Afforestation Techniques Research Articles

How Does The Change in Ratio of Vascular Plants to Biocrusts After Revegetation on Desert Soil Affect The Soil Hydrology?

Land desertification is one of the most serious challenges to the ecological environment in the world today, threatening the survival and development of mankind. China is one of the countries in the world with the most serious desertification problem, which causes land degradation, soil quality decline, reduced vegetation cover, sand and dust, and other catastrophic weather problems. Greening and afforestation is an effective measure to improve the local ecological environment of desertification, and different areas need to adopt different afforestation techniques, taking into account local climatic conditions and geological features. This study aims to rank the three basic types of sand-binding vegetation in terms of suitability to be cultivated in desert soil by evaluating their ability to absorb infiltrated water and find a suitable shrub/herb planting ratio to achieve sustainable development in the sand-controlled area.

Seeing the forest for the trees? An exploration of the Miyawaki forest method in the UK

ABSTRACT The “Miyawaki forest” is described as a dense, fast-growing and biodiverse native forest. It is based on afforestation management methods pioneered by Dr Akira Miyawaki in the 1970s. The “Miyawaki Forest method (MFM)” relies on intensive ground preparation and dense tree planting from the onset, a system that claims to enhance tree growth and be biologically richer than other afforestation techniques. Applied in urban environments, it claims to reconnect people with nature and enhances human wellbeing. It has recently been introduced in Western countries culminating in hundreds of recent MFM tree planting projects in the UK dating from 2020 onwards. However, there is very little accompanying research investigating how feasible and applicable MFM is in the UK context. This paper addresses this gap by ascertaining the knowledge of, and attitudes towards, MFM of a small sample of professionals and practitioners (n = 12). The results showed how those opinions varied on the potential of applying the method in a temperate climate. Half the interviewees supported using MFM in practice and there was broad support for its application in specific urban landscapes, including school playgrounds and pocket parks. Cost was seen to be an important factor with perceived high initial costs and high tree mortality through competition. Interviewees did not consider MFM to be feasible in rural areas. Interviewees agreed that the MFM could be useful for ecosystem services such as carbon sequestration and storage, flood management and connecting people to nature, but they also called for more, and longitudinal, research into the method to fully understand its suitability in the UK.

Fertilization reduces root architecture plasticity in Ulmus pumila used for afforesting Mongolian semi-arid steppe.

In this study, we assessed the functional and architectural traits in the coarse roots of Ulmus pumila trees, which are used for afforesting the semi-arid steppe of Mongolia. Tree growth was supported by different watering regimes (no watering, 2, 4, and 8 L h−1) and by two types of soil fertilization (NPK and compost). In July, 2019, for each of these treatments six trees, outplanted in 2011 as 2-year-old seedlings from a container nursery, were randomly selected, excavated by hand, and digitized. The build-up of root length correlated positively with increasing levels of watering for both soil depths analyzed. The application of fertilizers led to root growth suppression resulting in a general reduction of root length in a lowered rooting depth. When root system characteristics were analyzed in relation to wind direction, unfertilized trees showed higher root diameter values in both soil layers of leeward quadrants, likely a response to mechanical forces to improve stability. On the contrary, fertilized trees did not show differences in root diameter among the different quadrants underscoring a strong reduction in root plasticity with a lack of morpho-architectural response to the mechanical forces generated by the two prevailing winds. Finally, the root branching density, another important trait for fast dissipation of mechanical forces, was significantly reduced by the fertilization, independently of the quadrants and watering regime. Our results suggest that knowledge of the root response to the afforestation techniques applied in the semi-arid steppe of Mongolia is a necessary step for revealing the susceptibility of this forest shelterbelt to the exacerbating environmental conditions caused by climate change and, thus, to the development of a sustainable and successful strategy to restore degraded lands.

The relationship between carbon fixation and dendrometric characteristics of native species in São Paulo's forest fragments

The increase in carbon dioxide (CO2) implies the intensification of the greenhouse effect, since from a quantitative point of view it is the most responsible for the process. The result of this effect is the disturbance of the energy balance between the earth and the atmosphere, causing climate change on the planet. There is the possibility of reducing greenhouse gas emissions to the atmosphere through planting with forest species, combined with sustainable reforestation and afforestation techniques in areas that have suffered human disturbance. In this context, our goal is to evaluate the potential for carbon sequestration and fixation in three forest fragments in the Tottori friendship forest in the City of São Paulo at eight years of age for 33 forest species. The species were grouped into four distinct groups, with distinct main characteristics. However, it was observed that 28 from 35 species do not present an outstanding characteristic for the grouping. The other seven species stood out for presenting dendrometric characteristics with carbon sequestration and fixation, specifically Clitoria faichirdina and Samanea saman. Among the characteristics that are most related to carbon sequestration and fixation were DBH, Stem volume and total volume, wood density was the characteristic that was least correlated with the others evaluated. It is recommended that an assessment be carried out at older ages to verify whether the grouping and values of carbon sequestration and fixation change over time, and possibly explain how the botanical family of a given species can influence carbon sequestration and fixation and plantations of forest fragments.

Influence of water and nutrients on cork oak radial growth – looking for an efficient fertirrigation regime

The widespread cork oak (Quercus suber L.) mortality and reduced afforestation /regeneration are causing an overall reduction in cork production. To enhance trees’ growth and vitality, afforestation techniques using fertirrigation were tested. The main objective was the promotion of trees’ growth on new dense plantations using minimum water requirements until reaching productive forests. The experimental plot – Irricork – was installed in 2017 in a ≈1 ha stand with 14 years’ age cork oaks summer-fertirrigated since plantation. Four fertirrigation treatments were applied during fertirrigation campaigns. Radial growth, meteorological parameters and fertirrigation volume were measured every 15–30 days over four years. It was observed that weather, tree size, debarking and trees’ intra-competition had a significant effect on radial increments. Fertirrigation significantly enhanced growth during summer drought and decoupled increments from air vapor pressure deficit constraints. There was a linear relationship between trees’ radial increments and fertirrigation volume up to 140 m3 week–1. Above this value, increments were smoother. In conclusion, summer fertirrigation of 140 m3 week–1 efficiently enhanced the radial growth of trees with 50–75 circumference at breast height, under the particular edaphoclimatic conditions of the stand. This study showed to be, therefore, promising in the use of efficient fertirrigation the enhance cork oaks’ radial growth.

Evaluation of geomorphometric characteristics and soil properties after a wildfire using Sentinel-2 MSI imagery for future fire-safe forest

Understanding spatiotemporal geomorphological and pedological changes as a consequence of wildfires can allow stakeholders, land planners, and policymakers to design efficient fire safety-based afforestation and restoration programs of forest lands. The use of remote sensing techniques is a key tool to achieve this goal. The suitable combination of Sentinel-2 MSI data for mapping of different spectral indices related to burn severity and their relationship with other morphometric and soil properties can contribute to a better understanding of the impact of fire, and this is relevant in regions where is still scarce fire-related research such as Turkey. In this investigation, the use of NDVI (Normalized Difference Vegetation Index), dNDVI (Difference Normalized Difference Vegetation Index), NDWI (Normalized Difference Water Index), NBR (Normalized Burn Ratio), dNBR (Difference Normalized Burn Ratio), RBR (Relativized Burn Ratio), SBI (Soil Bare Index), As (Upslope area), CTI (Compound Topographic Index), TCI (Terrain Characterization Index), SPI (Stream Power Index) and Curvature (Standard Curvature) were combined. As a study case, 47.43 ha in a burned area of Çınarpınar forest unit, Andırın, Kahramanmaraş in Turkey was selected. The results showed that dNDVI, dNBR, RBR, SBI contribute to relevant information about the effect of the wildfire. According to the dNBR fire severity classification, 75% of the total area has been exposed to high-severity fire. The relationship of Sentinel MSI satellite images with some soil and morphometric features have been found meaningful to understand the impact of forest fire in Mediterranean ecosystems. The information collected in the Turkish forest areas affected by wildfires should be relevant for planning and represent a key contribution to the selection of restoration programs and afforestation techniques for a future fire-safe forest.

Aeolian Activities and Protective Effects of Artificial Plants in Re-vegetated Sandy Land of Qinghai Lake, China

Land desertification and aeolian activity are currently the greatest threats to alpine ecological environments and are also the primary challenges of desertification control and ecological restoration projects. Afforestation of sandy lands around the Qinghai Lake in China has effectively controlled the desertification of this watershed. However, certain issues remain which challenge its overall success, including lack of diverse biological species and poor theoretical understanding of aeolian processes, such as controlling wind-sand flow in relation to complex alpine ecological factors. Therefore, to help improving afforestation techniques, this research focused on Hippophae rhamnoides, Salix cheilophila, Pinus sylvestris, Populus simonii and Artemisia desertorum vegetation implanted in the mobile dunes on the eastern shore of Qinghai Lake. Aeolian transport characteristics and annual changes to community ecological factors from 2010–2016 were monitored in comparison with uncontrolled sand dunes. Based on simultaneous observations using gradient anemometers and sand samplers, it was found that the aeolian activities exhibited the following features: 1) In re-vegetated lands, the logarithmic growth of wind speed was disrupted by the wind speed amplification in the middle and high layers and wind speed reduction in the low layers, while vegetation had significant wind-breaking (> 37%) and sand-fixing (> 85%) effects in 2016. 2) Wind speeds in re-vegetated lands and mobile dunes showed a linear correlation, especially in lower layers of H. rhamnoides and S. cheilophila, while sand transport in re-vegetated land increased linearly or exponentially with increasing wind speed. 3) The four artificial shrubs and forests had greater sand deposition with intensities of 280–860 t/(ha·yr), largely concentrated during winter and spring which accounted for 60%–85% of the annual cycle, while A. desertorum experienced significant root undercutting; and 4) Intensity of aeolian activity in re-vegetated lands, except for A. desertorum, was significantly negative with respect to plant growth structure, community cover, topsoil moisture, and regional precipitation. Overall, these five sand-binding species produced optimistic wind-sand protection effects for the alpine sandy lands, which relied on the plants’ physical disturbance of wind-sand flow during the early stages of community development. In comparison, H. rhamnoides and S. cheilophila individually maintained stable wind-sand protection effects, while P. sylvestris and P. simonii were better in mixing with other shrubs and herbs to achieve a comprehensive ecological system for future control of aeolian activity.

Fish‐scale pit effects on erosion and water runoff dynamics when positioned on a soil slope in the Loess Plateau region, China

AbstractSoil moisture construction is a very important way to reduce soil erosion and maintain crop growth in arid and semiarid regions of China. A microcatchment technique for soil erosion prevention widely used on soil slopes on the Loess Plateau are fish‐scale pits (FSPs). This technique is combined with afforestation techniques to store runoff, interrupt the dynamics of soil erosion, and help mitigate frequent water deficiencies encountered by forest trees. This study investigated the effects of FSPs on soil erosion dynamics including rill formation and runoff. A three‐dimensional (3D) laser scanner was used to evaluate the erosion resistance of a 15° slope treated with FSPs arranged in a triangular pattern and the hydraulic characteristics of the flow on this slope during several intermittent simulated rainfall events. The following results were obtained. (a) The FSP‐treated slope displayed eight progressive stages of erosion: splash erosion, sheet erosion, scouring by water streams, formation of the scour pits, rill erosion, down‐slope erosion, up‐slope erosion, and collapse of the pit walls. (b) As the rainfall duration increased, the runoff velocities at various locations on the slope fluctuated, but generally, the runoff velocities were significantly higher in the down‐slope positions than for the midslope and upslope positions. When the cumulative rainfall duration reached approximately 58 min and the total rainfall reached approximately 88.5 mm, the ability of the FSPs to intercept and store runoff rapidly decreased. In the first two rainfall events, both the runoff reduction benefits (RRB) and sediment reduction benefits (SRB) were positive, but following the third rainfall event, the SRB and RRB of the FSPs were negative. The accuracy of erosion parameters extracted using the 3D laser equipment and the ArcGIS software in comparison with the measured rill erosion parameters all less than 10%. The relative error between the measured sediment and the calculated sediment is within 5.66–22.13%. (c) During the rainfall process, the flow on the upslope was constantly in the laminar regime, but after the FSPs were completely filled with water, the laminar flow on the downslope transitioned into a turbulent flow. (d) As the cumulative rainfall duration increased, the degree of topographic relief and the number of rills increased, as did the measurements of surface roughness and flow resistance. In conclusion, the microcatchment methods reduced the rill erodibility and enhanced the soil's resistance to concentrated flow erosion.

Bibliometric evaluation of the status of Picea research and research hotspots: comparison of China to other countries

Picea Mill. species are important components of boreal and subalpine forests. They have a wide geographical range in the Northern Hemisphere, extending from the Eurasian continent to North America. In this study, publications on Picea species from 2002 to 2016 were identified via the Web of Science (WoS) and the China National Knowledge Infrastructure (CNKI) databases, and subjected to relationship network visualization using CiteSpace software. This study represents the first such analysis of Picea and provides a reference for bibliometrics in forest tree species research. The results show that the total number of publications on Picea archived in WoS was 20,958 and that the number of papers published annually has increased over time, peaking at 1725 in 2013. The studies were mainly conducted in North America, Europe and Asia; among them, Canada published the most papers and showed the strongest betweenness centrality (0.11). Among research institutions, the Swedish University of Agricultural Sciences in Uppsala had the highest publication record. The research contributions of the Chinese Academy of Sciences, the Chinese Academy of Forestry, and Beijing Forestry University have improved rapidly in recent years, greatly enhancing the international impact of Chinese research in this field. The research contents were grouped into five categories: forest ecosystems, pest resistance, extraction and functional analyses of active ingredients from various plant organs, nursery and afforestation techniques, and timber quality research. In China, the number of papers from the CNKI database was 4532, increasing at an even pace. The research topics on Picea included forest ecosystems, seedling and afforestation techniques, basic studies on individual species and populations, and pests and diseases. Within and outside China, hotspots in Picea research included the relationships between Picea and environmental factors, and the genomic sequences of Picea.

Effects of secondary succession and afforestation practices on soil properties after cropland abandonment in humid Mediterranean mountain areas

Cropland abandonment and subsequent revegetation processes (due to secondary succession and afforestation practices) are global issues with important implications in Mediterranean mountain areas. Several publications have reviewed the impact of cropland abandonment and revegetation on the soil properties dynamics but, so far, limited attention has been paid to Mediterranean humid mountain areas. This paper examines six neighbouring land covers, in the Central Spanish Pyrenees to determine the effects of land covers, cropland abandonment and consequently secondary succession and afforestation practices on soil properties. For this purpose, a total of 85 samples from 6 land covers and from two soil depths were analysed. We observed that changes in soil properties after cropland abandonment were limited, even if afforestation practices were carried out, and no differences were observed between natural succession and afforestation. Land cover and depth had a significant effect on the physical and chemical variables, being larger in the uppermost 0–10cm depth. The organic and inorganic carbon and N concentration, SOC and TN stocks, CN ratio, organic matter, and bulk density showed significant differences. Afforestation improved soil properties, aggregate stability and carbon concentration and stocks when compared to neighbouring bare soils. A soil quality index −based on statistical analysis- suggested that natural forests and Pinus nigra areas developed a higher soil quality rating. Our general results also demonstrated that the impact of disturbance by afforestation techniques (microsites) is difficult to discern. The differences found with respect to the native forest appear to indicate that the afforested soils have not yet reached their maximum soil quality and maximum potential as soil organic carbon sink. As there was no difference found between the soil improvement by natural succession in comparison to afforestation, these results put the question forward which type of forest and landscape management is most appropriate to decide for the best practices after cropland abandonment for soil recovery and erosion control.

Changes in soil aggregation and microbial community structure control carbon sequestration after afforestation of semiarid shrublands

Changes in plant cover after afforestation induce variations in litter inputs and soil microbial community structure and activity, which may promote the accrual and physical-chemical protection of soil organic carbon (SOC) within soil aggregates. In a long-term experiment (20 years) we have studied the effects, on soil aggregation and SOC stabilization, of two afforestation techniques: a) amended terraces with organic refuse (AT), and b) terraces without organic amendment (T). We used the adjacent shrubland (S) as control. Twenty years after stand establishment, aggregate distribution (including microaggregates within larger aggregates), sensitive and slow organic carbon (OC) fractions, basal respiration in macroaggregates, and microbial community structure were measured. The main changes occurred in the top layer (0–5 cm), where: i) both the sensitive and slow OC fractions were increased in AT compared to S and T, ii) the percentage and OC content of microaggregates within macroaggregates (Mm) were higher in AT than in S and T, iii) basal respiration in macroaggregates was also higher in AT, and iv) significant changes in the fungal (rather than bacterial) community structure were observed in the afforested soils (AT and T) – compared to the shrubland soil. These results suggest that the increase in OC pools linked to the changes in microbial activity and fungal community structure, after afforestation, promoted the formation of macroaggregates – which acted as the nucleus for the formation and stabilization of OC-enriched microaggregates.

Carbon dynamics after afforestation of semiarid shrublands: Implications of site preparation techniques

Climate change is a potential threat to soil organic carbon (SOC) in semiarid ecosystems. Several studies advocated afforestation as an important way to achieve soil C accumulation, but few deal with the mechanisms of C stabilization. The knowledge of these mechanisms is a key aspect in the preservation of SOC in the face of climate change. In a long-term experiment in southeast Spain, we analyzed the effect on C sequestration and stabilization mechanisms of two Pinus halepensis afforestation treatments: (a) terracing (T) and (b) terracing with soil amendment (AT). Twenty years after installing the pine plantations, changes were measured in: (a) chemical, physical, and biological soil properties, (b) ecosystem C stocks, and (c) three functional SOC pools: particulate organic matter (POM), sand and stable aggregates (S+A), and silt plus clay (S+C). The results show that the afforestation treatment had a distinct impact on soil properties. Compared with the adjacent native shrubland, the AT treatment led to improved soil fertility, while the T treatment had a negative impact on soil properties. In turn, AT led to a C gain in the ecosystem of 1.3kgCm−2, while with T there was a decline of 0.60kgCm−2 over 20years. This decline was due to the impact of the terracing work. The potential ecosystem C sequestration capacity of the afforestation was 160 and 65gCm−2year−1 in AT and T, respectively. Focusing on sequestration in the mineral soil, the average annual sequestration rate was 28gCm−2year−1 in AT and 17gCm−2year−1 in T. In relation to the functional SOC pools, the C sequestered showed the following distribution: 30% POM, 46% (S+A), and 24% (S+C). The results show that C sequestration, through afforestation of semiarid areas, can be increased by using suitable afforestation techniques. Site preparation involving large soil disturbance is not recommended. Twenty years after planting, the potential capacity for C sequestration of the afforested ecosystems is far from being saturated and they will continue sequestering C as they reach maturity.

Assessment of Landuse Change and Its Impact on Watershed Hydrology Using Remote Sensing and SWAT Modeling Techniques—A Case of Rawal Watershed in Pakistan

Assessment of hydrological effects of the landuse transformations on both water yield and flow regimes is an imperative aspect in watershed management. Dealing with water management issues requires analyzing of different elements of hydrologic processes taking place in a watershed area. In the present study, hydrological response of the Rawal watershed (located in the sub-Himalayan region) was studied to historical landuse evolution and variable landuse change scenarios using SWAT -Soil and Water Assessment Tool model. The temporal analysis of LANDSAT TM (1992) and LANDSAT ETM plus (2010) image data revealed a decrease of over 16% in the scrub forest coverage while built-up land increased three folds during 1992-2010 period. Major part of the scrub forest had converted into agriculture and built-up land besides rangeland in some areas. The landuse changes resulted in an increase of about 6.0% in the water yield and 14.3% in the surface runoff of the watershed. The scenario of extreme deforestation likely due to growth in urbanization, exhibited a decrease of about 0.4% in the water yield and an increase of about 122% in the sediment yield from base conditions of 2010 period. In case of an afforestation scenario (e.g. increase of scrub coverage to about 76%), the sediment yield decreased by about 11.4%. Appropriate soil conservation measures based on suitable afforestation techniques can prove influential in mitigating the risk of soil erosion in this fragile mountain ecosystem of the Himalayan region.

Discussion on Afforestaion Techniques in Salt-Alkaline Soil in Northern Ningxia

based on the investigation of afforestation project in 2007 in Pingluo city of Ningxa province, this paper analyzed the change of salt concentration of soil and the planting survival rate, and then proposed the afforestation techniques system for saline-alkaline soil in northern Ningxia. The result showed that: (1) Under application of organic fertilizer and irrigation water to reduce salt concentration in the soil, the salt concentration of the soil depths of 10 cm to 30 cm and 30 cm to 50 cm were (1.37 g/l), and the planting surviving rates for Tamarix chinensis, Amorpha fruticosa, Elaeagnus angustifolia, and Populus euphratica were 75%, 75.4%, 96.8% and 92.6% respectively. But with the film covering on the bottom of the planting hole and irrigating water to reducing salt, the salt concentrations for the two soil depths were all 1.28g/l, and the planting surviving rate of D was only 11.4%. (2) Under elevating the planting surface and increasing the soil depth by 80 cm to 100 cm with the soil from trench, and application of organic fertilizer and irrigation water to reducing salt, the salt concentrations for two depth layers were around 0.36g/l, and the planting surviving rates of Elaeagnus angustifolia, Sophora japonica, Tamarix chinensis, and Amorpha fruticosa were 84/1%, 91.1％, 99.5%, and 82.5% respectively. But when soil depth was increased by 40cm to 60cm, the salt concentrations were between 0.65g/l to 0.71g/l, and the planting surviving rates for Amorpha fruticosa, Tamarix chinensis, Elaeagnus angustifolia, Sophora japonica, Euonymus bungeanus were 81.2%, 64.3%, 93.6%, 83.8%, and 100% respectively. (3) Afforestation is a kind of systemic project, if planting is based on selecting some salt resistance tree species such as Amorpha fruticosa, Tamarix chinensis, Elaeagnus angustifolia, Populus euphratica, Atriplex canescens, Nitraria sibirica, Hippophae rhamnoides, Lycium chinense, Sophora japonica, Euonymus bungeanus etc. with the techniques of elevating the planting surface and increasing the soil depth, covering film on the bottom of planting hole, ground surface covering and seedling treatment with chemicals, and application of organic fertilizer, soil amending chemicals and irrigation water to reduce salt, the planting survival rates will be increased in salt-alkaline soil in northern Ningxia.

New approaches concerning forest restoration in a protected area of central Italy: an introduction

Following a review of the traditional afforestation techniques in Italy, the new forest restoration criteria and techniques require creativity with a solid scientific knowledge and further aims need to be pursued to maintain or enhance biodiversity and repair ecosystem functions. A case study concerning forest restoration of abandoned agricultural land in the Gran Sasso and Monti della Laga National Park (central Italy) was analysed. The choice of native tree species was carried out according to the symphytosociological approach; the restoration of vegetation may be accelerated by planting early successional tree species belonging to the same series of vegetation. The cultural techniques included the partial release of shrub vegetation invading abandoned land, and site preparation techniques of low environmental impact (i.e. clustered arrangement, curved rows) applied according to soil morphology. Five years after planting, damage by animals, survival rates, vitality status and total height of different tree species, and effects of competition by shrub vegetation on tree growth were assessed.

Establishing a Research and Demonstration Area Initiated by Managers: The Sharkey Restoration Research and Demonstration Site

Abstract As forest scientists increase their role in the process of science delivery, many research organizations are searching for novel methods to effectively build collaboration with managers to produce valued results. This article documents our experience with establishment of a forest restoration research and demonstration area in the Lower Mississippi Alluvial Valley (LMAV), a region that has experienced extensive afforestation of former agricultural land over the past 15 years. Although basic establishment techniques for production plantations had been developed and applied on small areas, land managers lacked critical knowledge to implement operational-scale afforestation practices that would accommodate multiple forest restoration objectives. In 1993, managers with the US Fish and Wildlife Service made a 1,700-ac agricultural tract available to scientists interested in partnering research and demonstrating various aspects of bottomland hardwood ecosystem restoration. Through collaborative efforts, resource managers and scientists have installed numerous experiments on the Sharkey Restoration Research and Demonstration Site to address relevant issues in afforestation and restoration of bottomland hardwood ecosystems. Development of this research and demonstration area has provided a science-based resource for educating landowners, foresters, wildlife managers, and the general public on afforestation techniques appropriate for restoration of bottomland hardwood forests; has served as a platform for scientists and land managers to cooperate on the development of innovative approaches to forest restoration; and has provided a venue for education and debate among policymakers active in the LMAV. Early results showed the viability of low-cost techniques such as direct seeding oaks, as well as introducing the interplanting technique for rapid development of forest conditions. We recognize that the value of the research and demonstration site is attributed in part to site characteristics and experimental design, and expect continued work at the location to contribute to improved afforestation practices that will foster establishment of sustainable bottomland hardwood forests.

Afforestation method affects the isotopic composition of planted Pinus halepensis in a semiarid region of Spain

We used an isotopic approach to evaluate the effects of three afforestation methods on the ecophysiology of an Aleppo pine plantation in semiarid Spain. The site preparation methods tested were excavation of planting holes (H), subsoiling (S), and subsoiling with addition of urban solid refuse to soil (S+USR). Five years after plantation establishment, trees in the S+USR treatment were over three times larger than those in the S treatment, and nearly five-fold larger than those planted in holes. Differences in tree biomass per hectare were even greater due to disparities in initial planting density and pine tree mortality among treatments. Pine trees in the S+USR treatment showed higher foliar P concentration, δ13C and δ15N than those in the S or H treatments. Foliar δ15N data proved that trees in the S+USR treatment utilized USR as a source of nitrogen. Foliar δ13C and δ18O data suggest that improved nutrient status differentially stimulated photosynthesis over stomatal conductance in the pine trees of the S+USR treatment, thus enhancing water use efficiency and growth. In the spring of 2002, trees in the S+USR treatment exhibited the most negative predawn water potentials of all the treatments, indicating that the rapid early growth induced by USR accelerated the onset of intense intra-specific competition for water. The results of this study have implications for the establishment and management of Aleppo pine plantations on semiarid soils. Planting seedlings at low density and/or early thinning of pine stands are strongly recommended if fast tree growth is to be maintained beyond the first few years after USR addition to soil. Foliar C, O and N isotope measurements can provide much insight into how resource acquisition by trees is affected by afforestation techniques in pine plantations under dry climatic conditions.

Afforestation techniques and evaluation of different tree species for waterlogged saline soils in semiarid tropics

Long‐term field studies were conducted on about three dozen woody perennial species to develop suitable techniques for afforestation of waterlogged saline soils in arid and semiarid regions of India. The soils of the study area were saline sandy loams with a preponderance of chloride and sulfates of Na+, Ca2+, and Mg2+. The soil's initial electrolytic conductivity (ECe) was 36.4 dS m−1 in the upper 30 cm. The water table was shallow, fluctuating between 1.5 m depth to the surface in different seasons of the year, and the water was brackish (average EC was 29.8 dS m−1). Three methods of planting, namely, ridge‐trench, subsurface, and furrow, were compared. The furrow technique provided favorable niches for plant survival and growth and was also the most economical for such soils. Prosopis juliflora, Tamarix sp., Casuarina glauca, Acacia farnesiana, A. nilotica, A. tortilis, and Parkinsonia aculeata were found to be the most promising species for these saline soils. Casuarina glauca and Salvadora oleoides survived even prolonged stagnation of floodwaters for 9 months.

98/03370 Impact of coal waste piles on the environment and their afforestation techniques in China: Hu, Z. Q. DGMK Tagungsber., 1997, 9704, (Proceedings ICCS '97, Volume 3), 1895–1898

98/03370 Impact of coal waste piles on the environment and their afforestation techniques in China: Hu, Z. Q. DGMK Tagungsber., 1997, 9704, (Proceedings ICCS '97, Volume 3), 1895–1898

OBSTACLES TO TREE PLANTING FOR WOOD FUEL IN ARID AND SEMI-ARID LANDS WITH PARTICULAR REFERENCE TO INDIA AND KENYA

SUMMARY Environmental factors and practical afforestation techniques are not the major constraints to tree planting in arid and semi-arid lands (ASAL). More important are social features (including land use and tenure, community organization) and economic constraints (such as the lack of a monetarized economy, poor transport and marketing systems, and poor understanding of long-term cost-benefit appraisal). There is a great need to devise incentives and encourage participation in tree planting schemes by local populations and, hence, for professional and nonprofessional training in extension techniques for arid zones.