Pinus Elliottii Plantations Research Articles

Assembly and co-occurrence pattern of microbial communities in bulk and rhizosphere soils of Pinus elliottii plantations on sandy lands in China

Assembly and co-occurrence pattern of microbial communities in bulk and rhizosphere soils of Pinus elliottii plantations on sandy lands in China

The Carbon Storage of Reforestation Plantings on Degraded Lands of the Red Soil Region, Jiangxi Province, China

To assess the effects of reforestation on ecosystem carbon storage, a long-term Forest Restoration Experimental Project (FREP) was established in 1991 on southern degraded red soil in Taihe County, Jiangxi Province, China. In this study, we selected five types of plantations: Schima superba plantation (SS), Liquidambar formosana plantation (LF), Pinus massoniana plantation (PM), Pinus elliottii plantation (PE), and P. elliottii and broadleaf mixed plantation (MEB). The unforested land was used as an experimental control check (CK). We aimed to assess the changes in carbon storage in plantations and the factors affecting them. Thirty years after reforestation, the ecosystem carbon storage of the five types of plantations was significantly higher than that of the control site, and there were also significant differences in the ecosystem carbon storage between the different plantation types (p < 0.05). The ecosystem carbon storage of SS, MEB, LF, PM, and PE were 211.71 Mg ha−1, 199.02 Mg ha−1, 160.96 Mg ha−1, 155.01 Mg ha−1, and 142.88 Mg ha−1, respectively. Compared to the CK, these values were increased by 436.8%, 404.6%, 308.1%, 293.1%, and 262.3%, respectively. The ecosystem carbon storage was significantly positively correlated with soil porosity, total nitrogen (TN), and stand density, and was significantly negatively correlated with pH, Pielou’s evenness index (PEI), and the Shannon–Weiner diversity index (SWDI). The soil water content (SWC), bulk density (BD), SWDI, and stand density can be used as indicators of the impact of reforestation plantings on ecosystem carbon storage. The research results has shown that reforestation plantings significantly increase ecosystem carbon storage, and that afforestation should be encouraged on degraded land.

Investments in Pinus elliottii Engelm. Plantations: Real Options Analysis in Discrete Time

Background: The commonly used methods for the financial evaluation of plantation forest investment projects do not incorporate uncertainties and ignore the value related to flexibility. The real options analysis makes it possible to capture these values in investment projects, increasing their value and return. Despite this, studies involving real options in forest investment projects are scarce, specifically those related to Pinus spp. Therefore, this study aimed to: (a) analyze whether the real options analysis adds value to investment projects of Pinus elliottii Engelm. plantations; and (b) make the real options analysis more accessible to forest managers and potentially increase its use in the investment projects of Pinus spp. plantations. Methods: We evaluated two investment projects in P. elliottii plantations in southern Brazil, which differed in the way of obtaining the land for planting: with lease or purchase of land on a planning horizon of 21 years. In the real options analysis, we used deferral, expansion, and abandonment. Results: Individually, the deferral, expansion, and abandonment options add value to investment projects in Pinus elliottii plantations. The option to expand the forested area is one that adds the most value to the investment project with land lease. In the investment project with land purchase, it is abandonment. Conclusions: Investment projects in Pinus elliotti plantations that contemplate the land purchase analyzed through the real options analysis present higher financial returns than those that consider land lease, inverting the result provided by the traditional analysis.

Interspecific competition for inorganic nitrogen between canopy trees and underlayer-planted young trees in subtropical pine plantations

Although the area of monospecific plantations in China ranks first in the world, these plantations possess poor disease resistance, low quality, and low ecological benefit. Planting broadleaf seedlings into the understory of monospecific coniferous plantations is an effective and common forest management method to improve plantation structures and enhance their resistance to adverse conditions, disease, and pests. Species that are desired and suitable are selected according to the complementarity of their functional traits to ensure optimal resource utilization and species coexistence. Thus, in Pinus massoniana and Pinus elliottii plantations where three broadleaf species were underplanted, any alterations to root functional traits and inorganic nitrogen (N) uptake rates in response to interspecific competition were studied in situ using 15N isotope labelling technology. The results showed that the five species preferred to absorb ammonium (dominant N form in native soils) rather than nitrate from the soil. Coniferous species showed higher plasticity in root biomass, physiology of N uptake rate, morphology, and mycorrhizal colonization than broadleaf species responding to interspecific competition. Coniferous trees reduced the investment in root biomass while enhanced N uptake rates to acclimate to belowground interspecific competition. Broadleaf species M. maudiae and S. superba were more dependent on mycorrhizal symbiosis to acquire resource in response to environmental variations. The amount of inorganic N uptake by P. massoniana and P. elliottii roots were inhibited by the presence of Michelia maudiae and Schima superba roots, respectively. Based on inorganic N uptake amount, M. maudiae and S. superba may be suitable for underplanting in the P. elliottii and P. massoniana plantations, respectively. Liquidambar formosana was suitable for both two pine plantations. The responses of root N uptake rate, mycorrhizal colonization and morphological traits to interspecific competition can provide supplemental data for species selection to improve structures of artificial plantations.

Long‐term Pinus plantations reduce the bud bank in Cerrado areas

AbstractQuestionThe Cerrado represents the largest savanna of the Neotropics. Nowadays, this ecosystem is threatened by the afforestation by monocultures, such as Pinus spp., leading to serious damage to native herbaceous species. Afforestation of savanna ecosystems can affect their ability to regenerate naturally, which relies on different strategies, such as resprouting from below‐ground bud‐bearing organs. Therefore, we investigated the impact of ca. 50 years of Pinus elliottii plantations, compared to undisturbed areas of Cerrado savanna, estimating the bud bank size by counting buds on bud‐bearing organs. We hypothesized that long‐term P. elliottii plantations negatively affected the bud‐bearing organs, leading to decreases in the bud bank.LocationCerrado savanna areas and Pinus elliottii plantations, southeastern Brazil.MethodsOpen savanna areas (hereafter Cerrado) and “P. elliottii plantations” were considered the vegetation types. Within each vegetation type, we designated three areas. In each area, we established 10 plots (1 m2). For each plot, the bud bank was sampled from 5 cm above to 10 cm below ground level in subplots (0.25 m2). We developed generalized linear mixed models (GLMM) for each response variable to test differences between both vegetation types.ResultsThe presence of the P. elliottii plantations for almost 50 years has led to massive reductions in the bud bank size and the number of bud‐bearing organs, when compared to the Cerrado areas (p < 0.0001).ConclusionsThe reduction in the below‐ground bud‐bearing organs density led to decreases in the bud bank and thus, loss of resilience in these areas. Regeneration in planting areas may not occur naturally after the removal of the plantations. Restoration of the herbaceous layer after P. elliottii removal will rely on the introduction of a new source of propagules through active interventions.

Soil enzyme activities and their stoichiometry of typical plantations in mid-subtropical China

We measured the activities of six kinds of enzyme, including β-glucosidase (BG), β-N-acetyl-glucosaminidase (NAG), leucine aminopeptidase (LAP), acid phosphatase (AP), polyphenol oxidase (POX), peroxidase (POD), as well as enzyme stoichiometric ratios and soil physical and chemical properties at 0-10 and 10-20 cm layers across typical Pinus massoniana plantation, Pinus elliottii plantation and mixed plantation of P. massoniana and Schima superba (broadleaved-conifer mixed plantation) in mid-subtropical China. Key factors driving the variation in soil enzyme activity and stoichiometry among different stand types were investigated. The results showed that the activities of soil BG and LAP were significantly affected by stand type. Soil BG activity at 10-20 cm soil layer was significantly higher in P. elliottii plantation than in P. massoniana plantation, while the activity of LAP was highest in the P. massoniana plantation. Soil BG/(NAG+LAP) and BG/AP at 10-20 cm layer of P. elliottii plantation were significantly higher than those of P. massoniana plantation, while (NAG+LAP)/AP of P. massoniana plantation was significantly higher than those of P. elliottii plantation and mixed plantation. The vector length of enzyme stoichiometry at 10-20 cm soil layer was significantly different among stand type, with an order of P. elliottii plantation > broadleaved-conifer mixed plantation > P. massoniana. The vector angles of enzyme stoichiometry in the three plantations were greater than 45°, with the vector angle in the P. elliottii plantation at 10-20 cm soil layer being significantly greater than that of the P. massoniana plantation. Results from redundancy analysis showed that soil carbon quality index and the ratio of soil organic carbon to total phosphorus (C/P), soil water content and C/P were the key factors affecting soil enzyme activity and stoichiometry at 0-10 and 10-20 cm soil layers, respectively. The quantity and quality of soil carbon and phosphorus, and soil water content played a key role in regulating nutrient cycling in mid-subtropical plantation ecosystem.

Understory Vegetation Richness and Diversity of Eucalyptus benthamii and Pinus elliottii Plantations in the Midsouth US

AbstractIn the Western Gulf region of the United States cold-tolerant eucalyptus have been explored as pulpwood feedstock. However, non-native plantations may alter understory species diversity, modifying environmental conditions and soil characteristics. Few studies have compared eucalyptus plantations with native ecosystems to understand the impact on understory vegetation in the United States. In this study, we compared understory plant species richness and diversity during 2014–2016 in (1) slash pine (Pinus elliottii) established in 2008, (2) slash pine established in 2013, and (3) and Camden white gum (Eucalyptus benthamii) established in 2013. Overstory characteristics, soil pH, and soil nutrient concentrations were measured to understand factors that affected understory species richness and diversity. Results indicated a decline in understory species richness over time, with Camden white gum in an intermediate condition between same-age slash pine (highest richness) and older slash pine (lowest richness). Leaf area index, soil pH and K, and tree height were the most important factors influencing understory species richness and diversity. The adoption of fast-growing eucalyptus on these sites will probably accelerate the deterioration of natural habitats and reduce open-condition species in favor of shade-tolerant species, overturning the conservation efforts already put in place by governmental agencies and conservation groups.

MODELING PINUS ELLIOTTII GROWTH WITH MULTITEMPORAL LANDSAT DATA: A STUDY CASE IN SOUTHERN BRAZIL

Abstract Remote sensing data are a key proxy to forest monitoring and management at local, regional and global scales. Considering the hypothesis that NDVI and EVI can be used at least during one decade to monitor Pinus elliottii in Southern Brazil, the objective of this study was to identify saturation time after planting of these vegetation indices in a Pinus elliottii plantation and the most suitable index by adjusting theoretical functions to each one of them. Based on Landsat Surface Reflectance Higher-Level Data Products, 32 scenes were selected between 1984 to 2015. A set of theoretical polynomial, gaussian and logistic mathematical functions were applied to fit the experimental data on vegetation indices. The determination coefficient (R²) and RMSE at 95% probability were also used. Finally, EVI efficiency was tested by changing the L parameter. The logistic model was the one that best explained the data resulting from NDVI and EVI over time. NDVI was more effective than EVI for this forest monitoring, identifying the forest growth pattern until its 18 years of age. EVI may have been saturated after 14 years and the L factor may be set to near to zero to achieve a higher coefficient of determination.

Diversity and Enzyme Activity of Ectomycorrhizal Fungal Communities Following Nitrogen Fertilization in an Urban-Adjacent Pine Plantation

Rapid economic development and accelerated urbanization in China has resulted in widespread atmospheric nitrogen (N) deposition. One consequence of N deposition is the alteration of mycorrhizal symbioses that are critical for plant resource acquisition (nitrogen, N, phosphorus, P, water). In this study, we characterized the diversity, composition, and functioning of ectomycorrhizal (ECM) fungal communities in an urban-adjacent Pinus elliottii plantation under ambient N deposition (~24 kg N ha−1 year−1), and following N fertilization (low N, 50 kg N ha−1 year−1; high N, 300 kg N ha−1 year−1). ECM functioning was expressed as the potential activities of extracellular enzymes required for organic N (protease), P (phosphomonoesterase), and recalcitrant polymers (phenol oxidase). Despite high ambient N deposition, ECM community composition shifted under experimental N fertilization, and those changes were linked to disparate levels of soil minerals (P, K) and organic matter (but not N), a decline in acid phosphatase (AP), and an increase in phenol oxidase (PO) potential activities. Based on enzyme stoichiometry, medium-smooth exploration type ECM species invested more in C acquisition (PO) relative to P (AP) following high N fertilization than other exploration types. ECM species with hydrophilic mantles also showed higher enzymatic PO:AP ratios than taxa with hydrophobic mantles. Our findings add to the accumulating evidence that shifts in ECM community composition and taxa specialized in organic C, N, and P degradation could modulate the soil nutrient cycling in forests exposed to chronic elevated N input.

Short-term responses of foliar multi-element stoichiometry and nutrient resorption of slash pine to N addition in subtropical China

We conducted a field experiment with three levels of N addition (0, 40 and 120 kg N·hm-2·a-1) in a Pinus elliottii plantation in subtropical China and collected green and senesced needles of P. elliottii at the peak (July) and the end (October) of each growing season in 2014 and 2015 for clarifying effects of nitrogen additions on concentrations of nine elements (C, N, P, K, Ca, Mg, Al, Fe and Mn) in the green and senesced needles and their corresponding resorption efficiency and resorption proficiency. Our results showed that N addition had positive effects on concentrations of N, Al and Mn, negative effects on the P concentration and the Ca concentration in 2014, and neutral effects on concentrations of C, K, Mg and Fe in green needles. N addition signifi-cantly increased foliar N/P. These stoichiometric responses were N level-dependent (stronger at high N rate). N addition significantly decreased N resorption efficiency in 2015 and increased that of K in 2014. Compared with the resorption efficiency, resorption proficiency responded more strongly to increased available N. N addition significantly decreased resorption proficiency of N, and increased that of P, K, and the concentration of Fe in senesced needles, however, there were no significant effects on the concentrations of Ca, Mg, Al and Mn in senesced needles. We concluded that responses of foliar stoichiometry to N addition were element-specific, and plants might cope with changing environments via adjusting internal nutrient cycle (resorption). The elevated foliar N/P and K/P suggested a shift from N and P co-limitation to P limitation with N additions, and increased concentrations of Al and Mn might imply potential toxicity of metal ions to P. elliottii.

Disentangling critical drivers of stem CO2 efflux from Pinus elliottii trees in Subtropical China

Stem CO2 efflux (Es) plays a critical role in forest carbon budgets and net ecosystem CO2 exchanges, but there is still a significant knowledge gap on Es and its controlling factors in subtropical forests where forest productivity and transpiration are both very high. In this study, Es and the possible controlling factors such as stem temperature (Ts), sap velocity (vs), and other climatic variables were simultaneously measured in a Pinus elliottii plantation of Subtropical China from January 2014 to July 2015. Temporal dynamics of Es followed similar trends as Ts at a 1-cm depth with bell-shaped curves. The monthly Es values were significantly higher during the fast-growing season (April to October) than in the slow-growing season (November to next March). However, temperature sensitivity (Q10, the relative increase of Es with a 10°C rise in temperature) fluctuated throughout the entire year without a clear pattern. Significant and exponential relationships were found between Es and Ts, with correlation factors higher during the slow-growing season than in the fast-growing season. Additionally, the coefficients of determination of Es to stem temperature were highly divergent with respect to tree size during the fast-growing season but not in the slow-growing season. The residuals (ΔEs), calculated as the difference between the modeled fluxes (Ep) based on night-time data at zero sap flow and the measured fluxes (Em) during the daytime when sap flow occurred, became more prominent during the fast-growing season. Thus, significant and positive correlations were observed between the ratio of ΔEs to Ep and vs during the fast-growing season (r2=0.59, p<0.01) but not in the slow-growing season. Combined with the maximum value of vs, sap flows could potentially reduce the measured CO2 efflux to up to 25% of those predicted values on temperature alone during the daytime. Our results clearly demonstrated that temperature was not sufficient to quantify Es, and thus, the effect of sap flow on Es must be integrated into any models simulating stem respiration and carbon budgets in forest ecosystems.

Effect of Thinning and Clear-cuts on the Transmission of Fire in Slash Pine Plantations during Restoration to Longleaf Pine

Restoration of the Pinus palustris (longleaf pine) bunch grass ecosystem that once dominated the southeastern coastal plain has become a goal for many managers on public lands. However, fire exclusion and conversion to Pinus elliottii (slash pine) plantations has provided the conditions for much of the forest to become susceptible to what Lindenmayer et al. (2011) call a “landscape trap,” where ecological processes no longer function to maintain the ecosystem. For the longleaf pine-bunchgrass ecosystem, the trap occurs when fire-dependent herbaceous vegetation have been replaced with woody shrubs, and there are no fine fuels that will readily transmit frequent fire. Restoration of slash pine plantations to longleaf pine forest will require continued transmission of fire across the restoration areas. With the cooperation of the US Forest Service, we conducted an experiment to study the effectiveness of thinning and patch clear-cuts in slash pine plantations and compared the burnability of these treatments. Eighty percent of the thinned plots burned, but only 12% of the patch clear-cuts did. These differences resulted from reduced needle cast in the clear-cuts. Plots in which the ground cover was dominated by herbaceous vegetation were significantly more likely to burn (97%) than those dominated by woody vegetation (38%). Plots without fire for eight years prior to the experimental burn did not burn across the clearcut patches that had no recent needle cast from canopy trees. Maintenance of the canopy is important in fire transmittal because fire allows longleaf pine restoration without expensive site preparation and groundcover reintroduction.

Effects of nitrogen additions on soil hydrolase and oxidase activities in Pinus elliottii plantations.

We evaluated responses of hydrolase and oxidase activities in a subtropical Pinus elliottii plantation through a nitrogen (N) addition field experiment (dosage level: 0, 40, 120 kg N·hm-2·a-1). The results showed that N additions significantly decreased the carbon, nitrogen and phosphorus related hydrolase and oxidase activities. The activities of β-1,4-glucosidase (BG), cellobiohydrolase (CBH), β-1,4-N-acetylglucosaminidase (NAG) and peroxidase (PER) activities were decreased by 16.5%-51.1% due to N additions, and the decrease was more remarkable in the higher N addition treatment. The activities of α-1,4-glucosidase (aG), β-1,4-xylosidase (BX), acid phosphatase (AP) and phenol oxidase (PPO) were decreased by 14.5%-38.6% by N additions, however, there was no significant difference among the different N addition treatments. Soil enzyme activities varied obviously in different seasons. The activities of BG, NAG, BX, CBH, AP and PPO were in the order of March > June > October, and aG and PER activities were in the order of October > March > June. Most of the soil hydrolase and oxidase activities were positively correlated with soil pH, but negatively with NO3--N content. It indicated that N additions inhibited soil hydrolase and oxidase activities by reducing soil pH and increasing soil nitrification. N additions inhibited the soil organic matter mineralization and turnover in the subtropical area, and the effects were obvious with the increasing dosage of N additions.

Soil Microbial Community Structure and Metabolic Activity of Pinus elliottii Plantations across Different Stand Ages in a Subtropical Area.

Soil microbes play an essential role in the forest ecosystem as an active component. This study examined the hypothesis that soil microbial community structure and metabolic activity would vary with the increasing stand ages in long-term pure plantations of Pinus elliottii. The phospholipid fatty acids (PLFA) combined with community level physiological profiles (CLPP) method was used to assess these characteristics in the rhizospheric soils of P. elliottii. We found that the soil microbial communities were significantly different among different stand ages of P. elliottii plantations. The PLFA analysis indicated that the bacterial biomass was higher than the actinomycic and fungal biomass in all stand ages. However, the bacterial biomass decreased with the increasing stand ages, while the fungal biomass increased. The four maximum biomarker concentrations in rhizospheric soils of P. elliottii for all stand ages were 18:1ω9c, 16:1ω7c, 18:3ω6c (6,9,12) and cy19:0, representing measures of fungal and gram negative bacterial biomass. In addition, CLPP analysis revealed that the utilization rate of amino acids, polymers, phenolic acids, and carbohydrates of soil microbial community gradually decreased with increasing stand ages, though this pattern was not observed for carboxylic acids and amines. Microbial community diversity, as determined by the Simpson index, Shannon-Wiener index, Richness index and McIntosh index, significantly decreased as stand age increased. Overall, both the PLFA and CLPP illustrated that the long-term pure plantation pattern exacerbated the microecological imbalance previously described in the rhizospheric soils of P. elliottii, and markedly decreased the soil microbial community diversity and metabolic activity. Based on the correlation analysis, we concluded that the soil nutrient and C/N ratio most significantly contributed to the variation of soil microbial community structure and metabolic activity in different stand ages of P. elliottii plantations.

Effects of mixture of branch order-based roots and nitrogen addition on root decay in a subtropical pine plantation

Non-additive effects may occur when branching order-based fine roots decompose in mixture, due to their distinct chemical composition. However, these effects and how they respond to increased nitrogen (N) availability are poorly known. We conducted a 524-day field litterbag experiment to examine the potential non-additive effects of order-based fine root decomposition and their responses to different rates of N addition in a Pinus elliottii (slash pine) plantation in China. The intact fine roots of slash pine trees were hierarchically dissected and split into two groups (lower-order roots (the first and second order roots) and higher-order roots (the third to fifth order roots)). The decomposition of these two root groups was monitored either separately or in 1:1 mixture. The non-additive effects did not occur when the two root groups decomposed in mixture. However, high rate of N addition shifted the root group interactions from additive to synergistic effects through contrasting effects on individual root group (lower-order roots). High rate of N addition retarded the decomposition of lower-order roots more in isolation than in mixture, due to the decreased binding of acid-unhydrolyzable residue to inorganic N ions in mixture. Therefore, we suggest that although stoichiometric heterogeneity holds within the branching hierarchy of fine roots, the tight coupling of N with acid-unhydrolyzable residue of root tissues may limit N use by microdecomposers, and thereby causing the additive effect. Since the mixing effect of order-based root decomposition is affected by N addition, understanding the chemical heterogeneity within fine root systems and their linkage with ambient N availability during decomposition either in isolation or in mixture may facilitate the accurate prediction of root decomposition responses to N loading.

Low Nitrogen Retention in Soil and Litter under Conditions without Plants in a Subtropical Pine Plantation

Soil acts as a major sink for added nitrogen (N) in forests, but it remains unclear about the capacity of soil to immobilize N under conditions without plant roots and whether added N interacts with ecosystem N to affect N retention. We added 15NH415NO3 to in situ soil columns (with leaching) and leaf litter (without leaching) of two tree species in a subtropical Pinus elliottii plantation. Soil and litter were collected three or eight months after N addition to measure concentrations of indigenous and exogenous N. About 70% of exogenous N was retained in soil three months after N addition, of which 65.9% were in inorganic forms. Eight months after N addition, 16.0% of exogenous N was retained in soil and 9.8%–13.6% was immobilized in litter. N addition increased the mineral release and nitrification of soil indigenous N. Loss of litter indigenous N was also increased by N addition. Our results suggest that N deposition on lands with low root activities or low soil carbon (C) contents may lead to increased N output due to low N immobilization. Moreover, the effects of added N on ecosystem indigenous N may decrease the capacity of soil and litter in N retention.

Allelopathic effects of Eucalyptus on native and introduced tree species

Allelopathy is widely considered to be one of the causes of biodiversity reduction in Eucalyptus plantations. However, most research conducted on the allelopathic effects of Eucalyptus is performed in the laboratory with weeds and crops as receptors, which fail to fully reflect natural ecosystems. In this study, we conducted two field trials and a greenhouse trial to assess the influence of soil allelopathy, allelochemical volatilization, and foliage litter decomposition on seed germination and seedling growth of three native (Acmena acuminatissima, Cryptocarya concinna and Pterospermum lanceaefolium) and one introduced (Albizia lebbeck) tree species in a Eucalyptus urophylla and Pinus elliottii plantation. In order to avoid confounding factors relating to management strategies and environmental influences, only one plantation of each species was used for experimentation. In the allelopathy experiment, the root length of the three native species was significantly inhibited in the E. urophylla plantation compared with that in the P. elliottii plantation. In the volatilization experiments, the seedling survival rate of the three native species was greater in the E. urophylla plantation, but significant differences were found for A. acuminatissima and C. concinna. Root length and dry weight of P. lanceaefolium increased significantly in the E. urophylla plantation, in the foliage litter decomposition experiments. There was no significant difference between the two plantations for A. lebbeck, except that the seedling survival rate was greater in the E. urophylla plantation in the foliage litter decomposition experiment. We concluded that allelopathy in the E. urophylla plantation was selective, which inhibited the growth of the native tree species but had no significant influence on the introduced A. lebbeck species. Allelopathy from volatilization and foliage litter decomposition contributed little to the inhibitory effects. We suggest that the introduced nitrogen-fixing species, A. lebbeck could be a potential choice for the establishment of mixed stands with Eucalyptus.

Global Warming Impact of E85 Fuel Derived from Forest Biomass: A Case Study from Southern USA

This study estimates global warming impact (GWI) of E85 fuel needed to run a small passenger car for its average lifetime, i.e., 241,402 km (150,000 miles). The ethanol needed for the production of E85 fuel was derived from an intensively managed slash pine (Pinus elliottii) plantation in the southern USA. We assumed that only pulpwood and harvesting residues obtained at the time of harvesting were used for ethanol production. A suitable system boundary was defined and a detailed life-cycle assessment was undertaken to determine GWI of all the steps present within the system boundary. Results indicate that the overall GWI of the E85 fuel was about 76% less than an equivalent amount of gasoline needed to run a small passenger car for its average lifetime. Within the system boundary, the GWI of the ethanol production stage was highest followed by the stage of E85 fuel consumption in a small passenger car. A need exists to evaluate impacts of utilizing forest biomass for E85 fuel production on forest ecology and traditional forest biomass-based industries.

Diversity of the families of Coleoptera captured with pitfall traps in five different environments in Santa Maria, RS, Brazil

The conservationist community is giving special attention to epigean insects due to their importance in the preservation of terrestrial habitats. This work analysed the diversity, richness, abundance and similarity at the soil surface of Coleoptera composition among five environments: native forest, native grassland, Pinus elliottii plantation, Eucalyptus saligna plantation and degraded area by soil use in southern Brazil, from October 2004 to October 2005. A total of 1,812 individuals were collected, attributed to 45 morph-species and 14 families. The higher richness and abundance were observed in native forest (31 species and 782 individuals) and the lower richness and abundance in degraded area (14 species, 86 individuals). Scarabaeidae was the richest family captured, with nine morph-species, and the most frequent family was Nitidulidae (1,113 individuals). According to the Shannon-Wiener index, the degraded area had smaller diversity in relation to the native forest, E. saligna and Pinus elliottii plantations. No difference in diversity between evaluated areas was found for the Simpson diversity index. The most dominant site was the degraded. The correlation between the total number of morph-species captured was not different to the degraded area and the P. elliottii monoculture (r = 0.47) and the correlation between the total individuals number was not significant between native forest and native grassland (r = 0.46) and between degraded areas and the other sites. According to the Jaccard Similarity Index, the greatest similarity for the organism composition occurred between P. elliottii plantation and E. saligna plantation, presenting 74% of overlap.

Forest management effects on in situ and ex situ slash pine forest carbon balance

In this study we analyzed the effect of silviculture on carbon (C) budgets in Pinus elliottii (slash pine) plantations on the southeastern U.S. Coastal Plain. We developed a hybrid model that integrates a widely used growth and yield model for slash pine with allometric and biometric equations determined for long-term C exchange studies to simulate in situ C pools. The model used current values of forest product conversion efficiencies and forest product decay rates to calculate ex situ C pool. The model was validated from a variety of sources, accurately simulating C estimates based on multiple measurement techniques and sites. Site productivity was the major factor driving C sequestration in slash pine stands. On high productivity sites, silvicultural schemes that promote sawtimber-type products are more suitable for increasing C storage (even not taking in account the consequent economical revenues associated with sawtimber production). When rotation length was increased from 22 to 35 years on unthinned and thinned stands, respectively, we estimated net increments of 26 and 20 MgC ha −1 in average C stock of the first five rotations. Even though in situ C pool in slash pine accounts for most of this net increment, C in sawtimber products increased from 8 and 14 to 23 and 24 MgC ha −1, on unthinned and thinned stands, respectively. Thinning effects on net C stock depended on intensity and timing of intervention, mainly due to changes in diameter classes that promote higher proportion of long-lived products. Emissions associated with silvicultural activities, including transportation of logs to the mill, are small compared to the magnitude of net C sequestration, accounting for between 2.2 and 2.3% of gross C stock. This slash pine plantation C sequestration model, based on empirical and biological relationships, is appropriate for use in regional C stock assessments or for C credit verification.