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Modelling resin production distributions for Pinus pinaster Ait. stands in NW Spain
Abstract
Pine resin, a viscous material secreted as a defensive response to biotic or abiotic damage, is a highly valuable non-wood forest product with multiple uses in the industrial sector. Resin production can be induced by tapping live trees, but not all pine species produce resin of suitable quality and/or in profitable quantities. Maritime pine (Pinus pinaster Ait.) is currently the only species tapped in Spain, where resin tapping activity has been recovered in the last few decades. Most studies on resin production focus on the mean production per tree or per area, and less attention is given to determining how the production is distributed across individuals or production classes. We modelled the distribution of resin production in Pinus pinaster stands in Galicia (NW Spain) by using the Weibull function and the moment-based parameter recovery method. We observed a high level of variance in resin production between plots (different sites, stimulants used, tapping method or year) and within plots, between trees. All resin production distributions modelled using the arithmetic mean resin production (x¯) and the variance of the distribution (σ²) per plot satisfied the Kolmogorov-Smirnov (KS) test, in which critical values were obtained by Monte Carlo simulation. The variance of the distribution (σ²) was positively correlated with x¯, and the relationship was described by an exponential model. When resin production distributions were modelled using x¯ and estimated variance (σˆ2), 7% of the distributions (corresponding to trees in which chemical stimulants were not used) did not satisfy the KS test. The mean production (x¯) can be easily determined by dividing the stand production by the number of trees. However, x¯ could also be estimated before commercial tapping by sampling a representative number of trees. We conclude that in order to estimate x¯, a minimum sample of 50–60 trees should be tapped, to yield a relative standard error (RSE) below 10%; 10–15 trees should be considered for RSE < 20% and 5–10 for RSE < 30%.
... The sample plots used to obtain the study data were established by the Centro de Investigación Forestal de Lourizán (Pontevedra, Galicia) in monospecific Pinus pinaster stands close to the final felling stage [26,27]. The plot in Caldas de Reis (province of Pontevedra), of surface area 2.9 ha, is situated at an elevation of 250 m above mean sea level (m.s.l.) in an area close to the coast. ...
... The yearly resin production in each tree was calculated by summing the production from each groove (after subtracting the weight of the pot or pots when two faces were tapped) [27]. The final weight of resin also included the resin adhered to the face, which was scraped into the pot. ...
... The study findings demonstrate that the variables of location, treatment (combination of number of faces and wound width) and production year affect resin production. The effect of location on resin production can be tested in a representative sample of trees [27] or by using microtapping techniques [55]. The potential resin production can even be evaluated in "microtapping" trials in young stands or plants grown in greenhouses [56]. ...
Resin or gum is secreted by conifers, mainly members of the genus Pinus, in response to physical and/or chemical stimulation, which can be induced by tapping live trees, i.e., by making repeated wounds in the trees. Resin production could potentially complement timber production (the main economic activity) in pine stands in Galicia (NW Spain). In addition, the particular characteristics of Galician woodlands (smallholdings, sloping land, presence of shrubs, high density of trees) imply different yields and costs than in pine stands dedicated to resin production in other parts of Spain. Therefore, a specific regional management model that is different from the traditional model established for other resin producing areas in the Iberian Peninsula is required. In this study, resin tapping was applied in each of the three years before the trees were felled, in two different locations, with one or two faces tapped and wounds of two different widths (12 and 16 cm) made across the face(s). Tapping two faces yielded more resin than tapping a single face, thus confirming the study hypothesis. When only one face was tapped, the plot location acquired greater importance, with production being higher in the location characterised by a higher mean annual temperature. Increasing the width of the wound did not always increase the amount of resin obtained per tree, which depended on the number of faces open: when two faces were tapped, increasing the width of the wound increased resin production in both locations in each of the three years of the trial. The weather conditions in each year masked the effect of the tapping season, and production did not follow any particular trend over time. The importance of the local weather conditions in the study areas and the environmental conditions in each year are discussed. The study findings are important for decision-making regarding the treatment and selection of areas for resin extraction.
... Particularly, the resin tapping sector is progressively recovering in the Iberian Peninsula, where it has been a main activity in the past, mainly on low productivity and harsh environments of the Central Plateau (Rodriguez-Garcia et al. 2016). The current resurgence is even prompting the introduction of resin tapping activities on timber-oriented and highly-productive pine forests of the Atlantic areas (Gómez-García et al. 2022;Zas et al. 2020a). Little experience on resin production is available for this type of pine forests that had no history of resin tapping in Spain. ...
... A number of patents of new formulations for resin tapping stimulation have emerged in recent years, some of which are starting to be used in commercial resin tapping in different countries. Among them, the "Cunningham" paste (based on sulfuric acid and ethephon or CEPA (2-chloroethylphosphonic acid), an ethylene-releasing agent widely used in subtropical Pinus elliotii forests), and the Asacif paste (based on sulfuric acid and salicylic acid), specifically developed for tapping southern coastal European pine forests, have shown promising results (Michavila et al. 2021) and are timidly bursting in the Iberian resin sector (Gómez-García et al. 2022). However, little is still known about whether the relative efficiency of these alternative formulations may vary depending on the pine species, the environmental conditions (Neis et al. 2018) and the moment of application within the season (but see Lukmandaru et al. 2021). ...
Pine resin is a valuable non-wood forest product with an increasing interest in multiple industrial sectors. Resin-tapping activities also provide valuable ecosystem services in timber-oriented and highly productive pine forest of Atlantic regions, where little previous experience in resin-tapping is available. The objectives of this study were to determine the efficiency of different stimulant pastes and its variation with pine species, site conditions, seasonality and frequency of tapping interventions. We conducted parallel experiments using both conventional and micro-tapping techniques in mature pine stands in NW Spain. We tested four stimulants (control and Zeta, Cunningham and Salicylic pastes) and two groove frequencies (every 2 or 3 weeks). All stimulant pastes significantly increased resin yield compared to the control, being resin stimulation highly consistent across years, sites and species. In conventional resin tapping, resin yield was maximized with the Cunningham and Salicylic pastes while in micro-tapping Salicylic was the most outstanding stimulant treatment. According to the rapid decay of resin flow after wounding, total resin yield decreased with more spaced grooves. However, the reduction was low, and the global efficiency of the tapping operations are likely maximized with grooves applied every three weeks, which would allow increasing the number of tapped trees. Micro-tapping techniques were valuable for screening stimulant pastes and anticipating variation among sites in resin production. Altogether, the Salicylic paste is recommended, especially at the beginning of the resin campaign, when the effect of the pastes was maximized, and if tapping is conducted using closed atmospheres and containers.
... Since the 1980 s, resin tapping activity has lost importance until it practically ceased at the beginning of this century (Soliño et al., 2018). But since 2000 s it has been growing in importance again within the national forestry sector and is expected to continue to grow in the coming years (Gómez-García et al., 2022). This is reflected in the increase in publications on the subject in some regions of Spain in recent years, as in the case of Galicia (García-Méijome et al., 2023;Touza et al., 2021;Zas et al., 2020a,b). ...
... The unprecedented nature of this production modelling poses a challenge to the discussion, given the lack of previous studies on resin to establish a comparative framework. Fitting models describing the trend of cumulative production during the NTFP harvest season is challenging due to the high variability in individual tree production (Gómez-García et al., 2022;López-Alvarez et al., 2023b) and the influence that environment changes have on the yield of this renewable product (Vázquez-González et al., 2021b). ...
In southern Europe, especially in Spain and Portugal, maritime pine resin is one of the main non-timber forest products. After suffering a crisis at the end of the 20th century, it is currently a growing sector. In Spain, depending on the area, the management of pine forests is one of the pillars of the national bioeconomy. In addition to timber production, these forests may be oriented towards resin production only, or resin production as a complementary activity to timber production. In both cases, as in any sector, it is essential to have tools to manage and anticipate production, especially in the new context of the bioeconomy. For this reason, the aim of this study is to develop a dynamic model to estimate the accumulated resin yield during the resin production season. For this study, 180 trees from three plots located in the northwest of the Iberian Peninsula were resin tapped using two extraction methods (non-mechanized and mechanized circular notching) and stimulant pastes. Four base models were used from which eight equations were derived using ADA and GADA techniques. The most efficient equations, both for modelling with the train data and for prediction with the test data, were those derived from the Bertalanffy-Richards model. The RRMSE was 23% for the non-mechanised method and 29% for the mechanised circular method. The results of this study make it possible to add the cumulative annual resin yield of maritime pine to the processes that the Bertalanffy-Richards equation is capable of modelling. Furthermore, the great versatility of these models will be of great use to the forest manager in optimising the annual harvesting season as well as for the scientific community.
... For each of the two extraction methods, different stimulant pastes were applied either in the inner-upper border of the horizontal grooves or in the inner contour of the circular holes. Three different treatments were considered, a control without stimulant paste and two commercial pastes that have shown promising results in previous experiments (Michavila et al. 2021;Gómez-García et al. 2022), the Ethephon (8% Ethephon(60% v/v), 14% sulfuric acid (50% v/v), 55% distilled water, 1.7% polysorbate, 1% cetyl alcohol, 4% vaseline, 5.5% silica, 10.8 sawdust) (Gómez-García et al. 2022) and the salicylic paste ASACIF (1% salicylic acid, 25% sulfuric acid (96% v/v), 5% propylene glycol, 19% wheat straw, 50% distilled water) (Michavila et al. 2021). The production per tree was weighed each time a new groove was made with a scientific scale calibrated in decigrams. ...
... For each of the two extraction methods, different stimulant pastes were applied either in the inner-upper border of the horizontal grooves or in the inner contour of the circular holes. Three different treatments were considered, a control without stimulant paste and two commercial pastes that have shown promising results in previous experiments (Michavila et al. 2021;Gómez-García et al. 2022), the Ethephon (8% Ethephon(60% v/v), 14% sulfuric acid (50% v/v), 55% distilled water, 1.7% polysorbate, 1% cetyl alcohol, 4% vaseline, 5.5% silica, 10.8 sawdust) (Gómez-García et al. 2022) and the salicylic paste ASACIF (1% salicylic acid, 25% sulfuric acid (96% v/v), 5% propylene glycol, 19% wheat straw, 50% distilled water) (Michavila et al. 2021). The production per tree was weighed each time a new groove was made with a scientific scale calibrated in decigrams. ...
Selecting the best resin tapping method and stimulant paste in the resin tapping process is crucial. In timber-oriented rainy Atlantic pine forests of north-west Spain, the interest in resin tapping is raising but information on the best tapping methods and pastes is still lacking. In this study, an appropriate experimental design used on five representative plots of Pinus pinaster, allowed us to explore the resin productive differences between two tapping methods (traditional Spanish method and circular groove) and three stimulant treatments (control, Ethephon and ASACIF). The use of a standardized measure of resin yield allowed to adequately compare methods differing in groove length. Results indicated that the standard resin yield was 1.43 times greater with the traditional method than with the circular groove method. The two stimulant pastes drastically increased resin yield (up to sixfold) in all sites and for all tapping methods. The effectiveness of the paste was also influenced by the tapping method, obtaining greater increases in resin yield after the application of stimulant paste in trees with the circular groove method. Resin yield was only slightly related to the dasometric variables and varied among test sites when no pastes were used, but differences among sites disappeared when stimulant pastes were used. Our results contribute to the understanding of the factors involved in resin performance and the technological development of the sector.
Selecting the best resin tapping method and stimulant paste in the resin tapping process is crucial. In timber-oriented rainy Atlantic pine forests of north-west Spain, the interest in resin tapping is raising but information on the best tapping methods and pastes is still lacking. In this study, an appropriate experimental design used on five representative plots of Pinus pinaster, allowed us to explore the resin productive differences between two tapping methods (traditional Spanish method and circular groove) and three stimulant treatments (control, Ethephon and ASACIF). The use of a standardized measure of resin yield allowed to adequately compare methods differing in groove length. Results indicated that the standard resin yield was 1.43 times greater with the traditional method than with the circular groove method. The two stimulant pastes drastically increased resin yield (up to 6 fold) in all sites and for all tapping methods. The effectiveness of the paste was also influenced by the tapping method, obtaining greater increases in resin yield after the application of stimulant paste in trees with the circular groove method. Resin yield was only slightly related to the dasometric variables and varied among test sites when no pastes were used, but differences among sites disappeared when stimulant pastes were used. Our results contribute to the understanding of the factors involved in resin performance and the technological development of the sector.
En este artículo, se revisan las experiencias de resinación desarrolladas en Galicia desde la década de los 50 a los 70, basándose en publicaciones y en el estudio de antiguos documentos rescatados del Instituto Forestal de Investigaciones y Experiencias (IFIE). Los documentos recopilados resumen los ensayos de investigación realizados en Galicia que en primer lugar, pueden servir de base para facilitar las futuras investigaciones sobre resinación que se realicen en el noroeste de la Península Ibérica, y en segundo lugar, aportar unos primeros fundamentos que permitan desarrollar una selvicultura que compatibilice la extracción complementaria de resina con el aprovechamiento de la madera en el pino pinaster en Galicia.
Aim of the study: We tested alternative active principles to the most widely used resin tapping stimulant which contains sulphuric acid. We also studied the effect of wounding in five-year-old Pinus pinaster seedlings with a microtapping method.Area of study: The experiment was carried out at the Universidad Politécnica de Madrid in Spain.Material and Methods: The experiment consisted of six treatments: control (no stimulant no wounding), wound (no stimulant), and pines stimulated with sulphuric acid, ethrel, salicylic acid and citric acid. We evaluated the resin yield differentiating between released resin and internal resin (resin retained within the xylem), and the physiological status of the tree.Main Results: Wounded plants produced on average three times more resin than control plants. Plants stimulated with salicylic and citric acids showed the highest resin yield and produced on average 15% more resin than those stimulated with sulphuric acid, mainly because the released resin was higher. Tree diameter affected resin yield and thicker trees produced more resin. We did not observe any significant effect of the treatments on stomatal conductance and only a marginal significant effect (p<0.10) on water potential.Research highlights: Salicylic acid and citric acid seem to be promising stimulants for the resin tapping activity to be further tested in field experiments with adult trees.Keywords: sulphuric acid; ethrel; pine resin; microtapping; wounding; water potential; stomatal conductance.Abbreviations used: TR: total resin content; RR: released resin; IR: internal resin; gs: stomatal conductance; Ψleaf: midday leaf water potential.
Pinus pinaster Ait. is the most widespread conifer in Spain and is now the only species tapped for its oleoresin. External induction of resin secretion, based on the defense system of Pinus trees, has been performed by humans since Classical times through various methods. The socio-economic implication of this practice in Spain justifies a new approach to improve tapping methodology and understand the effects of this activity on the tree. In the last five years, sharp increases in the price of natural resins, accompanied by technological advances directed toward mechanization, have made resin tapping a strategic activity for rural development and forest conservation. The resin industry demands more efficient tapping methods and forest management plans as a way to increase competitiveness in a global market. In this way, this work focuses on the study of the defense system of P. pinaster, with the aim to understand the effects of anatomical and physiological characteristics and environmental conditions on resin yield. The relationships between anatomical variables -with special focus on resin canals-, dendrometric and dasometric variables, and resin yield will be evaluated (objective 1). The tapping wound effects (objective 2) and the intra- and inter-annual variability of climate conditions and soil water availability influence (objective 3) on resin yield will be also studied. The plant and soil material and the resin yield and climatic data used in this thesis have been collected in stands of three public forests of P. pinaster; Armuña, Melque de Cercos and Nieva, located in Segovia (Central Spain). Trees were tapped using two different methods: mechanized or traditional tool, in both upwards and downwards direction. Twenty-six tapped trees of contrasting resin yield classes and twelve non-tapped (control) trees, growing in two locations (Armuña y Melque de Cercos) with the same climate but different stand density and soil characteristics, were selected for studying the role of tree size, xylem anatomy at distal parts aside from the tapping wound (objective 1) and climate influence (objective 3) on resin yield. Concerning the tree defenses induced by the tapping wound (objective 2), the xylem of eight trees, tapped with the two described methods in both upwards and downwards direction, were analyzed. From each tapped tree, eight cores were collected at different locations and varying distances from the tapping wound. In each core, a histological analysis was made. Growth ring width, earlywood and latewood width, and axial canal frequency, area, mean size and location were measured. The effect of the tapping method on resin yield was assessed in 561 P. pinaster tapped trees in a stand in Nieva. In tissues not affected by the tapping wound, the frequency of radial resin canals and the total volume of resin canals were related to resin yield. The frequency of radial canals and the resin yield were strongly related to tree diameter and percentage of live crown. High area of axial resin canals per mm2 was related to high yielding trees, but only in the location with higher plant density and poorer soil quality. In tapped trees, an increase in axial canal frequency and area was found during the three years following the start of tapping activity, suggesting that canal formation is a systemic induced response to wounding. The highest mean annual resin yield was found using the traditional tool in upwards direction, which also induced the highest increase in axial canal frequency and area. The lowest yield was found for mechanized tapping, which showed no differences between the upwards and downwards directions. The strongest induction of systemic induced responses in terms of resin canal frequency and area was detected one year after tapping for upwards tapping. This suggests the involvement of signaling processes that spread mainly upwards, and the importance of adaptive processes as a defense against periodic insect attacks. Intra-annual variation in resin yield was strongly correlated with temperature, solar radiation, potential evapotranspiration and soil water deficit. Inter-annual variation in resin yield and resin canal abundance were correlated with temperature and water deficit in spring, but above a certain threshold of cumulated water deficit in summer rainfall favored resin yield. Under adverse climate scenarios where resource optimization is desirable, a reduced tapping season during the warmest months (June–September) would be advisable, assuming a very small production loss relative to traditional tapping season. Similarly, in years with a rainy summer and/or dry spring, a slightly longer tapping season could be suggested, as resin yield increases after these events. Tree diameter and percentage of live crown, and radial resin canal frequency could be useful criteria for estimating resin yields in P. pinaster. Vigorous trees in lower density stands and growing up in good quality soils will be the most productive. These conclusions could be applied to improve tapping management and breeding programs. These works are complemented with socio-ecological characterization, the identification of the main ecosystem services and an assessment of the possible economic impact derived from the tapping practice. To conclude, more scientific studies are necessary for understanding the anatomical and physiological processes behind resin synthesis and their interactions with the environment. This would afford further progresses towards an extensive and reliable bibliography and improved tapping methods and optimal selvicultural guide lines.
RESUMEN En 1994 se inició un programa de mejora genética de Pinus pinaster para producción de resina en la Tierra de Pinares segoviana. Se ha constituido una población base formada por 270 árboles,180 de ellos con producciones estimadas superiores a 20 kglaño, y los 90 restantes superiores 10 kg. Cada árbol está identificado por una ficha descriptiva. En 1995 se inició la instalación de un banco clonal, en el que actualmente hay representados 91 indi-viduos. Se cuenta con un ensayo de progenies en vivero, formado por 102 familias. 1. INTRODUCCIÓN Desde la introducción en España, a media-dos del siglo pasado, de las técnicas extracti-vas e industriales empleadas en el suroeste francés, la producción de resina ha sido uno de los más característicos y valiosos aprove-chamientos de nuestros pinares de Pinus pinaster, condicionando la temprana ordena-ción de una parte muy importante de los mismos. El destino tradicional de estas producciones ha sido la elaboración de trementina, esencias y colofonia, con impor-tantes aplicaciones en la industria química y farmaceutica. Sin embargo, la producción nacional de miera ha caido drásticamente en los últimos veinticinco años, reduciéndose desde unas 45.000 Tm en 1967 a las 9.000 que se produ-cen en la actualidad. De hecho, pocos montes -casi todos ellos ubicados en la provincia de Segovia-continúan resinándo-se. Pese a ello, el consumo de productos resi-nosos se ha mantenido en unas 30.000 Tm anuales de miera, de las que se obtienen 20.000 Tm de colofonia. El consumo anual de este derivado en los paises de la Unión Europea se eleva a 200.000 Tm.
The moment-based parameter recovery method (PRM) has not been applied in Finland since the
1930s, even after a continuation of forest stand structure modelling in the 1980s. This paper presents
a general overview of PRM and some useful applications. Applied PRM provided compatibility for
the included stand characteristics of stem number (N) and basal area (G) with either mean (D), basal
area-weighted mean (DG), median (DM) or basal area-median (DGM) diameter at breast height
(dbh). A two-parameter Weibull function was used to describe the dbh-frequency distribution of Scots
pine stands in Finland. In the validation, PRM was compared with existing parameter prediction
models (PPMs). In addition, existing models for stand characteristics were used for the prediction
of unknown characteristics. Validation consisted of examining the performance of the predicted
distributions with respect to variation in stand density and accuracy of the localised distributions,
as well as accuracy in terms of bias and the RMSE in stand characteristics in the independent test
data set. The validation data consisted of 467 randomly selected stands from the National Forest
Inventory based plots. PRM demonstrated excellent accuracy if G and N were both known. At its
best, PRM provided accuracy that was superior to any existing model in Finland – especially in
young stands (mean height < 9 m), where the RMSE in total and pulp wood volumes, 3.6 and 5.7%,
respectively, was reduced by one-half of the values obtained using the best performing existing PPM
(8.7–11.3%). The unweighted Weibull distribution solved by PRM was found to be competitive
with weighted existing PPMs for advanced stands. Therefore, using PRM, the need for a basal area
weighted distribution proved unnecessary, contrary to common belief. Models for G and N were
shown to be unreliable and need to be improved to obtain more reliable distributions using PRM.
Pinus pinaster is of great ecological and economic importance and has traditionally been subjected to intensive uses such as wood and resin extraction. In the last decade, dendrochronological methods are increasingly being used to analyze the effects of climatic factors on the growth of the maritime pine, although tapped trees were generally avoided because it was thought that their growth was affected by resin extraction. In Spain, however, it is hard to find a long-lived forest of P. pinaster that has not been subjected to tapping for resin. In the present paper, we performed dendrochronological analyses of this species from wood cores and cross sections taken from both resin-tapped trees and resin-untapped trees killed by a fire in 2008 in the central Iberian region. On the one hand, we reconstructed the history of forest management by means of analysis of resin scars in the cross sections of resin-tapped trees. This facet of dendrochronological dating had not heretofore been developed, and little is therefore known about it. We dated 46 scars, which indicate a history of intensive resin extraction in the 1920–1950 period. Moreover, we attempted to answer the question: Have the old resin extractions in P. pinaster precluded the use of their growth rings for dendrochronological and dendroclimatic studies? We found that resin extraction did not alter general short-wavelength variability, and we developed a local chronology with all synchronized series, and the response function with respect to climate is similar to other oldest P. pinaster forests studied in Spain. The information we have recorded can be of use for providing tools to land managers for interpreting forest dynamics in resin-tapped regions.
Pinus pinaster Ait. is the most widespread conifer in Spain and is now the only species tapped for its oleoresin. The role of tree size and xylem anatomy at distal parts (⩾10 cm) aside from the tapping wound in the resin yield potential of this species was evaluated. Twenty-six tapped trees with contrasting resin yield classes and 12 non-tapped (control) trees, growing in two locations with the same climate conditions but different stand density and soil characteristics, were selected for the study. In tissues not affected by the tapping wound, the number of radial resin canals per mm2 and resin canal volume per growth ring unit are related to resin yield. The number of radial canals per mm2 and resin yield are strongly related to tree diameter and percentage of live crown. The area per mm2 of axial resin canals is related to high yielding trees, but only in the location with higher plant density and poorer soil quality. In tapped trees, an increase in axial canal frequency and area was found during the three years following the start of tapping activity, suggesting that canal formation is a systemic induced response to wounding. Tree diameter and percentage of live crown and radial resin canal frequency could be useful criteria for estimating resin yields in P. pinaster and could be applied to improve tapping management and breeding programs. The systemic defense system of trees should be taken into account to improve tapping techniques and resin yield.
Pine oleoresin is an abundant source of useful terpenes. It has two major
fractions: turpentine, which is the volatile fraction, and rosin, which is the
solid fraction. A key element of tree defense, oleoresin is an important nonwood forestry product because of the various conventional and potential uses of
its terpenes. Oleoresin derivatives can be used by different industries, including
pharmaceutical, cosmetic, and food industries, as well as by the chemical
industry in the manufacturing of various products, such as paint, varnishes,
adhesives, insecticides, and disinfectants. Biotic and abiotic factors that affect
oleoresin production can be used to improve yields by promoting specific
signaling and biochemical defense pathways. Oleoresin production strategies
and the industrial applications of this complex blend of natural products are
analyzed in this chapter.
The Weibull and the Chaudhry-Ahmad probability density functions were used to model resin production distributions for maritime pine stands. Maximum likelihood was used for parameter estimation. Data were collected during one season in two sets of plots. Set 1 consisted of two 50-tree and one 100-tree plots. Bootstrap re-sampling showed that the Weibull parameters had smaller estimation errors for small sample sizes. Set 2 consisted of thirty-seven 10-tree plots. No significant differences in the fit of the density functions were detected. Parameters of both models were found to be well correlated with the mean plot production as well as with the within plot coefficient of variation. The results did not reveal any major differences between the Weibull and the Chaudhry-Ahmad probability functions. The most appropriate model should be chosen at later stages when parameters of both functions are regressed against easily measured stand attributes.
The extraction of induced oleoresin from Pinus elliottii through bark streaking supplies products to the food, pharmaceutical and chemical industries. Resin flow is a typical defense response in conifers and is controled by various environmental factors. Although many studies have focused on oleoresin production in temperate forests, particularly in response to bark beetle attacks, relatively little is known about the physiological regulation of sustainable resin exudation in subtropical planted forests, in which commercial exploitation of this product is favored by the absence of significant pest insect populations. Therefore, the annual oleoresin yield of approximately 2660, 28-year-old trees from different sites was monitored for two consecutive years in southern Brazil. Plain wounding and wounding followed by application of a commercial resin stimulant paste containing the ethylene precursor 2-chloroethylphosphonic acid (CEPA) were used as reference treatments. Different concentrations of auxin, paraquat, yeast extract, and salicylic acid (isolated or in combination with CEPA) were also tested. Higher resin yields were associated with spring and summer, whereas winter had lower but significant yields. Auxin and salicylic acid stimulated the production of oleoresin relative to commercial paste in at least one concentration. Replacement of CEPA with auxin or salicylic acid yielded equivalent oleoresin production, indicating a comparable or complementary effect of these molecules in the process, as well as having implications for new stimulant paste formulations.
Non-wood forest products (NWFP) like cork, edible mushrooms, pine nuts, acorns, resins, medicinal plants, and floral greens, among others, provide important recreational and commercial activities in the rural forested areas of the world, their production being in certain regions more profitable than traditional timber production. Despite the importance of non-wood forest products and services, forest management and planning methods and models in Europe have been traditionally wood production oriented, leading to a lack of tools that could help foresters to manage for optimizing these products. In the present work we'll discuss the main factors and challenges limiting the development of classical empirical models for NWFP, and we will review the existing models for the main NWFP in Europe: cork, pine nuts, berries, mushrooms and resins.
Around 50% of the wood harvested annually in Spain for industrial purposes is produced in the north-western region of Galicia. In this study, species-specific equations were developed for estimating dry harvest residues (kg) from stem volume (m³) in the fast-growing Pinus pinaster Ait., Pinus radiata D. Don and Eucalyptus spp., which generate around 95% of harvested wood. The presence of heteroscedasticity was taken into account in model fitting. Regional dry harvest residues were estimated using the equations and regional harvested volume records (m³), by assuming a mean harvested tree of diameter at breast height of 45 cm for pines and 25 cm for eucalyptus. A moisture content (M) of 25% was assumed for direct combustion of harvest residues; therefore, wet values were calculated from dry estimates, and a lower heating value (M = 25%) was used. The bioenergy potentially produced from the estimated harvest residues (M = 25%) was 377 ktoe year⁻¹ in the period 2018–2019, equivalent to 4.7% of the total primary energy consumption in Galicia in 2018. Currently 70% of potential bioenergy production is concentrated in a sub-region representing 40% of the whole region. The approach used provides a direct link between regional or local harvested volume (registered or simulated) and accurate estimation of potential bioenergy from direct combustion of harvest residues, thus supporting decision-making related to climate change targets and to decreasing dependence on fossil fuels. However, further research that takes into account environmental, economical and social constraints in removing harvest residues is required.
Pine resin is a highly valuable and sought-after non-timber forest product with multiple uses in many industrial sectors. Maritime pine (Pinus pinaster Ait.) is the main tapped species in Europe, where resin tapping activities are concentrated in only a few specific Mediterranean regions. Although maritime pine also occupies vast extensions under Atlantic climates, the resin tapping potential of these forests remains unexplored. The objectives of this study were to determine the main factors driving resin yield under Atlantic conditions and to adapt extraction practices to these regions. Resin yield was assessed in two naturally regenerated maritime pine forests in NW Spain. The effects of tree age, inter-tree competition, dendrometry, seasonality and wounding time on resin production were tested. The feasibility of a simple and rapid microtapping procedure to predict resin yield was also assessed. Tree age was identified as the main factor driving resin production, which increased considerably with tree age. Tree slenderness, tree size and inter-tree competition also significantly influenced resin production, although the effects were lower and likely mediated by age variation. Resin yield followed marked seasonal patterns, with maximum production in late summer and minimum production in winter. Resin flow decreased rapidly with time after wounding. More than 95 % of resin yield flowed in the first week after trees were wounded. The proposed microtapping procedure, which estimates resin flow from small wounds in just a few days, was shown to be a useful and reliable tool both for phenotyping and to predict resin yield in new stands. The results confirm the high potential for resin tapping in Atlantic maritime pine forests, although tapping should be restricted to stands older than 30 years and a season should be delimited for this activity in the region studied. Additionally, the periodicity of grooves (typically fortnightly) may need to be increased.
Pine trees produce large amounts of oleoresin to defend against biotic threats. Resin is highly costly to produce and investment in its production must be accurately optimized in relation to allocation to other life functions such growth. As a result of these costs, resin production is highly variable both genetically (among and within species) and plastically (across temporal and spatial environmental heterogeneity). The relative contribution of these sources of variation is, however, far from being completely understood. Besides being a main defensive mechanism, pine resin is also a valuable non-timber forest product that is regaining attention as a renewable resource for different industrial sectors. Improving our knowledge on the main drivers of resin production is vital to fine-tune resin-tapping management, especially in regions with little tradition in resin-tapping such are the Atlantic areas of the Iberian Peninsula. Here, we assessed resin flow and growth in a network of seven Maritime pine (Pinus pinaster) provenance tests established in North West Spain to explore the within species variation in resin flow, the plasticity of resin flow across sites and across the season and the (phenotypic and genotypic) relationships between resin flow and tree growth. Resin flow was assessed in three contrasting Maritime pine populations at three times within the season using a micro-tapping procedure that predicts well the resin yield potential for exploitation purposes. Results supported the theoretical predictions as resin flow significantly varied among populations, with populations from more favorable environmental conditions producing less resin than those from harsher conditions. Resin flow was positively correlated with tree size at the phenotypic level. However, the genetically-based relationship between growth potential and resin flow was markedly negative. Fast growing populations produced less resin than slow growing origins. Resin flow was also highly plastic across sites and across seasons, with resin flow consistently increasing towards the end of the growing season. Temperature and water deficit immediately before sampling emerged as main drivers of the observed variation in resin flow across sites and seasons. Results are valuable to understand the extremely large variation in defensive investment on resin-based defenses in conifer species, to model the potential of Atlantic Maritime pine forest for resin tapping, and to fine-tune the resin-tapping management of these forests.
Pine resin, a natural source of industrially relevant terpenes, is a major non-wood forestry commodity. Resin is obtained by wounding the bark of adult trees and applying stimulant pastes with different adjuvants on the wound. Identifying new adjuvants and high resin producing trees in adult forests often requires long time and intense labor. Microtapping, i.e. use of young plants of Pinus elliottii var. elliottii cultivated in greenhouse to extract resin, was evaluated as an alternative to carry out these activities. Compounds with known effect in adult plants (ethrel, benzoic acid and potassium sulfate) and molecules involved in the transduction of defense signals (methyl jasmonate, salicylic acid, linolenic acid and isoleucine) were evaluated in young plants. One, two and three-year-old plants consistently increased resinosis when treated with potent adjuvants, mainly methyl jas-monate. The more lignified basal stems produced more resin than apical ones in the 1-year-old plants. Resin yield increased after the second year. All plants were responsive to successive stimuli, just as adult plants. High resin-yield individuals were identified by microtapping, and this phenotype was further supported by terpene-related gene expression studies associated with resinosis. Therefore, microtapping can be used for early, rapid, and simple identification of adjuvants with high resin induction capacity and of putative elite individuals for field evaluation, breeding, and clonal propagation.
Pines constitute a major tree crop, providing an array of products to several industrial sectors, but still holding significant new and unrealized potential worldwide. Among non-wood pine products resin is one of the best known and most exploited. Resin is a complex mixture of terpenes produced by specialized cells dedicated to tree defense. Terpenes from resin find various applications in industry, including chemicals, pharmaceuticals, agrochemicals, food additives, and bioenergy. More recent potential uses of resin products are biodegradable batteries and as components in the manufacturing of green plastics. Besides resin, other non-wood products from pines include needles, cones and bark, which can be used for landscaping, as well as plant cultivation substrates, biofuels and bioherbicides. Additional applications include medium-density fiberboard ingredients, metal biosorption composites, and production of nanofibrillated cellulose. The availability of industrial quantities of renewable non-wood biomass is a topic of significance due to the depletion of fossil-based raw materials and the respective environmental impact of their use. In this review, current and emerging applications of non-wood pine products are discussed, highlighting the importance of fully exploiting these forest resources in a sustainable fashion for maximum revenue generation.
Pines constitute a major tree crop, providing an array of products to several industrial sectors, but still holding significant new and unrealized potential worldwide. Among non-wood pine products resin is one of the best known and most exploited. Resin is a complex mixture of terpenes produced by specialized cells dedicated to tree defense. Terpenes from resin find various applications in industry, including chemicals, pharmaceuticals, agrochemicals, food additives, and bioenergy. More recent potential uses of resin products are biodegradable batteries and as components in the manufacturing of green plastics. Besides resin, other non-wood products from pines include needles, cones and bark, which can be used for landscaping, as well as plant cultivation substrates, biofuels and bioherbicides. Additional applications include medium-density fiberboard ingredients, metal bio-sorption composites, and production of nanofibrillated cellulose. The availability of industrial quantities of renewable non-wood biomass is a topic of significance due to the depletion of fossil-based raw materials and the respective environmental impact of their use. In this review, current and emerging applications of non-wood pine products are discussed, highlighting the importance of fully exploiting these forest resources in a sustainable fashion for maximum revenue generation.
Biomass of pine resin finds several applications in the chemical, pharmaceutical, biofuel and food industries. Resin exudation after injury is a key defense response in Pinaceae since this complex mixture of terpenes has insecticidal, antimicrobial and wound repair properties. Resin yield is increased by effectors applied on the wound area, including phytohormones and metal cofactors of terpene synthases. The interaction of resinosis mechanism effectors is not fully understood, particularly in adult forest setups under natural environmental variations. The aim of this work was to determine how resin exudation by wounded trunks of adult P. elliottii responded to combined chemical effectors involved in different regulatory pathways of resinosis (metal cofactors of terpene synthases, benzoic acid and plant growth regulators) and whether seasonal and tree distribution variations affected these responses. Symmetrically planted and scattered trees regenerated from the seed bank had similar resin biomass yields, suggesting that the homogeneity in development and spatial arrangement were not significant factors in resin yield. This new finding is of practical importance with the used tapping system since costs of implanting forests by regeneration can be advantageous compared to planting. In addition, it was shown for the first time that the salicylic acid precursor benzoic acid and the auxin naphthalene acetic acid promoted resin exudation when individually applied to wound sites. Both these adjuvants are two orders of magnitude less costly compared to the conventionally used ethylene precursors, besides facing less environmental and health restrictions for use. Most adjuvant-treated trees showed higher resin flow in the second year, indicating mechanisms of response build up. Overall, temperature was more important than rainfall as environmental parameter affecting resin biosynthesis, which was higher in the warmer months of spring and summer. The combination of resinosis stimulant effectors from different signaling pathways showed no significant synergistic or additive effect, suggesting possible converging signaling pathways and/or limitation of common intermediate transducing molecules.
Since ancient times, Mediterranean pine forests have been habitat for human activity, providing a wide range of goods such as timber, seeds, resin and derived products. Among them, tar and resin have played an historical role on the interaction between human activity and forests. In Spain, the resin played an important role in the economic and social development in rural areas during 20th century. But after 1980, resin production plummeted and the virtual disappearance of resin tapping caused the abandonment of traditional forest activities and the subsequently losses of ecosystem forest services (provision, regulation and cultural). This paper deals with some of the ecosystem services provided by resin tapped pine forests and shows how the abandonment of this traditional forestry activity would lead to a loss of social welfare beyond the economic activity. Among these ecosystem services, special attention is paid to the biodiversity of the pine forests. For that purpose, a stratified vegetation sampling was conducted in the leading resin-tapping Spanish region. Ecological analysis was therefore compared with the social preferences for several attributes associated to resin-tapped pine forests in Spain, including the biodiversity of flora.
The Weibull function has been widely used to characterize diameter distributions in a forest stand. Methods have been developed to predict the Weibull parameters, either directly or indirectly, from stand age, density, and dominant height. In this study, four existing methods and two new methods of obtaining the Weibull parameters were evaluated using data from a loblolly pine (Pinus taeda L.) plantation. While both new methods performed well, one of them produced consistently better goodness-of-fit statistics than those from the existing methods.
The production of oleoresin from Pinus trees is a relevant economic activity in developing countries, since it provides terpenes used in the chemical industry. The oleoresin production by trees of Pinus elliottii in southern Brazil was investigated. Trees of approximately 28 years of age were individually analyzed for oleoresin yield using the bark streak method of wounding for resin tapping. Plain wounding and wounding followed by application of commercial resin stimulant paste, composed of an ethylene precursor (CEPA) and sulphuric acid, were used as reference treatments. The optimum concentrations of CEPA and sulphuric acid in the stimulant paste were investigated in relation to oleoresin yield, as well as the shape of wound and tree diameter. The replacement of CEPA with auxin in the resin stimulant paste was also evaluated. The results showed that both horizontal and V-shaped streaks are equivalent for oleoresin yield. Trees with larger diameter at breast height, defined as the trunk diameter 1.4 m above the ground (22–23.5 cm) yielded more oleoresin than their smaller counterparts (18–19.5 cm). Oleoresin yield was equivalent with stimulant pastes containing between 1.5 and 4.5% CEPA. Trees exposed to stimulant pastes containing from 3 to 4.5% CEPA had average year oleoresin yield above 5 kg. The use of 20% sulphuric acid in the stimulant paste resulted in higher oleoresin yields. Auxin (2,4-D at 1 mM) was effective in replacing CEPA in the stimulant paste, particularly in smaller DBH trees or after 1 year of application in larger DBH individuals. In conclusion, cost reductions on resin tapping can be achieved by adjusting stimulant paste components and managing subsets of trees in specific fashion based on DBH ranges.
The standard tables used for the Kolmogorov-Smirnov test are valid when testing whether a set of observations are from a completely-specified continuous distribution. If one or more parameters must be estimated from the sample then the tables are no longer valid.A table is given in this note for use with the Kolmogorov-Smirnov statistic for testing whether a set of observations is from a normal population when the mean and variance are not specified but must be estimated from the sample. The table is obtained from a Monte Carlo calculation.A brief Monte Carlo investigation is made of the power of the test.
The oleoresin produced by many conifers has a deleterious effect on numerous associated herbivores, including bark beetles (Coleoptera: Scolytidae), and may have evolved as a plant defense mechanism. Three experiments with juvenile loblolly pine (Pinus taeda L.) used mechanical wounding to drain resin reserves and assess the effects of prior bark wounding on subsequent resin flow up to 7 days post-treatment. Resin flow returned to pre-treatment values within 2 days after wounding began and, in nearly every tree in each experiment, continued to increase on subsequent days. On average, resin flow reached double the pre-treatment values (mean ± SE: 2.10 ± 0.10 vs. 1.13 ± 0.10 g/3 h and 2.28 ± 0.09 vs. 0.90 ± 0.09 g/3 h for wounded vs. pre-treatment in experiments 1 and 2, respectively). Considering its timing and magnitude, this previously undescribed response may be important in modulating interactions between pine trees and bark beetles. In addition, resin flow following treatment was greater in trees in larger crown size classes (thinned > edge of stand = unthinned in experiment 1; edge of stand > thinned > unthinned in experiment 2). This may help explain why trees in thinned stands are less susceptible to southern pine beetle (Dendroctonus frontalis Zimm.) infestation than trees in unthinned stands.
The Weibull probability density function is proposed as a diameter distribution model. Its advantages include flexibility in shape and simplicity of mathematical derivations. Estimation and interpretation of parameters are discussed and illustrated with published data. Forest Sci. 19:97-104.
Diameter, crown-length ratio, and average ring width are useful criteria for estimating gum yields of slash and longleaf pine. The authors have computed estimated gum yields based on these criteria and use the results as evidence in favor of raising the present minimum diameter limit for turpentining on poorer than average sites.
The ecological literature abounds with studies of environmental effects on plant antiherbivore defences. While various models have been proposed (e.g. plant stress, optimal allocation, growth-differentiation balance), each has met with mixed support. One possible explanation for the mixed results is that constitutive and induced defences are differentially affected by environmental conditions. In this study, constitutive oleoresin flow from Pinus tadea was least during periods of rapid tree growth and most when drought conditions limited growth; this is as expected if constitutive secondary metabolism is a function of the carbohydrate pool size after growth has been maximised. Induced increases in resin flow, however, were greatest in the fastest growing trees during the season of greatest growth. Apparently, resin production becomes an allocation priority after wounding but not before. Understanding environmental effects on plant antiherbivore defences requires physiological and evolutionary models that account for the differences between constitutive and induced secondary metabolism.
Diameter distributions and yields of thinned loblolly pine plantations. School of Forestry and Wildlife Resources, VPI and SU
- Q V Cao
- H E Burkhart
- R C Lemin
Cao, Q.V., Burkhart, H.E., Lemin, R.C., 1982. Diameter distributions and yields of
thinned loblolly pine plantations. School of Forestry and Wildlife Resources, VPI and
SU, Publication No. FSW-1-82.
El antiguo oficio de resinero. Hojas divulgativas nº 2116 HD. Ministerio de Agricultura
- L Hernández Muñoz
Hernández Muñoz, L., 2006. El antiguo oficio de resinero. Hojas divulgativas nº 2116
HD. Ministerio de Agricultura, Pesca y Alimentación. Gobierno de España.
Hanging scale HDB-N/HDB-XL
- Sohn Kern
- Gmbh
Kern and Sohn GmbH, 2021. Hanging scale HDB-N/HDB-XL. Available at: 〈https://www.
kern-sohn.com/shop/en/industrial-scales/hanging-scales-crane-scales/HDB-N/
HDB-XL/〉 (Accesed 15 February 2021).
La resina: Herramienta de conservación de nuestros pinares
- F M Pinillos
- A Picardo
- M Allué-Andrade
Pinillos, F.M., Picardo, A., Allué-Andrade, M., 2009. La resina: Herramienta de
conservación de nuestros pinares. Cesefor, Junta de Castilla y León, Fundación
Biodiversidad, Soria, Spain.
Modern gum naval stores methods
- R W Clements
Clements, R.W., 1974. Modern gum naval stores methods. USDA Forest Service,
Asheville, North Carolina, Gen. Tech. Rep. SE-7.
An improved method for collecting and monitoring pine oleoresin. 0434-2306-MTDC
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Karsky, D., Strom, B., Thistle, H., 2004. An improved method for collecting and
monitoring pine oleoresin. 0434-2306-MTDC. Missoula, MT. USDA Forest Service,
Missoula Technology and Development Center.
Production of oleoresin from southern pine trees
- Harrington
Harrington, T.A., 1969. Production of oleoresin from southern pine trees. For. Prod. J. 19
(6), 31-36.
EUFORGEN Technical Guidelines for Genetic Conservation and use for Maritime pine (Pinus pinaster). International Plant Genetic Resources Institute
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- S Martín
Alía, R., Martín, S., 2003. EUFORGEN Technical Guidelines for Genetic Conservation and
use for Maritime pine (Pinus pinaster). International Plant Genetic Resources
Institute, Rome, Italy.
Gum Naval Stores: Turpentine and Rosin from Pine Resin
- J J W Coppen
- G A Hone
Coppen, J.J.W., Hone, G.A., 1995. Gum Naval Stores: Turpentine and Rosin from Pine
Resin. Natural Resources Institute. FAO, Rome.