Afforestation Of Farmland Research Articles

Linkages of C:N:P stoichiometry and bacterial community in soil following afforestation of former farmland

Ecological stoichiometry (C:N:P ratios) in soil plays an important role in ecosystem dynamics and functioning; however, its relationship with below-ground microbial diversity following afforestation remains poorly understood. To illustrate the linkage of C, N, and P in soil and microbial biomass, and the effect on the soil bacterial community, soil samples were collected from farmland and from three afforested land, namely Robinia pseudoacacia L., Caragana korshinskii Kom, and abandoned land, which have been arable for the past 40years. Quantitative PCR and Illumina sequencing of the 16S rRNA genes were used to analyze soil bacterial abundance, diversity, and composition. Additionally, soil properties and C, N, and P levels in soil and microbial biomass were estimated. The results revealed that C, N, and P levels in soil and microbial biomass increased following afforestation, with a significant correlation observed, especially for the N:P ratio. Additionally, a rise in 〈alpha〉- and 〈beta〉-diversity of soil bacteria was observed in response to afforestation, and was linked to soil C:P and N:P ratios. Soil bacterial phyla with high relative abundance (relative abundance>1%) across all samples showed inconsistent directional trends in the composition response after afforestation. An increased abundance of Proteobacteria, Acidobacteria, and Nitrospirae were observed, while the abundance of Chloroflexi was opposite (P<0.05) following afforestation. Those were largely influenced by changes in the N:P ratio in soil and microbial biomass. Taken together, significantly increased N:P ratio in soil reflected the deficient P that would be limited for increased microbial biomass and diversity. Thus, P status should be an important factor for sustainable restoration of the forest during the process of afforestation.

Changes in soil organic matter composition after afforestation of arable farmland in northeast China

ABSTRACTSince the 1970s, a substantial area of arable farmland in a semi-humid area of northeast China has been planted as deciduous forests (Populus tomentosa Carr.). This study investigates the effects of afforestation on soil organic carbon (SOC) content and the chemical composition of the soil. Soil samples (Calcic chernozem) were collected from the upper 10 cm of paired arable land and secondary forests established 5 and 25 years previously. Carbon isotope analysis and pyrolysis–gas chromatography/mass spectrometry were used to determine SOC composition. The results show that (i) compared to the arable land, five years of afforestation caused a decrease in SOC and N concentration, while 25 years of afforestation resulted in an increase in SOC content; (ii) stable isotope δ13C analyses of the forest soils show gradual loss of crop-derived C and an accumulation of forest-derived C; and (iii) afforestation increased lignin abundance and decreased decompositional activity in the 25-year-old forest topsoil. Higher amounts of short-/mid-chain aliphatic compounds were observed in the 5-year-old forest (5–10 cm); and (iv) the arable soil contained substantially higher amounts of decomposed plant material and microbially derived substances. The results obtained suggest that long-term afforestation increases the SOC concentration, and alters the chemical composition of SOC.

Assessing agricultural land-use change in the Midlands region of KwaZulu-Natal, South Africa: application of mixed multinomial logit

On-farm tree cultivation is considered an important strategy to mitigate detrimental environmental impacts of agricultural land-use change (ALUC). In South Africa, however, little is known about farm-level incentives and constraints that govern ALUC decisions among small-scale farmers. To address this knowledge gap, this study employs a mixed multinomial logit model by using a combination of revealed and stated preference data. After correcting for endogeneity, the estimated results show that decisions about ALUC are rationally derived and driven by clear but heterogeneous preferences and trade-offs between crop productivity, food security and labour saving. The results further show that the decision to plant sugarcane is constrained by landholding, whilst farmland afforestation is negatively influenced by household size. Decisions to convert land use are also driven by the behaviour of peer groups and agro-ecological conditions. Based on these findings, important policy implications for sustainable land use are outlined.

Contribution of afforestation subsidies policy to climate change adaptation in the Czech Republic

European Union countries provide substantial subsidies for farmland afforestation. Most of the research so far has focused on contribution of afforestation to carbon sequestration, afforestation schemes’ uptake, social and economic efficiency and their impact on local biodiversity. Less attention has been given so far to the relevant performance of subsidy schemes’ specific design in climate change adaptation, an emerging policy objective. This paper investigates adaptive capacity of subsidised afforestation projects in a Central European country. Subsidies are found to be concentrated primarily to highland regions that already have got high forest cover, with Norway spruce as the preferred tree species and a deficit of European beech, an arrangement that may undermine the payment scheme's contribution to land use adaptation to climate change. Lack of clear policy objectives and related technical subsidy design, rather than appropriation towards competing policy goals, appear to be the ultimate reason behind spatial distribution and structure of subsidised projects. Subsidy spending seems to follow recipients’ choices instead of any deliberate policy priorities.

Financial Dilemmas Associated with the Afforestation of Low-Productivity Farmland in Poland

In Poland, 82% of forests are State-owned, and only 17% of forests constitute private property. Each year, forests are converted to other land-use types, mainly for road construction. The afforestation rate on privately-owned low-productivity land is decreasing steadily. The owners and perpetual usufructuaries of this kind of land are eligible to government subsidies to cover establishment expenditures in whole or in part, provided that the afforestation scheme complies with the local zoning plan or an outline planning permission. The above creates a dilemma for farmers—is this a profitable option of managing low-productivity land? Owners of small farms particularly often face such dilemmas. Owners of small farms, which consist of low-yield agricultural land, can be regarded as investors operating on the real estate market, but those investors have features characteristic of agricultural producers. This study relied on the net present value (NPV) criterion, which is popularly used to assess the effectiveness of investments on the real estate market. A financial feasibility assessment performed with the use of such method in view of afforestation statistics and the 5% discount rate on the Polish forest market revealed the highest increase in net cumulative cash flows in the first five years, followed by a gradual decrease in successive years. The first negative cash flow was reported in year 20. NPV would remain negative because farmers would be charged with periodic maintenance expenditures until the stand reaches harvestable age at approximately 40 years. The longer the investment period, the lower the profits, even if discount rate is excluded. Investments of the type are difficult to terminate because forests younger than 20 years are difficult to sell at a price that covers growing outflows. Afforestation projects are also influenced by other economic and non-economic factors. The paper validates the research hypothesis that afforestation is a long-term investment that delivers benefits for future generations.

Assessment of Farmland Afforestation in the Upstream Yangtze River, China

The conversion of marginal farmland in China to forest or grassland has been in progress for more than 10 years, but the effects and problems of afforestation need to be investigated so as to affirm and improve farmland afforestation in China's Twelfth Five-Year Plan (2011–2015). According to results from remote sensing and field studies in one county, the local government-registered farmland area was much greater than the actual afforested area. This is likely to be linked to the subsidy payments available for afforestation. The most serious problems are the cultivation of exotic fast-growing forest species (not native pioneer species) selected for forest planting, and the use of single-species rather than mixed plantations. Afforestation of farmland is a systematic, long-term and complicated process, which needs to be performed step by step. The proportion and position of afforested land in the study area were analysed quantitatively on the basis of soil fertility, variation in ecological significance and different soil erosion levels. In light of the findings, the authors discuss how to prioritize afforestation areas.

Restoration of Biodiversity and Ecosystem Services on Agricultural Land

Cultivation and cropping are major causes of destruction and degradation of natural ecosystems throughout the world. We face the challenge of maintaining provisioning services while conserving or enhancing other ecosystem services and biodiversity in agricultural landscapes. There is a range of possibilities within two types of intervention, namely “land sharing” and “land separation”; the former advocates the enhancement of the farmed environment, but the latter a separation between land designated for farming versus conservation. Land sharing may involve biodiversity-based agricultural practices, learning from traditional farming, changing from conventional to organic agriculture and from “simple” crops and pastures to agro-forestry systems, and restoring or creating specific elements to benefit wildlife and particular services without decreasing agricultural production. Land separation in the farmland context involves restoring or creating non-farmland habitat at the expense of field-level agricultural production—for example, woodland on arable land. Restoration by land sharing has the potential to enhance agricultural production, other ecosystem services and biodiversity at both the field and landscape scale; however, restoration by land separation would provide these benefits only at the landscape scale. Although recent debate has contrasted these approaches, we suggest they should be used in combination to maximize benefits. Furthermore, we suggest “woodland islets”, an intermediate approach between land abandonment and farmland afforestation, for ecological restoration in extensive agricultural landscapes. This approach allows reconciliation of farmland production, conservation of values linked to cultural landscapes, enhancement of biodiversity, and provision of a range of ecosystem services. Beyond academic research, restoration projects within agricultural landscapes are essential if we want to halt environmental degradation and biodiversity loss.

The value of the trackway system within a lowland plantation forest for ground-active spiders

European forest management guidelines include conservation and enhancement of biodiversity. Within plantation forestry, trackways provide contiguous permanent open-habitat with potential to enhance biodiversity. We examined the ground-active spider assemblage in the trackway network of Thetford Forest, Eastern England, the largest lowland conifer forest in the UK, created by afforestation of heathland and farmland. Results are relevant to other forests in heath regions across Europe. We used pitfall trapping to sample the spider assemblage of trackways within thicket-aged stands (n = 17), mature stands (n = 13) and heathland reference sites (n = 9). A total of 9,314 individuals of 71 species were recorded. Spider assemblages of the trackway network were distinct from those of the heathland reference sites; however, trackways were found to support specialist species associated with grass-heath habitats, including nationally scarce species. Richness of grass-heath species was similar for trackways in thicket-aged forest and heathland reference sites, although the abundance of individuals was three times greater in the reference sites. Trackways in mature stands had lower grass-heath species richness and abundance than both thicket trackways and heath reference sites. Wide trackways within thicket stands contained greater richness and abundance of specialist xeric species than narrower trackways. However, fewer xeric individuals were found in trackways compared to heathland reference sites. Either inferior habitat quality in trackways or poor dispersal ability of specialist xeric species may largely restrict these to relict areas of heathland. Targeted widening of trackways to allow permanent unshaded habitat and creating early successional stages by mechanical disturbance regimes could improve trackway suitability for specialist species, helping to restore connectivity networks for grass-heath biodiversity.

The Accumulation of Organic Carbon in Mineral Soils by Afforestation of Abandoned Farmland

The afforestation of abandoned farmland significantly influences soil organic carbon (OC). However, the dynamics between OC inputs after afforestation and the original OC are not well understood. To learn more about soil OC dynamics after afforestation of farmland, we measured the soil OC content in paired forest and farmland plots in Shaanxi Province, China. The forest plots had been established on farmland 18, 24, 48, 100, and 200 yr previously. The natural 13C abundance of soil organic matter was also analyzed to distinguish between crop- and forest-derived C in the afforested soils. We observed a nonlinear accumulation of total OC in the 0–80 cm depth of the mineral soil across time. Total soil OC accumulated more rapidly under forest stands aged 18 to 48 yr than under forest stands aged 100 or 200 yrs. The rate of OC accumulation was also greater in the 0–10 cm depth than in the 10–80 cm depth. Forest-derived OC in afforested soils also accumulated nonlinearly across time, with the greatest increase in the 0–20 cm depth. Forest-derived OC in afforest soils accounted for 52–86% of the total OC in the 0–10 cm depth, 36–61% of the total OC in the 10–20 cm depth, and 11–50% of the total OC in the 20–80 cm depth. Crop-derived OC concentrations in the 0–20 cm depth decreased slightly after afforestation, but there was no change in crop-derived OC concentrations in the 20–80 cm depth. The results of our study support the claim that afforestation of farmland can sequester atmospheric CO2 by increasing soil OC stocks. Changes in the OC stocks of mineral soils after afforestation appear to be influenced mainly by the input of forest-derived C rather than by the loss of original OC.

Calandra lark habitat selection: Strong fragmentation effects in a grassland specialist

Conserving grassland birds in farmed landscapes requires the maintenance of favourable agricultural land uses over a range of spatial and temporal scales. Here we examined the field and landscape-scale habitat requirements of the calandra lark ( Melanocorypha calandra), an obligate grassland bird often associated with open Mediterranean farmland. Breeding and wintering lark densities were assessed in 42 fallow fields in southern Portugal, and related to three sets of variables reflecting field, landscape and neighbourhood effects. Variation partitioning was used to isolate the unique and shared contributions of sets of variables to explained variation in lark distribution and abundance models. At the field scale, the presence of trees and shrubs showed the strongest negative effects on calandra lark. At the landscape scale there were strong positive response of larks to the amount and patch size of open farmland habitats, and negative responses, albeit weaker, to drainage and road densities. Calandra lark distribution and abundance was also positively related to that of conspecifics in surrounding fields, particularly in spring. Results suggest that calandra larks are highly sensitive to habitat fragmentation, requiring fallow fields with no shrubs or trees, embedded in large expanses of open farmland. This supports the view that grassland bird conservation in Mediterranean agricultural landscapes may require a combination of land-use regulations and agri-environment schemes preventing ongoing shrub encroachment and afforestation of marginal farmland.

Ecosystem carbon accumulation following fallow farmland afforestation with red pine in southern Quebec

We assessed the organic C stocks and inferred their changes in vegetation biomass, forest floor, and soil using a 50 year chronosequence of red pine ( Pinus resinosa Ait.) plantations established on postagricultural fields in southern Quebec, Canada. The data come from soil and tree field surveys carried out in the 1970s in 348 sites. Organic C concentrations were usually measured in three major mineral soil horizons; for the remaining soil horizons, they were estimated using pedotransfer functions. The effect of soil order, drainage, and texture was analysed. Over 22 years, organic C accumulation rates (Mg C·ha–1·year–1) were 1.66 ± 0.03 in vegetation biomass, 0.56 ± 0.07 in forest floor, 0.86 ± 0.47 in loamy soils (0–100 cm), and –0.18 ± 0.24 in sandy soils (0–100 cm). The greater rate of C accumulation in loamy soils was due to the contribution of the 30–100 cm subsoil layer. The overall net accumulation of organic C in these plantation ecosystems was estimated to 51.4 ± 4.8 Mg C·ha–1at 22 years. Soils of these plantations acted as a C sink in the first two decades, particularly in loamy soils compared with sandy soils, with no major differences among soil order or drainage.

Mapping hotspots of multiple landscape functions: a case study on farmland afforestation in Scotland

Many conservation and restoration efforts in developed countries are increasingly based on the premise of recognising and stimulating more ‘multi-functionality’ in agricultural landscapes. Public policy making is often a pragmatic process that involves efforts to negotiate trade-offs between the potentially conflicting demands of various stakeholders. Conservationists’ efforts to influence policy making, can therefore benefit from any tool that will help them to identify other socio-economic functions or values that coincide with good ecological conservation options. Various types of socio-economic objectives have in recent years been mapped across landscapes and so there are now important opportunities to explore the spatial heterogeneity of these diverse functions across the wider landscape in search of potential spatial synergies, i.e. ‘multiple win locations’ or multifunctional ‘hotspots’.

Soil carbon sequestration under different exotic tree species in the southwestern highlands of Ethiopia

At Belete forest in southwestern Ethiopia (7°33′N, 36°35′E), tree plantations were established on abandoned farmland, which was previously mainly used for maize cultivation. Total carbon and 13C analyses were used to evaluate the changes in soil organic carbon (SOC) pools associated with land use changes using a comparative approach. Forest clearing followed by continuous cultivation of crops caused a loss of 43% (75.4 Mg ha − 1 ) total SOC and 73% (128.4 Mg ha − 1 ) forest derived SOC after nearly 75 years. The net loss of SOC was lower because of addition of 53.0 Mg ha − 1 of SOC of C 4 crop origin (mainly maize) to the farmland. On the other hand, afforestation of farmland led to a net accretion of SOC of 69.6 and 29.3 Mg ha − 1 after 20 years under Cupressus lusitanica and Pinus patula stands, respectively . The SOC accretion of plantation origin amounted to 63.3 Mg ha − 1 under C. lusitanica and 24.2 Mg ha − 1 under P. patula. Contrary to the results obtained in some other studies, the SOC of C 4 origin did not decline in these stands. This could be attributed to pasture grasses of C 4 origin that took over after land abandonment and continued to grow under the tree canopies. The grasses could thus have compensated for the SOC loss. SOC might also have been close to a steady state under the pre-plantation period. Based on the SOC amount found in a reference stand of native forest, afforestation with Eucalyptus grandis during 20 years, preceded by 20 years of cultivation and 35 years of pasture, returned the total SOC to nearly pre-deforestation levels. SOC accumulation rates of 1–3.2 Mg ha − 1 y − 1 are apparently possible 20 years after afforestation of an abandoned farmland but the accumulation rate is species dependent.

Soil δ15N and nutrients under exotic tree plantations in the southwestern Ethiopian highlands

This study was undertaken to evaluate the effect of tree species on soil properties. Soil δ 15N, total N, C:N ratio, base cations and available P were analyzed under farmland, native forest and tree plantations established on abandoned farmland at Belete forest. Changes associated with land use were evaluated using a comparative approach. Forest clearing followed by continuous cultivation of annual crops resulted in a significant decline in total N, base cations and available P within 0–10 or 0–20 cm depth. Assuming a linear rate of loss, total N declined by 90.6 kg ha −1 year −1 or by 38% (6.8 Mg ha −1) of the level in native forest during the 75 years of cultivation. The 15N enrichment of soil and litter N in the farmland may indicate losses of N through leaching and harvest. The degree of change in soil properties under exotic trees after 20 years of afforestation of former farmland depended on tree species. Total N within 0–50 cm depth increased by 5.7 Mg ha −1 under Cupressus lusitanica and 2.0 Mg ha −1 under Pinus patula. The decrease in δ 15N value with afforestation was greater for C. lusitanica than for P. patula, indicating that N cycling under C. lusitanica progressed more towards ‘native forest like’ conditions. Under C. lusitanica, exchangeable Ca 2+ increased significantly at 0–5 cm. Exchangeable K + increased significantly within 0–30 cm depth under both C. lusitanica and P. patula. The increased C:N ratio under these tree species was attributed to recent organic matter (OM) addition. The soil under Eucalyptus grandis, established on former mixed land use (pasture plus farmland), had nearly similar δ 15N, TN, exchangeable Ca 2+ and K + to native forest. The residual effect of 15N-depleted C 4 pasture grasses might explain the lack of difference in soil δ 15N profile below 10 cm depth between E. grandis and native forest. Greater OM inputs by E. grandis probably account for the greater C:N ratio relative to native forest soil.

Afforestation of European landscapes: How do different farmer types respond to EU agri-environmental schemes?

This paper investigates how different types of farmers manage the landscape with primary emphasis on farmland afforestation, planned landscape changes, and the extent to which EU agri-environmental schemes take farm type specific characteristics into account in information strategies. The empirical data concern landscape practices of more than 2,000 landowners in 16 European areas in eight countries who were surveyed using quantitative questionnaires. Supplementary in-depth interviews were conducted for two case areas in Denmark to further investigate the role of the policy information environment. The analysis is based on a categorization of the farmers into hobby, part-time, full-time and retired farmers. This study shows that hobby farmers constitute a high proportion of landowners and manage a large part of the rural landscape. At the same time, hobby farmers are relatively more interested in landscape changes and differ from other landowners by considering farmland afforestation more often than full-time landowners, for example. Yet, 40% of the hobby farmers who are considering farmland afforestation are not familiar with the agri-environmental scheme for farmland afforestation. One reason may be their low membership rate in traditional information networks such as farmers’ or foresters’ associations, as revealed by the in-depth analysis of the cases in Denmark. Thus, it is proposed that policy impact may be improved if farmer type specific differences are explicitly taken into account in the scheme logistics for EU agri-environmental schemes.

Birds as indicators of recent environmental changes in the Apennines (Foreste Casentinesi National Park, central Italy)

Starting from a data‐set of 175 point counts (5 min duration) repeated twice a year from 1992 to 2002 in the Foreste Casentinesi National Park (Apennines, central Italy), the trends of species and of some selected ecological and phenological guilds were analysed. Among the 61 testable species, a significant increase (linear or quadratic regressions) involved 15 species, whereas 8 decreased. No significant trend was found for the remaining 38 species. The bark feeders guild, as well as tree‐cavity nesters and ground feeders showed an increase, whereas foliage feeders and ground nesters showed no significant changes. Short‐distance migrants and residents showed an increase, whereas long‐distance migrants showed no change. The overall picture obtained from these data fits well the habitat changes occurring in the study area: i) ageing of woods (with a remarkable increase in the proportion of mature stands in the study period); ii) afforestation of pastures and farmland, a long‐term process that started at least 150 years ago. These processes are widespread in the Mediterranean mountains, and it is therefore possible that the situation in the Foreste Casentinesi could have some general meaning, though the lack of regional bird monitoring programs impedes reliable comparisons.

Sowing and transplanting of broadleaves ( Fagus sylvatica L., Quercus robur L., Prunus avium L. and Crataegus monogyna Jacq.) for afforestation of farmland

Transplanting of bare-rooted seedlings is the common practice for afforestation with broadleaves on former farmland in Denmark and southern Sweden. This is an expensive method and the development of less costly alternatives is needed. The present study included three field experiments, with different treatment combinations of transplanting and sowing of beech, oak, wild cherry and hawthorn, vegetation control, seed and seedling protection by small tubes. Establishment percentage as well as the growth of seedlings was recorded annually from 1995 to 1998. By the end of the experiments, transplanting generally resulted in higher establishment percentages for all species compared to sowing and sowing in tubes. However, sowing of oak resulted in high establishment percentages. There was a clear indication of rodent damage to seeds and seedlings in some of the experiments. Establishment percentage following sowing in tubes was generally better when compared to sowing only, but other problems for seedling development appeared in the tubes. The general effect of vegetation control on the survival of seedlings was minor. In contrast, vegetation control had a strong effect on seedling growth development. In conclusion, sowing of different broadleaved species has the potential to become a viable alternative to transplanting for afforestation of farmland. However, development of new methods for protection against mice and weeds are recommended.

Content, Distribution, and Solubility of Cadmium in Arable and Forest Soils

Afforestation of former farmland decreases soil pH and thus increases the solubility of Cd in the soil, which may cause Cd leaching to streams and groundwater. The Cd concentration in soil and soil solution were determined in 11 pairs of Danish arable and forest soil profiles representing three different texture classes (sand, loamy sand, and sandy loam). The soil pH did not change or decrease with depth through the arable profiles, but did increase with depth in the forest profiles. Significantly higher Cd contents were found in the upper 30 cm of the arable soil compared with that of the forest soil. The total soil Cd concentrations correlated with the effective cation‐exchange capacity (ECEC), clay content, and organic matter content, but not the soil pH. The soil solution pH was unchanged or decreasing downwards through the arable profiles, but increasing with depth in the forest profiles. The soil solution concentration of Cd was significantly higher in the forest soils than in the arable soils. The Cd concentration in the soil solution decreased as pH increased. Both total soil and soil solution Cd concentrations were higher in the sandy loam soils compared with the loamy sand and sand soils. It is concluded that afforestation may lead to higher soil solution concentrations of Cd as decreasing pH and ECEC diminish Cd retention and reduces Cd concentrations in the forest topsoils.