Variation in Vegetation and Its Driving Force in the Middle Reaches of the Yangtze River in China

The temporal and spatial characteristics of vegetation in the middle reaches of the Yangtze River (MRYR) were analyzed from 1999 to 2015 by trend analysis, co-integration analysis, partial correlation analysis, and spatial analysis using MODIS-NDVI time series remote sensing data. The average NDVI of the MRYR increased from 0.72 to 0.80, and nearly two-thirds of the vegetation showed a significant trend of improvement. At the inter-annual scale, the relationship between NDVI and meteorological factors was not significant in most areas. At the inter-monthly scale, NDVI was almost significantly correlated with precipitation, relative humidity, and sunshine hours, and the effect of precipitation and sunshine hours on NDVI showed a pronounced lag. When the altitude was less than 2500 m, NDVI increased with elevation. NDVI increased gradually as the slope increased and decreased gradually as the slope aspect changed from north to south. NDVI decreased as the population density and per capita GDP increased and was significantly positively correlated with afforestation policy. These findings provide new insights into the effects of climate change and human activities on vegetation growth.

Large-scale afforestation for ecosystem service provisioning: learning from the past to improve the future

Context Afforestation is one of the major drivers of land cover change in the world. In spite of its multiple applications, forest generation has been fostered during the last century to achieve few specific objectives such as timber production or catchment erosion protection. However, new afforestation programs are required to meet multiple objectives such as carbon sequestration, reducing environmental risks and enhance biodiversity conservation to reach sustainability. Objectives Assessing the general efficiency of past large-scale afforestation programs on the provision of ecosystem services (ES) and other socio-ecological attributes. We also determined whether this efficiency depended on the type of ecosystem used for comparison. Methods We carried out a semi-quantitative meta-analysis from 75 studies analyzing the effects of 128 afforestation actions developed in one of the EU countries with larger areas of afforested land during the twentieth century. Results Spanish afforestation policy improved timber provision and carbon sequestration. However, our results show that afforestation programs did not enhance regulating ES when compared to natural land plots, but only when compared to highly degraded areas prior to restoration actions. Conclusions Large-scale afforestations have difficulties in assuring the provisioning of regulating ES and the conservation of biodiversity when only productivity criteria are prioritized. Our results suggest the need for an afforestation agenda that embraces more comprehensive landscape management approaches that allow reducing undesired ES trade-offs while getting multiple objectives from different ecosystems.

Enhancement of soil organic carbon storage and aggregation following cropland afforestation

<p>The cropland afforestation policy was initiated in 2002 in Taiwan and had been approaching the 20-year term. From the scientific perspective, it is a critical issue to understand the public welfare role and ecosystem services provided by the cropland afforestation. In this study, we investigated the changes of soil organic carbon (SOC) on plantations after 14 years conversion from the sugarcane fields. Soil samples were collected at 0-10 and 10-20 cm depth. Soil organic C concentration, bulk density, soil aggregation, and the stable isotopic <sup>13</sup>C of the SOC and aggregates were determined. The results indicated the SOC stocks on the afforested plots were between 1000 and 1500 g m<sup>-2 </sup>significantly higher than those under the sugarcane plots (p < 0.05). The analyses of stable <sup>13</sup>C indicated that the net increases in SOC stocks on the afforested plots were mainly attributed to the inputs of the forest-derived SOC that outweighed the loss of sugarcane-derived SOC. The afforestation also enhanced the aggregation with higher stability and SOC concentration. The comparatively depleted <sup>13</sup>C values in the stable macroaggregates further suggested the ecological function from this new SOC source. Combining with the stand development and aboveground biomass accumulation, we expected the cropland afforestation would provide ecosystem services and functions.</p>

Afforestation in Bulgaria

The historical development of afforestations in Bulgaria was investigated. Some of the more important decisions and events which determine the correct state policy in the field of afforestations are pointed out. The most significant achievements are in: erosion control, incl. water tank protection from silting up; increasing the tree volume and forest growth; protection of agriculture via forest protection belts; landscape improving. The social importance for more employment and improvement of means of livelihood is mentioned. Proved reasons for decreasing the afforested areas since 1980s are given. The main mistakes and problems are mentioned as well as the changes in the afforestation policy and future challenges.