Fast-growing Tree Plantations Research Articles

Assessing Land-Cover Changes in the Natural Park ‘Fragas do Eume’ over the Last 25 Years: Insights from Remote Sensing and Machine Learning

The ‘Fragas do Eume’ Natural Park includes one of the best-preserved Atlantic forests in Europe. These forests are part of the Natura 2000 Network. This scientific study focuses on analysing land-cover changes in the ‘Fragas do Eume’ Natural Park (NW Spain) over a 25-year period, from 1997 to 2022, using machine learning techniques for the classification of satellite images. Several image processing operations were carried out to correct radiometry, followed by supervised classification techniques with previously defined training areas. Five multispectral indices were used to improve classification accuracy, and their correlation was evaluated. Land-cover changes were analysed, with special attention to the transitions between eucalyptus plantations and native deciduous forests. A significant increase in eucalyptus plantations (48.2%) (Eucalyptus globulus Labill.) was observed, while native deciduous forests experienced a decrease in their extent (17.6%). This transformation of the landscape affected not only these two habitats, but also cropland and scrubland areas, both of which increased. Our results suggest that the lack of effective conservation policies and the economic interest of fast-growing tree plantations could explain the loss of native deciduous forests. The results highlight the need to implement pro-active and sustainable management measures to protect these natural forest ecosystems in the ‘Fragas do Eume’ Natural Park.

Methods of energy production from biomass

Biomass, in addition to being used for heating purposes in households, is increasingly used for the production of electricity, as well as liquid fuels for motor vehicles. Similar to other renewable resources, the analysis of the possibility of using biomass (theoretical, technical and economic potential) should include a systematic analysis of available potentials and technologies, as well as economic parameters related to its price (biomass as raw material), the price of energy obtained from biomass (effectiveness of applied technology of transformation of primary into useful form of energy) and competitiveness in relation to other energy sources (static and dynamic economic-financial parameters). As there are different techniques and methodologies for estimating the potential of biomass, it is possible to significantly deviate from the obtained results in the estimated quantities, so it is necessary to further analyze the acceptability of the error in the assessment. The biggest obstacle in the use of biomass as an energy source for industrial purposes for energy production is the lack of a fuel cycle of a chaos system of processes, technologies and equipment that allow fuel from its natural state (primary form of fuel) to be prepared and brought into a usable state (usable forms of energy). The process of formation and development of the fuel cycle for biomass is further complicated by the diversity of forms and properties of biomass, its wide distribution and low energy concentration, as well as its seasonal character. The potential of biomass in the territory of Republic of Srpska comes from various production activities (residues from field, fruit, vineyard, livestock and forestry production, as well as municipal waste). Farming and animal husbandry have a long tradition among farmers in the Republic of Srpska, as well as fruit, vineyard and forestry production. The structure and quantities of communal waste depend on housing density, economic and communal activities, cultural habits and social environment. Biomass as an energy source is available in the form of waste from forestry and wood processing (waste wood from forestry, sawdust, bark, construction waste, wood packaging, plant residues from fruit production, plant residues from agricultural production - straw, corn, etc.), plantation of energy crops (energy cereals, fast-growing energy tree plantations, sugar-rich plants, oilseeds, etc.), as well as organic waste. The process of conversion of biomass into energy is most often observed from the thermal, i.e., thermo-chemical, biological or physic-chemical process. Within this chapter, an overview of the state and directions of development of technologies for the conversion of biomass as an energy source into a useful form of energy (primarily into electricity and heat) is given. Each method of energy production used, including methods that use biomass as fuel, has its advantages and disadvantages. Special emphasis was given to overcoming significant shortcomings in the use of biomass as an energy resource, as well as its impact on covering the total consumption of electricity and heat and technological steam in industrial plants, as well as consumption as biofuels in transport technology. A special segment is given to the impact of biomass as an energy source on environmental protection, as well as on the conditions that need to be provided in order to achieve CO2 neutrality. Also, the sustainability of each of the methods for the transformation of biomass into a useful form of energy was analyzed.

Land-use patterns of energy crops in the agricultural landscape

Lignocellulosic energy crops can produce substantial amounts of biomass for energy purposes, but their introduction implies land-use changes as they are mainly cultivated in agriculturally dominated landscapes. This thesis presents a land-use analysis of lignocellulosic energy crops in the agricultural landscape in Sweden, specifically aiming to i) assess different energy crops’ regarding production, location and climatic profiles, ii) characterise and define the surrounding agricultural landscape, and iii) study the overall land-use changes derived from the establishment of energy crops in the country. The analysis is based on empirical data from commercial fast-growing tree plantations (willow, poplar, and hybrid aspen) and energy grasses (reed canary grass) at multiple spatial scales from field to landscape level, during the period 1986-2018. At field level, there is a trend for smaller and more regular fields dedicated to energy crops, with cultivation patterns moving towards more productive lands, reflecting an intensification in the land-use management. Willow was initially established mainly on fallow lands, but many plantations were subsequently replaced by cereals due to changes in global cereal prices. In the case of grasses, this pattern was similar, although changes appeared later and not so markedly. At landscape level, energy crops significantly diversify the agricultural landscape, as fast-growing tree plantations are largely introduced in cereal areas and grasses in forest-dominated landscapes. The methods and analysis of this thesis contribute to a better understanding of land-use changes associated to energy crops, and help define their contribution to diversifying the agricultural landscape.

Effects of key forest management practices and climatic factors on the growth of Populus tomentosa plantations in the North China Plain

This study aimed to provide sustainable management recommendations for long-term poplar plantations in the North China Plain (NCP) within the context of climate change. Within the NCP, through primary literature and field surveys, we collected tree growth data of 2515 individual trees from monoculture stands of Populus tomentosa with different stand ages (1–40 years). Using linear mixed effects models, we examined the effects of different management practices (planting density, irrigation, and fertilization) and climatic factors (mean air temperature and climate moisture index) on tree growth at different stand ages. Results showed significant effects of all management practices on tree growth across stand ages. Also, the relative importance of management practices was higher than climatic factors. The effects of planting density and growing season climate moisture index (CMI) on tree growth gradually increased with stand ages. In contrast, no significant effect of growing season mean air temperature on tree growth was observed regardless of stand ages. Irrigation was the most important factor impacting tree growth in young stands. In addition, we found that irrigation and fertilization reduced the effect of CMI on tree growth in young stands. The relative importance of planting density and CMI did not differ for younger trees. However, the relative importance of planting density was higher than CMI in middle-aged and mature stands. We also found that the biologically mature age of unmanaged P. tomentosa stands in the NCP was about 15 years. In conclusion, our study highlights the importance of forest management practices and climatic factors for long-term poplar plantations in the NCP. Especially, planting density and moisture were critical factors for managing poplar plantations. The findings of this study can be relevant for intensively managing fast-growing tree plantations in other water-limited areas.

Comparison of Juvenile, Drought Tolerant Black Locust (Robinia pseudoacacia L.) Clones with Regard to Plant Physiology and Growth Characteristics in Eastern Hungary: Early Evaluation

(1) Background: The aim of our study is to present the results of initial growth and plant physiology studies of newly selected, vegetative propagated black locust clones, with a view to assess their suitability for the establishment of fast growing tree plantations for the production of high quality timber in marginal (semi-arid) sites. (2) Methods: In the spring (May) and autumn (November) of 2021, full inventories were carried out in the black locust industrial tree plantation. The Normalized Difference Vegetation Index (NDVI) values were observed monthly from May to September 2021. For measuring the assimilation parameters the net assimilation, transpiration, stomatal conductance, intercellular CO2 concentration, and other physiological parameters were recorded. (3) Results: Robinia pseudoacacia ‘NK2’ clone showed the highest assimilation rate and it produced the most height increment in the growing season, from May 2021 to November 2021. The discriminant analysis classified successfully the black locust clones, 86.7% of original grouped cases were correctly classified. (4) Conclusions: The study of industrial tree plantations is of great practical importance. As black locust can tolerate even marginal site conditions, the lack of timber can be reduced in the future by establishing black locust industrial tree plantations. To be able to produce good quality industrial wood on the plantations, it is essential to study the phytophysiological properties of the trees (biomass production, vegetation activity of plants, chlorophyll content, photosynthetic activity) in addition to the traditional stand full inventories.

Potential Areas in Poland for Forestry Plantation

Plantations have many advantages when compared to natural or semi-natural forests, such as shortening production cycles, the production of wood with specific characteristics, and near-market production concentrations. The intensive development of this form of industrial wood production is practiced all over the world. The wood industry in Poland struggles in recent years, with a large shortage of wood. The deficit of wood has been accumulated for several years and is steadily increasing. One of the possibilities to change this trend can be development of fast-growing trees plantations. The main aim of this study was to determine the potential of land in Poland, which could be used for the cultivation of fast-growing trees plantations. The analyses took into account the area and marginal agricultural land. The potential plantation land areas were determined for poplar cultivar “Hybrid 275” and European larch (Larix decidua Mill.). The results show a possibility to generate a considerable area that can be developed into plantations of fast-growing trees in Poland. According to the analyses carried out for the purpose of this study, with only 5% use of the sown area and 5% use of forest lands, as well as the boscage (wooded land and bushy land), it is possible to obtain approximately 0.6 MM ha of land for fast-growing tree plantations. In the case of planting 50% of these lands with larch and 50% with poplar, and if a 50% capacity of the plantation is assumed, it will be possible to obtain nearly 6 MM m3 of wood per year.

Selection of Eucalyptus camaldulensis Families for Sustainable Pulpwood Production by Means of Anatomical Characteristics

Sustainable pulpwood production from fast-growing tree plantations is needed for pulp and paper industries. To increase the pulpwood production efficiency, the anatomical characteristics and derived-wood properties of 75 trees from 15 half-sib families of Eucalyptus camaldulensis Dehnh. planted in Thailand were investigated, and then the family was classified by suitability of wood as raw material for pulp and paper products using principal component analysis and clustering. The mean values of vessel diameter, vessel frequency, fibre diameter, fibre lumen diameter, and fibre wall thickness at 2 cm from the cambium were 128 µm, 16 no./mm2, 11.1 µm, 7.1 µm, and 1.88 µm, respectively. In addition, the Runkel ratio, Luce’s shape factor, flexibility coefficient, slenderness ratio, solids factor, and wall coverage ratio (i.e., derived-wood properties) were 0.53, 0.42, 0.64, 85.3, 68 × 103 µm3, and 0.34, respectively. Significant differences in fibre diameter, fibre lumen diameter, and Runkel ratio were found among families. Although significant differences among families were not found for other anatomical characteristics and derived-wood properties, the p-values obtained by an analysis of variance test ranged from 0.050 to 0.088. Based on the results of a principal component analysis and cluster analysis, 15 families were classified into four clusters with different expected pulp and paper characteristics. The suitability of wood from E. camaldulensis half-sib families for pulp and paper can be evaluated by principal component analysis using anatomical characteristics and physical properties as variables. Based on the results, desirable pulp and paper quality may be obtained through the selection of families from this species.

Mapping of Eucalyptus in Natura 2000 Areas Using Sentinel 2 Imagery and Artificial Neural Networks

Plantations of fast-growing Eucalyptus trees have become a common sight in the western Iberian peninsula where they are planted to exploit their economic potential. Negative side-effects of large scale plantations including the invasive behavior of Eucalyptus trees outside of regular plantations have become apparent. This study uses medium resolution, multi-spectral imagery of the Sentinel 2 satellites to map Eucalyptus across Portugal and parts of Spain with a focus on Natura 2000 areas inside Portugal, that are protected under the European birds and habitats directives. This method enables the detection of small incipient as well as mixed populations outside of regular plantations. Ground truth maps were compiled using field surveys as well as high resolution satellite imagery and were used to train Feedforward Neural Networks. These models predict Eucalyptus tree cover with a sensitivity of up to 75.7% as well as a specificity of up to 95.8%. The overall accuracy of the prediction is 92.5%. A qualitative assessment of Natura 2000 areas in Portugal has been performed and 15 areas have been found to be affected by Eucalyptus of which 9 are strongly affected. This study demonstrates the applicability of multi-spectral imagery for tree-species classification and invasive species control. It provides a probability-map of Eucalyptus tree cover for the western Iberian peninsula with 10 m spatial resolution and shows the need for monitoring of Eucalyptus in protected areas.

Tree plantations replacing natural grasslands in high biodiversity areas: How do they affect the mammal assemblage?

Monoculture plantations of fast-growing trees are increasing worldwide and, in many cases, these replace highly diverse natural environments. The Mesopotamian Savannas and the Iberá marshes ecoregions of northeastern Argentina are a mosaic of habitat types in which extensive areas of natural grasslands have been replaced by the planting of non-native pines (Pinus spp.). Their impact on the natural communities is unknown. We evaluated the effect of these plantations, the landscape configuration and the forestry management practices on the assemblages of medium to large-size terrestrial mammals of this region at landscape and stand levels. Camera-trap stations were deployed in three environments: 89 in natural grasslands, 54 in native forest patches, and 91 in tree plantations. At a landscape level, we evaluated the effect of the type of environment and of the extent of different land covers on mammal richness per station using GLM, and on species composition using one-way PERMANOVA and redundancy analysis. At a stand level, we assessed the effect of understory vegetation, and of the age and density of tree plantation stands, on the similarity in mammal species composition between tree plantations and native environments, using non-metric multidimensional scaling analyses and GLM. Species richness and species composition differed between native forests and other environments, but not between grasslands and plantations. The variations in composition between the environments differed among the two ecoregions: the species composition in the plantations was different from the grassland assemblage only in the Iberá marshes, which suggests that the impact of tree plantations depends on the local pool of species. Mammal assemblages were also affected by the proportion of forests and wetlands and the environmental heterogeneity in the landscape. The similarity between the mammal assemblages of pine plantations and those of native forests increased with the age of the stand and at intermediate tree densities. In this grassland-dominated but heterogeneous landscape, it seems that most medium and large grassland mammals do not perceive tree plantations as a barrier, regardless of their management. Actions at a stand level, such as planting at intermediate tree densities and promoting longer rotation times, are desirable to encourage the forest mammal assemblage to use the plantations. Forests and wetlands are acting as keystone habitats for many species that are clearly associated with the presence of these environments in the landscape. Keeping large areas of natural grasslands and wetlands sprinkled with forests is essential for the conservation of the mammal assemblages of this region.

Deep soil carbon stock, origin, and root interaction in a tropical integrated crop–livestock system

Integrated crop–livestock systems (ICLS) with fast-growing tree plantations are an environmentally sound approach for agricultural production. Soil carbon stocks can be increased under these systems, but there is no information on the relative contributions of the pasture and the trees in building soil C in tropical regions. This study aimed to investigate C storage, origin, and roots sequestration in the soil profile (1.0 m) in a pasture-forest system. The study was conducted in a 6-year-old ICLS in which Eucalyptus (C3) were introduced into a palisade grass pasture [Urochloa brizantha (Hochst. Ex A. Rich.) R. Webster ‘Marandu’, C4]. Samples were collected at four locations perpendicular to the Eucalyptus planting line: 0 (planting line), 2.0, 4.0, and 6.0 m (middle of the plot). A monoculture palisade grass pasture was included for comparison. The insertion of Eucalyptus in the pasture modified the quantity and distribution of grass above and belowground. Forage root and shoot biomass were lower in the integrated system compared to the monoculture pasture, mainly near Eucalyptus. However, plant C sequestration in the ICLS was 68% higher than in the monoculture pasture, due to the C accumulated by aboveground trees biomass. Overall, monoculture pasture had higher soil C4–C stocks at the 0–0.20 m depth, while integrated system with Eucalyptus stored more C3–C in deeper soil layers (0.60–1.0 m) near Eucalyptus. Soil C stock increased in both systems, but the contribution of Eucalyptus was deeper in the soil profile, while the grass contribution was greater in the upper 0.20 m soil layers.

Economic profitability of particleboards production with a diversified raw material structure

To achieve sustainable development, coherence of three key elements is necessary: economic growth, social inclusion and environmental protection. They are interconnected and all are extremely important for achieving the well-being of individuals and entire societies. One of the key drivers of sustainable economic growth is the furniture industry, which is related to the maximum optimization of production cost while main-taining the high quality of the offered products. However, the expected material deficit may contribute to a significant weakening of growth dynamics. One of the possible solutions to this problem is harvesting timber from plantations of fast-growing trees that could supplement the increasing deficit of wood raw material. The research aimed to determine the cost-effectiveness of particleboard technology modification involving the change in the structure of raw material by introducing wood from fast-growing tree plantations. The research included an estimation of the unit cost of 1 m3 particleboard manufactured in the series production process. The analysis was carried out on the example of one of the leading particleboard suppliers for the Polish furniture industry and consisted in comparing the cost of production of particleboards based on wood from fast-growing tree plantations with the cost of particleboards, which are commonly available on the market. Three variants of the diversified raw material structure were taken into account: 100 % share (1), 50 % share (2) and 25 % share (3) of raw material from fast-growing tree plantations. The time range of the studies was adopted for the years 2014-2020. The research indicates that the introduction of wood from fast-growing tree plantations into the production of particleboards enables the production of material and energy cost savings at the level of 6 % (3rd variant) to even 17 % (1st variant). Variant 1 of material structure can lead to cost reduction at the level of US$ 13,0 million (in case of particleboards production capacity 570000 m3)

Slow-growing trees sequester more carbon

Tree Demography Dendrochronology—the study of tree growth patterns through the analysis of annual growth rings—is a powerful tool for studying the past but may also help to inform the future. Through tree-ring analysis of living and dead conifers from highland ecosystems in Spain and Russia, Buntgen et al. show that longest-lived individuals are those with the slowest juvenile growth rates. This means that higher levels of carbon accumulation are achieved in communities of slow-growing species, which indicates potential limits to the effectiveness of policies for carbon sequestration that rely on fast-growing tree plantations to mitigate the effects of global warming. Nat. Commun. 10 , 2171 (2019).

Effects of converting a temperate short-rotation coppice to a silvo-arable alley cropping agroforestry system on soil quality indicators

Short-rotation coppices (SRC) and alley cropping agroforestry systems (ACS) provide ecosystem services and environmental benefits. Particularly, their role in improving soil quality has frequently been emphasised. However, the economic lifetime of fast growing tree plantations may be limited, making a transition indispensable. Since information on effects of such land-use changes on soil microbial properties is scarce, the aim of this study was to assess effects of converting a German poplar-based SRC to a silvo-arable ACS, comprising rootstock incorporation and reduced tillage, on soil quality indicators after one year. Soils were sampled under poplars and within the re-converted alleyway. Distance transects were considered to further include potential beneficial effects of remaining trees on alleyway topsoil quality. We analysed soil organic carbon (SOC), total nitrogen, soil microbial biomass C and N, ergosterol, microbial activity (enzyme activities, multi-substrate-induced respiration rates), ratios relative to SOC, fungal abundance and microbial functional diversity at two topsoil depths (0–5, 5–20 cm). Repeated measures mixed effects models were calculated for each depth, considering spatial dependence structures and potential heterogeneity of abiotic factors (pH, clay contents). SRC to ACS conversion decreased SOC, microbial biomass and activity in upper topsoils within the arable alleyway, irrespective of tree distance. Furthermore, shifts in the composition of main microbial groups towards a lower fungal abundance and functional diversity were observed. Reductions of fungal indices were also identified in lower topsoils. Unexpectedly, results demonstrated that partial conversion of a SRC back to arable cropping decreased soil quality within as little as one year.

Ant taxonomic and functional diversity show differential response to plantation age in two contrasting biomes

The increasing global demand for lumber and pulp has led to the conversion of natural habitats into monocultures of fast-growing tree plantations. The environmental filtering model proposes that both environmental characteristics of anthropogenic habitats and biotic interactions act as a filter that can be passed through by some species of the regional pool, driving the formation of local assemblages. Therefore, environmental filtering promotes the selective loss of species and convergence of functional traits, resulting in assemblages of species that are functionally more similar than expected by chance. In Argentina, pine monocultures have expanded in both subtropical forest and grassland biomes. Typically, environmental similarity between plantations and natural habitat decreases in the grassland and increases in the subtropical forest with increasing plantation age (time since pine stands were planted). Then, we predict that changes in biological diversity with plantation age will be opposite when plantations develop in environmentally contrasting biomes. To test the prediction, we studied taxonomic (species richness) and functional (based in morphological functional traits) diversity of epigeal ant assemblages in pine plantations of different ages (from 1 to 12 years old), developing in contrasting biomes that determined different contexts of the main natural (i.e., native) habitat: subtropical forest and grassland. Temperature, humidity and vegetation cover were recorded, and ants were collected using pitfall traps. For plantations and natural habitats of both biomes, we estimated functional diversity in sets of randomized communities and compared them with the observed functional diversity throughout plantation age. As expected, results showed opposite environmental similarity gradients between natural habitats and plantation ages. In the subtropical forest, ant species richness remained similar but functional diversity increased with increasing plantation age, associated with the presence of predatory ants. In the grassland, species richness showed a maximum at intermediate ages, but functional diversity remained similar with increasing plantation age. Null model analyses showed lower functional diversity than expected by chance in young plantations developing in the subtropical forest and at all ages in grassland, indicating convergence of functional traits. Our findings support environmental filtering as the primary mechanism driving the formation of ant assemblages along pine plantation cycle. To our best knowledge, this is the first study analysing patterns of diversity along tree plantation cycles developing in contrasting biomes. Our results show that the biome effect should be taken into consideration to predict diversity responses to commercial forestry and to unify a theory of assemblage formation in monoculture plantations.

Grounding nature-based climate solutions in sound biodiversity science

The current narrow focus on afforestation in climate policy runs the risk of compromising long-term carbon storage, human adaptation and efforts to preserve biodiversity. An emphasis on diverse, intact natural ecosystems — as opposed to fast-growing tree plantations — will help nations to deliver Paris Agreement goals and much more.

Eucalyptus grandis plantations: effects of management on soil carbon, nutrient contents and yields

The expansion of fast-growing tree plantations is a worldwide process, with consequences on soil fertility and soil carbon storage. Disparate results were found on the effects of afforestation with Eucalyptus on soil carbon and other nutrient contents. These discrepancies are usually caused by differences in climate, land use history, soil texture as well as by management related factors such as plantation age, number of rotations, method of establishment (plantation or coppice), harvest residue management and soil preparation. We studied the effect of plantation age, number of rotations, and method of establishment on soils and plant nutrient concentrations in Eucalyptus grandis plantations in NE Argentina on different textured soils. We also determined if yields changed with nutrient variations in soils, and compared soils under plantations to soils under grasslands they replaced. Thirty-one E. grandis stands of different ages, number of rotations and method of establishment were evaluated as well as eight grassland sites. Levels of carbon, nitrogen, phosphorus, potassium, calcium and magnesium were determined for soils and plants. Soil carbon and nitrogen decreased over the number of rotations and were more pronounced in soils with 50–60% sand than soils with > 75% sand. Coppice stands showed higher soil carbon and nitrogen levels than plantations, suggesting a negative effect of site preparation before planting on soil nutrient conservation, especially in fine-textured soils. Foliar nutrient concentrations did not follow the trends observed for soil nutrients nor did they reflect nutrient limitations. There was no evidence of decreased yields over successive rotations. Soil carbon and nitrogen contents decrease when grasslands are replaced by E. grandis plantations, and therefore a yield limitation may occur in a medium to long-term frame, especially in stands re-established for short-rotation management. Harvest residue management and site preparation must be specifically designed for improving soil nutrient management.

Fast-growing hybrids do not decrease understorey plant diversity compared to naturally regenerated forests and native plantations

Plantations of fast-growing hybrid trees, such as hybrid poplars and hybrid larch, are increasingly used for wood and timber production, but they are also believed to impair forest biodiversity. Most studies that have assessed how such plantations may alter the diversity and composition of understorey plants were established in agricultural landscapes or have compared tree plantations with old-growth natural forests. Moreover, many important aspects of biodiversity have been overlooked in previous studies, such as functional and beta-diversity. Here, we present results from a study that was aimed at quantifying alpha- and beta-diversity of understorey plant species and functional groups in hybrid poplar (9–10 years) and hybrid larch plantations (16 years) located within a forested landscape of Quebec, Canada. These hybrid plantations were compared to naturally regenerated secondary forests and to native plantations of black spruce of the same origin (clear cut) and similar age. Our results indicate that fast-growing hybrid plantations do not present lower taxonomic and functional alpha-biodiversity indices, but may harbour more diverse communities, in part through the introduction of plant species that are associated with open habitats. We provide further evidence that planted forests may be as heterogeneous as naturally regenerated forests in terms of understorey plant composition. Plant species and functional composition differed slightly between stand types (naturally regenerated forests, native and fast-growing hybrid plantations), with plantations offering a greater potential for colonisation by ruderal species, while being detrimental to species of closed forest habitats. Lastly, plantations of fast-growing hybrids do not induce greater changes in understorey vegetation relative to native plantations of black spruce, at least during the first stand rotation.

A Robust Productivity Model for Grapple Yarding in Fast-Growing Tree Plantations

New techniques have recently appeared that can extend the advantages of grapple yarding to fast-growing plantations. The most promising technique consists of an excavator-base un-guyed yarder equipped with new radio-controlled grapple carriages, fed by another excavator stationed on the cut-over. This system is very productive, avoids in-stand traffic, and removes operators from positions of high risk. This paper presents the results of a long-term study conducted on 12 different teams equipped with the new technology, operating in the fast-growing black wattle (Acacia mangium Willd) plantations of Sarawak, Malaysia. Data were collected continuously for almost 8 months and represented 555 shifts, or over 55,000 cycles—each recorded individually. Production, utilization, and machine availability were estimated, respectively at: 63 m3 per productive machine hour (excluding all delays), 63% and 93%. Regression analysis of experimental data yielded a strong productivity forecast model that was highly significant, accounted for 50% of the total variability in the dataset and was validated with a non-significant error estimated at less than 1%. The figures reported in this study are especially robust, because they were obtained from a long-term study that covered multiple teams and accumulated an exceptionally large number of observations.

Carbon storage in biomass, litter, and soil of different native and introduced fast-growing tree plantations in the South Caspian Sea

Replantation of degraded forest using rapid-growth trees can play a significant role in global carbon budget by storing large quantities of carbon in live biomass, forest floor, and soil organic matter. We assessed the potential of 20-year old stands of three rapid-growth tree species, including Alnus subcordata, Populus deltoides and Taxodium distichum, for carbon (C) storage at ecosystem level. In September 2013, 48 replicate plots (16 m × 16 m) in 8 stands of three plantations were established. 36 trees were felled down and fresh biomass of different components was weighed in the field. Biomass equations were fitted using data based on the 36 felled trees. The biomass of understory vegetation and litter were measured by harvesting all the components. The C fraction of understory, litter, and soil were measured. The ecosystem C storage was as follows: A. subcordata (626.5 Mg ha−1) > P. deltoides (542.9 Mg ha−1) > T. distichum (486.8 Mg ha−1) (P < 0.001), of which 78.1–87.4% was in the soil. P. deltoides plantation reached the highest tree biomass (206.6 Mg ha−1), followed by A. subcordata (134.5 Mg ha−1) and T. distichum (123.3 Mg ha−1). The highest soil C was stored in the plantation of A. subcordata (555.5 Mg ha−1). The C storage and sequestration of the plantations after 20 years were considerable (25–30 Mg ha−1 year−1) and broadleaves species had higher potential. Native species had a higher soil C storage while the potential of introduced species for live biomass production was higher.

Evaluation on community tree plantations as sustainable source for rural bioenergy in Indonesia

Indonesia has forest plantation resources in rural areas far from the national electricity grid that have potential as feedstock for biomass based electricity generation. Although some fast growing tree plantations have been established for bioenergy, their sustainability has not been evaluated to date. This research aimed to evaluate the growth of several tree species, cultivated by rural communities in Jawa Island, for their sustainability as a source for bio-electricity. For each tree species the biomass was calculated from diameter and height measurements and an estimate made for potential electricity generation based on density of available biomass and calorific content. Species evaluated included Acacia mangium, A. auriculiformis, A. crasicarpa, Anthocephalus cadamba, Calliandra calothirsus, Eucalyptus camaldulensis, Falcataria moluccana, Gmelina arborea, Leucaena leucochephala and Sesbania grandiflora. Among these species Falcataria moluccana and Anthocephalus cadamba showed the best potential for bioenergy production, with up to 133.7 and 67.1 ton/ha biomass respectively, from which 160412 and 80481 Kwh of electricity respectively could be generated. Plantations of these species could potentially meet the estimated demand for biomass feedstock to produce bioenergy in many rural villages, suggesting that community plantations could sustainably provide much needed electricity.