Carbon sequestration in resin-tapped slash pine (Pinus elliottii Engelm.) subtropical plantations

Every year more than 150,000 tons of resin used in a myriad of industrial applications are produced by Brazilian plantations of Pinus elliottii Engelm. (slash pine), which are also used for timber. A pine tree can be tapped for resin over a period of several years. Resin is a complex mixture of terpenes, which are carbon-rich molecules, presumably influencing pine plantation carbon budgets. A total of 270 trees (overall mean DBH of 22.93 ± 0.11 cm) of 14-, 24-, and 26-year-old stands had their C content measured. Three different treatments (intact, wounded panels, and wounded + chemically stimulated panels, 30 trees each) were applied per site. Above- and belowground biomass, as well as resin yield, were quantified for two consecutive years. Data were statistically evaluated using normality distribution tests, analyses of variance, and mean comparison tests (p ≤ 0.05). The highest resin production per tree was recorded in the chemically stimulated 14-year-old stand. Tree dry wood biomass, a major stock of carbon retained in cell wall polysaccharides, ranged from 245.69 ± 11.73 to 349.99 ± 16.73 kg among the plantations. Variations in carbon concentration ranged from 43% to 50% with the lowest percentages in underground biomass. There was no significant difference in lignin concentrations. Soils were acidic (pH 4.3 ± 0.10–5.83 ± 0.06) with low C (from 0.05% to 1.4%). Significantly higher C stock values were recorded in pine biomass compared to those reported for temperate zones. Resin-tapping biomass yielded considerable annual increments in C stocks and should be included as a relevant component in C sequestration assessments of planted pine forests

Historical forest use constrains tree growth responses to drought: A case study on tapped maritime pine (Pinus pinaster)

Resin extraction from Pinus pinaster (maritime pine) trees was an important economic activity for most of the 20th century in Mediterranean forests, until the decrease in resin prices that led to their abandonment in the 1960s-1970s. Reduced tree growth is often observed after long periods of resin tapping, but it is unknown how these formerly tapped stands respond to recent climate warming and aridification. We sampled three historically tapped maritime pine stands in Teruel, eastern Spain, to understand differential growth and responses to climate in resin tapped and non-tapped trees. Using dendrochronological methods, we compared tree growth trends and responses to climate in tapped and non-tapped trees. Overall, tree growth was higher in resin tapped trees than in non-tapped trees, which were generally younger. However, tree growth decreased over time, increasing the negative effects of late spring temperatures, summer drought and reduced summer precipitation, with increased sensitivity to drought in tapped than non-tapped trees. Among tapped trees, those with larger wound area grew more than those less tapped, and were more sensitive to drought, particularly after the 80 s. Our results suggest that the legacy effects of previous management can constrain tree responses to climate change by increasing the sensitivity of tree growth to drought

PINE RESIN PRODUCTIVITY AT SAO HILL FOREST PLANTATION, SOUTHERN TANZANIA

A study on resin productivity from Pinus patula and P. elliottii was carried out at Sao Hill Forest Plantation. Four and three compartments for Pinus patula and P. elliottii, respectively covering age between 5 and 25 years were selected. In each compartment, three plots (12m × 12m) were systematically established. All trees in each plot were measured for diameter at breast height (Dbh) and three trees (smallest, medium and largest in diameter) measured for total height and crown diameter. All trees in treatment plots were tapped for resin. Weighing and re-wounding of tapped trees was done after every ten days in ten sessions. The findings show that annual resin yield ranged from 0.56kg tree-1 to 1.32kg tree-1 and from 0.47kg tree-1 to 1.98kg tree-1 for P. patula P. elliottii, respectively. The Dbh and crown diameter were important predictors resin production. Over 31% of annual resin production was explained by stand level variables. It was recommended that integration of resin tapping into the current schemes of timber will improve the contribution of the forest sector in economic growth. Further, introduction of resin tapping may be an attractive option for early income generation while waiting trees to attain the rotation age

Carbon Sequestration in Resin-Tapped Slash Pine (Pinus elliottii Engelm.) Subtropical Plantations.

Every year more than 150,000 tons of resin used in a myriad of industrial applications are produced by Brazilian plantations of Pinus elliottii Engelm. (slash pine), which are also used for timber. A pine tree can be tapped for resin over a period of several years. Resin is a complex mixture of terpenes, which are carbon-rich molecules, presumably influencing pine plantation carbon budgets. A total of 270 trees (overall mean DBH of 22.93 ± 0.11 cm) of 14-, 24-, and 26-year-old stands had their C content measured. Three different treatments (intact, wounded panels, and wounded + chemically stimulated panels, 30 trees each) were applied per site. Above- and belowground biomass, as well as resin yield, were quantified for two consecutive years. Data were statistically evaluated using normality distribution tests, analyses of variance, and mean comparison tests (p ≤ 0.05). The highest resin production per tree was recorded in the chemically stimulated 14-year-old stand. Tree dry wood biomass, a major stock of carbon retained in cell wall polysaccharides, ranged from 245.69 ± 11.73 to 349.99 ± 16.73 kg among the plantations. Variations in carbon concentration ranged from 43% to 50% with the lowest percentages in underground biomass. There was no significant difference in lignin concentrations. Soils were acidic (pH 4.3 ± 0.10?5.83 ± 0.06) with low C (from 0.05% to 1.4%). Significantly higher C stock values were recorded in pine biomass compared to those reported for temperate zones. Resin-tapping biomass yielded considerable annual increments in C stocks and should be included as a relevant component in C sequestration assessments of planted pine forests

MODELO DE AFILAMENTO PARA ÁRVORES RESINADAS E NÃO RESINADAS DE Pinus elliottii ENGELM

A comunidade cientifica apresenta uma evolução importante sobre estudos da forma e funções de afilamento para diversas espécies, mas há uma escassez de informações sobre funções de afilamento para árvores resinadas e não resinadas, visto que os plantios ainda podem ter a sua madeira utilizada para fins comerciais. Desse modo, com o intuito de verificar se o ato de resinar árvores influencia na forma do fuste quando comparado com as árvores não resinada, esse trabalho irá para responder a seguinte questão de estudo: Os coeficientes das funções de afilamento são diferentes entre árvores resinadas e não resinadas? Para tanto, utilizaram-se dados provenientes de duas áreas de plantios de P. elliottii estabelecidas nos anos 1980, uma resinada e outra não resinada, localizadas no litoral sul do Rio Grande do Sul. Foram ajustados os modelos de Kozak Modificado (1969) e Schöepfer (1966) para os dados estratificados em grupos resinado, não resinado e para os dados totais. Em seguida, aplicou-se o teste de identidade de Graybill (1969) para verificar a igualdade das equações desenvolvidas para os grupos e para o total das árvores. O modelo Schöepfer (1966) se ajusta melhor aos dados de Pinus elliottii Engelm, tanto para plantios resinados como não resinados, quando comparado ao modelo de Kozak et al. (1969). A resinagem das árvores proporciona perfil de fuste diferente quando comparado a plantios não resinado

Genetics and Genomics of Forest Trees

Forest tree genetics and genomics are advancing at an accelerated rate, thanks to recent developments in high-throughput, next-generation sequencing capabilities, and novel biostatistical tools. Population and landscape genetics and genomics have seen the rise of new approaches implemented in large-scale studies that employ the use of genome-wide sampling. Such studies have started to discern the dynamics of neutral and adaptive variation in nature and the processes that underlie spatially explicit patterns of genetic and genomic variation in nature. The continuous development of genetic maps in forest trees and the expansion of QTL and association mapping approaches contribute to the unravelling of the genotype-phenotype relationship and lead to marker-assisted and genome-wide selection. However, major challenges lie ahead. Recent literature suggests that species demography and genetic diversity have been affected both by climatic oscillations and anthropogenically induced stresses in a way calls into question the possibility of future adaptation. Moreover, the pace of contemporary environmental change presents a great challenge to forest tree populations and their ability to adapt, taking into consideration their life history characteristics. Several questions emerge that include, but are not limited to, the interpretation of forest tree genome surveillance and their structural/functional properties, the adaptive and neutral processes that have shaped forest tree genomes, the analysis of phenotypic traits relevant to adaptation (especially adaptation under contemporary climate change), the link between epigenetics/epigenomics and phenotype/genotype, and the use of genetics/genomics as well as genetic monitoring to advance conservation priorities