Shelter Forest Research Articles

Impact of Implementation of Large-Scale Drip Irrigation in Arid and Semi-arid Areas: Case Study of Manas River Valley

With the large-scale application of drip irrigation under mulching, drip-irrigated areas have experienced significant changes in the past 10 years in the Manas River valley. Based on long-term monitoring data of soil salt content and groundwater depth and the investigation of shelter forest growth and seedling emergence, this article analyzed the distribution characteristics of soil salt content in different drip-irrigated soil layers and their effect on the environment. The main conclusions are as follows: (1) Two obvious soil layers of salt accumulation are 40–80 cm deep after drip irrigation and 0–5 cm deep before drip irrigation. (2) Salt accumulated in different soil layers after drip irrigation for several years: 0–40 cm and 40–100 cm deep after drip irrigation for 3 and 7 years respectively. (3) Extension of the drip-irrigated area has caused a number of environmental problems in the study area, and countermeasures for agricultural development in arid and semi-arid areas are proposed.

Mapping afforestation and deforestation from 1974 to 2012 using Landsat time-series stacks in Yulin District, a key region of the Three-North Shelter region, China

The Three-North Shelter Forest Program is the largest afforestation reconstruction project in the world. Remote sensing is a crucial tool to map land use and land cover change, but it is still challenging to accurately quantify the change in forest extent from time-series satellite images. In this paper, 30 Landsat MSS/TM/ETM+ epochs from 1974 to 2012 were collected, and the high-quality ground surface reflectance (GSR) time-series images were processed by integrating the 6S atmosphere transfer model and a relative reflectance normalization algorithm. Subsequently, we developed a vegetation change tracking method to reconstruct the forest change history (afforestation and deforestation) from the time-series Landsat GSR images based on the integrated forest z-score (IFZ) model by Huang et al. (2009a), which was improved by multi-phenological IFZ models and the smoothing processing of IFZ data for afforestation mapping. The mapping result showed a large increase in the extent of forest, from 380,394 ha (14.8% of total district area) in 1974 to 1,128,380 ha (43.9%) in 2010. Finally, the land cover and forest change map was validated with an overall accuracy of 89.1% and a kappa coefficient of 0.858. The forest change time was also successfully retrieved, with 22.2% and 86.5% of the change pixels attributed to the correct epoch and within three epochs, respectively. The results confirmed a great achievement of the ecological revegetation projects in Yulin district over the last 40 years and also illustrated the potential of the time-series of Landsat images for detecting forest changes and estimating tree age for the artificial forest in a semi-arid zone strongly influenced by human activities.

The effects of the Taklimakan Desert Highway on endemic birds Podoces biddulphi

We access the abundance of Xinjiang ground jay near the Taklimakan Desert Highway in Northwestern China, and also we used alert distance and flight initiation distance to evaluate the effects of the Taklimakan Desert Highway on Xinjiang ground jay responses to human encroachment. The results showed that Xinjiang ground jay were more abundant adjacent to the roadway than further way, and the alert distance and flight initiation distance of the Xinjiang ground jay decreased significantly with increasing road effect. These results indicated that the Taklimakan Desert Highway and its shelter forest attracted more Xinjiang ground jay to live near the road, and also the highway significantly affected the bird’s vigilance behavior.

Soil microbial diversity, site conditions, shelter forest land, saline water drip‐irrigation, drift desert

Soil microbes in forest land are crucial to soil development in extreme areas. In this study, methods of conventional culture, PLFA and PCR-DGGE were utilized to analyze soil microbial quantity, fatty acids and microbial DNA segments of soils subjected to different site conditions in the Tarim Desert Highway forest land. The main results were as follows: the soil microbial amount, diversity indexes of fatty acid and DNA segment differed significantly among sites with different conditions (F < F0.05 ). Specifically, the values were higher in the middle and base of dunes than the top part of dunes and hardened flat sand, but all values for dunes were higher than for drift sand. Bacteria was dominant in the soil microbial community (>84%), followed by actinomycetes and then fungi (<0.05%). Vertical differences in the soil microbial diversity were insignificant at 0-35 cm. Correlation analysis indicated that the forest trees grew better as the soil microbial diversity index increased. Therefore, construction of the Tarim Desert Highway shelter-forest promoted soil biological development; however, for enhancing sand control efficiency and promoting sand development, we should consider the effects of site condition in the construction and regeneration of shelter-forest ecological projects.

Response of vegetation restoration to climate change and human activities in Shaanxi-Gansu-Ningxia Region

The “Grain for Green Project” initiated by the governments since 1999 were the dominant contributors to the vegetation restoration in the agro-pastoral transitional zone of northern China. Climate change and human activities are responsible for the improvement and degradation to a certain degree. In order to monitor the vegetation variations and clarify the causes of rehabilitation in the Shaanxi-Gansu-Ningxia Region, this paper, based on the MODIS-NDVI and climate data during the period of 2000–2009, analyzes the main characteristics, spatial-temporal distribution and reasons of vegetation restoration, using methods of linear regression, the Hurst Exponent, standard deviation and other methods. Results are shown as follows. (1) From 2000 to 2009, the NDVI of the study area was improved progressively, with a linear tendency being 0.032/10a, faster than the growth of the Three-North Shelter Forest Program (0.007/10a) from 1982 to 2006. (2) The vegetation restoration is characterized by two fast-growing periods, with an “S-shaped” increasing curve. (3) The largest proportion of the contribution to vegetation restoration was observed in the slightly improved area, followed by the moderate and the significantly improved area; the degraded area is distributed sporadically over southern part of Ningxia Hui Autonomous Region as well as eastern Dingbian of Shaanxi province, Huanxian and Zhengyuan of Gansu province. (4) Climate change and human activities are two driving forces in vegetation restoration; moreover anthropogenic factors such as “Grain for Green Project” were the main causes leading to an increasing trend of NDVI on local scale. However, its influencing mechanism remains to be further investigated. (5) The Hurst Exponent of NDVI time series shows that the vegetation restoration was sustainable. It is expected that improvement in vegetation cover will expand to the most parts of the region.

Assessing phenological change in China from 1982 to 2006 using AVHRR imagery

Long-term trends in vegetation phenology indicate ecosystem change due to the combined impacts of human activities and climate. In this study we used 1982 to 2006 Advanced Very High Resolution Radiometer Normalized Difference Vegetation Index (AVHRR NDVI) imagery across China and the TIMESAT program to quantify annual vegetation production and its changing trend. Results showed great spatial variability in vegetation growth and its temporal trend across the country during the 25-year study period. Significant decreases in vegetation production were detected in the grasslands of Inner Mongolia, and in industrializing regions in southern China, including the Pearl River Delta, the Yangtze River Delta, and areas along the Yangtze River. Significant increases in vegetation production were found in Xinjiang, Central China, and North-east China. Validation of the NDVI trends and vegetated area changes were conducted using Landsat imagery and the results were consistent with the analysis from AVHRR data. We also found that although the causes of the vegetation change vary locally, the spatial pattern of the vegetation change and the areas of greatest impact from national policies launched in the 1970s, such as the opening of economic zones and the ‘Three-North Shelter Forest Programme’, are similar, which indicates an impact of national policies on ecosystem change and that such impacts can be detected using the method described in this paper.

Effects of different grassland restoration approaches on soil properties in the southeastern Horqin sandy land, northern China

In the semi-arid Horqin sandy grassland, continuous grazing has led to decreased ground cover. The bare land surface is then directly exposed to strong wind erosion, leading to desertification. Different restoration approaches have been used to recover these desertified sandy grasslands. This study compared soil properties subjected to different grassland restoration approaches, i.e., three restoration treatments and an unrestored control: FG, grassland enclosed by sheltering forest (Populus×beijingensis); MG, artificially sparse Pinus sylvestris var. mongolica grassland; UG, artificially sparse Ulmus pumila grassland; CK, desertified grassland. Soil samples were taken from depths of 0–20cm, and physical (i.e., bulk density, particle size distribution, waterholding capacity, total porosity), chemical (i.e., pH, soil organic matter, total N, total P, total K, available N, available P, available K, cation exchange capacity, exchangeable Ca2+, exchangeable Mg2+, exchangeable Na+, exchangeable K+), and biological (i.e., microbial biomass carbon, substrate richness index, Shannon's diversity index) properties were selected as soil indicators. The three different approaches to grassland restoration were confirmed to alleviate wind erosion and enhance sand surface stabilization, as well as improve soil physicochemical and biological properties, in comparison with unrestored control. Soil physical, chemical, and biological properties in two types of artificial sparsely forested grassland were significantly better than those in grassland enclosed by shelter forest; however, there was no significant difference between the two types of artificial sparsely forested grassland. These results suggest that an artificial sparsely forested grassland restoration approach may be more effective at restoring the poor and arid soils of desertified sandy grasslands, such as the Horqin sandy land.

Leaf nitrogen and phosphorus stoichiometry across forty-two woody species in Southeast China

Abstract Ecological stoichiometry is an indicator of function and nutrient limitation from individual to ecosystem levels, yet it is still unclear whether leaf stoichiometry patterns are homologous at different scales. We determined the leaf nitrogen (N) and phosphorous (P) concentrations, N:P ratio and leaf traits across 42 woody species planted at Hangzhou Bay Coastal Shelter Forest Experimental Site in Southeast China. We analyzed variation patterns in leaf stoichiometry, correlated leaf stoichiometry with leaf traits, and determined nutrient limitations based on leaf stoichiometry. Leaf N and P concentrations and N:P ratio averaged 18.58 mg g −1 , 2.24 mg g −1 and 9.56, respectively. Leaf N and P concentrations were positively correlated while leaf P and leaf N:P ratio were negatively correlated across all species. Leaf dry matter content (LDMC) had a significant relationship with leaf P concentration and N:P ratio for all species, while specific leaf area (SLA) was significantly related to leaf N concentration for broadleaf species. Leaf N concentration and N:P ratio varied greatly within a site. Among the 42 species, 27 were found to be limited by N, one by P, one co-limited by N and P, and the rest not limited by either N or P. Our results provide a theoretical guideline for the construction and management of coastal shelter forests in Southeast China.

Effects of land use changes on the groundwater table and the decline of Pinus sylvestris var. mongolica plantations in southern Horqin Sandy Land, Northeast China

Since the Three-North Shelter Forest Program was launched in 1978, more than 3.0×105ha of Mongolian pine (Pinus sylvestris var. mongolica, MP) plantations have been introduced to control erosion in sandy areas. However, MP plantations in the earliest introduction area (Zhanggutai region in Horqin Sandy Land, which dates back to 1954) declined at the beginning of the 1990s. Meanwhile, a linear decrease in the groundwater table was found during the years 1953–2009. This gave rise to concerns regarding the influence of introduced MP plantations on the environment. To clarify the relationships between land use changes, the decrease in the groundwater table, and the decline of MP plantations, land use changes from 1953 to 2009 were explored using remote sensing data, and the levels of water consumption associated with different types of land use were estimated using a modified CROPWAT model. The results showed that during the period 1953–2009, the area of bare sandy land in the study region sharply decreased by 89.7%. Agricultural land and broadleaved forests were the two major consumers of water resources, accounting for more than 40.0 and 20.0% of the total water consumption, respectively. MP plantations, in contrast, accounted for only about 12.0% of the total water consumption. The establishment of MP plantations has played a significant role in controlling the expansion of sandy land. Compared with agricultural land and broadleaved forests, MP plantations contribute less to the decrease in the groundwater table. The decline of the MP plantations may be a result of the decrease in available groundwater, but the MP plantations contributed less than expected to this decrease. To ensure a sustainable water balance, the area of agricultural land and broadleaved forests should be maintained below the maximum that can be supported by the guaranteed water resource.

Characteristics of flow production and sediment production of &amp;lt;i&amp;gt;Pinus tabulaeformis&amp;lt;/i&amp;gt; through artificial rainfall simulation

In order to know well the relationship between vegetation and water in North China, especially Beijing, with exceptional water resources, we studied the characteristics of flow production and sediment production under different rainfall intensities by artificial rainfall simulation device. Results showed that increase of rainfall intensity would prolong the whole process of flow production, and vegetation on the slope would delay that process. Within the same duration, total runoff volume of each runoff plot and rainfall intensity had significant linear relationship. When vegetation kept unchanged, runoff velocity increased significantly with the increase of rainfall intensity, and owing to the formation of low permeable layer, the velocity increased fiercely during the early 3 minutes, reached stable at 10 - 15 minute. With the same rain intensity, total sediment yield decreased with rise of vegetation coverage, but increased obviously with rise of rain intensity and effectiveness of controlling sediment about 1 m x 1 m Pinus tabulaeformis stand decreased firstly and then increased, while that about 1.5 m x 1.5 m Pinus tabulaeformis stand kept decreasing. Since the tags with A, B and C for 0.42 mm/min, 0.83 mm/min, 1.29 mm/min, order of sediment concentration of wasteland plot was B > C > A, and 1 m x 1 m Pinus tabulaeformis plot B > A > C. Through this study, some suggestions were expected to be provided for water balance of Beijing area and certain basis for construction of shelter forest.

Sap flow characteristics of four typical species in desert shelter forest and their responses to environmental factors

Sap flows of four typical species, Populus. russkii Jabl., Populus euphratica Olive., Ulmus pumila L., and Elaeagnus angustifolia L., of artificial shelter forest in a desert area were monitored in all-weather conditions using SF300 Sap flow Meter based on the theory of thermal compensation. Meanwhile, air temperature (T a), leaf temperature (T l), soil temperature (T s), relative humidity (RH), and wind velocity (V w) were simultaneously recorded by an automatic weather station. The results indicate that (1) the diurnal processes of stem sap flows of P. russkii Jabl., P. euphratica Olive., and U. pumila L., but not E. angustifolia L., show an obvious circadian rhythm. Significant differences of stem sap flow rates were found among species, but not genus. The average sap flow rate of P. russkii Jabl. is 13.8-fold of that of E. angustifolia L. The order of sap flux density (SFD) from the largest to the smallest is P. russkii Jabl., P. euphratica Olive, U. pumila L. and E. angustifolia L.; (2) compared with 373 mm, 747 mm irrigation can induce microenvironmental changes that result in the suppression of photosynthesis and transpiration and the decline of stem sap flow rates of the above four species, indicating 373 mm irrigation meets the growth needs of the above species during experiment; (3) sap flow rates are different at different stem positions: the flow rates of P. russkii Jabl., U. pumila L. and E. angustifolia L., but not P. euphratica Olive, decline gradually from cambium to pith; (4) the correlation analysis indicates that stem sap flow is negatively correlated with RH and T s and positively correlated with T a, T l and saturation vapor pressure deficit (VPD). The sap flow rate of P. russkii Jabl. is significantly affected by V w due to its large size and height. In addition, a model was established by stepwise regression analysis to estimate the relationship between the environmental factors and stem sap flows of the above four typical species of shelter forest in the desert area.

Environmental Impacts of the Shelter Forests in Horqin Sandy Land, Northeast China

Assessing environmental effects of shelter forests is primarily necessary for realizing their greatest protective benefits. The Three-North Shelter Forest Program (TNSFP), the largest ecological afforestation program in the world, has been operated for three decades in China but so far lacks comprehensive assessment of its environmental impacts. Horqin Sandy Land (HSL) in Northeast China is one of the key areas in the TNSFP implementation. To identify the principal contributors to environmental changes in HSL, we evaluated impacts of variations in landscape features, shelter forest areas, climatic factors, and social factors on changes in sandy land areas from 1978 to 2007, by using Gray Relational Analysis. Our analysis showed that during the period 1978 to 2007, the sandy land area decreased by 3.9% in low aeolian dunes, 14.5% in low mountains and hills, and 98.9% in high elevation alluvial flats of HSL. Factors with Gray Correlation Degrees >0.9 were identified as the patch shape index (PSI) and the landscape isolation index (LII) of grasses in low aeolian dunes, PSI of grasses in mountains and hills, and area of broadleaved forests and LII of shrubs in alluvial flats. It is concluded that establishment of the shelter forests has played a significant role in controlling the expansion of sandy land in HSL. To sustain the long-term environmental benefits of the shelter forests in the remaining period for TNSFP construction, suitable tree species should be selected and planted at appropriate densities based on the local precipitation, groundwater and landform conditions, and the system stability of the total landscape.

Assessing vegetation dynamics in the Three-North Shelter Forest region of China using AVHRR NDVI data

The Three-North Shelter Forest Programme (TNSFP) covers 551 Chinese counties and an area of 4,069,000 km2 mostly in arid and semi-arid regions. In this paper, we discuss the temporal and spatial changes in value of the normalized-difference vegetation index (NDVI) in this region, and the relationships between NDVI and climatic factors (temperature and precipitation) based on NOAA Advanced Very High Resolution Radiometer Global Inventory Modeling and Mapping Studies NDVI data with 8-km resolution from 1982 to 2006. During the past 25 years, the vegetation cover has generally increased in eastern regions of China and the oasis in the north piedmont of Tianshan Mountains, but has decreased northwest of Xinjiang and in the Hulunbeier Plateau. The multi-year monthly average NDVI distribution map showed that NDVI increased from April to August, but in the western and northern plateau areas, the lower temperatures and high altitude created a shorter growing season (1 or 2 months). The vegetation of the study area has generally increased in the regions covered by the TNSFP. Linear regression analysis of the vegetation cover showed an increasing trend over large areas. The largest annual growth rate per pixel (the slope of the regression) was 0.009; the largest negative annual change was −0.004. The correlation between NDVI and precipitation was higher than that between NDVI and temperature, suggesting that precipitation is the most important factor that affects NDVI changes in the study area, especially for temperate desert vegetation in northwestern China.

Impact of China's Large-Scale Ecological Restoration Program on the Environment and Society in Arid and Semiarid Areas of China: Achievements, Problems, Synthesis, and Applications

Since, 1978, China has pursued some of the world's most ambitious conservation programs, including the Three Norths Shelter Forest System Project, Grain for Green Project, and the Natural Forest Conservation Program. After 30 years of experience with these programs, researchers have found that improving agricultural technology and providing appropriate payment for ecosystem service (PES) to farmers displaced by these programs can improve both the environment and society while avoiding the malignant cycle in which poverty leads to environmental destruction, which then deepens poverty. However, flaws in the implementation of these programs mean that it remains necessary to watch for damage to the environment and society caused by inappropriate technology and policy.

Effects of sandy desertified land rehabilitation on soil carbon sequestration and aggregation in an arid region in China

The rehabilitation of sandy desertified land in semi-arid and arid regions has a great potential to increase carbon sequestration and improve soil quality. Our objective was to investigate the changes in the soil carbon pool and soil properties of surface soil (0–15 cm) under different types of rehabilitation management. Our study was done in the short-term (7 years) and long-term (32 years) desertification control sites in a marginal oasis of northwest China. The different management treatments were: (1) untreated shifting sand land as control; (2) sand-fixing shrubs with straw checkerboards; (3) poplar ( Populus gansuensis) shelter forest; and (4) irrigated cropland after leveling sand dune. The results showed that the rehabilitation of severe sandy desertified land resulted in significant increases in soil organic C (SOC), inorganic C, and total N concentrations, as well as enhanced soil aggregation. Over a 7-year period of revegetation and cultivation, SOC concentration in the recovered shrub land, forest land and irrigated cropland increased by 4.1, 14.6 and 11.9 times compared to the control site (shifting sand land), and increased by 11.2, 17.0 and 23.0 times over the 32-year recovery period. Total N, labile C (KMnO 4–oxidation C), C management index (CMI) and inorganic C (CaCO 3–C) showed a similar increasing trend as SOC. The increased soil C and N was positively related to the accumulation of fine particle fractions. The accumulation of silt and clay, soil C and CaCO 3 enhanced the formation of aggregates, which was beneficial to mitigate wind erosion. The percentage of >0.25 mm dry aggregates increased from 18.0% in the control site to 20.0–87.2% in the recovery sites, and the mean weight diameter (MWD) of water-stable aggregates significantly increased, with a range of 0.09–0.30 mm at the recovery sites. Long-term irrigation and fertilization led to a greater soil C and N accumulation in cropland than in shrub and forest lands. The amount of soil C sequestration reached up to 1.8–9.4 and 7.5–17.3 Mg ha −1 at the 0–15 cm layer over a 7- and 32-year rehabilitation period compared to the control site, suggesting that desertification control has a great potential for sequestering soil C and improving soil quality in northwest China.

Rice yield of five farmland shelter-belt models on Chongming Island,Shanghai

Farmland shelter-belts are the main component of Chongming Islands shelter forest network. The objective of this study was to select the optimum farmland shelterbelt type by determining the optimal shelter forest porosity. After choosing the main shelter forest models（Taxodium ascendens forest，mixed Metasequoia glyptostroboides（water fir）-Cryptomeria fortunei forest，M. glyptostroboides forest，Populus spp. （poplar） forest，and C. fortunei forest） and surveying the community structure，rice yield and 1 000-grain weight were determined for each shelter forest. Results showed that at different distances within the same sample plot，forest protection significantly improved rice yield and 1 000-grain weight；leaf area index also improved. Among the different models，yield increase was in the order T. ascendens＞the mixed forest of M. glyptostroboides and C. fortunei＞M. glyptostroboides＞Populus spp.＞C. fortunei. The range of shelter forest porosity was 0.31 - 0.39，and the most effective protective distance was 5H（fivefold height of the tree）－10H. In addition，the mixed forest was better than the monotypic forest with the mixed forest of M. glyptostroboides and C. fortunei being the optimal shelterbelt model. ［Ch，3 fig. 3 tab. 21 ref.］

Effects of a Severe Frost on Riparian Rainforest Restoration in the Australian Wet Tropics: Foliage Retention by Species and the Role of Forest Shelter

Restoration of ecological communities that can withstand future climate and land use changes requires information on species responses to various natural disturbances. Frost is an important disturbance that regulates plant species distributions, and although rare in tropical rainforest, it can occur in upland areas, especially where deforestation has occurred. We report the impacts of a severe frost that occurred in June and July 2007 on the Atherton Tablelands, Queensland, Australia and caused extensive damage to riparian restoration plots of upland rainforest species. We estimated proportion foliage retention to (1) compare impacts across 45 species; (2) examine the influence of plant height on frost effects; and (3) determine if plantings under shelterbelts of mature trees received less damage. Species exhibited different levels of foliage retention. Species that were particularly frost resistant included those from riparian habitats and a conifer. Some heavily impacted species are deciduous and may survive frost by shedding leaves; this warrants further investigation. Plant canopy height above ground level was only weakly correlated to foliage retention. Sheltered plants were much less damaged than unsheltered conspecifics, suggesting a useful way to mitigate frost impacts. These principles should help guide the development of resilient ecological communities in frost-prone areas.

Variability of the cones of Siberian larch in variously designed shelter belts in the Shira steppe

The paper presents data on individual variability of Siberian larch cones in the shelter belts in Shira steppe in Khakassia depending on the scheme of planting and design of the forest shelter belt. According to their color, three forms of cones are revealed: green, red, and transitional. The technical germinating capacity and quality of seeds from different forms of cones are determined.

Rise of ground water in the Ishim steppe

In the 1980–2000s, a rise of ground-water table within the Ishim-Irtysh steppe watershed was recorded. An effect of forest shelter belts, ditches, villages, and tilled microdepressions on the long-term dynamics of the ground-water level has been studied.

The influence of vegetation on the abundance of cereal aphid entomophages in the forest-steppe of Western Siberia

The role of forest shelter belts, perennial and biennial grasses (alfalfa, melilot, sainfoin, clover, and smooth brome), and wild herbs in increasing the number of entomophages of cereal aphids was studied in Western Siberia.