The Impact of Resin Harvest History on Properties of Scots Pine Wood Tissue
Abstract
This study was conducted in Central Europe (Poland) in pine forests that were subjected to the process of resin harvesting in the 1970s. Forty trees were designated for the study, which had one or two resin blazes. The objectives of the experiment were to determine the effect of resin tapping on the changes in annual growth, wood density, and mechanical strength of wood in the damaged trees. Resin tapping affected the development dynamics, especially in trees with a single resin blaze. In addition, bark cutting affected wood density over the cross-section. However, no significant variation was found in terms of the mechanical properties of wood, which may support the theory of adaptive tree growth and optimization of tree’s structure to its functions.
... Resin production slows tree growth, creating a trade-off between growth rate and tree size (Génova et al. 2014). However, this reduction in growth does not stop trees entirely; they adapt to the slower growth while maintaining their functions (Kopaczyk et al. 2023). ...
The relationship between dendrometric and meteorological parameters and resin production in Pinus pinaster plantations was studied using data from 90 trees collected between June and October. Resin production was measured every 15 days over a five-month period to explore how environmental factors influence resin production rates. The correlation between diameter at breast height (DBH) ranging from 20 cm to 49 cm and total and average resin production was examined, with the goal to optimize resin harvesting practices and to understand the ecological significance of resin in these plantations. The bimonthly resin production was tested using the open wound tapping method over a five-month period beginning in June. Through regression models, significant seasonal variability in resin production was observed. Specifically, higher resin yields were recorded in June (354 g) and lower yields in October (53.5 g). The impact of DBH, tree height, basal area, and volume on resin yield were also assessed. Descriptive statistics, correlation, and regression analyses elucidated the relationships between tree metrics, meteorological factors, and resin production. This study contributes new insights into how tree characteristics influence resin production and how this relationship is modulated by seasonal changes. Such findings can inform sustainable forest management practices and improve resin harvesting methods.
In the 1970s, Portugal was one of the world’s largest producers of natural resin. Competition from countries like China and Brazil, along with a lack of domestic labor, resulted in a decrease in extraction activities, significantly impacting the Portuguese industry, which became dependent on resin imports. However, as natural resin is a renewable resource and an alternative to fossil fuels, there is currently the possibility of integrating this resource within the bioeconomy. This article presents some of the strategic challenges for the resin sector, particularly in terms of the production and exploitation of maritime pine forests. It highlights the need to: (a) develop silvicultural models for stands managed simultaneously for wood and resin; (b) develop resin yield models that consider productivity zones and factors influencing production; (c) adapt legislation regulating resin tapping activities in line with advances in knowledge; (d) provide training and working conditions for resin tappers to make the activity attractive; (e) value the indirect services to the forest and society associated with resin tapping; (f) develop a genetic improvement program for resin production.
The resin tapping of pine trees in Poland ended in the early 1990s. However, we can still find individual trees, and sometimes larger groups of trees, that were tapped. This study focused on the effect of the mechanical wounding of trees during resin tapping on the growth and climatic sensitivity of pine trees. The study concerned a 160-year-old pine stand in northwestern Poland in which resin tapping was last performed in the 1970s. All the trees had remained standing because of their high quality, which had destined them for seed collection. The stand included both resin-tapped (RT) and non-RT (NRT) trees. Our study was based on a dendrochronological analysis of two signals—annual tree ring widths (TRWs) and their delta blue intensity (DBI). We observed a significant increase in annual TRW after resin tapping had ceased, alongside a decrease in the DBI. The temporal stability in growth response was examined using daily climatic correlations from 1921 to 2021. It was found that the climatic sensitivity of RT and NRT pines was similar. There were differences in only some of the years, most while resin tapping was occurring, and then approximately 20 years after the resin tapping had ceased. However, these were small differences that mainly related to the strength of the correlation. It was also discovered that we can obtain different types of information from the study of TRWs and DBI.
p class="Abstract">The most common human pathogen that colonizes in a third of healthy people around the world are Staphylococcus aureus , and one of the materials allegedly able to overcome the pathogen is resin. Resin has been used in folk medicine for thousands of years to treat diseases. The antimicrobial activity of natural resins can be associated with a variety of organic compounds contained in them such as diterpenoids and triterpenoids. This research aimed to explore the antibacterial and antioxidant activities of Pinus merkusii, P. oocarpa, P. insularis, Agathis loranthifolia resins and essential oil. Resin was separated by distillation process to get essential oil and the residue was extracted using n -hexane, ethyl acetate (EtOAc), and methanol (MeOH). Antioxidant activity was performed by DPPH (1,1diphenyl-2-picryl hydrazyl) radical scavenging method. The antibacterial activity of resins and essential oil of the samples determined using the disc diffusion method against Staphylococcus aureus and Escherichia coli . The results showed that the yield of resin extract was ranging from 8.44 % to 95.56%. All extracts and essential oil could not inhibit E coli growth but inhibit the S. aureus growth. This experiment concluded that resin n -hexane extract from P.oocarpa was the most potent as antibacterial activity against S. aureus . All of the samples used had less potential antioxidant activity compared to positive control ascorbic acid. Result of this study show that pine resin from Indonesia has potential as an antibacterial agent. </p
Resin is a natural defensive substance produced by trees in response to injury and infection and is a sustainable and valuable non-timber forest product. Resin tapping is a traditional activity that besides increasing the economic profit of forest plantations, it provides ecosystem services and promotes the development of rural areas. However, the effect of resin tapping on tree growth remains elusive. Furthermore, there is evidence connecting resin production with climatic conditions, but tree-growth responses to climatic conditions and stand characteristics in resin-tapped and non-tapped trees remains unclear. Our aim is to understand if resin tapping affects tree growth, and how tree age, edaphoclimatic conditions and stand characteristics interplay. A dendrochronological study was conducted in six Pinus pinaster stands across a latitudinal gradient from North to the Centre of Portugal. The stands that had been resin-tapped for 5 to 7 years, presented different climate conditions and characteristics, i.e. different cambial ages. When tree-growth (tree ring-width; TRW) on tapped and untapped trunk sides was compared during the resin-extraction period, there was a slight enhancement of growth in the resin-tapped side of the youngest populations (<30 years) and no changes in older populations (>40 years). Annual resin-tapping impact (RTI), calculated as the ratio between TRW during resin harvesting years and the 5-year average TRW before tapping, was below (above) 1 in the younger (older) stands. Among other stand characteristics, RTI was negatively correlated with tree competition. Climatic conditions did not have a major influence on tree growth in response to resin tapping. In conclusion, the effect of resin extraction on growth is age dependent, with younger trees being more negatively affected. Our results seem to indicate that the co-production of resin and timber should be performed in pine populations older than 40 years.
Key message
After 5–6 decades since inflicting resin tapping wounds, overmature (> 120 years old) Pinus sylvestris stems remain undecayed and vigorous.
Abstract
Overmature trees of Pinus sylvestris bearing large wounds made by resin tapping decades ago are still present in woodlands of south-eastern Baltic Sea region. The aim of the present study was to investigate health condition of those trees focusing on fungal infections and to estimate impact of the injury on radial stem growth. The study was conducted in Latvia in three overmature stands of P. sylvestris , resin-tapped in 1950–1970 s. On the studied ninety 120–167-year-old trees, exposed sapwood constituted from 1140 to 7755 cm ² per individual stem. Of the 127 wounds sampled, 52 (41%) showed wood discoloration. The discoloration in its extent was limited, expanding beyond wound margins approx. 1 (max 3) cm in radial, and 6–7 cm in longitudinal directions. Of the 127 wood samples/wounds subjected to fungal isolations, 96% resulted in fungal growth, yielding 236 fungal isolates that represented 47 fungal taxa. The most common among macro-fungi was basidiomycete Porodaedalea pini , which was isolated from 9% of stems. The fungus is currently classed not as a tree pathogen, but instead as an indicator species for woodland sites to be considered for nature conservation. Data from tree ring widths have revealed that tree reacted to the resin tapping injury by increasing radial increment of the un-affected part of the circumference of the stem. Current study demonstrated that even on the long term, resin tapping has little influence on health condition and vitality of P. sylvestris , even at the very old age. This should be considered as a supporting message in case resin taping practices in the region are to be revived.
Tree resin is a macroergic component that has not yet been used for energy purposes. The main goal of this work is to determine the energy content of the resin of spruce, pine, and larch and of wood components—pulp and turpentine. The combustion heat of resin from each timber was determined calorimetrically. Approximately 1.0 g of liquid samples was applied in an adiabatic calorimeter. The energy values of the tree resin (>38.0 MJ·kg⁻¹) were 2.2 and 2.4 times higher than that of bleached and unbleached cellulose, and the highest value was recorded for turpentine (>39.0 MJ·kg⁻¹). Due to the high heating values of the resin, it is necessary to develop approaches to the technological processing of the resin for energy use. The best method of resin tapping is the American method, providing 5 kg of resin ha⁻¹ yr⁻¹. The tapped resin quantity can be raised by least 3 times by applying a stimulant. Its production cost compared to other feedstocks was the lowest. Tree resin can be applied as a means of mitigating global warming and consequently dampening climate change by reducing the CO2 content in the atmosphere. One tonne of tree resin burned instead of coal spares the atmosphere 5.0 Mt CO2.
Slash pine (Pinus elliottii Engelm. var. elliottii) is a resin-producing species grown worldwide for significant economic benefits for wood production. Resin tapping creates a carbon sink at the expense of carbon allocation for growth and consequently, wood production may be reduced. Non-structural carbohydrates comprising starch and sugars stored in plant organs, may serve as intermediate pools between assimilation and utilisation. However, the effect of resin tapping between tree growth and non-structural carbohydrates is not well understood. This study investigated (1) the effects of resin tapping on radial growth, (2) the effects of resin tapping on non-structural carbohydrate pools in different compartments, and (3) the feasibility of resin production without disruption of tree growth. Twenty one-year-old slash pines were subjected to resin tapping over two successive years. Non-structural carbohydrate concentrations in needles, branches, stem phloem, and roots of tapped and untapped trees in summer and winter were determined after the second year of resin harvest. The results showed that tapping had no significant effects on annual increments. Starch was the dominant non-structural carbohydrate fraction, regardless of tissues and season, and constituted up to 99% of the total non-structural carbohydrates in the phloem and roots. Glucose and fructose were the dominant sugars; sucrose was negligible. Compared with the controls, tapped trees showed 26% lower non-structural carbohydrate concentration in the phloem above the tapping wound in summer, which was attributable to the decreased abundance of starch, glucose, fructose, and sucrose. In winter, the altered non-structural carbohydrate profiles in the phloem above the tapping wounding were minimised as a result of recovery of the sugar concentrations. In contrast to free sugars, which accumulated substantially in needles and branches during winter, starch was enriched in the phloem, roots, and current-year needles. The results provide evidence for a localised effect of resin tapping, and highlight the observation that resin extraction does not always cause a sacrifice in wood growth under a moderate resin-tapping intensity in slash pine plantations.
Completely biobased and biodegradable thermoplastic starch (TPS) based materials with a tunable performance were prepared for food packaging applications. Five blends were prepared by blending TPS with 10 wt%. of different pine resins derivatives: gum rosin (GR), disproportionated gum rosin (RD), maleic anhydride-modified gum rosin (CM), pentaerythritol ester of gum rosin (LF), and glycerol ester of gum rosin (UG). The materials were characterized in terms of thermo-mechanical behavior, surface wettability, color performance, water absorption, X-ray diffraction pattern, and disintegration under composting conditions. It was determined that pine resin derivatives increase the hydrophobicity of TPS and also increase the elastic component of TPS which stiffen the TPS structure. The water uptake study revealed that GR and LF were able to decrease the water absorption of TPS, while the rest of the resins kept the water uptake ability. X-ray diffraction analyses revealed that GR, CM, and RD restrain the aging of TPS after 24 months of aging. Finally, all TPS-resin blends were disintegrated under composting conditions during the thermophilic incubation period (90 days). Because of the TPS-resin blend’s performance, the prepared materials are suitable for biodegradable rigid food packaging applications.
In pine stands systematic harvesting of forest products, such as resin extraction, are known to affect trees’ vitality and consequently their response to fungal diseases. The latter constitutes a serious threat for standing vigorous trees, thus early warning signals and short diagnosis time of fungal pathogens, are crucial for designing effective forest management practices. In this study, we explored the effects of the resin extraction process, which was one of the most prominent economic traditional activities throughout the Mediterranean region, on the pines’ growth, and we detected fungal presence in resin-tapped and non-tapped pine trees. For this, we obtained data from 333 resin-tapped and 163 non-tapped Pinus brutia trees, in 20 forest stands, on the island of Lesvos, Greece, by combining in-situ minimally invasive (tree coring) and non-invasive diagnostics (infrared thermography), with the trees’ phenotypic traits and indices. In each stand (30 × 30 m), tree cores were extracted from 34% of the total trees, while the fungal presence was confirmed (a) by the discoloration and decay patterns in the tree cores, (b) by external indicators of decay, such as fruiting bodies, and (c) by the sudden change in boring resistance during the tree cores’ extraction. To evaluate the effect of resin tapping on pines' growth, we developed hierarchical multiple linear regression models controlling parameters related to pines’ phenotypic traits, while for estimating the fungal presence, we used a set of logistic regression models. The results indicated that the number of tapping scars on the pines’ trunk surface, resulting from the resin extraction process, explained the decrease of (a) the average annual growth of the pines by 9.2%, (b) the annual growth after the resin extraction process by 11.7%, while the explanatory power increased to 19% in trees that were tapped early in their life. Fungal presence was successfully classified (a) in 91.5% of the resin-tapped trees, and (b) in 94.9% of the resin-tapped and non-tapped trees when combining trees’ phenotypic traits and indices with non-invasive diagnostics. These findings may contribute in monitoring forest stand dynamics in order to prevent or mitigate their degradation, and also towards effective management plans concerning resin extraction.
Resin tapping might affect tree-ring growth, but details on the physiological responses of trees to resin tapping are still lacking, particularly for long-term responses. This study aimed to explore the physiological processes underlying resin-tapping of Chinese pine (Pinus tabuliformis) by using tree-ring stable isotopes. We compared tree-ring earlywood and latewood stable carbon (δ13C) and oxygen (δ18O) isotopes in the pre-resin tapping and post-resin tapping period for tapped trees and compared their values between tapped and untapped trees and their responses to climate variables in a forest stand from 1984 to 2017. Furthermore, we used a dual isotope model to distinguish between the effects of the photosynthetic assimilation rate and stomatal conductance. Results indicated that tapped and untapped trees showed similar inter-annual variation for two isotopes, while the absolute values of tapped trees were slightly (P > 0.05) lower than tapped trees in the two years following resin tapping. Climate response analysis indicated that resin tapping had no significant effect on climatic sensitivity for either stable isotope. Earlywood stable isotopes were mainly influenced by temperature, relative humidity, and Palmer Drought Severity Index (PDSI) from May to July, while latewood isotopes were mainly influence by relative humidity form July to August and PDSI from July to September. The conceptual model results indicated that resin tapping lead to a slight, but not significant, decrease in the intrinsic water-use efficiency caused by increased stomatal conductance for the first two to three years following resin tapping. We conclude that tree-ring physiological responses could be less affected by short-term resin tapping activities.
Resin harvesting is a traditional forestry activity that provides economic revenue along with crucial ecosystem services (i.e., fire protection and employment) thus contributing to the socioeconomic development of rural areas. In the Iberian Peninsula, Pinus pinaster Aiton has traditionally been exploited for resin to complement the profitability of timber harvesting. Trade-offs between resin yield and radial growth are not fully understood, however. Resin ducts, the anatomical structures that produce and transport resin within the tree, have been used as a proxy for resin yield or resistance to pathogens as they represent the tree's investment on resin defences throughout its lifespan. It is not yet clear if these structures can be linked to growth or how well the resin duct network correlates with resin yield in tapped trees. To answer these questions, we investigate annual tree-ring width, resin duct traits (absolute and standardized), and resin yield of two maritime pine stands tapped for resin extraction in the North of Portugal (VPA and PCO). Resin duct features are assessed before and during tapping periods as may show the constitutive investment, as well as the combination of constitutive and induced ones. Before resin tapping, average tree-ring width in PCO and VPA was ~2.25 and ~1.13 mm year − 1 , respectively. During tapping, standardized growth rates increased by ca. 40% in VPA, the population living under lower water availability and shorter growing seasons, while growth rates were almost unaffected in PCO. Median resin production in 2016 was 2.9 kg (PCO) and 1.8 kg (VPA), but inter-tree variance was high in both sites. Resin duct production increased exponentially with tree-ring width similarly in the different sites and for the same periods, but wider rings and ducts in PCO resulted in greater areas occupied by resin ducts. Within the population , constitutive anatomical resin-based defences did not trade-off with radial growth, although, lower growth rates were related to higher resin duct investments in response to tapping. Despite this, annual resin production did not correlate with resin duct density or relative area. Conversely, resin yield was positively associated with trunk perimeter, average growth, and absolute resin duct traits. These variables will thus be the most valuable when trying to identify the best resin producers in a stand. Differences in growth sensitivity to resin tapping between sites suggested that the impact of resin harvesting on radial growth is site-dependent and may not be as negative as previously thought.
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