bluuebunny/crossref_metadata_2025 huggingface dataset:
Small-format aerial photographic systems for the evaluation of forest resources in Latin America
Authors: Pernia E.
Published: May 2024

For several decades, 35 and 70 mm aerial photographic systems have been used in North America, Europe and other regions, for the acquisition of forest resources information on relatively small extension areas. On the contrary, in Latin America, where there is a lack of information about those resources, the small-format systems have recieved limited use. In part, this is situation is due to the scant knowledge that exists in the region about the potential these systems have and the ways of using them. The purpose of this article is to provide personnel and institutions involved in the evaluation and monitoring of forest resources with basic information and support references about the general characetristics, the integration of small-format aerial photographic systems, the planning and execution of missions of this type, the interpretation and restitution of 35 and 70 mm photographs, and applications in forestry.
Hidrosystem anatomical features of principal woody plants of Chaco, Argentina
Authors: Moglia G. , Gimenez A. Mª.
Published: May 2024

Selected wood anatomy characteres of fourty six species of the principal trees of the Chaco Region were studied in order to analyze the hydraulic conductivity and safety of the xylem system, and compared with data from other habitats. Wood microscopic features considered were: ring porosity, vessel arrangement, tangential vessel diameter, number of vessels per mm2, Vulnerability Index, vessel element length, perforation plate, helical thickening and tracheas. A predominance of characters that probably contribute to hydraulic safety was observed: diffuse porous, numerous grouped or multiple vessels of small diameter, short vessel elements, with simple perforation plate. Maytenus vitis-idaea, Rupretchia apetala, Castela coccinea, Parkinsonia aculeata, Jodina rhombifolia species of the driest part of Chaco Region, present the most xerophytic features.
Analysis and modeling of diameter distributions of Pinus pinaster Ait. in Galicia
Authors: Alvarez Gonzalez J. G. , Ruiz Gonzalez A. D.
Published: May 2024

The purpose of this study is to compare five density functions (“A” of Charlier, Weibull, Pearl-Reed, Johnson SB and Gamma) in describing diameter distributions in stands of Pinus pinaster in Galicia. The material of the study consists of 454 diameter distributions obtained from 112 sample plots. The behaviour of each one of the five functions was compared using the Kolmogorov-Smirnov goodness fit test. Finally, prediction equations were developed for the “A” of Charlier, Weibull and Gamma functions relating the parameters with the stand variables to construct stand tables.
Two models for fire occurrence prediction in Whitecourt Forest, Canada
Authors: Vega Garcia C. , Woodard P. M. , Titus S. J. , Adamowicz W. L. , Lee B. S.
Published: May 2024

This study models the daily human-caused wildfire occurrence in Whitecourt Forest, Alberta, Canada. Two models were developed, a logit model and a neural network model. Both achieved similar accuracy when applied to daily prediction (74 vs. 76 %). This paper describes the methods used for the models development and discusses the management implications and limitations of the study.
Spatial pattern of a subalpine forest-alpine pasture ecotone (Las Cutas, Ordesa, Central Pyrenees)
Authors: Camarero J. J. , Gutierrez E.
Published: May 2024

We describe the spatial pattern of a subalpine forest-alpine pasture ecotone in the Central Pyrenees, that includes altitudinal timberline and treeline, and it is dominated by Pinus uncinata Ram. A rectangular (30 x 140 m) plot was located crossing the ecotone with its longest side parallel to the slope. We measured for each P. uncinata individual inside the plot: location (coordinates x, y), and structure (e. g. height) and growth form variables (number and type —living or dead, vertical or shrubby— of stems per individual). P. uncinata individuals were classified according to their size (adults, poles, saplings and seedlings) and growth form (krummholz —shrubby and multistemmed individuals— and krummholz with vertical stems). We described quantitatively the type of substrate (bare soil, organic matter, gravel and rock) and cover of herbs, shrubs and P. uncinata using transects parallel to the slope. The ecotone structure was described through: (1) point pattern (Ripley’s K) and (2) surface pattern analyses (spatial correlograms of height); (3) the detection and description of boundaries using density, size or growth form variables; (4) the synthesis of variations of presence and diversity of substrates and herbs and shrubs; and (5) the ordination of quadrats (the plot was previously subdivided into 115 6 x 6 m quadrats), according to their spatial position in the ecotone, the type of substrate, the cover of herbs and shrubs and the number, size and growth form of P. uncinata individuals. Most P. uncinata living individuals were krummholz, located above the timberline. Krummholz individuals showed significant and positive spatial interaction with seedlings. Bigger, vertical and unistemmed individuals predominated in the lower area of the ecotone, in the forest. The change of height with increasing elevation was abrupt and masked an underlying pattern of patches of trees with similar height in the forest. The structure variables were more sensitive because they produced a greater number of boundaries. These boundaries were arranged forming a “diagonal” (in the lower and upper areas of the ecotone for big and small individuals, respectively) because of the sequential location of progressively bigger unistemmed individuals descending across the ecotone. The shrubby individuals were associated with rocky substrates, that decreased in the forest, where organic matter predominated. The snow-wind interaction can explain the location of the studied timberline that could be considered a local phenomenon. Krummholz can buffer seedlings against the harsh climatic conditions of this ecotone (strong wind, reduced snowpack, low temperature). The spatial location of the different classes of individuals, the spatial interaction between seedlings and krummholz individuals, and changes of growth form (from shrubby to vertical growth form or vice versa) can cause some inertia in the response of ecotone P. uncinata populations to environmental changes.
Phytoclimatic characterization of experimental sites of Lanjarón (Southern aspect of Sierra Nevada)
Authors: Cuadros R. , Francia J. R.
Published: May 2024

Climate and phytoclimate aspects of various areas belonging to an experimental forest location in Sierra Nevada, Lanjaron (Granada) southeast Spain, are described. Many of them have been settled with an important number of tree species experimentation plots for as many sixty years. To overcome the lack of local data, those of six nearest, including one serving as a reference, meteorological stations were used to obtain an estimate of altitudinal precipitation and temperature gradients that are used to calculate basic climatic variables and the climodiagrams of Gaussen - Walter. Results allow us to classify the zones into phytoclimate classes with a bigger accuracy.
Aboveground productivity and nutrient dynamic in a reforestation of Pinus pinaster Ait. with different intensities thinning
Authors: Montero G. , Ortega C. , Cañellas I. , Bachiller A.
Published: May 2024

Thinning of different intensity have been carried out on a Pinus pinaster plantation and results have been compared with that of a control treatment and one plot with the maximum biological density for this species and age. The experimental design consists of randomized blocks. Four inventories were made in summer in 1984, 1988, 1992 and 1996. With this information the volume, basal area and number of tree before thinning, thinning and after thinning were calculated. Standing biomass and mineral element concentration before thinning, biomass removed with thinning and standing biomass after thinning have been estimated trough inventories and subsequent determination of modular values (a sample with 100 trees). Litter fall represented by needles fall and dead branches has been measured as well as its evolution through the year on plots representing four different stand densities.
Holm oack forest restoration model based on grabing of coppiced shrub
Authors: De Simón E. , Bocio I.
Published: May 2024

This work tray to contribute on the forest holm oak restoration; for this we propose a restoration model based on the holm oak regeneration strategies by using the holm oak scrub grubing (pruning 1 or 2 cm below the soils surface) treatment to obtain a large number of news shoots and roots plant. This model is being applied to regenerate the north slope holm oak forest of Sierra Nevada, Almeria, (Spain).
Biotechniques used in native forest species
Authors: Abedini W. , Boeri P. , Marinucci L. , Ruscitti M. , Scelzo L.
Published: May 2024

The «talares» are a native wooded community of Buenos Aires province (Argentine). They are be coming extined due to the agricultural frontier expansion, the urbanization and seed regeneration problems. The most important forest species that constitute them are: Celtis tala Gill. ex Planch. (tala), Acacia caven (Mol.) Mol. (espinillo), Parkinsonia aculeata L. (cina-cina) and Erythrina crista-galli L. (seibo). The aim of this work is the adjustment of a protocol for the micropropagation in vitro, through the adventitious organogenesis from the young material of this native forest species. As explant it was used sections of seedling obtained from seeds germinated in vitro, wich were prepared and desinfected for his cultivation. The basal medium more appropiated was the Broadleaved Tree Medium (BTM) (Chalupa, 1983), complemented with different growth regulators. It was obtained calli, roots and buds. Whole plants regenerated are in the aclimated stage.
Relationships between site characteristics and the productivity in a plantation of Salix nigra located in the Paraná delta (Argentina)
Authors: Casaubón E. A. , Gurini L. B. , Cueto G. R.
Published: May 2024

We studied the quality of forest site in a 6 years old commercial plantation of Salix nigra, located in the Paraná delta (Argentina), which shows a lower productivity than the average in the region. The objective of this study is to identify site components that determine this lower productivity. The environmental factors evaluated were the floristic community, the relief and the edafic factors and their relationship with the height of dominant trees and the site productivity. The lowest height growths were detected in high altitude sites or in plots with the former stratum of soil very wide (with clay-slimy texture), while the best height growths of trees were registered in low altitude sites with a very thin first soil horizon.
A review of the plant communities associated with Scots pine (Pinus sylvestris L.) in Europe, and an evaluation of putative indicator/specialist species
Authors: Kelly D. L. , Connolly A.
Published: May 2024

Plant communities dominated by Pinus sylvestris (Scots pine) occur over an extraordinarily wide range of climatic and edaphic conditions. The salient features of communities from different parts of Europe are outlined, drawing mainly on phytosociological literature. The degree to which a number of specialist species (mainly mycotrophic herbs) are associated with Scots pine is assessed. We conclude that no species or species group is associated with Scots pine through all or even most of its geographic and edaphic range. It follows that separate indicators of semi-natural Scots pine-dominated communities must be sought for different regions and different habitat-types.
Genetic markers: tools for identifying and characterising scots pine populations
Authors: Forrest I. , Burg K. , Klumpp R.
Published: May 2024

Genetic diversity is the basis for ecological biodiversity; it can only be assessed by using markers which reflect the variation present within the genome. Biochemical plant constituents interact with other components of the ecosystem and are thus of greater value as adaptive markers than as truly genotypic characters; however, the terpene components of coniferous resin systems are under strong genetic control and are valuable population diversity indicators. Molecular markers are impervious to environmental modification and therefore represent the genotype most faithfully. A survey is presented of the applications of the major biochemical and molecular marker systems in the analysis of Scots pine populations, together with indications of the advantages and limitations of each category of marker. The unusually high phenotypic diversity evident within the species at the morphological and physiological levels, both within populations and between geographical regions, is further substantiated by the degree of genotypic diversity evident from biochemical and molecular analysis. Molecular markers currently available mostly measure selectively neutral variation; among the most important needs for the future is the development of molecular markers for adaptive traits.
Quantification of forest stand structure applied to Scots pine (Pinus sylvestris L.) forests
Authors: Kint V. , Lust N. , Ferris R. , Olsthoorn A. F.M.
Published: May 2024

The use and the application possibilities of forest structure description are discussed. The quantitative description of forest stand structure is studied by way of three structural characteristics: positioning, mixture and differentiation. Therefore various non-spatial and spatial indices are proposed. Some spatial indices are applied to a mixed oak-pine stand in the Belgian Campine region, and the advantages and disadvantages of the calculated indices are considered. Results indicate the utility of these indices, both in describing the stand structure accurately, and in reflecting the operative processes causing stand evolution.
Silviculture and stand dynamics in Scots pine forests in Great Britain; implications for biodiversity
Authors: Mason W. L.
Published: May 2024

There are 241,000 hectares of Scots pine forest in Great Britain or about 10 percent of the total forest area. Traditionally, a distinction has been drawn between a small area of native pinewoods with high conservation value in northern Scotland and the younger plantations of Scots pine to be found in many parts of Britain. The latter have been primarily managed for timber although they are now expected to meet multipurpose objectives including enhanced biodiversity. Silvicultural practices in the plantations are based upon a system of clear felling and artificial regeneration. However, older plantation stands can be colonised by rare species previously thought to be confined to the native pinewoods. The structure of Scots pine stands of different ages is examined using modern concepts of stand dynamics. The analysis highlights that the native pinewood stands have features characteristic of «old-growth» such as: a lower stocking density; more large trees; greater variation in diameter; a clumped distribution of stems; and appreciable quantities of standing deadwood. By contrast, most plantation stands have higher stocking densities, less variation in diameter, more uniform spacing and limited amounts of deadwood. By quantifying these structures it becomes possible to propose thinning regimes which can be introduced into plantations to accelerate the development of old-growth conditions without undue sacrifice of timber values. Natural disturbance histories in British pinewoods indicate a return period for stand replacing events (fire, windthrow) of once every 100 years which suggests that a maximum of 10 per cent of the pine resource should be managed as old growth stands. The age structure of some remnant pinewoods shows a lack of younger age classes and the desired old-growth habitat will diminish over time unless suitable plantation stands are managed as potential old-growth habitat. The maintenance of biodiversity in British pinewoods requires an integrated approach that applies to both the native pinewoods and the plantation stands.
Risks associated with measures to enhance biodiversity in European Scots pine forests
Authors: Ferris R. , Pritchard E. K.
Published: May 2024

The conservation and enhancement of biodiversity in European forests is an integral part of sustainable forest management, making it necessary to incorporate into forest operations measures specifically designed to meet the needs of wildlife. Scots pine forests make up a considerable proportion of the total forest area of western Europe and so could make an important contribution to forest biodiversity within the European Union. Pine silviculture is often based on clearfelling and replanting regimes, which produce relatively simple stand structures and landscapes. However, the growing appreciation of the importance of biodiversity has led to modifications being made to forestry methods, including changes to silvicultural systems, the retention of broadleaved trees, provision of deadwood as wildlife habitat, sensitive open ground and edge zone management, prescribed burning, and encouragement of natural regeneration. In many instances, these measures have been adopted with only limited attention given to their potential ecological and economic risks, such as pests and pathogens, habitat loss and fragmentation for some species, and future operational problems. This paper reviews the range of measures which have been proposed and, in some instances, adopted; and assesses the risks associated with them.
Current and future status of Scots pine (Pinus sylvestris L.) forests in Europe
Authors: Mason W. L. , Alía R.
Published: May 2024

There was a major expansion in the area of Scots pine forests in Europe during the twentieth century so that this forest type now exceeds 20 per cent of the productive forest area of the EU. Although the main aim of this expansion was to increase timber production, a wider range of management objectives has become more important during recent decades. These changes may affect the future status and development of Scots pine forests. To analyse the potential impacts, a questionnaire was distributed among the participants in this Concerted Action (CA) to compare the present and future situation in Scots pine forests in different European countries. The results showed the role of Scots pine in different countries of Europe varies from a pioneer plantation species on degraded agricultural land to a dominant component of a native forest ecosystem. There is a general expectation of a move away from simple management systems towards a more complex silviculture based upon greater use of natural regeneration and with a greater diversity of tree species and ages. This move is likely to be more pronounced in central and western Europe where the economic returns from current management are low. These changes are likely to have benefits for biodiversity, particularly where they are accompanied by increased provision of deadwood. Until recently, studies of genetic diversity in Scots pine have laid greatest emphasis on improving growth traits to enhance timber production. There are successful breeding programmes in a number of member states which are reporting potential gains of 10-20 per cent in volume. However, increasing interest is now being given to the conservation of isolated populations which are found under extreme environmental conditions for the species and which have potential importance in the maintenance of genetic diversity. A number of these populations are under threat and action is required to safeguard their future. Despite these changes, Scots pine will continue to be a most important forest species in Europe for the foreseeable future. The anticipated changes in management practices are in line with the recommendations of resolutions on sustainable forest management passed at the 1998 Lisbon Ministerial Conference on Protection of Forests in Europe. The challenge is to develop management systems that are economically viable, but provide the range of non-market benefits required by the needs of sustainable forest management.
Genetic conservation of Populus sp. in Spain
Authors: Alba N.
Published: May 2024

The main objectives of the Populus nigra L EUFORGEN network is the establishment of new methodologies for in situ and ex situ conservation. Different activities developed by the State Administration, as well as the Regional Administrations, stress the increasing interest for genetic conservation of autochthonous Populus species. Activities on conservation have usually been focused on installation and maintenance of in situ collections for natives species: P. nigra, P alba and P. tremula. However, recent works have been focused to study genetic diversity in both collections and natural populations, as a necessary tool to define a suitable methodology for genetic resources management. In this paper, the state of the inventories and collections for genetic conservation purposes is summarised, and a review of different studies on genetic diversity characterisation is presented. The identification of research needs and different strategies, taking into account the special importance of Spanish populations, is necessary for the long-term conservation of diversity in the distributional range of these species.
Mediterranean Oaks. EUFORGEN Genetic Conservation Network
Authors: Varela Mª. C.
Published: May 2024

Mediterranean oaks play an important ecological and cultural role, since they provide diversified goods. However, economic changes has driven many species into a secondary role. They have been substituted by faster growing species, in addtion of other threats as fragmentation and lost of populations, genetic drift, etc. Capturing the existing diversity and providing conditions for evolution is the goal of gene conservation. Some factors that must be taken into account are the effective size (Ne) and the presece of rare genes. A review of conservation methodologies for different cases found within mediterranean Quercus species is presented: multiuse managed forests, small and marginal populations, species with o without breeding programmes. A strategy is proposed for the frequent situation in which agriculture and grazing activities are carried out under the forest canopy. In these cases, natural regeneration is possible and must be promoted. The relevance of indirect actions in the defence of use of mediterranean oaks, such as CORK MARK process, is also remarked.
Genetic resource conservation of Canary «Monte Verde» forest formation
Authors: Fernández López A. , Marrero Gómez M.
Published: May 2024

The «monteverde», from the Canary Islands, is a forest formation composed by evergreen trees and shrubs, and is associated to a high level of humidity from rainfall or mist. In this special ecosystem, according to the IUCN categories, 166 species are threatened, and 10 have deficient data. These species represent 30% of the endemic flora of the Canary Islands. The conservation of the species is linked to the maintenance of the whole forest system. In this paper, the main threats to the “monteverde” are analysed: reduction of the habitat, fragmentation, cattle pressure and introduction of exotic species. The Canary National Parks have implemented a programme based on the protection of specific taxa or populations, by means of the creation of protected areas. The first results, and a complete description of the programme is presented.
Autoecology of beech woodstands in Catalonia (Spain)
Authors: Elena R. , Sánchez F. , Rubio A. , Gómez V. , Aunós A. , Blanco A. , Sánchez O.
Published: May 2024

This study was carried out after field sampling and analysis of 24 beechwood stand plots selected by means of a beech distribution area stratification system based on CLATERES Land Classification. At each sampling plot, 3 physiographic, 15 climatic and 18 edaphic parameter values were measured, allowing us to define central and marginal parameter ranges, which were used for drawing landform, climatic and soil habitat diagrams of beech (Fagus sylvatica L.) woodstands in Catalonia [N.E. Spain]. Such diagrams show that most of the Catalonian beech stands are located on soils developed from a series of different rocks: igneous, volcanic, metamorphic, and sedimentary, both acid and basic. Soil texture are predominantly loam, sandy loam and silt loam. According to FAO criteria, soils are mainly classified as Cambisols. Although soil water holding capacities are low, there is no significant drought stress. Soil humus forms are forest mull and calcic mull. Moreover, several silvicultural stand parameters have been calculated: Stand density, Coppice density, Basal area, Age, Site index, Top Height, Hart-Becking indexes and Canopy cover indexes. After their correlation with the ecological ones, it is concluded that the best beechwoods are located on more thermic sites, but under enough summer rainfalls to avoid critical drought stress.
Genetic variation in progenies of Prosopis alba
Authors: López C. , Maldonado A. , Salim V.
Published: May 2024

Prosopis alba is the most widely spread native species in Argentina. It is economically important because it is good for both, the human and the livestock consumption. Over de last decade, excessive logging of the natural stands and a strong degradation of the available genetic resources has occurred because of the excellent technological properties of its wood. To improve the available material to obtain good quality seed for reforestation, an improvement plan by phenotypic individual selection for form stem and volumetric growth in natural populations of four Argentinean provinces was conducted. Fifty-seven open pollinated progeny families from eight different provenances of Prosopis alba were established at San Carlos, Santiago del Estero, Argentina, in 1990. The trial, laid out in a Complete block design, was assessed in 1998 for height and diameter growth. Results revealed differences among and within provenances. The best provenance is 20 % and 23.8 % superior compared to the worst, for height and diameter growth respectively. Large genetic variations among families were found for the traits studied. Estimates of genetic parameters indicate genetic gains of 13,5 % for height and 21,2 % for diameter for selection among and within families.
An approximation to the dynamics of the Galician forests. Stocks and evolution of forest types in Pontevedra province
Authors: García O.
Published: May 2024

Some tools for studying the future of the forestry sector in Galicia, Spain, are presented. Sample plots from successive national forest inventories are first used to estimate historic trends and the current condition of the forests. Then, this information is used to develop a Markov matrix model that can project future areas by forest type. Finally, we examine approaches for estimating age distributions and timber yields, necessary for the application of more detailed planning models.
Quality and properties of Spanish Laricio Pine (Pinus nigra Arn. Salzmannii)
Authors: Fernández-Golfín J. I. , Díez M. R. , Baonza M. V. , Gutiérrez A. , Hermoso E. , Conde M. , Van den Eynde V.
Published: May 2024

An extensive characterisation of Spanish laricio pine, Subsp. Salzmannii (Pinus nigra Arn. Subsp. Salzmannii) lumber has been carried out. The forest area for this species accounts for 352.954 Has and the average production for 310.000 m3/year (roundwood with bark). The study of technological characterisation of Pinus nigra Arn. Subsp. Salzmannii lumber is focussed only on three (Region 6 «Alto Maestrazgo», Region 7 «Sistema Ibérico Meridional» y Region 8 «Cordilleras Béticas») of the ten Regions of provenance that the species has in Spain due to the special interest of those forests and because they accounts for the 70,57 % of the total area and the 95 % of the total production of sawnwood. A test sample with 107 trees from 11 different sampling zones has been selected. 2886 boards, 500 disks and a very high number of small clear test samples, coming from 507 logs, has been prepared and tested. All the tests were carried out according to standards. Drying ability and quality have also been studied. This lumber seems to be highly resistant, with a high level of extractives and with a pronounced level of warp when drying. This lumber also seems to be very appropriated for structural purposes.
Monetary forestry accounting including environmental goods and services
Authors: Kriström B. , Skånberg K.
Published: May 2024

There is substantial current interest in expanding accounting systems, such that they include services appropriated from the ecological systems. Much of this activity has focused upon forest resources; there are currently more than 100 «green» forest accounting studies, covering many different countries. This paper provides a view of some theoretical and empirical issues on «green» forest accounting. It discusses some issues in calculating «true» income from forests, as well as the measurement problems that arise when valuing non-priced services. It also reviews recent efforts at EUROSTAT and includes a detailed illustration of a comprehensive official Swedish application on «green» forest accounting. The paper concludes by arguing that future work on green forest accounting should be directed towards tying together theory and practice to a even larger extent than what is currently the case.
Environmental accounting in agriculture and forestry: a stepwise approach
Authors: Merlo M. , Boschetti A.
Published: May 2024

This paper illustrates a stepwise enterprise approach to enterprise environmental accounting. It starts with traditional balance sheets of four agricultural and forest enterprises following traditional accounting principles. A second step separates environmental/recreational activities from conventional ones, that is timber and agricultural products. A third step outlines near market values, as perceived by the entrepreneur as hidden private values. A fourth step opens up to positive and negative public effects and externalities making possible a quantification of public welfare effects. The last step, therefore, aims at incorporating all non-market benefits and costs. Satellite accounts and addenda, including physical biological aspects, can also be used. The methodology, though enlarged to environmental/social issues, remains strictly based on accounting principles. So far, it has been applied to several case studies proving to be a useful tool both in managerial economics as well in environmental and social planning and decision-making in rural areas.
Quercus petraea actual stands in Galicia
Authors: Vila Lameiro P. , Díaz-Maroto Hidalgo I. J.
Published: May 2024

The presence and characterization of Quercus petraea in the northwest of the Iberian Peninsula have been slightly studied. Although Rivas (1987) restricts his filings to the Orocantábrica Province, subsequent studies have confirmed the presence of Quercus petraea out of this place. The present investigation was undertaken to study the placing and dasometry of that specie in Galicia (Spain). Twenty-two plots with Quercus petraea as dominant specie were studied. Data about placing characteristics (location, orography, fisiografia, vegetation...) and stand variables (diametrical measurements, height, and sticks extraction for analysing of ages and growths) were checked. Basic parameters of dasometric characterization were obtained in cabinet, and subsequently the statistic analysis of multiple variables was used to study and classify stands. With both studies, we can assure that it is possible to speak of two big groups of stands: one of them clearly has typical features of hybridisation with Quercus robur and Quercus pyrenaica, that are localized near Orocantábrica Province; and the other group, that does not present those hybridisation features, is localized in the more oriental mountains. Finally, this classification in confirmed with other results as weight parameters, age, growth, etc. Consequently, the more pure stands produce data of greater maturity and a clear relation between their distribution and the classic idea of their preference by shady exhibitions is not observed in this area.
Interactions among site, plague and a trunk disease in a plantation of Populus deltoides cv Catfish-2 in the Low Delta of Paraná River (Argentina)
Authors: Casaubon E. , Cueto G. , Hodara K. , González A.
Published: May 2024

This work is aimed at studying the interactions among the plantation site quality of poplars with damages caused by «Taladro de los Forestales» (Platypus mutatus Chapuis), and with cankers (one trunk disease). We carried out the study in a 2 ha plantation of Populus deltoides cv Catfish-2, which is the most widespread clone in the delta area. The plantation was 12 years old and it was placed in the Low Delta of Paraná River (Argentina). We detected a direct relation among the forest site quality, the presence of the plague (Platypus mutatus) and a trunk disease (cankers). The poplars of greater diameter and height were the most affected trees by the boring insect's attack and they showed the most quantity of active holes and cracks at galleries height, as a consequence of the plague effect, while the poplars of less growth were those more infected by cankers in their trunks. The percentage of plants affected by the boring insect and infected by cankers was significantly greater at the most productive and the highest forest site («albardón» protected by dams). However, the low sites («bañados» protected by dams) had lower growth values and volumetric yields, fewer active holes, less percentage of plants broken by the wind at the height of galleries produced by boring insects and less number of plants with cankers in the trunks.
A dendroecological study of a Epinotia subsequana Hw. (Lepidoptera: Tortricidae) attack on a fir (Abies alba Mill.) forest in the Aragón Pyrenees (Diazas, Torla)
Authors: Camarero J. J. , Martín Bernal E. , Gil-Pelegrín E.
Published: May 2024

We found many narrow or missing annual tree-rings during the period from 1996 to 1998 in most of fir trees sampled in the Diazas forest (Torla; 42º 37’ 50’’ N, 0º 05’ 40’’ W, 1528 m a.s.l.). These tree-rings were synchronic with attacks in that area of the leaf miner Epinotia subsequana Hw. (Lepidoptera). This temporal coincidence motivated this dendroecological study. The radial growth in Diazas was compared with that observed in other 13 fir forests sampled across the Aragón Pyrenees and not affected by E. subsequana. During the 1996-98 period, the radial growth in Diazas was 12-22 % with respect to the mean growth in the rest of stands. The decrease of radial growth during these three years was the cause of the high frequency of missing rings. These were rarely found in others fir forests. This fact suggested that some local factor have caused the growth reduction. The lower radial growth was produced by the intense defoliations done by E. subsequana. The most pronounced reduction of growth was observed in 1997, one year after the maximum level of defoliation was reached (1996). This temporal lag may be due to the fact that the defoliation observed in 1996 reduced the reserves and growth potential to form the tree-ring in the next year. In fact, the radial growth did not increase notably until 3 years (1999) after the first intense growth reduction (1996) was observed
Structural timber of Pinus sylvestris L.: mechanical characterization
Authors: Hermoso E. , Fernández-Golfín J. I. , Díez M. R.
Published: May 2024

The results of the mechanical characterization of structural timber of Pinus sylvestris L. considering the last standard modifications are given. The former dates are adapted and new samples of different provenances and plank sizes are included. Grading of wood planks are obtained according to UNE 56.544 visual Spanish grading standard and then they are tested to rupture according to the standardized methodology of EN 408, hence the characteristic values of mechanical properties are calculated according to EN 384 standard. Conclusions about assignment of visual grades, efficiency of the variables and parameters used currently to determine the strength quality and a comparison with results of similar Spanish pine studies and Pinus sylvestris European provenances are provided.
Growth models and yield tables for Pinus radiata D. Don in Galicia (northwest of Spain)
Authors: Sánchez F. , Rodríguez R. , Rojo A. , Álvarez J. G. , López C. , Gorgoso J. , Castedo F.
Published: May 2024

In this paper, growth models and yield tables for Pinus radiata D. in Galicia (northwest of Spain) are shown. These models were obtained from the measurement of 175 permanent sample plots, stem analyses of dominant trees and index trees. Polymorphic site index curves and three different types of yield tables corresponding to other three possible stand density evolutions are obtained. Optimal biomass rotations range from 28 to 44 years, and mean annual increment varies from 8.1 to 19.8 m3 ha–1year–1 at 30 years, depending on site index. Wood productions to different standard diameters are estimated, and alternative silvicultural regimes are discussed.
Review. Reproductive ecology of riparian elms
Authors: López-Almansa J. C.
Published: May 2024

This paper review our current knowledge of the reproductive ecology in the genus Ulmus, for which few investigations has been conducted and relatively little information is available. In the genus Ulmus, as in other riparian or sub-riparian genera, trees reproduce either vegetatively (by sprouting) or sexually. These mechanisms work differently. Sprouting permits colonization of open areas close to the trees, being especially frequent from large trees following death of their stem. Sprouting from the surviving roots of trees affected with Dutch Elm Disease is abundant in Spanish Ulmus minor. Sexual reproduction is infrequent, and requires some special conditions to be successful. It probably occurs coincidently with massive river floods that remove riparian vegetation and deposit a fertile muddy bed suitable for seed germination. Many Ulmus minor genotypes do not produce seed owing to seed abortion and other mechanisms. As a result, two gender-classes, male and cosexual, are presumably present in Spain, although this requires confirmation. A hypothesis trying to explain female sterility as the result of a trade-off between sexual and vegetative reproduction has been recently proposed, but it requires to be confirmed. Further research is also necessary for a better knowledge of flooding effect on elm regeneration and for evaluating other aspects of its reproductive ecology.
Ecology of elms in Romania
Authors: Borlea G. F.
Published: May 2024

The resistance of indigenous elm species to Dutch Elm Disease (DED) has been studied since 1991 with emphasis on natural forests. The situation varies with altitude, local conditions, species and with stand origin. The variability in morphological characteristics is important and some varieties are described. The taxonomy of elms in Romania, as in the whole of Europe, seems to be confusing (Ulmus ambigua was described in 1952 by Beldie in Flora of Romania). Natural hybrids between field elm and mountain elm were observed both in natural and artificial stands, especially in border zones for the altitudinal distribution of the species. Seedlings from the natural provenances and open pollinated seedlings from hybrids produced in the Dutch breeding programme were artificially inoculated with Ophiostoma ulmi- Buism.. Most of the seedlings died, but results show an important number of surviving individuals from natural provenances. In some natural and artificial stands, it was observed that beside transmission of the disease by insects (Scolytus spp.), it was spread through root sprouts especially in field elms, from the dead «mother tree» within a few years, as well as by root grafts to proximal healthy trees («biogroups»). Because of the genetic incompatibility of individuals in some cases, the grafting cannot succeed and neither can infection. In the natural forest where the ecosystem is in equilibrium and functions normally, DED is present but its damages are not so important. The study of elms in natural forests provides valuable information for the problems caused by DED.
Elm bark components and their potential influence on bark beetle feeding
Authors: Martín D. , García-Vallejo M. C. , Pajares J. A. , López D. , Diez J. J.
Published: May 2024

In order to better understand the chemical factors involved in the host feeding selectivity by Scolytus, components were extracted from elm bark and studied. Sampled trees were located in an elm stand that survived the Dutch twig elm disease pandemia, and from elm clones from throughout the Iberian Peninsula. The main samples studied were from Ulmus minor, and the other samples from U. pumila, U. laevis and several hybrids. The main compounds in the extracts obtained from current-year twigs were aliphatic hydrocarbons (particularly heptacosane and nonacosane) and from 2- to 4-year-old stems were triterpenes. Three of the triterpenes were identified for the first time in Ulmus (lupenol, alnulin, and ilexol) and two in Ulmaceae (moretenol and betulin). Differences occurred in the compounds isolated from U. minor from the two locations, and between species.
Optimization of elm regeneration in vitro using leaf explants and evaluation of the process in transformation experiments
Authors: Dorion N. , Ben Jouira H. , Jouanin L.
Published: May 2024

We set up a regeneration process for the elm hybrid ‘Sapporo’ resistant to Dutch Elm Disease, using leaf discs from in vitro grown plants and tested it in transformation experiments. Two steps were needed : bud induction (3 weeks) followed by bud elongation (4 weeks). Bud meristems initiated near the cut ribs, from several tissues (phloem, procambium, rib upper parenchyma) except epidermis. Regeneration depended on the use of agarose (6 g/l LSM) and diluted MS medium (1/2). The best results (11-14 buds/explant) were obtained in presence of 0.1 μM TDZ and 0.06 μM IAA and when maltose (55-110 mM) or sorbitol (110 mM) were used as carbohydrate sources. During shoot elongation TDZ should be decreased to 0.01 μM or replaced by 1-2 μM BAP and 1.4 μM of GA3 added. At this stage, a mixture of 55 mM sorbitol and 27.5 mM maltose was required. Up to 7 shoots / explant developed and were easily rooted (96%) and acclimatized when sorbitol (27.5 mM) and active charcoal (2 g/l) were added to the rooting medium. Transformation experiments were performed with Agrobacterium tumefaciens disarmed strain GV3101-pMP90 (pKyGUSintron). Regeneration zones exhibited stable GUS expression. However, all shoots grown in vitro died on a selective rooting medium (50 mg/l kanamycin). When attempts for in vitro selection were made (12.5 mg/l kanamycin), some buds were initiated but elongation was prevented. Susceptibility to neomycin seemed very high, therefore, selection markers and selection steps must be revised carefully.
The influence of the mycorrhization with black truffle in growth, gas exchange and mineral nutrition of Pinus halepensis
Authors: Domínguez Núñez J. A. , Planelles R. , Rodríguez Barreal J. A. , Saiz de Omeñaca J. A.
Published: May 2024

Influence of Tuber melanosporum Vitt mycorrhization in plant quality of Pinus halepensis Mill. was assessed from June to November during first nursery year. Seedlings were regularly watered. Mycorrhization causes increment in height, diameter, root and aerial weights, and number of root shoots induced. Mycorrhized plants showed both higher phosphorous and lower calcium concentration levels. Under water availability, influence of mycorrhization on water potential of the plant is not well defined, although both photosynthetic and transpiration rates occasionally increased.
Establishment and growth of Nothofagus regeneration after selective cutting of a stand in Patagonia, Argentina
Authors: Dezzotti A. , Sbrancia R. , Roat D. , Rodríguez-Arias M. , Parisi A.
Published: May 2024

In 1994, a group selection silvicultural system on a natural forest dominated by Nothofagus dombeyi, N. obliqua, and N. nervosa (Nothofagaceae) was implemented. Age and growth of seedlings (stem height LT < 30 cm, n = 720 plants) and saplings (LT ≥ 30 cm, n = 480) randomly collected in the center and northern periphery of gaps were analysed eight years after treatment. The three species became established simultaneously within the gaps. However, the lower light demanding N. nervosa exhibited a mean age slightly larger given the presence of «advanced regeneration» established previously to cutting implementation. Although immature phases located in the centre of gaps showed an equivalent age than those in the northern periphery, they exhibited a growth rate between 7 and 29% faster probably caused by a greater amount of photosynthetically active radiation. N. dombeyi grew at rates between 13 and 30% slower than the other two species, probably due to the smaller nutrient content of its seeds which would consequently produced less competitive seedlings. Saplings belonged to the same age cohort than seedlings though they grew at rates between 2.6 and 4.8 times faster. The early development of size hierarchy within juvenile trees would be related with the particular morphology and physiology of seeds and plants, and microsite condition.
CO2 fixation by Pinus sylvestris L. and Quercus pyrenaicaWilld. in «Pinar de Valsaín» and «Matas de Valsaín» stands
Authors: Montero G. , Muñoz M. , Donés J. , Rojo A.
Published: May 2024

Biomass and carbon dioxide accumulated amounts have been estimated in two Pinus sylvestris and Quercus pyrenaica forests («Matas de Valsaín» and «Pinar de Valsaín», Segovia). Data obtained in samplings made by CIFOR-INIA for both species have been utilized in this study. For each species, three trees per diameter class were selected, being then felled and separated into their biomass fractions (stems, branches with diameter over 7 cm, branches with diameter between 2 and 7 cm and branches thinner than 2 cm). Every tree fraction was weighed at field. The stump of one tree per diameter class was also extracted and weighed. Dry weights were determined at the laboratory through a sample of each fraction, and linear regression models to relate dry biomass with diameter for each biomass fraction were fitted. Using these models, a biomass table was constructed to be applied to inventory data (number of trees per diameter class) for determining total biomass within the stands. The CO2 fixed per biomass unit was calculated through the ratio biomass/carbon. Balances of net CO2 fixation have been determined knowing the annual increment and annual extractions.
Characterisation of the xylem of 352 conifers
Authors: García Esteban L. , De Palacios de Palacios P. , Guindeo Casasús A. , García Fernández F.
Published: May 2024

Following the traditional methods of preparation and description of wood at microscopy level, 352 descriptions of the woods of conifers were made. For the characterisation of each wood a multiple entry key was prepared, with a total of 81 features divided into four groups: tracheids with 29 features, axial parenchyma with 8, wood rays with 37 and resin canals with 7.