bluuebunny/crossref_metadata_2025 huggingface dataset:
Results of a reforestation experience using tree species of canarian laurel forest
Authors: Gonzalez Artiles F. J. , Cabrera Perez M. A. , Gonzalez Martin M.
Published: May 2024

It is shown a study about the evolution of a laurel forest restoration done in Finca de Osorio (Teror, Gran Canaria, Canary Islands, Spain). The evolution of heights, basal diameters and their correlation have been studied in three plots under different microclimatic and soil conditions. The aim of this study is to compare the development of different tree species of laurel forest in reforestation works.
Faustmann model aplicability to forest protection
Authors: Mendoza M. A. , Cespedes S. E.
Published: May 2024

Managerial theory; basic support for forest management economy, is also applicable to the rational allocation of scarce inputs in forest protection programs. Forest protection economy is more complex because there is no marketable products, provided forest protection aims to avoid catastrophic events and to reduce damages caused by pests, diseases and other destructive agents. To quantify avoided damages is an elusive goal, but necessary in order to justify protection budgets. We propose the use of economic concepts of actuarial theory on insurance against disaster from the point of view of economic rationality. Using this idea, we try to demonstrate that forest protection decisions can be made from the concept of integrated management of forest resources.
Notes on the role of potassium in soil erosion in mountain pastures: Basis for a hypothesis
Authors: Menghi M. , Pineda F. D.
Published: May 2024

Soil erosion in mountain pastures has often been described in terms of rising or falling geomorphological gradients of erosion along slope. In some locations, however, small sectors of eroded soil coexist in any geomorphological zone alongside intact sectors. This has inspired some authors to explain the underlying factors in other forms of erosion, including those which are manifested in mosaics of rhexistasis-biostasis, lobules of solifluction, small tiers, etc. Geomorphological anomalies such as those related to cracks and vertical movements in small rocky blocks, melting snow or animal activity, have helped to describe the coexistence of these sectors. This paper considers that the variation of potassium in soil can permit an explanation of the frequent intact-eroded soil mosaics in siliceous substrata highlighted by herbaceous vegetation.
Conversion of forest plantations of non native species into sustainable forest systems in Argentina
Authors: Cozzo D.
Published: May 2024

Important naturalization processes are taking place in forest plantations of non-native pine species established for wood production 15 years ago in Argentina. In this paper a review is carried out on the bio-silvicultural featues of these conventional forest plantations, as well as the consequent naturalized forest systems. These ones are described from the dasonomic point of view, including level of apearance and development, censures of growing stock, and successive steps of competition. After analysing the dimension and perssitence of the biogenic diversification of their components, and their association with the other secondary vegetation step, the author considers that these plant systems, derived from autoreforestation, are becoming a new model for conventional silviculture of forest plantations.
Economic profitability and financial rotations of poplar plantations in Spain
Authors: Diaz Balteiro L. , Romero C.
Published: May 2024

In this paper the financial rotations and profitabilities of the underlying investments in Spanish poplar plantations are dealed. With that purpose are studied the following clons: Campeador, I-214 and I-MC. It is also studied the effects on financial rotations and profitabilities of the economic acids contemplated by the Royal Decree 378/93 which attempts to encourage forest investments in agriculture farms.
Experimental analysis of drying of sawdust in a spouted bed
Authors: Moreno R. M. , Paredes M. A. , Astudillo J. A.
Published: May 2024

Forest activity in Chile has brought about an important amount of waste from the explotation and elaboration of wood, such as sawdust, chips, and barked splinters. This work aims at showing the results obtained through an analysis of drying of sawdust in a spouted bed. An experimental laboratory equipment was designed and built to analyse hydrodynamics, and heat and mass transfer process. The equipment was tested with sawdust of 2.78 x 10-3m particle average size and moisture between 117 and 147 p. 100, dry base and the operating parameters of the unit were obtained: height of the bed, air velocity, pressure drop of the bed, and time of drying. In addition, level of production, energy consumption, and heat performance of the process were determined.
Influence of gibberellic acid and potassium nitrate on seed germination of Nothofagus betuloides (Mirb.) Oerst.
Authors: Martinez Pastur C. , Arena M. E. , Fernandez C.
Published: May 2024

N. betuloides (Fagaceae) is an economically important tree species from Fuegian forest (Argentina). The present work was carried out aiming to study the effects of gibberellic acid and potassium nitrate on the release of dormacy, and the presence of differences in germination of 2-winged and 3-winged. 3-winged seeds are significantly bigger than 2-winged but this factor did not affect neither rate germination nor germinative energy. Immersion time and gibberellic acid concentration affect significantly the rate of germination and germinative energy. The potassium nitrate did not produce the same response. Unlike other Nothofagus species, it is easy to release N. betuloides seeds from dormancy.
Bioelectric methods to detect tree damage caused by fire. II. Eucalyptus globulus
Authors: Bara S. , Vega J. A. , Rozados Mª. J.
Published: May 2024

Tree stem electric conductivity, biocurrents and square waves voltage attenuation and change of shape were periodically measured for eighteen months to detect changes originated by an experimental moderately intense fire (480 Kw · m-1) on E. globulus trees. Lethal temperatures at the inner bark of the most part of trees were recorded for several minutes during the fire. Two months after fire epicormic shoots, on more than the half of trees, were observed and one year after fire, leaves decolorization in the half of them was conspicuous. There was no evidence of root damage by the heat pulse. Conductivity significantly decreased for the burnt trees when compared to the control trees along the period of study. Ten days post-fire measurements gave an useful information to estimate the recovery or deterioration trend of individual trees in the next months following the fire. Biocurrents values were sigfnicantly lower for burnt trees than for control, but with a lower signification than conductivity. Square waves transmission (one probe method) showed, in the burnt trees, output voltages significantly higher than in control ones, and also higher V50/V50k ratio. Three probe method also gave output voltages significantly higher in burnt trees than in controls. 50 Hz and 1KHz were the best frecuencies of characterize the damage, and P1 and P3 the best positions of probes.
Effects of fraying by deer on forest plants in the southern Cantabrian Mountains (NW Spain)
Authors: Costa L. , Saenz de Buruaga M.
Published: May 2024

Distinctive features of red and roe deer fraying signs found in three forest types and conifer plantations at the southern slopes of the Cantabrian Mountains are described. When compared with roe deer frayings, the measurementsof red deer frayings were much larger, the animals used thicker ligneous stems and the damaged sprouts died more frecuently, Both cervids frayed selectively on certain tree or shrub species and within characteristic thickness intervals. Data revealed a period of intensive fraying damage in july and an assessment of the spread of fatal frayings among forest type and plant species is made. Several specially attractive forest plants for fraying are idenfitied and the overall impact of damage on regeneration of forests and growth of plantations is assessed.
Variation of equilibrium moisture content of cork with relative humidity. Nonlinear regression models for sorption isotherms
Authors: Gonzalez Adrados J. R. , Calvo Haro R. M.
Published: May 2024

Water sorption by cork and its relation with relative humidity and temerpature of the air are studied in this work. Particularly, variation of cork moisture content when relative humidity grows up, for a given temperature (20ºC and 40ºC) is analyzed (sorption isotherms). Non-linear regression techniques are used to compare different models. It may be concluded that the EMPIRICAL model P1 P3 M = —— + —— + ε P2 P4 — - 1 — +1 H H is the one that better fits the experimental data. Resultant curves show the typical sigmoidal shape of hygroscopic materials. Both terms of the equation show the two forms of sorption (monolayer and multilayer) present, following the BET theory.
Survival and growth of seedlings from five Pinus pinaster Ait. provenances grown under different water regimes
Authors: Fernandez M. , Gil L. , Pardos J. A.
Published: May 2024

Survival and growth parameters were measured in five Pinus pinaster Ait. provenances (Oria, Arenas de San Pedro, Oña, San Leonardo and Landas). Plantas were grown in nursery under cover in two different growing media, during one growing season and they were submitted to three water supply regimes, R1, R2, R3, set to field capacity every 1, 2 and 3 weeks respectively. General results show significative differences for water supply regimes, as well as for provenances and growing medium. With low water supply (R3) the growing medium with higher water storage capacity allows higher survival (80 p. 100) than the other (20 p. 100). The lowest survival is correlated to water potential less than -2.6 MPa. Landes and Arenas provenances show the highest height growth, Oria the lowest one. A common pattern to stop growth at the end of summer may be atributed to photoperiod reduction since temperature still allows growth. Significant differences throughout the growing season are found for seedling dry weight, mainly shoot weight, for provenances and for water supply regimes, as well as for their interaction; but water disponibility changes the ranking of provenances. Relative growth rate (RGR) is higher for R1. The water stress (R2, R3) has on RGR different effect among provenances and the ranking for them is not the same as for total dry weight at the end of growing period. Net assimilation rate (NAR) and RGR are positively correlated except for the end of summer. Low values for specific leaf area (SLA) and for leaf area ratio (LAR) point out a strategy to avoid lost of water. Their decrease in autumn is higher for R1 than for R2 and R3; it is expressed in higher dry weight and subsequent higher dry weight and subsequent higher reserves storage, since the growth height does not progress any more. It is concluded that under favourable water disponibility growth parameters in the first growing season, may be used as estimative criteria to predict future performance of provenances in the field.
Influence of irrigation on leave's size, growth in height and diameter of Prosopis alba, P. flexuosa y P. alpataco (Mimosaceae) growing in a greenhouse
Authors: Vilela A. E. , Brizuela M. M. , Palacios R. A.
Published: May 2024

A total of 250 individuals belonging to three species of Prosopis (P. flexuosa, P. alba, and P. alpataco) were cultivated in a greenhouse. Two treatments were used: irrigation 1: 300 mm per year; Irrigation 2: 1,200 mm per year. After one year, three variables were statistically analized: pinna's lenght, growth in height and growth in diameter. The results show thath height, diameter and pinna's length are modified in all species and provenances studied in responce to irrigation. Individuals under irrigation 2 duplicate in diameter and height those under irrigation 1. The thickest stems were observed in Prosopis alba.
Macroscopic characteristics in stems of Castanea creanata x C. sativa
Authors: Baonza M. V. , Gutierrez Oliva A.
Published: May 2024

Thirty trees of Castanea crenata x C. sativa from three stands located in Galicia were selected. Both stand and height effect on follows characteristics were studied: thickness and percentage of bark; thickness, rings number and percentage of sapwood; growth rate, green moistue content and wood basic density. Except wood basic density and bark percentage, all the variables studied show significant differences among stands. Height in the stem have no significant effect on growth rate, both thickness and rings number of sapwood, and both percentage and moisture content of bark. At 1.5 m height, average diameter and growth rate show a significant positive correlation coefficient with both bark and sapwood thickness, and they are inversely correlated with bark percentage. No relationship has been found between wood density and growth rate.
Subterranean biomass of Quercus coccifera L. shrublands in eastern Spain
Authors: Cañellas I. , San Miguel A.
Published: May 2024

Subterranean biomass of kermes oak (Quercus coccifera L.) shrublands has been studied by controlled excavation of 24 m2 of eight experimental areas located in Valencia, eastern Spain. The age of the aboveground component of the ecosystem was estimated using the date of the last fire. Total belowground biomass ranged from 34 to 81 t/ha D.M. (average 53 t/ha). Most subterranean biomass was located in the uppermost 15 - 30 cm of the soil. Ths distribution area of belowground biomass always exceeded that of the aboveground biomass. The average dry weight root/shoot (R/S) ratio ranged from 2.61 to 4.73 (average 3.5). These figures are higher than those of other Mediterranean ecosystems.
Study of the utility of the spectral information Landsat TM for the inventory of beech forests in North Spain
Authors: Cuevas J. M. , Gonzalez-Alonso F. , Herron M.
Published: May 2024

The spectral information of a Landsat TM image has been used to stratify through not supervised clustering the ground inventoried area of the forests of the Council of Oroquieta-Erviti, in the west part of the beech forests in the Autonomous Community of Navarra (Spain). The obtained strata are significantly different for the dasometric values of the ground pltos in them included. The results show that Landsat TM information is a tool of great interest for the forest inventory stratification.
Influence of climatic factors in productivity of three been of the genus Boletus associated with hybrid of Castanea
Authors: Rodriguez Fernandez A. , Fernandez de Ana Magan F. J.
Published: May 2024

Phenologic response of three species of ectomycorrhizal fungi (Boletus fragans, Boletus edulis and Boletus erythropus) asociated with hybrid chestnut were analized. To this objective, we use the data of ten years (1984-1993) and the principal component analysis was applied to delimit the climatic variables that have influence on these species yield. We obtained an equations that could permit to predit the number of fruitbody produced depending on climatic conditions
Fitting volume and taper functions to four pine species planted in Northeastern Mexico
Authors: Navar J. de J. , Dominguez P. A.
Published: May 2024

The objective of this study was to observe the goodness of fit of eight volume models and four taper functions to four pine species (Pinus brutia Ten., Pinus eldarica Medw., Pinus halepensis Mill., and Pinus estevezii Mart.) planted in northeastern Mexico. Trees were measured in diameter at several sections of the stem. The 90 p. 100 of the total available information (145, 39, 227 and 48 trees for volume and 2,350, 1,280, 4,407 and 1,320 for taper) were used to fit four taper functions (Clutter, Amidón, Kozak, Newnham) and eight volume equations by least square techniques in linear and non-linear regression analysis. To test the goodness of fit, volume and taper functions were fitted to 10 p. 100 of the remaining information with estimators of the coefficient of determination, standard error, and total volume. The results showed that different models described best total volume for different species. However, the Schumacher and Hall equation consistently had the best goodness of fit. The variable-form taper resulted in more precise volume estimates for the test trees. The taper functions, in general, described best total trees volume of test trees than the volume equations. Therefore, the variable-form taper function of Newnham is recommended for describing the stem profile and total volume of plant species in northeastern Mexico.
Potential productivity evaluation of fully hidrostatic transmission light forwarders
Authors: Prades C. , Rubio J. J.
Published: May 2024

This article establishes and validates a model that allows, with a certain degree of rebility, the potential productivity of fully hidrostatic transmission light forwarders in short wood logging system. This proposal deals with part of the analysis of a high technology, fully mechanized, 1+1, short wood logging system, subject of the Doctoral Thesis "Bases for the utilization of a High Technology Mechanized Logging System" acomplished by Cristina Prades and directed by José Rubio. This model may help as starting point of later studies that provide new data and improve the prediction degree.
Effect of climatic conditions on the physico-mechanical properties of MDF boards
Authors: Fernandez-Golfin J. I. , Diez M. R.
Published: May 2024

Four types of surface coating, on commercial MDF 19 mm thick panels, are used to study the behaviour of MDF panels under four different conditions of relative humidity. The behaviour of the panels is studied by means of the comparison between the initial and final (after conditioning) values of the Modulus of Rupture (MOR), Modulus of Elasticity (MOE), Internal Bonding (RTP), Equilibrium Moisture Content (HEH) and density. In some cases the evolution of some properties is monitorized during the conditioning treatment. Four different environmental conditions are considered, three of them constant (20º C/65 p. 100 rh, 20º C/90 p. 100 rh, 20º C/35 p. 100 rh) and one variable (20º C/35-90 p. 100 rh). Boards under a constant environment of 20ºC/90%rh used to exhibit a clear worse behaviour than under variable climate of 20º C/ 35-90 p. 100 rh. This general behaviour is just the opposite than the one exhibited by particleboards in a previous work.
Preliminary yield models for evenaged stands of Pinus nigra Arn. in the catalan pyrenees
Authors: Gonzalez Molina J. Mª. , Meya D. , Arrufat D.
Published: May 2024

Three detailed management models are developed for even-aged black pine (Pinus nigra Arn.) stands of the Pyrenees. These models consist of a descriptive part, named Final Stand Type, from the first thinning to the regeneration concepts. Several goals to be reached in terms of final medium diameters and rotations are defined for each site index class. This part is complemented by Management Tables that represent quantitatively the stand evolution according to the proposed treatment regimen.Starting by a selective thinning combined with low thinning, weights and rotations of interventions are spread out at intervals depending on the growth dynamics of the species in the different site index classes. Finally, comparative economic valuation is carried out between the proposed models and the management as uneven-aged forest, which is the traditional management method of these stands in the Pyrenees.
Forest management models based on linear programming. An application to Navafría forest (Segovia, Spain)
Authors: Diaz Balteiro L. , Prieto Rodriguez A.
Published: May 2024

This paper illustrates how analytical methods like linear programming can be fruitfully applied to forest management problems. This kind of approach is rather ignored in Spain. In fact, since last century Spanish forests have been managed with the help of German methods, which are not supported by any optimisation model. A linear programming model is built and applied to the Spanish forest Navafría. This forest has been chosen for our exercise because it has been deeply studied with the help of classic methods, so that different methodologies can be compared. Four objectives functions have been defined. Two are typically linked to silvicultural goals: maximise the total timber volume and veneer volume, and the other two show economic targets: maximise the net present value and maximise a similar cash flow in each period. Several constraints have been introduced. In all cases except one a feasible solution was found. Besides, a sensitivity analysis have been incorporated in order to check the influence of variations of the discount rate and expected wood price. The management alternatives proposed in this paper show harvest flows longer than the harvest flow indicated in the management project. In short, the results generated in our application by classic (German) methods can be considered a particular case of the results provided by the optimisation models based upon linear programming.
Census methods and big-game optimization in Sierra Morena (Córdoba, Spain)
Authors: Lenzano R. , Zamora R.
Published: May 2024

Some census methods (transects, direct counts and hunting results) are compared and applied in a private owned hunting land in Sierra Morena, in order to estimate deer (Cervus elaphus) population, avoiding to exceed carrying game capacity. These methods can be easily implemented and make good estimates of deer populations. Some cases are also analyzed with respect to fence the estate or keep it as an open land, seeking to maximize the profit margin for the owner. Cost of finishing present enclosure is considered as initial investment. The best option found was to hunt once each three-year period, after an initial four years period of population adjustment. In this case, the net income varied between 4435-5317 pta/ha, with a investment return period of 7-10 years, depending on variations of current costs.
Production of Sulfate Pulps from Cardoon (Cynara cardunculus L.). The effect of Chipping of Pulp Quality
Authors: Villar J. C. , Poveda P. , Tagle J. L.
Published: May 2024

In the utilization of cardoon (Cynara cardunculus L.) to produce sulfate pulps the cooking conditions and the chip size are the factors that determine the final pulp quality. The aim of this work is to stablish the range of cooking variables that produce good delignified pulps and to study the effect of chip size on the pulp quality. The results have shown that cooking time not inferior than 90 min (30 up to 170° C plus 60 at 170° C) and 16 % active alkali) are neccesary to obtain good delignified pulps. Chipping into a small size (1.7 cm) greatly improves delignification with no negative effect on paper quality. Cardoon sulfate pulps refine easily and showed good mechanical properties, although they present drainage difficulties and an extremely low porosity. So, it is neccesary to go into a procedure to dephithing that avoid the problems caused by the high fines content.
Development of a dynamic growth model of even-aged Pinus pinaster Ait. Stands in Galicia
Authors: Alvarez Gonzalez J. G. , Rodriguez Soalleiro R. , Vega Alonso G.
Published: May 2024

A growth model obtained from a dynamic methodology based on the prediction of the annual basal area increment is presented. The sample data come from permanent and temporary plots installed in even-aged stands of Pinus pinaster Ait. in Galicia (Northwestern Spain). A basal area removed-total basal area ratio is used to define the type of thinning and this ratio allows to obtain the instantaneous change of the stand due to the treatment. The adventages of this type of models and their practical use in the forest management is discussed.
Information on the presence of cork oak (Quercus suber L.) in the province of Guadalajara (Central Spain)
Authors: Serrada Hierro R. , García Viñas J. I.
Published: May 2024

The paper gathers information on the so believed only natural presence of cork oak (Quercus suber L.) in the province of Guadalajara (Central Spain). It is the extremes eastern location of that species in the southern face of the Central Range of Mountains. The most important botanical, ecological and dasometrical aspects of the stand are described. An ecological homologation of the stand, based on Allué Andrade’s work, has also been carried out.
Comparative analysis of the First and Second National forest inventories of Ávila province
Authors: Yagüe Bosch S.
Published: May 2024

The author compares the figures of First and Second National Forest Inventories (IFN-1 and IFN-2 respectively) for the province of Ávila (Spain), in order to study the evolution, for the last 27 years, of wooded areas, number of major trees, growing stock for timber industry outside bark, and number of minor trees. Main differences between definitions of different categories of surfaces contained in both inventories are highlighted. Lastly, those differences are analysed and the author briefly draws the most important conclusions in relation to the evolution of agriculture, the silviculture carried out and the forest fires occurred.
Comparison between sampling methods
Authors: Ríos N. , Acosta V. , Gaillard de Benítez C. , Pece M.
Published: May 2024

This research was carried out in a giant Chinaberry tree (Melia azedarach var. gigantea) plantation located in the Province of Santiago del Estero, Argentina. At seven years of age, the plantation had reached the stage of high forest, with an original spacing of 4 m X 4 m. Fixed area plots are already installed for a study on growth and yield. Measurements were conducted on these plots by using two sampling methods of probability proportional to size (PPS), i.e., horizontal point sampling and horizontal line sampling, with variable size plots. Basal area factors K=1 and K=2 of the Bitterlich relascope were used in order to select the trees which made up the sample. Basal area, volume, and number of trees per hectare were estimated for each method. The resulting data were assorted by diameter class and subjected to analysis of variance in a random block design, where diameter classes were considered as blocks, basal area factors, as treatments, and fixed area plot sampling methods as controls. The relative efficiency of each method was also calculated. No significant difference among treatments was found at the one percent probability level. The horizontal point and the horizontal line sampling estimates are as accurate as those obtained with the control, whereas the relative efficiency of the PPS methods was greater than that of the control.
Evaluation of taper equations models for Pseudotsuga menziesii in the Argentina Patagonian Andes
Authors: Davel M. , Trincado G.
Published: May 2024

Different taper equations for Pseudotsuga menziesii (Mirb.) Franco plantations were evaluated in the Argentina Patagonian Andes. Functions fitted by Bruce et al. (1968), Real and Moore (1986), Kozak (1988) and Pérez et al. (1990) were tested. Data were collected from 268 trees scattered throughout 68 stands. The models were compared based on their bias and error when predicting volume, diameter and height. The validation was performed on a separate set of data. The best models were those developed by Kozak (1988) and Bruce et al. (1968).
Anatomical features determing wood variability in Schinopsis quebracho-colorado (Schlecht) Barkl. et Meyer, Anacardiaceae
Authors: Giménez A. Mª. , López C. R.
Published: May 2024

The objective of this paper is to characterize wood features and radial variation in Schinopsis quebracho-colorado and to determine the influence of age in wood structure. Ten trees with DBH(diameter at breast height) greather than 30 cm, from the natural forest of Los Pirpintos, Copo Department, Santiago del Estero, Argentina, were studied. The methodology adopted for xylem study is that of Helinska; and the terminology of IAWA. Wood variability was explained by vessel diameter, vessel number and area, and percentage of isolated vessels. Results showed highly significant differences among age classes (treatments) for the variables thickness rings, vessel number, vessel diameter and vessel area. The rest of the variables did not evidence differences among treatments. There were no significant differences among individuals. The results showed that distance to the pith (age) was the most important source of variation for the traits studied, being the conductive elements the most relevant to wood variability.
Autoecology of chestnut (Castanea sativa Miller) in Galicia (Spain)
Authors: Blanco A. , Rubio A. , Sánchez O. , Elena R. , Gómez V. , Graña D.
Published: May 2024

A stratified sampling on 22 plots has been carried out on chestnut (Castanea sativa Miller) stands in Galicia (Spain). Central and marginal parameters ranges have been stablished for defining physiographic, climatic and soil habitat diagrams of chetnut stands. Most stands are located between 400 and 750 m elevation, with around 1,300 mm annual rainfall. According to FAO criteria, soil are classified as distric Cambisols and distric Luvisols. Several silvicultural parameters have also been calculated. After their correlation with the ecological ones, it is concluded that the best Galician chestnut forest sites are located on northern aspects, with low summer drought and around 13 C/N ratio in soils. Finally, a comparative analysis between chestnut habitat and habitat of three other tree species of the region shows that chesnut has less ecological aptitude than pedunculate oak, Maritime pine and Monterrey pine.
A note on genetic diversity in natural populations and cultivated stands of Scots pine (Pinus sylvestris L.)
Authors: Koski V.
Published: May 2024

Aspects of genetic diversity in Scots pine are reviewed with particular emphasis upon the interactions with silvicultural practices such as the use of natural or artificial regeneration. There is little evidence that greater use of artificial regeneration will result in decreased genetic diversity at the stand level. This result appears to hold whether the planted seedlings are derived from wild stands, from seed stands or from seed orchards. However, in the last instance, the orchard should contain at least 40 clones to provide the heterozygosity expected of natural populations. There is limited knowledge of genetic diversity in adaptive traits such as cold hardiness or drought tolerance. Despite nearly a century of research into the genetics of Scots pine, there is still inadequate knowledge of the desirable level of genetic diversity in forests of this species and the interactions with management practices. However, current European regulations on Forest Reproductive Materials pay due attention to issues such as genetic conservation and matching of seed sources to regions. Therefore, it seems unlikely that current silvicultural practices will limit genetic diversity in Scots pine.
Silviculture and management of Scots pine in Sweden
Authors: Egnell G.
Published: May 2024

This paper gives some information about silvicultural trends in Sweden with the main focus on management of Scots pine stands and measures proposed to enhance biodiversity. During the last decades there has been a shift away from volume production orientated forestry towards forestry focusing on both production and environment with a special emphasis on biodiversity. Our current Forestry Act has two equal goals, (i) forest production and (ii) environment with sustained biodiversity. The major Swedish forest companies and other forest owners are signing agreements in order to meet certification requirements and show that their forest management considers the sustainability of the whole forest ecosystem and the environment of surrounding ecosystems. Even though Scots pine will still mainly be managed on a clear-cutting system, these developments will change Swedish Scots pine forests from even aged, uniform monocultures towards more mixed species and multi-storied stands. Prescribed burning will be practised on Scots pine sites as a site preparation measure that also enhances biodiversity. In this way silviculture will mimic the major natural disturbance agent in boreal Sweden – forest fire. Measures to enhance biodiversity are based on the best available knowledge, but the effect of these measures on biodiversity and forest production is largely unknown. Another uncertainty is how these new stands should be managed in an efficient way.
Scots pine in Belgium and the Netherlands
Authors: Lust N. , Geudens G. , Olsthoorn A. F.M.
Published: May 2024

Scots pine is the most important tree species in the Netherlands (39 % of the forest area), and one of the three main conifer species in Belgium (10 % of the forest area). The management goals for Scots pine have changed very much during the twentieth century: from the production of mining timber until the 1970’s, to multifunctional forest management at the end of the century. The natural forest types with Scots pine in the Netherlands are discussed. In Belgium, Scots pine is not considered to be indigenous. The forest succession with Scots pine is described, mostly from degraded heathland or windblown sand to forest ecosystems. Usually, Scots pine plays an important role in the beginning of this succession, but decreases when broad-leaved tree species become dominant in the forest canopy in later successional stages. The silviculture has changed very much, both through forest succession and change in management goals. The early, planted monocultures are replaced with more diverse forest structures often using natural regeneration. Clearcutting is performed less and less; with many interventions taking place on a small scale. Stand age is increasing, and the canopy becomes progressively more open through ongoing thinnings until the complete canopy is removed. The site quality is also changing, mainly through acidification and nitrogen inputs from air pollution. While the area of Scots pine is gradually decreasing, the originally low biodiversity in the young stands is now increasing in the remaining areas with Scots pine.
Social Broadleaves. EUFORGEN genetic conservation network
Authors: Kremer A.
Published: May 2024

The «Social Broadleaves» EUFORGEN network include temperate oaks and beeches, as broadleaved species living in large population in pure or mixed forest. Most important economic Social Broadleaves have a wide distribution (Q. petraea, Q. robur and F. sylvatica). They occupy also a large ecological range, giving many opportunities for natural selection to differentiate populations. Species delineation is imprecise in oaks, and various names and classification are proposed in different countries. The main objective of the network is the development of «joint, long-term, practically oriented gene conservation strategies». Most urgent needs were expressed by each member mainly in the area of in situ conservation methods. Other objectives are to «stimulate collaborative initiatives related to conservation activities». These initiatives concern dissemination of information and research results, and the raising of awareness on conservation issues. A review of the current knowledge on genetic structure and dynamics is summarised in order to define the Genetic Resource Conservation Strategy for Social Broadleaves. There is an important morphological variation that encompasses taxonomic units. There is clearly a need to provide some common methodology for assigning oak trees to taxonomic units. Oak species belonging to the same botanical section intercross naturally. Natural hybridization can be seen as a mechanism to enrich genetic diversity. Oaks and beeches are preferentially outbreeding, with extensive gene flow by pollen. There is a common agreement that practical actions should be taken, even if knowledge on population structure is still lacking. Conservation strategies should be established not only to maintain diversity but also to safeguard the evolutionary potential of the species. In situ conservation measures are implemented in most countries for both Fagus and Quercus (mostly Q. petraea and Q. robur) based mostly on pragmatic rules. Ex situ measures are promoted in a few countries in the case of oaks. No additional measures are requested by the different members in the case of beech, since natural regeneration is widely used to renew the stands.
Oaks and beeches in Spain. Genetic resources conservation
Authors: Goikoetxea P. G. , Agundez D.
Published: May 2024

Spain is an active member in EUFORGEN Social Broadleaves Network since 1999. This network includes Beech and European white oaks. Quercus spp includes a complex of species intimately related geneticaly and ecologicaly. It therefore reveals the Iberic Peninsula, together with F. sylvatica, as an interesting emplacement with a high genetic potential sharing the species nemoral and mediterranean climate. In this paper a revision of the conservation state of the forest genetic resources of oaks and beech is presented. The problematic of these species is also studied as well as an evaluation of the works already done towards this area in order to be able to define a conservation program of the genetic resources. Actually we have available information about geographic variation of the species across the delimitation of regions of provenance and regions of identification and use. The filogenetic relationship studied through chloroplast DNA reveals 2 European lineages for Beech and various lineages from inside and outside the Iberian Peninsula for Oaks, indicating furthermore a strong relationship within it. The structure of the genetic diversity is partially known for Beech showing a clear geographic trend. There are several provenance tests for Beech, an evaluation of which is essential to learn about the behavior of our genetic material and to be able to make recommendations for the use of the species. When Oaks are considered the situation is more precarious and studies aiming the knowledge of genetic variation must be reinforced.
Evolutionary genetics and gene conservation
Authors: Eriksson G.
Published: May 2024

In this paper, the main aspects to consider from a evolutionay genetic point of view in gene conservation are summarised. Most traits of adaptive significance are quantitative which means that no distinctive classes are segregating in the progeny. These traits are regulated by many genes, most of them have a small and identical effect on the trait, and one gene may be substituted by another resulting in the same effect. Therefore, there is no need to conserve rare genes in gene conservation. Presence of additive variance for a trait is a prerequisite for change via natural selection. Evolution is change of genetic set-up of a population. Natural selection, genetic drift, and mutations cause evolution while gene flow and phenotypic plasticity are constraints to it. All of them may act simultaneously, leading to a very dynamic situation. The continued existence of rare genes (< 1 % in a population), is dependent on chance events whether the gene contributes to fitness or not. The present genetic set-up is one out of many possible and it is transient. Therefore, it should not be the target in a dynamic gene conservation. A random selection of 500 trees in a population capture almost all genetic variation of importance for natural selection. It is important to distinguish between what is useful for a population for natural regeneration (Darwinian fitness) and what is demanded for production of human utilities (domestic fitness). Gene resource populations and breeding populations need a large additive variance. Production populations only need the amount of genetic variation that is satisfactory for production of the utilities demanded.
Legislation of Forest genetic resources conservation in Spain
Authors: Iglesias Sauce S.
Published: May 2024

The history of forest conservation in Spain began with the first forest regulation dated 1575. Recently, the International Agreements endorsed by Spain, including the Agreement on Biological Diversity (Rio, 1992) and the pan-european conferences on the protection of forest (Strasbourg, 1990, Helsinki, 1993, Lisbon, 1998) are the main foundations for the protection of forest in Spain. Although no specific legislation on forest genetic resources conservation have been established in Spain, the National Forest Strategy and the Forest Plan (coordinated by the Ministry of Environment) are the main documents to base future actions related to conservation issues.
State of the art of the machine strength rating of lumber (Review)
Authors: Fernández-Golfín Seco J. I. , Díez Barra M. R. , Hermoso Prieto E.
Published: May 2024

Over the last forty years, the machine strength grading of lumber has been developed considerably all over the world, especially in the Nordic and Anglo-Saxon countries. In this paper the beginnings and development of the machine strength grading system are studied. A comparison is also made of the running principles of the machines operating in the market. The variables of the system and their influence in the grading process are also studied. An analysis is also made regarding the mathematical models used to relate classifier variables with predictive variables, measured by the machines, assessing the factors that affect the method and the best way to be taken these into account. Indications about the best way to derive machine settings, according to the standardized methodology approved by the European Committee of Standardization (CEN), are also included. Conclusions are drawn concerning the applicability, present state of the technology, accuracy, reliability and efficiency of the technology, as well as the research necessary to set this technology under way to grade new timber species and the best way to consider all the influencing factors in the grading process.
Radial variation trend in the wood of Aspidosperma quebracho blanco
Authors: Moglia J. G. , López C. R.
Published: May 2024

Radial wood variation patterns were determined for quebracho blanco (Aspidosperma quebracho-blanco L.) one of the most important species of The Chaco Region. Ten adult trees from two sites, trees per site were used. From each tree, disks were removed at breast height. Patterns of variation of pore area, fibber diameter, lumen fibber, fibber cell wall thickness, percentage of pores, fibbers, parenchyma and rays were examined using sites, trees and radial distances as sources of variation. Univariate analysis was performed using a nested design, with random effect on sites and trees and fixed on distance to the pith. Variance Components were estimated by Restricted Maximum Likelihood. The results showed that distance to the pith was the main source of variation for the traits studied. The wood anatomical features studied were not affected by site. Fibber diameter, fibber cell wall thickness and pore percentage showed an increasing pattern along the radius. The diameter lumen fibber, fibbers percentage and rays percentage showed a not definite pattern of radial change. Along the radius the tissue proportions of fibber diameter, and fibber cell wall thickness increased more rapidly up to a distance of 10,5 cm. Mature wood was not observed up to the distances studied.
Impact of red deer frying (Cervus elaphus L.) on cornicabra (Pistacia terebinthus L.) in «Quintos de Mora» (Los Yébenes, Toledo, Spain)
Authors: Moreno Gómez A. , Rodríguez Vigal C. , Ferrandis Gotor P. , De las Heras Ibáñez J.
Published: May 2024

The current status of Pistacia terebinthus and damages produced by fraying of Cervus elaphus on P. terebinthus populations of Quintos de Mora (Los Yébenes, Central Spain) are studied in this paper. Deer impact is evaluated considering several parameters (diameter, height, number of sprouts, damage level, etc.) of 1753 P. terebinthus individuals located throughout Quintos de Mora. Results showed a high damage level in all the studied zone, primarily in shadow exposures and in the «raña». Furthermore, the highest mortality rate has been found in the individuals of lower diametric class (2.5-3). In the other hand, Comparison between two situations, one considering the presence of C. elaphus and the other in absence of this species is evaluated, by means of the study of 355 individuals of P. terebinthus. A damage level increase of 8.99 % was registered. Results obtained seems to recommend several actuations in Quintos de Mora in order to protect the current P. terebinthus population. A efficient deer population control and the protection in situ of several young P. terebinthus individuals could be several management proposals to carry out in Quintos de Mora.
A new high-pressure flowmeter for the estimation of hydraulic resistance in whole shoots of woody plants
Authors: Sisó S. , Camarero J. J. , Gil-Pelegrín E.
Published: May 2024

A new high-pressure flowmeter has been developed and used to estimate hydraulic resistance in whole shoots of woody plants. It is based on the perfusion of pressurized water in the plant, and the simultaneous measurement of water flow (introduced volume of water per unit of time). This device was first calibrated, and then used to estimate the hydraulic resistance of stems and leaves in 1-yr seedlings of broadleaf Quercus species (Q. rubra, Q. cerris, Q. velutina, Q. petraea, Q. frainetto, Q. pyrenaica). The measured values are reliable and similar to those reported in the literature, but taking into account that this study dealt with seedlings. We have found significant differences between species and groups of species according to their hydraulic resistance values for stems and leaves. Those species whose seedlings showed lower leaf hydraulic resistance values can rehydrate their leaves more quickly and survive in environments with certain water stress (e.g., Q. pyrenaica). The high leaf hydraulic resistance of other species indicate that they can not resist these levels of water stress (e.g, Q. rubra). This study provided new insight to the importance of leaf hydraulic resistance as an adaptative trait to face water stress. Hydraulic resistance variability must be studied in depth as an additional mechanism within a wide array of morphological and ecophysiological adaptations that provide tree species a greater drought tolerance.
Extended cost-benefit analysis of holm oak dehesa multiple use and cereal-grass rotations
Authors: Martín D. , Campos P. , Cañellas I. , Montero G.
Published: May 2024

The historical formation of holm oak (Quercus ilex L.) dehesa woodlands has often resulted in either rapid deforestation episodes by means of clear cuts or slower depletion of oak woodlands due to tree natural mortality and the absence of tree natural regeneration. Consequently, holm oak woodlands have been progressively converted into rough pasturelands, cereal croplands and scrublands. Whilst this tendency of holm oak exhaustion was not socially questioned, scientists and conservationists defending oak woodland conservation providing long run economic and environmental arguments were regarded as romantics ignoring the necessity for social progress and development. Today, these romantics are perceived as nature conservation pioneers and many of their arguments and concepts have been included in science and politics. This paper shows that cereal cropping and permanent grassland uses are more profitable to Extremadura’s landowners than holm oak artificial plantations and monitored holm oak natural regeneration. Increasing social demand for recreational and conservation services have been taken into account by Spanish and European public authorities. Along last decade, the European Union and the Spanish government have financed oak reforestation over extensive-use croplands of West and Southwest Spain, resulting in an unprecedented net increase in holm oak woodlands. The presented extended cost-benefit analysis shows that even after incorporating estimated income derived from public and private consumption of environmental services, uses associated to treeless cropland, pastureland and scrubland are still preferred to traditional extensive multiple use associated to dehesa holm oak woodlands.