 0.25 m, 0.50 m, 0.75 m, and 1.00 m. Measurements and leaf samples were taken in the end of May (leaves fully expanded BBCH 20–25), in the middle of July (beginning of apple maturity BBCH 73–75) and at the end of August (harvest time BBCH 87–88) according BBCH—growth stages. Photosynthetic rate was significantly the lowest in the spring and tended to rise until fruit ripening, when it increased up to 19.4% compared to spring. Significantly the highest chlorophyll b and carotene α and β contents were found at the BBCH 73–75. The lowest levels of fructose and sorbitol in leaves were found at BBCH 73–75. The amount of starch accumulated in the leaves increased three times in summer compared to spring. Reduced distance between trees to four times (from 1 m to 0.25 m) showed clear competitive stress, as the decrease of photosynthetic rate (up to 36.4–38.6%) and total starch (up to 37–53%) was observed. The photosynthetic behaviour of apple trees was significantly affected by the development stage during the particular season which is related with physiological changes of metabolites transport and their distribution during fruit ripening and leaf senescence.

Factors controlling individual branch development during early growth of an experimental plantation of Eucalyptus pilularis in sub-tropical Australia

Branch sizes and their vertical orientation increase progressively further up the lower stem to support a newly developing crown. 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. Stocking density at planting varied over 816–1667 stems ha-1 and rectangularity of planting (ratio of distance between rows to distance between trees within rows) over 1–6. Tree stem diameters, heights and crown dimensions were also measured. The height above ground at which branches emerged from the stem was a primary factor determining their growth; the higher they were, the greater was their diameter and the more vertical their orientation. This was believed to reflect both a need for newer branches to grow larger than older branches, to support greater amounts of foliage as the crowns expanded towards full size, and for branches to be better oriented to seek sunlight as the crowns of surrounding trees also expanded. Secondary factors determining branch size were tree size and spacing between trees, factors that are likely to interact with each other. Larger trees tended to have larger branches, to support more leaf weight in larger crowns. The direction of emergence of branches from stems seemed little affected by tree or stand characteristics at these early stages of tree development. The results did not suggest any need to modify existing pruning regimes that have been developed for fast-growing eucalypt plantations in Australia.

Verifying the Utility of Black Locust (Robinia pseudoacacia L.) in the Reclamation of a Lignite Combustion Waste Disposal Site in Central European Conditions

N-fixing tree species, such as black locust, have achieved very promising results in the reclamation of technosols, especially those at combustion waste disposal sites, which have extremely poor nutrients and adverse physicochemical parameters. This paper presents an assessment of the survival rates, growth parameters, and quality and vitality of and nutrient supply (NPK) to black locust (Robinia pseudoacacia L.) specimens that were experimentally planted on a lignite combustion waste disposal site. The black locust seedlings were introduced directly into the combustion waste using two variants of NPK (7% N, 5.5% P2O5, and 9% K2O) fertilisation, at doses of 250 and 500 kg ha−1, and in control plots with no mineral fertilisation. No significant impacts of the applied mineral fertilisation were found on the soil properties, growth parameters, or nutrient supplies to the trees. Black locust introduced to the landfill after three years of revegetation was characterised by a very high survival rate of 95%–100%, as well as good growth parameters (height and diameter at the root collar). Nutrient supply was determined on the basis of the chemical composition of the leaves, which indicated an adequate supply of nitrogen, similar to levels found under natural conditions. In the case of K and P, the supply levels were lower than optimal when compared with data from the literature. However, at this initial stage of tree development on the combustion waste disposal site, nutrient supply is similar on all variants and is not a critical factor for successful black locust introduction. We suggest using growth parameters, survival, and vitality of trees as decisive factors for the reclamation of combustion waste landfill sites strategy. All these factors confirmed the usefulness of black locust to the reclamation of combustion waste disposal sites.

Initial establishment of commercial tree species under enrichment planting in a Central Amazon secondary forest: Effects of silvicultural treatments

Enrichment planting has the potential to conserve wide areas of secondary forest in the Amazon. Therefore, it is necessary to understand the effects of silvicultural treatments applied to secondary forest management on the initial establishment of planted species. Enrichment planting was performed in a Central Amazon secondary forest to test whether the growth, mortality and presence of shoot borer attacks of six commercial trees species – in the first two years after planting – depend on canopy trees refinement and understory slashing. Six commercial tree species were planted under a gradient of light transmittance that was created by canopy trees refinement applied in six levels of basal area reduction (0; 20; 40; 60; 80 and 100%) and combined with two understory slashing levels (control and understory slashed). The effects of silvicultural treatments on root collar diameter and height growth (realized and relative), mortality and shoot borer attack were evaluated during the first and second year after planting. The relationships between realized growth and light transmittance were different among the species, but maximum growth was observed at high light transmittance for all species. Understory slashing slightly increased the response of realized growth to light transmittance. Species relative growth was strongly affected by light transmittance, but there was a reduced response in the second year after planting, particularly in the light-demanding pioneer species (Cedrela fissilis, Tabebuia rosea and Swietenia macrophylla). Pioneer species mortality was higher in deep shade (lowest transmittance) and was related to fast growth at full sun (highest transmittance) during the first, but not the second, year after planting. Shade-tolerant species (Hymenaea courbaril, Carapa guianensis and Bertholletia excelsa) have slower growth in full sun than pioneers, but only during the first year. Shoot borer attacks in Meliaceae species (C. fissilis, S. macrophylla and C. guianensis) occurred more frequently in high light transmittance and understory slashed environments but were absent in intermediary to low light transmittance and untreated understory. Thus, silvicultural treatments improve the initial establishment of commercial tree species in secondary forest enrichment planting sites. However, such findings should be analyzed considering the effects on growth, mortality and pest attacks during the seedling to juvenile tree development stages after planting.

Free Amino Acids in Vegetative Organs of Picea obovata L. and Pinus sylvestris L.

It was shown that the changes in the phenological stages of tree development, associated with the loss of frost resistance and the onset of the growing season, were accompanied by significant changes in free amino acid composition in the meristematic tissues of Picea obovata L. and Pinus sylvestris L. buds. In winter, in both species, the level of nonproteingeneous amino acids was doubled in comparison with spring. At the same time, P. obovata and P. sylvestris showed significant species-specific differences in the total content of nonproteaginous amino acids. At P. sylvestris their share in the composition of free amino acids reached 40%, which was twice as high as that of P. obovata. In the free amino acids in P. obovata and P. sylvestris, the nitrogen reserve was mainly in the form of glycine corresponding to 13 and 9%, arginine, 12 and 8%, and ornithine, 12 and 15%, respectively. In addition, in P. sylvestris an important role in the nitrogen storage was played by γ- aminobutyric acid, about 19%, and valine, about 6%; in P. obovata this role was played by lysine and glutamic acid, about 10%. At the same time, the content of proline (an amino acid, which, generally, coordinates the high−low-temperature resistance of plants) in low-resistance coniferous species was low at about 0.04–0.34%. In spring, with bud swelling in both species, the share of arginine and proline increased, and the share of ornithine and γ-aminobutyric acid sharply decreased. In addition to these amino acids, the lysine content in P. obovata was doubled. In spring, for P. sylvestris a high content of aspartic acid and asparagine of about 19% was characteristic, for P. obovata the content of amino acids with a short carbon chain (the total amount of serine + glycine) rose to 22%. As a reliable stress metabolite in both species, one may consider ornithine, whose content in bud meristems in winter was 3–5 times higher than in the meristems of swollen buds in spring.

Transcriptomic time-series analysis of early development in olive from germinated embryos to juvenile tree

BackgroundDespite its relevance, almost no studies account for the genetic control in the early stages of tree development, i.e. from germination on. This study seeks to make a quite complete transcriptome for olive development and to elucidate the dynamic regulation of the transcriptomic response during the early-juvenile period by RNAseq time-series expression analysis. The transcriptome was made from 342,049,597 paired-end reads of 101 bp in length. The assembled transcriptome contained 109,125 unigenes (N50 = 1490 bp, average length = 839).ResultsThe time-series-expression analysis showed that, embryonic structures present at the first month after the induction of germination reached a more differentiated state in two-month-old seedlings. Once the plants were between three and four months old and reached a size around 6–7 nodes, the first developmental stages appeared to be complete and the developing seedling became a juvenile plant. In addition, an AGL-gene was rapidly downregulated during the induction of germination. The repression of this gene was very strong, as evidenced by the low levels of gene expression during plant development from the embryonic seedling to undetectable levels of expression in the adult tree. These results suggest that this gene may be involved in seed dormancy and could be a repressor of the germination. Also, an APL1-like olive gene was found to be expressed at high levels during flowering, and was also expressed during the cold incubation in the activation of embryo germination, suggesting a probable role in embryonic development.ConclusionsThe early development from germination to the juvenile stage of olive seedlings occurred when plants reached a size around 6–7 nodes, and general changes of relevant groups of genes involved in development are described. An AGL-gene was proposed to be involved in germination repression. An APL1-like gene was found to have a probable role in embryonic development.

Evaluation of Silicon Fertilizers and a Resistance Inducing Agent for Control of Apple and Pear Scab under Field Conditions

Two field trials were conducted using established apple (Malus cv. Golden Delicious) and pear (Pyrus communis ‘Williams’ Bon Chrétien’) to assess the efficacy of a range of silicon (Si) fertilizers, a resistance-inducing (IR) agent based on salicylic acid and a combination of Si + IR when applied at four growth stages of tree development (i.e., bud break, green cluster, 90% petal fall, early fruitlet) against the foliar pathogens apple (Venturia inaequalis) and pear (V. pirina) scab. In addition, a comparative evaluation of a conventional synthetic fungicide (penconazole) used within the UK for apple and pear scab control was performed. Greatest protection against apple and pear scab was provided by a combination of a Si fertilizer + IR agent and the synthetic fungicide penconazole in both the 2014 and 2015 field trials where statistically comparable degrees of control were achieved. Efficacy as scab-protectant compounds (i.e., reduced scab severity of leaves and fruit) enhanced leaf chlorophyll content and fruit yield, and was confirmed when each Si fertilizer was applied at four growth stages during two growing seasons; however, there was little difference in the degree of control conferred by each Si fertilizer. The IR agent used alone proved the least effective scab protectant compound.

The impact of pollutants on the antioxidant protection of species of the genus Tilia at different developmental stages

The influence of transport fumes and industrial waste on the activity of catalase, benzidine-peroxidase and guaiacol-peroxidase was studied in the dormant buds, leaves and seeds of the following species of the genus Tilia:T. platyphyllos Scop., T. europaea L., T. amurensis Rupr. and T. begoniifolia Stev. We tested the hypothesis that the action of pollutants changes the state of antioxidant protection at different stages of tree development in contaminated phytocenoses. An increase in catalase activity was observed in leaves of all linden species, and the action of transport fumes caused excess over control level by 118, 118, 196, and 61% respectively for T. platyphyllos, T. europaea, T. amurensis and T. begoniifolia. The action of industrial waste was accompanied by a slight decrease in catalase activity in T. europaea leaves, and increase in activity in leaves of T. amurensis and T. begoniifolia (143% and 115%). Benzidine-peroxidase activity increased due to the influence of transport fumes on leaves of T. amurensis and T. begoniifolia (103% and 44%), but decreased due to the effect of industrial waste on leaves of T. europaea, T. amurensis and T. begoniifolia (46%, 30%, and 44% respectively), and was suppressed in the seeds of T. europaea, T. amurensis and T. begoniifolia both under the influence of transport (42%, 47% and 33% below control) and industrial emissions (19%, 19% and 45%), and was reduced in buds of T. platyphyllos, T. europaea and T. amurensis due to the effect of transport fumes (21%, 9% and 20% respectively). Guaiacol-peroxidase activity decreased due to the influence of transport fumes in buds of T. platyphyllos, T. europaea and T. amurensis (41%, 14% and 47% below control), while it increased in the seeds of T. platyphyllos and T. amurensis (104% and 83%), as well as in leaves of T. amurensis and T. begoniifolia both due to the effect of transport (129% and 144%) and of industrial emissions (respectively, 34% and 40% above control). The substantial restructuring of the antioxidant system components in leaves, dormant buds and seeds confirms the hypothesis that metabolic processes in Tilia trees adapt throughout all stages of their development in response to the polluted conditions in urban phytocenoses.

Modelling forage potential for red deer: a case study in post-disturbance young stands of rowan

Recently, the red deer ( Cervus elaphus ) population has increased considerably and caused serious damage in forest stands in Slovakia as well as in other Central-European countries. Rowan ( Sorbus aucuparia L.) is the tree species that is most intensively browsed and stripped by deer, especially during young stages of tree development. Our research focuses on estimating rowan mass consumption by red deer in young stands which developed after large-scale wind disturbance that occurred in the Tatra National Park in 2004. New models were developed for estimating the mass of tree components that are potentially edible by red deer using tree-base diameter as an independent variable. The results showed that the mass contribution of particular tree components to accessible deer forage depended on tree size (tree-base diameter). At stand level, total forage potential increased with an increase in tree size. However, whereas the quantity of bark available for stripping increased with tree size, the total mass accessible for browsing (leader shoot and branches with foliage) decreased. For instance, the contribution of stem bark to total forage potential in stands with a mean tree-base diameter of 20 mm and 50 mm was 15% and 50%, respectively. Theoretically, if all tree mass potential is consumed by red deer, young rowan stands (considering tree coverage of 50%) growing within an area of 100 m2 might provide sufficient forage for one adult deer for ca. 10 days. It is suggested that rowan species should not be removed from forest stands in territories with a high deer population in order to decrease the potential damage of other, commercially important, tree species.

Predicting apple tree (Malus × domestica Borkh.) canopy architecture: phytohormone balance in juvenile hybrids

Apple tree (Malus × domestica Borkh.) is one of the most widespread and economically important fruit trees. Productivity and economic effect of apple orchards depend on many strongly related factors, one of them being tree canopy architecture, which determines fruit bearing and demand for pruning. Main apple canopy architecture topics are related to application of growth regulators, fertilizers, studies of shoot development and pruning, and environmental influence while physiologic aspects are studied less. Phytohormones play a major role in controlling many physiological processes of plant growth and development. Different amounts of phytohormones are found in the shoots of apple trees depending on their canopy architecture. However, information about phytohormones and their ratio in juvenile orchard plants is insufficient. Our goal was to identify phytohormones related to apple canopy architecture and to evaluate their usage as biochemical markers in predicting future canopy ideotype of apple seedlings in the first year of growth. It was established that large amount of auxin and high auxin to zeatin ratio are specific to columnar apple trees and they can be used as biochemical markers in juvenile phase. These amounts and ratios are similar in juvenile and cropping columnar apple trees, so phytohormone amount and ratio is independent of tree development stage. It is possible to select columnar apple hybrids in the first year of growth, thus reducing breeding expenses.

Slow‐growing species cope best with drought: evidence from long‐term measurements in a tropical semi‐deciduous moist forest ofCentralAfrica

SummaryUnderstanding how drought affects annual tree growth in tropical forests is of crucial importance to predict their response to climate change. Previous studies, mainly led in theNeotropics and inSoutheastAsia, have yielded contradictory results which might be explained by differences in species studied, in the tree development stages considered, or by differences in other environmental factors than water availability.Here, we described the growth responses of functional groups of tree species to drought in aCentralAfrican semi‐deciduous moist forest. Species groups were automatically defined using a finite mixture model, which grouped species according to their growth model parameters. The growth model considered the variation in species response to drought, and the effect of competition for resources and of tree development stage on growth. Groups were further characterized by species functional traits. Nine species groups were identified. They differed in their ability to acquire, use and conserve resources, as suggested by their differences in maximum growth rate, regeneration guild, maximum dbh, wood density and leaf habit. The species were organized along a light requirement gradient that here closely matched a broader continuum of plant strategies for resource use, from slow‐growing shade‐tolerant conservative species to fast‐growing pioneer acquisitive species.Tree growth decreased with drought intensity, and species drought tolerance was found to be related to resource use strategy: slow‐growing species using a conservative strategy were the least sensitive to variations in water availability, while fast‐growing species using an acquisitive strategy were the most sensitive.Synthesis. Shade‐tolerant species, characterized by a low potential growth rate and thus a conservative strategy of resource use, were found to be the least sensitive to drought. This supports the hypothesis of a single axis summarizing multiple traits that represents a general trade‐off between the conservation and rapid acquisition of resources.

Remote management of deficit irrigation in almond trees based on maximum daily trunk shrinkage. Water relations and yield

This study assesses the usefulness of the remote scheduling of regulated deficit irrigation (RDI) in almond based on the maximum daily trunk shrinkage signal intensity (SIMDS). The 2-year experiment was carried out in SE Spain on 12-year-old almond trees (Prunus dulcis (Mill.) D.A. Webb cv. Guara). Four irrigation treatments were established to evaluate soil–plant water status, yield and water productivity: (i) control treatment (CTL), irrigated to satisfy the maximum crop water requirements (ETc), (ii) RDI1 and (iii) RDI2, both established to maintain different target thresholds of SIMDS according to the phenological stage and (iv) farmer treatment (FRM), irrigated by the grower according to his own experience. In 2009 and 2010 strategies 1.3-2.2-1.6 (SIMDS target threshold for each tree development stages II–III, IV and V, respectively) and 1.6-2.8-1.6 were applied in RDI1, respectively, and strategies 1.0-2.8-1.3 and 1.0-3.2-1.0 in RDI2. A supervisory control and data acquisition platform (SCADA) was created to monitor and remotely manage the irrigation scheduling. The obtained results indicate that SIMDS is a suitable parameter for irrigation scheduling throughout the growing season. The greater or lesser accuracy of fit of the measured SIMDS values to the thresholds depended on the phenological stage and the target stress intensity. SIMDS threshold values higher than 2.8, which involve midday stem water potential (Ψstem) values lower than −1.9MPa, were not suitable for almond irrigation management under our growing conditions. SIMDS-based RDI strategies were able to generate moderate to severe water stress in almond trees, which resulted in seasonal water savings around 50%. RDI strategies proved to be more cost-effective than full irrigation and farmer deficit irrigation treatment given the high price of irrigation water.