Multi-stemmed Shrub Research Articles

Improved Branch Volume Prediction of Multi-Stemmed Shrubs: Implications in Shrub Volume Inventory and Fuel Characterization

Improved Branch Volume Prediction of Multi-Stemmed Shrubs: Implications in Shrub Volume Inventory and Fuel Characterization

Ecological and biological features and prospects of the introduction of Cornus mas in Central Russia

Background. Cornus mas L. is grown in Europe, Central Asia, and the Middle East. Natural thickets are widespread in the Caucasus. The aim of this work was to analyze ecological and biological features of C. mas and the results of its introduction in order to justify the potential of its valuable agronomic traits for breeding and landscaping in Orel Province.Methods and materials. Specimens of C. mas preserved in the arboretum of the Russian Research Institute of Fruit Crop Breeding since 1968 were analyzed. The studies were conducted from 2012 through 2021. Winter hardiness, plant condition, degrees of flowering and fruiting were assessed using conventional techniques, while the degree of ornamentality was determined according to O. Yu. Emelyanova’s method.Results and conclusion. Under the conditions of the arboretum, C. mas is a multi-stemmed shrub, up to 5.3 m high, with an average crown projection diameter of up to 4.7 m, showing good vitality, active growth, and a high degree of resistance to damaging climatic factors of the winter season. No damage by diseases or pests was observed during the studies. The sum of effective temperatures for the beginning of C. mas flowering was 46.6 ± 2.0°C. Flowering started on April 15 (± 7 days). On average, flowering lasted 17 ± 5 days in the arboretum. Annually, the degree of flowering was high (4.8–5.0 points), and the vigor of fruiting was good (3.8–4.1 points). Peaks of C. mas ornamentality were observed in April, during the early abundant flowering of plants, and in August, during the ripening of fruits. The ornamental period of C. mas was on average 208 (± 12) days. The analysis of ecological and biological features of C. mas under the conditions of Orel Province showed the prospects of this species’ introduction. Formation and study of C. mas collection from neighboring regions will serve as a basis for successful breeding to obtain new cultivars with valuable traits for the conditions of Central Russia.

A contractor comparison of novel IPT tools and techniques for Brazilian peppertree (Schinus terebinthifolia) management

AbstractBrazilian peppertree (Schinus terebinthifolia Raddi) is a multistemmed shrub or small tree from South America that is invasive in Florida, Texas, Hawaii, and Australia. It forms multistemmed trunks with spreading branches that create dense thickets. State agencies in Florida manage it at annual costs of over $3 million, and individual plant treatment (IPT) techniques are widely used for control. Recent research testing novel hack and squirt approaches with aminopyralid and aminocyclopyrachlor and basal bark treatment with a new triclopyr formulation has shown these treatments are highly effective. However, they have not been evaluated at larger scales, which would be useful to land managers. Therefore, our objective was to compare the reduced hack and squirt technique using aminopyralid and aminocyclopyrachlor herbicides to basal bark treatment with triclopyr on a field scale. We used two contractor crews to apply treatments to twenty-four 0.2-ha plots. Treatments included aminocyclopyrachlor (120 g L−1) or aminopyralid (120 g L−1) applied with the reduced hack and squirt technique and triclopyr ester (108 g L−1) and triclopyr acid (34 g L−1) formulations applied with two basal bark treatment techniques. We confirmed that reduced hack and squirt significantly reduced the amount of herbicide and carrier applied compared with the basal bark treatments. By 540 d after treatment, aminocyclopyrachlor more effectively controlled S. terebinthifolia than aminopyralid with reduced hack and squirt and resulted in control comparable to that seen with either triclopyr basal bark treatment. These results verify reduced hack and squirt treatment with aminocyclopyrachlor and basal bark treatment with triclopyr acid as alternatives to basal bark treatment with triclopyr ester. Both resulted in significantly less herbicide use with comparable efficacy. This operational research approach has accelerated our understanding of novel IPT strategies and their implementation in the field.

Wood anatomy and dendrochronological potentiality of some woody shrubs from the southern Mediterranean coast in Egypt.

In tropical and subtropical regions, much research is still required to explore the dendrochronological potential of their trees. This study aims to evaluate the anatomical structure and dendrochronological potential of three Mediterranean desert shrubs in Egypt (Lycium schweinfurthii var. schweinfurthii, L. europaeum, and Calligonum polygonoides subsp. comosum) supported by X-ray density. The results showed that the target species had distinct growth rings at macroscopic and microscopic levels. The vessel traits reflected the adaptability of each species with the prevailing arid climate conditions. After the exclusion of the non-correlated series, we obtained three site chronologies that cover the years 2013-2022 for L. schweinfurthii, 2012-2022 for L. europaeum, and 2011-2022 for C. comosum. The mean series intercorrelation was 0.746, 0.564, and 0.683 for L. schweinfurthii, L. europaeum, and C. comosum, respectively. The EPS (expressed population signal) values ranged from 0.72 to 0.80, while the SNR (species-to-noise ratio) ranged from 9.1 to 21.5. Compiling all series of L. schweinfurthii raised the EPS value to 0.86. The chronologies developed for the studied species were relatively short since we dealt with multi-stemmed shrubs. The average percentage difference between latewood density (LWD) and earlywood density (EWD) in C. comosum, L. europaeum, and L. schweinfurthii were 11.8% ± 5.5, 5.2%± 1.87, and 3.6% ± 1.86, respectively. X-ray densitometry helped in the precise determination of the ring borders of the studied species. The relationships between the radial growth of the studied species and the climate variables were weak to moderate but mostly not significant (i.e., r < 0.7). Generally, the radial growth of the target species had a weak to moderate positive correlation with temperature and precipitation during the wet season (winter), while negatively correlated with temperature for the rest of the year, particularly in summer. Our data agrees with earlier findings that ring formation starts at the beginning of the long vegetative stage, then the rest of the assimilated carbohydrates are directed to the flowering and fruiting at the end of the vegetative stages. For more efficient dendrochronological studies on subtropical and Mediterranean trees, we recommend carrying out xylogenesis studies, collection of phenological data, sampling 45-80 trees per species, using new techniques, and choosing homogeneous and close sites for wood sampling.

A review of growth form and plant duration (life cycle) in Kalanchoe (Crassulaceae subfam. Kalanchooideae) in an evolutionary and classificatory framework

Representatives of Kalanchoe (Crassulaceae subfam. Kalanchooideae) are well-known for having evolved a range of reproductive mechanisms, at least some of which have contributed to certain species and nothospecies having become weeds in places remote from their natural habitats. In addition, kalanchoes have evolved a range of different growth forms in response to a diversity of historical environmental pressures prevalent in the locations where they grow naturally. In terms of growth form, many species are herbaceous, soft- to firm-stemmed perennials that remain small to medium-sized. In some of these same species, variants that are annuals, biennials, or multi-annuals are found. A further group of species are perennial, multi-stemmed shrubs with slightly woody but rather brittle stems and branches. A small group of Malagasy species have woody stems and branches, to the extent that the plants are truly arborescent or nearly so. The distribution of growth form, with special reference to stem and branch morphology, across the four subgenera at present formally recognised in Kalanchoe is reviewed in an evolutionary and classificatory framework, and illustrated.

Climate Overrides the Influence of Microsite Conditions on Radial Growth of the Tall Multi-Stemmed Shrub Alnus alnobetula at Treeline.

Green alder (Alnus alnobetula), a tall multi-stemmed deciduous shrub, is widespread at high elevations in the Central European Alps. Its growth form frequently leads to asymmetric radial growth and anomalous growth ring patterns, making development of representative ring-width series a challenge. In order to assess the variability among radii of one shoot, among shoots belonging to one stock and among stocks, 60 stem discs were sampled at treeline on Mt. Patscherkofel (Tyrol, Austria). Annual increments were measured along 188 radii and analyzed in terms of their variability by applying dendrochronological techniques. Results revealed a high agreement in ring-width variation among radii of one shoot, among shoots of one stock and largely among stocks from different sites, confirming the pronounced limitation of radial stem growth by climate forcing at the alpine treeline. In contrast to this, a high variability in both absolute growth rates and long-term growth trends was found, which we attribute to different microsite conditions and disturbances. These factors also override climate control of radial growth under growth-limiting environmental conditions. Based on our findings we provide recommendations for the number of samples needed to carry out inter- and intra-annual studies of radial growth in this multi-stemmed clonal shrub.

Steal the rain: Interception loses and rainfall partitioning by a broad-leaf and a fine-leaf woody encroaching species in a southern African semi-arid savanna.

Woody plant encroachment (WPE) has been found to alter ecosystem functioning and services in savannas. In rain-limited savannas, increasing woody cover can reduce streamflow and groundwater by altering evapotranspiration rates and rainfall partitioning, but the ecological relevance of this impact is not well known. This study quantified the altered partitioning of rainfall by two woody plant structural types (fine- and broad-leaved trees) across a gradient of encroachment in a semi-arid savanna in South Africa. Averaged across both plant functional types, loss of rainfall through canopy interception and subsequent evaporation roughly doubled (from 20.5% to 43.6% of total rainfall) with a roughly 13-fold increase in woody cover (from 2.4 to 31.4m2/ha tree basal cover). Spatial partitioning changes comprised fourfold increases in stemflow (from 0.8% to 3.9% of total rainfall) and a decline in throughfall proportion of about two-fifths (from 80.2% to 47.3% of total rainfall). Changes in partitioning were dependent on plant functional type; rainfall interception by the fine-leaved multi-stemmed shrub Dichrostachys cinerea was almost double that of the broad-leaved tree Terminalia sericea at the highest levels of woody encroachment (i.e., 49.7% vs. 29.1% of total rainfall intercepted at tree basal area of 31.4m2/ha). Partitioning was also dependent on rainfall characteristics, with the proportion of rainfall intercepted inversely related to rainfall event size and intensity. Therefore, increasing tree cover in African grassy ecosystems reduces the amount of canopy throughfall, especially beneath canopies of fine-leaved species in smaller rainfall events. Rainfall interception traits may thus confer a selective advantage, especially for fine-leaved woody plant species in semi-arid savannas.

A new species of Bauhinia ser. Cansenia (Cercidoideae, Leguminosae) endemic to the Atlantic Forest in the state of Bahia, Brazil

The genus Bauhinia belongs to the subfamily Cercidoideae (Leguminosae) and includes ca. 230 species with pantropical distribution. Sixty-two species are recorded in Brazil, 20 of which occur in the northeastern Brazilian state of Bahia. The genus is classified in eight sections, with sect. Pauletia being the most diverse. This article describes Bauhinia arleneae, a new species from this section, restricted to the humid forests of the central-eastern region of the state of Bahia. The new species is morphologically similar to B. cinnamomea, with both species sharing entire and elliptical leaves with acuminate apex and flowers paired along the pseudoracemes. B. arleneae differs from B. cinnamomea by the slender and flexuous multi-stemmed shrub or treelet habit, with glabrous leaves with 3 to 5 primary veins and fruit with coriaceous-woody, reticulate valves. We provide a description, illustrations, and a distribution map for the new species.

Characterization of Four New Compounds from Protea cynaroides Leaves and Their Tyrosinase Inhibitory Potential

Protea cynaroides (king protea) is a flowering plant that belongs to the Proteaceae family. This multi-stemmed shrub is the national flower of South Africa and has important economic and medicinal values. Traditionally, the main therapeutic benefits of this plant species include the treatment of cancer, bladder, and kidney ailments. There are very limited reports on the isolation of phytochemicals and their biological evaluation from P. cynaroides. In this study, the leaves of P. cynaroides were air-dried at room temperature, powdered, and extracted with 80% methanol followed by solvent fractionation (hexane, dichloromethane, ethyl acetate, and butanol). The ethyl acetate and butanol extracts were chromatographed and afforded four new (1–4) and four known (5–8) compounds, whose structures were characterized accordingly as 3,4-bis(4-hydroxybenzoyl)-1,5-anhydro-D-glucitol (1), 4-hydroxybenzoyl-1,5-anhydro-D-glucitol (2), 2-(hydroxymethyl)-4-oxo-4H-pyran-3-yl-6-O-benzoate-β-D-glucopyranoside (3), 3-hydroxy-7,8-dihydro-β-ionone 3-O-β-D-glucopyranoside (4), 4-hydroxybenzoic acid (5), 1,5-anhydro-D-glucitol (6), 3,4-dihydroxybenzoic acid (7), and 3-hydroxykojic acid (8). The structural elucidation of the isolated compounds was determined based on 1D and 2D NMR, FTIR, and HRMS spectroscopy, as well as compared with the available literature data. The tyrosinase inhibitory activities of the extracts and isolated compounds were also determined. According to the results, compounds 7 and 8 exhibited potent competitive tyrosinase inhibitory activity against L-tyrosine substrates with IC50 values of 0.8776 ± 0.012 and 0.7215 ± 0.090 µg/mL compared to the control (kojic acid, IC50 = 0.8347 ± 0.093), respectively. This study is the first chemical investigation of compounds 1–4 from a natural source and the first report of the biological evaluation of compounds 1–5 against the tyrosinase enzyme. The potent anti-tyrosinase activity exhibited by P. cynaroides constituents will support future exploration of the plant in the cosmetic field upon further biological and clinical investigations.

Multispecies allometric equations for shrubs and trees biomass prediction in a Guinean savanna (West Africa)

Currently, tools to predict the aboveground and belowground biomass (AGB and BGB) of woody species in Guinean savannas (and the data to calibrate them) are still lacking. Multispecies allometric equations calibrated from direct measurements can provide accurate estimates of plant biomass in local ecosystems and can be used to extrapolate local estimates of carbon stocks to the biome scale. We developed multispecies models to estimate AGB and BGB of trees and multi-stemmed shrubs in a Guinean savanna of Côte d’Ivoire. The five dominant species of the area were included in the study. We sampled a total of 100 trees and 90 shrubs destructively by harvesting their biometric data (basal stem diameter , total stem height , stump area , as well as total number of stems for shrubs), and then measured their dry AGB and BGB. We fitted log-log linear models to predict AGB and BGB from the biometric measurements. The most relevant model for predicting AGB in trees was fitted as follows: AGB = 0.0471 () (with AGB in kg and in g cm m). This model had a bias of 19%, while a reference model for comparison (fitted from tree measurements in a similar savanna ecosystem, Ifo et al. 2018) overestimated the AGB of trees of our test savannas by 132%. The BGB of trees was also better predicted from ρDb2H as follows: BGB = 0.0125 () (BGB in kg and in g cm m), with 6% bias, while the reference model had about 3% bias. In shrubs, AGB and BGB were better predicted from together with the total number of stems (). The best fitted allometric equation for predicting AGB in shrubs was as follows: AGB = 0.0191 () . This model had about 1.5% bias, while the reference model overestimated the AGB of shrubs of Lamto savannas by about 79%. The equation for predicting BGB of shrubs is: BGB = 0.0228 () that overestimated the BGB of the shrubs of Lamto savannas with about 3% bias, while the reference model underestimated the BGB by about 14%. The reference model misses an important feature of fire-prone savannas, namely the strong imbalance of the BGB/AGB ratio between trees and multi-stemmed shrubs, which our models predict. The allometric equations we developed here are therefore relevant for C stocks inventories in trees and shrubs communities of Guinean savannas.DbHSSnρDb2H0.915ρDb2H–1ρDb2H0.6899ρDb2H–1ρDb2HnρDb2H0.6227n0.9271ρDb2H0.7205n0.992

Sistemática de Cordiaceae en Argentina II: Las especies del género Varronia

A taxonomic treatment for Varronia P. Browne (Cordiaceae, Boraginales) in Argentina is presented for the first time. The genus consists of shrubs or subshrubs up to 5 m tall that are distributed mainly in the Neotropics. Plants are characterized by being multi-stemmed shrubs with flowers arranged into capitate or pseudospiciform inflorescences with a distinctly 2-branched style. The analyses of the morphological features support the recognition of six Varronia species in the country. A key to all Argentinian species, illustrations to aid identification both in herbaria and in the field, and distribution maps are provided. Synonymy, morphological descriptions, nomenclatural aspects, common names and uses are also provided. Varronia urticifolia is reported for the first time in Argentina and V. curassavica in La Rioja province.

Association Between Flaming Efficiency and Liquefied Petroleum Gas Pressure and Flaming Time in Hazelnut Sucker Control Done Using a Flame Torch

Turkish hazelnut (Corylus avellana L.) is naturally grown as a multi-stemmed shrub. This hazelnut produces lots of suckers. Suckers compete with the main branches for nutrients and water. Because the emergence of suckers negatively affects crop management in the hazelnut orchards are required to eliminate at least twice a year. Flaming is an alternative method to chemical and mechanical control methods. In this study, the effect of gas pressure, flaming time on fuel consumption and flaming efficiency in hazelnut sucker control were evaluated. The trials were carried out in an shrub ocak (in Turkish) type hazelnut orchard The results show that the torch flaming method is a useable method for hazelnut basal sucker cleaning. Gas pressure and flaming time had significant effects on fuel consumption and flaming efficiency. 150 s flaming duration and 3 bar pressure is sufficient for the flaming application. Durations above this time will increase fuel consumption and time loss.

Plant communities with naturalized Elaeagnus angustifolia L. as a new vegetation element in Altai Krai (Southwestern Siberia, Russia)

Elaeagnus angustifolia L. (Russian olive) is a deciduous small tree or large multi-stemmed shrub that becomes invader in different countries all other the world. It is potentially invasive in some regions of Russia. In the beginning of 20th century, it was introduced to the steppe region of Altai Krai (Russia, southwestern Siberia) to prevent wind erosion. During last 20 years, Russian olive starts to create its own natural stands and to influence on native vegetation. This article presents the results of eco-coenotic survey of natural plant communities dominated by Elaeagnus angustifolia L. first described for Siberia and the analysis of their possible syntaxonomic position. The investigation conducted during summer season 2012 in the steppe region of Altai Krai allows revealing one new for Siberia association Elytrigio repentis&amp;ndash;Elaeagnetum angustifoliae and no-ranged community Bromopsis inermis&amp;ndash;Elaeagnus angustifolia which were included to the Class Nerio&amp;ndash;Tamaricetea, to the Order Tamaricetalia ramosissimae. During the study, the following special features of communities have been described: polydominance of herbal layer, anthropogenic and grazing load, variation of the species richness, plant cover and vertical stratification into layers. These peculiarities mostly prove unestablished character of communities, all of them are relatively young (25&amp;ndash;30 years). Russian olive shrubberies varies in moisture and saline regime, which connected with their existence in different landforms (lake alluvial plains, gentle slopes of lakes, low lake terraces).

Boreal tree regeneration after fire and fuelwood harvesting in coastal Nunatsiavut

Consecutive landscape-scale disturbances are known to influence boreal forest regeneration, yet few published data exist on the compounding effects of natural and anthropogenic disturbance on regeneration in subarctic forests. We conducted a dendroecological study of eastern coastal boreal forest regeneration two decades after fire at three subarctic forest stands that are important sources of fuelwood for the people of Nunatsiavut (Labrador, Canada). We quantified spruce (Picea spp.) and balsam fir (Abies balsamea (L.) Mill.) seedling regeneration, standing dead tree density, trees harvested within burned forests, and aged proximal unburned stands. Age of unburned forest varied with site; however, each exhibited continuous regeneration over several decades. Despite low seedling regeneration at each site (stems·m−2; less than 35% of pre-fire stem density), model results indicated harvesting post-fire did not impact seedling regeneration. Findings suggest a negative pressure on seedling abundance from increased presence of tall multi-stemmed shrubs, yet we argue that because stands exhibit a range in tree age, shrubs may be a set of early successional species rather than indicating a change in successional trajectory. Examination of a larger chronosequence within coastal forest stands of Nunatsiavut is warranted to further understand forest regeneration in the eastern subarctic under changing disturbance regimes.

Accounting Process for Government Grants in Hazelnut Production within the Framework of International Accounting Standards: Turkey Sample

The subject of the study is the accounting of government grants for agricultural activities according to International Accounting Standards (IAS). In this context, IAS examines the government grants for agriculture under two standards. These standards are “IAS 41 Agriculture” and “IAS 20 Accounting for Government Grants and Disclosure of Government Assistance”. If a government grant related to a biological asset measured at its fair value less costs to sell to be recognized in profit or loss IAS 41 is applied but if a government grant relates to a biological asset measured at its cost less any accumulated depreciation and any accumulated impairment losses, IAS 20 is applied. The aim of this study is explaining the way for the accounting of government grants like “field-based income support” and "agricultural production support" for multi-stemmed shrubs (hazelnut trees) which are considered as a bearer plant. With this aim case study method was used and the subject of the study was illustrated by examining journal entries of government grants for hazelnut orchards of one of the leading companies in hazelnut industry in Turkey. Also, a diagram was developed for business which makes easier to decide to choice standard for accounting of any government grants for agriculture.

Woody Species Alpha-diversity and Species Abundance Distributions in an African Semi-deciduous Tropical Rain Forest

Understanding plant species diversity patterns and distributions is critical for conserving and sustainably managing tropical rain forests of high conservation value. We analyzed the alpha-diversity, species abundance distributions, and relative ecological importance of woody species in the Budongo Forest, a remnant forest of the Albertine Rift in Uganda. In 32 0.5-ha plots, we recorded 269 species in 171 genera and 51 families with stems of ≥2.0 cm in diameter at breast height (dbh). There were 53 more species with stems of ≥2.0 cm dbh than with stems of ≥10 cm dbh, of which 33 were treelets and 20 were multi-stemmed shrubs. For both minimum stem diameter cut-offs (i.e., ≥2 cm dbh vs. ≥10 cm dbh), the Fabaceae, Euphorbiaceae, Ulmaceae, and Meliaceae families and the species Cynometra alexandri, Lasiodiscus mildbraedii, and Celtis mildbraedii had the highest relative ecological importance. The relative ecological importance of some species and families changed greatly with the minimum stem diameter measured. Alpha-diversity, species richness, and species abundance distributions varied across historical management practice types, forest community types, and as a function of minimum stem diameter. Species richness and Shannon–Weiner diversity index were greater for species with stems of ≥2.0 cm dbh than of ≥10 cm dbh. The decrease in species evenness with an increasing number of plots was accompanied by an increase in species richness for trees of both minimum diameters. This forest is characterized by a small number of abundant species and a relatively large proportion of infrequent species, many of which are sparsely distributed and with restricted habitats. We recommend lowering the minimum stem diameter measured for woody species diversity studies in tropical forests from 10 cm dbh to 2 cm dbh to include a larger proportion of the species pool.

Genetic relationships and ecological divergence in Salix species and populations in Taiwan

Linking ecology with evolutionary biology is important to understand how environments drive population and species divergence. Phenotypically diverse Salix species, such as lowland riparian willow trees and middle- to high-elevation multistemmed shrubs and alpine dwarf shrubs, provide opportunities for studying genetic divergence driven by ecological factors. We used amplified fragment length polymorphism (AFLP) to quantify the genetic variation of 185 individuals from nine populations of four Salix species in Taiwan. Our phylogenetic analyses distinguished two riparian species and the separation of riparian species from multistemmed and dwarf shrub species. Variance partitioning for the total data found that environment explained a substantially larger proportion of genetic variation than geography. However, no genetic variation was explained by geography alone when only compared within and between species. Spatially structured regional environmental effects explained more variation than pure environments in most comparisons within and between species, suggesting that unmeasured environmental variables and/or past demographic histories played important roles in shaping population and species divergence. Based on forward selection analysis, annual mean temperature, aspect, and fraction of absorbed photosynthetically active radiation were the most influential ecological factors in shaping genetic variation within and between species. Nevertheless, different combinations of environmental variables correlated significantly with genetic variation within and between species. We identified eight AFLP loci that potentially evolved under selection intraspecifically using different outlier detection methods. These loci correlated with more than one environmental variable, suggesting local adaptation along environmental gradients at the population level.

Russian-olive (Elaeagnus angustifolia) Biology and Ecology and its Potential to Invade Northern North American Riparian Ecosystems

AbstractRussian-olive is a small tree or large multistemmed shrub that was introduced to Canada and the United States from Eurasia in the early 1900s. It was provisioned in large numbers during the last century to prairie farmers as a shelterbelt plant and remains a popular and widely available ornamental. Now invasive within some riparian ecosystems in the western United States, Russian-olive has been declared noxious in the states of Colorado and New Mexico. With traits including high shade tolerance and a symbiotic association with nitrogen-fixing bacteria, Russian-olive has the potential to dominate riparian vegetation and thus radically transform riparian ecosystems. Especially alarming is its capacity to influence nutrient dynamics within aquatic food webs. Our objective is to draw attention to Russian-olive as a potential threat to riparian ecosystems within Canada, especially in the southwest, where invasion is becoming commonplace. We review what is known about its biology and about the threats it poses to native organisms and ecosystems, and we summarize management and control efforts that are currently underway. We conclude by proposing a research agenda aimed at clarifying whether and how Russian-olive poses a threat to riparian ecosystems within western Canada.

CHILEAN HAZELNUT SITUATION AND PERSPECTIVES

Chile is the largest hazelnut producer in the Southern Hemisphere. Hazelnut cultivation covers about 13,000 ha between the region of Maule, central zone (Talca, Linares, Chillan) and the south zone of the country including the regions AraucanA­a, Los RA­os and Los Lagos (Temuco, Valdivia and Puerto Varas with an additional 800-1000 ha being added yearly) (Fig. 1). Historically this species was introduced in South Chile by European emigrants, in particular Germans, Italians, and Swiss, principally in Araucania, Los Rios and Los Lagos regions. The hazelnut industry in Chile is very young (Ellena, 2010). The first important commercial orchards were established in 1990 (100 ha) in the Curico and Talca areas with the introduction of a great amount of plants of ‘Tonda Gentile delle Langhe’, ‘Tonda di Giffoni’ and their pollinizers from Italy. Hazelnut plantings in Chile have increased strongly in the last 5 years and the crop is spreading, especially in AraucanA­a region (3000 ha). This trend is accompanied by an important demand for nursery plant material and by innovative cultivation techniques. However Chilean production of European hazelnut is based mainly on two cultivars: ‘Chilean Barcelona’ a similar material to ‘Oregon Barcelona’ and ‘Tonda di Giffoni’ most appreciated Italian cultivars with round nut (Ellena et al., 2012). The first material is principally for in-shell market with a low percent kernel (39-40%) and the second for kernel market (industry process) with about 47% kernel and good kernel blanching. In general, these cultivars are productive and adapted to the environmental conditions of central and south Chile. In research trials conducted per the Research Center INIA-Carillanca and commercial orchards both cultivars have shown a great production potential. Concerning the pollination, there is a large variety of pollinizers being established with uncertainty about their genetic compatibility. However, in the last years important progress has been achieved employing correct pollinizer cultivars and with research about artificial pollination on hazelnut. In connection with the training system, the orchards were planted with multi-stemmed shrubs or multisystem bush and as a free single trunk (free vase), this last mainly for the ‘Barcelona’ cultivar, which shows also a high vigor compared to ‘Tonda di Giffoni’. Concerning the plant density, the orchards are planted with 460-500 tree/ha. In order to reduce the initial low cropping of young trees, the tendency to increase the plant density (667-800 trees/ha) has been proved to be positive. Recently, studies realized by the Center INIA-Carillanca in south Chile show preliminary positive results in this matter, increasing the yields. Actually this research Center has begun a selection program to develop rootstocks in order to reduce height of trees and improve vegetative growth and yield performance, and lower sucker emission. The suckering is another important problem to resolve in growing hazelnut increasing the management cost and increasing probability of disease such as the bacterium Xanthomonas arboricola p.v. corylina (Miller and Bollen, 1964). In recent years, a lot of research has been done by the INIA-Carillanca Center to improve the development and production of hazelnut orchards as: density plant, foliar fertilizer programs, soil management, irrigation, artificial pollination, pruning and pest management with integrated control (MIP). One of the principal problems in hazelnut orchards are Aegorhinus superciliosus (GuA©rin-MA©neville) (Curculionidae) distributed in Chile from Maule region until Los Lagos region and Aegorhinus nodipennis (Hope) (Curculionidae) distributed from Maule region (central Chile) even AysA©n region. The Chilean hazelnut production is about 4500-5000 t destined principally to Europe, the United States and a smaller quantity is exported to South America and low quantities are employed for domestic markets. Important progress has been achieved with regards to the organization of growers for the selling of nuts and the building of a Plant Processing Industry in Araucania region, Gorbea area with an important national export company of nuts fruit “Pacific Nuts”. The aim of this association is to improve the trade of Chilean hazelnuts and to guarantee prizes to growers associated.

Determining the timing of willow shrub dieback using epicormic shoots

Riparian willows are declining throughout the Rocky Mountains, USA. Dendrochronological methods can be used to age dieback and disturbance dates in trees, however, these methods are not suitable for multi-stemmed shrub species. We present a new method for aging willow dieback using epicormic shoots and compare our findings with an aerial photo analysis of our riparian valley study site in Rocky Mountain National Park. Epicormic shoots initiate when stem wounding affects the apical meristem. We determined the date of stem death by comparing the age of the dead stem above a wound with the age of the live stem below a wound. Epicormic shoots initiated below wounds an average of 2 years prior to stem death, suggesting that it takes stems 2 years to die after being wounded. Aerial photo analysis demonstrated a sharp decline in willow canopy cover across the valley and we show a coinciding increase in epicormic shoots during the period of willow canopy decline. This was followed by a decrease in the number of epicormic shoots formed per year as the number of tall stems able to produce epicormic shoots has decreased. Age analysis of epicormic shoots is a promising new method for examining local scale willow dieback and decline.