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Afforestation and Reforestation: Drivers, Dynamics, and Impacts

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A special issue of Forests (ISSN 1999-4907). This special issue belongs to the section "Forest Ecology and Management".

Deadline for manuscript submissions: closed (25 July 2018) | Viewed by 48184

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Special Issue Editors

Dr. Jingfeng Xiao

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Guest Editor

Earth Systems Research Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824, USA
Interests: carbon cycle; remote sensing; climate-vegetation interactions; upscaling; terrestrial biosphere modeling
Special Issues, Collections and Topics in MDPI journals

Dr. Ge Sun

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Eastern Forest Environmental Threat Assessment Center, Southern Research Station, US Department of Agriculture Forest Service, Research Triangle Park, NC 27709, USA
Interests: effects of climate change and land management on water quantity and quality, and water supply and demand at a regional scale; Application of computer simulation models, GIS, and remote sensing in regional hydrology; Evapotranspiration and ecosystem productivity modeling at regional to continental scales
Special Issues, Collections and Topics in MDPI journals

Dr. Lu Hao

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Guest Editor

Nanjing University of Information Science and Technology, Nanjing, China
Interests: ecohydrology; climate change; meteorology, risk management

Dr. Gang Dong

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Guest Editor

Shanxi University, Taiyuan, P. R. China
Interests: reforestation, water and carbon balance; climate change

Dr. Zhiqiang Zhang

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Guest Editor

Beijing Forestry University, P.R. China
Interests: reforestation, water and carbon balance; watershed hydrology

Special Issue Information

Dear Colleagues,

Afforestation/Reforestation (or Forestation) has been implemented worldwide as an effective measure to sustain ecosystem services and address global environmental problems such as climate change. The conversion of grasslands, croplands, shrublands, or bare lands to forests can dramatically alter forest water, energy, and carbon cycles, and, thus, ecosystem services (e.g., carbon sequestration, soil erosion control, and water quality improvement). Large-scale afforestation/reforestation is typically driven by policies, and in turn can have substantial socioeconomic impacts as well. To be successful, forestation endeavors require novel approaches that involve a series of complex processes and interdisciplinary sciences. For example, exotic or fast growing tree species are often used to improve soil conditions of degraded lands or maximize productivity, and it often takes a long time to understand and quantify the consequences of such practices at watershed or regional scales. Maintaining the sustainability of man-made forests is increasingly challenging under a changing environment and disturbance regime change such as wildland fires, urbanization, drought, air pollution, climate change, and socioeconomic change. Therefore, this Special Issue focuses on case studies on the drivers, dynamics, and impacts of afforestation/reforestation at regional, national, or global scales. These new studies bring an update on science advances related to forestation. The information is urgently needed by land managers and policy makers to better manage forest resources under a rapidly changing environment today.

This Special Issue invites submissions based on field experiments, remote sensing, modelling, syntheses and reviews, as well as new technology used in forestation monitoring and assessment. Suggested topics are:

Monitoring and detecting the rates and extent of afforestation/reforestation
Quantifying impacts of afforestation/reforestation on ecosystem services (e.g., carbon sequestration, water supply, soil conservation, micrometeorology, biodiversity)
Impacts of afforestation/reforestation on regional and global climate
Human dimensions of afforestation and reforestation (e.g., policies, governance, and socioeconomic impacts)
Innovative management approaches (e.g., prescribed fires, thinning) to sustain ecosystem services of man-made forests under a changing environment.

Dr. Jingfeng Xiao
Dr. Ge Sun
Dr. Lu Hao
Dr. Gang Dong
Dr. Zhiqiang Zhang
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Forests is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

Reforestation
Afforestation
Ecosystem services
Ecohydrology
Forest wildfire
Carbon and water flux
Forest management
Climate change

Published Papers (11 papers)

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Research

15 pages, 1916 KiB

Open AccessArticle

Nursery Production of Pinus engelmannii Carr. with Substrates Based on Fresh Sawdust

by María Mónica González-Orozco, José Ángel Prieto-Ruíz, Arnulfo Aldrete, José Ciro Hernández-Díaz, Jorge Armando Chávez-Simental and Rodrigo Rodríguez-Laguna

Forests 2018, 9(11), 678; https://doi.org/10.3390/f9110678 - 29 Oct 2018

Cited by 9 | Viewed by 3638

Abstract

Substrate is a factor that significantly influences the quality and production costs of nursery seedlings. The objective of this study was to evaluate combinations of peat moss, composted pine bark, and fresh pine sawdust in order to identify the proportions that favour the quality of Pinus engelmannii Carr. seedlings and minimise the production costs in the nursery. Substrates were formed using mixtures of peat moss (15% to 50%), composted pine bark (15% to 50%) and fresh pine sawdust (20% to 70%), with 2, 4 and 6 g L⁻¹ of controlled release fertilizer (Multicote^®, Haifa, Israel). A completely randomised experimental design with a factorial arrangement of 7 × 3 was used. The evaluated factors are root collar diameter, biomass, N-P-K content, and production costs of the substrates which were determined based on the container volume and three commercial quotations. Significant differences were found in root collar diameter and biomass, highlighting the treatments using 50% to 70% sawdust with 6 g L⁻¹ of fertilizer. Assimilated values of N-P-K were acceptable in all treatments with 4 and 6 g L⁻¹ of fertilizer. In the substrates with high percentages of sawdust, seedlings with morphological characteristics and nutritional levels within the values recommended for conifers were produced. In addition, it was possible to reduce the production cost of the substrates by up to 67%. Full article

(This article belongs to the Special Issue Afforestation and Reforestation: Drivers, Dynamics, and Impacts)

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16 pages, 3608 KiB

Open AccessArticle

Quantitative Assessment of Surface Runoff and Base Flow Response to Multiple Factors in Pengchongjian Small Watershed

by Lei Ouyang, Shiyu Liu, Jingping Ye, Zheng Liu, Fei Sheng, Rong Wang and Zhihong Lu

Forests 2018, 9(9), 553; https://doi.org/10.3390/f9090553 - 10 Sep 2018

Cited by 13 | Viewed by 4109

Abstract

Quantifying the impacts of multiple factors on surface runoff and base flow is essential for understanding the mechanism of hydrological response and local water resources management as well as preventing floods and droughts. Despite previous studies on quantitative impacts of multiple factors on runoff, there is still a need for assessment of the influence of these factors on both surface runoff and base flow in different temporal scales at the watershed level. The main objective of this paper was to quantify the influence of precipitation variation, evapotranspiration (ET) and vegetation restoration on surface runoff and base flow using empirical statistics and slope change ratio of cumulative quantities (SCRCQ) methods in Pengchongjian small watershed (116°25′48″–116°27′7″ E, 29°31′44″–29°32′56″ N, 2.9 km²), China. The results indicated that, the contribution rates of precipitation variation, ET and vegetation restoration to surface runoff were 42.1%, 28.5%, 29.4% in spring; 45.0%, 37.1%, 17.9% in summer; 30.1%, 29.4%, 40.5% in autumn; 16.7%, 35.1%, 48.2% in winter; and 35.0%, 38.7%, 26.3% in annual scale, respectively. For base flow they were 33.1%, 41.9%, 25.0% in spring; 39.3%, 51.9%, 8.8% in summer; 40.2%, 38.2%, 21.6% in autumn; 24.3%, 39.4%, 36.3% in winter; and 24.4%, 47.9%, 27.7% in annual scale, respectively. Overall, climatic factors, including precipitation and ET change, affect surface runoff generation the most, while ET affects the dynamic change of annual base flowthe most. This study highlights the importance of optimizing forest management to protect the water resource. Full article

(This article belongs to the Special Issue Afforestation and Reforestation: Drivers, Dynamics, and Impacts)

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19 pages, 12750 KiB

Open AccessArticle

Spatio-Temporal Dynamic Architecture of Living Brush Mattress: Root System and Soil Shear Strength in Riverbanks

by Dong Zhang, Jinhua Cheng, Ying Liu, Hongjiang Zhang, Lan Ma, Xuemei Mei and Yihui Sun

Forests 2018, 9(8), 493; https://doi.org/10.3390/f9080493 - 13 Aug 2018

Cited by 13 | Viewed by 4088

Abstract

As a basal measure of soil bioengineering, the living brush mattress has been widely applied in riparian ecological protection forest construction. The living brush mattress shows favorable protective effects on riverbanks. However, there are few reports on the root structure and the soil strengthening benefit of the living brush mattress. The present work reports a series of experiments on root morphology and soil shear strength enhancement at the temporal and spatial scales. The object of the study is 24 living brush mattress trees constructed with Salix alba L. ‘Tristis’ (LBS hereafter). Traditional root morphology and mechanical measurement methods were used to collect the parameters. The results showed that the root systems of LBS had the characteristics of symmetry and upslope growth. The roots were mainly distributed in a cylindrical region of the soil (radius × thickness: 0.4 m × 0.5 m) and their biomass increased with different growth rates for the periods from 1 to 5 and from 5 to 7 years. Both age and slope position were factors that influence root growth. The root diameter falls within 0–5 mm, has a significant effect on the soil shear strength and provides a conical-shape potentiation zone to ensure the efficient protection of a riverbank. The results of this study demonstrate that LBS is an efficient and feasible engineering measure in the field of riverbank protection. Full article

(This article belongs to the Special Issue Afforestation and Reforestation: Drivers, Dynamics, and Impacts)

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19 pages, 3663 KiB

Open AccessArticle

Modeling Hydrological Appraisal of Potential Land Cover Change and Vegetation Dynamics under Environmental Changes in a Forest Basin

by Jie Wang, Shaowei Ning and Timur Khujanazarov

Forests 2018, 9(8), 451; https://doi.org/10.3390/f9080451 - 26 Jul 2018

Cited by 1 | Viewed by 3084

Abstract

An integrated multi-model approach to predict future land cover in the Da River Basin in Vietnam was developed to analyze future impacts of land cover change on streamflow and sediment load. The framework applied a land cover change model and an ecological model to forecast future land cover and leaf area index (LAI) based on the historical land cover change, and these data were then used in a calibrated distributed hydrological model and a new sediment rating curve model to assess hydrological changes and sediment load in the river basin. Results showed that deforestation would likely continue, and that forest area would decrease by up to 21.3% by 2050, while croplands and shrublands would replace forests and increase by over 11.7% and 10%, respectively. Streamflow and sediment load would generally increase due to deforestation in the Da River Basin in the 2050s, in both the wet and dry seasons, but especially in the wet season. In this case, the predicted annual sediment load was expected to increase by about 9.7% at the Lai Chau station. As deforestation increased, sediment load and reservoir siltation could likely shorten the lifespan of the recently constructed Son La Reservoir. The applied integrated modeling approach provides a comprehensive evaluation of land/forest cover change effects on the river discharge and sediment load, which is essential in understanding human impacts on the river environment and in designing watershed management policies. Full article

(This article belongs to the Special Issue Afforestation and Reforestation: Drivers, Dynamics, and Impacts)

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14 pages, 3079 KiB

Open AccessArticle

Understory Plants Regulate Soil Respiration through Changes in Soil Enzyme Activity and Microbial C, N, and P Stoichiometry Following Afforestation

by Fazhu Zhao, Jieying Wang, Lu Zhang, Chengjie Ren, Xinhui Han, Gaihe Yang, Russell Doughty and Jian Deng

Forests 2018, 9(7), 436; https://doi.org/10.3390/f9070436 - 20 Jul 2018

Cited by 17 | Viewed by 4969

Abstract

Soil respiration (SR) is an important process in the carbon cycle. However, the means by which changes in understory plant community traits affect this ecosystem process is still poorly understood. In this study, plant species surveys were conducted and soil samples were collected from forests dominated by black locust (Robinia pseudoacacia L.), with a chronosequence of 15, 25, and 40 years (RP15, RP25, and RP40, respectively), and farmland (FL). Understory plant coverage, evenness, diversity, and richness were determined. We investigated soil microbial biomass carbon (MBC), nitrogen (MBN), phosphorus (MBP), and stoichiometry (MBC:MBN, MBC:MBP, and MBN:MBP). Soil enzyme assays (catalase, saccharase, urease, and alkaline phosphatase), heterotrophic respiration (HR), and autotrophic respiration (AR) were measured. The results showed that plant coverage, plant richness index (R), evenness, and Shannon-Wiener diversity were higher in RP25 and RP40 than in RP15. SR, HR, and AR were significantly higher in the forested sites than in farmland, especially for SR, which was on average 360.7%, 249.6%, and 248.2% higher in RP40, RP25, and RP15, respectively. Meanwhile, catalase, saccharase, urease, and alkaline phosphatase activities and soil microbial C, N, P, and its stoichiometry were also higher after afforestation. Moreover, significant Pearson linear correlations between understory plants (coverage, evenness, diversity, and richness) and SR, HR, and AR were observed, with the strongest correlation observed between plant coverage and SR. This correlation largely depended on soil enzymes (i.e., catalase, saccharase, urease, and alkaline phosphatase), and soil microbial biomass C, N, and P contents and its stoichiometry, particularly urease activity and the MBC:MBP ratio. Therefore, we conclude that plant communities are drivers of soil respiration, and that changes in soil respiration are associated with shifts in soil enzyme activities and nutrient stoichiometry. Full article

(This article belongs to the Special Issue Afforestation and Reforestation: Drivers, Dynamics, and Impacts)

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15 pages, 4441 KiB

Open AccessArticle

Different Influences of Vegetation Greening on Regional Water-Energy Balance under Different Climatic Conditions

by Dan Zhang, Xiaomang Liu and Peng Bai

Forests 2018, 9(7), 412; https://doi.org/10.3390/f9070412 - 09 Jul 2018

Cited by 21 | Viewed by 4289

Abstract

Vegetation serves as a key element in the land-atmospheric system, and changes in vegetation can impact the regional water-energy balance via several biophysical processes. This study proposes a new water-energy balance index that estimates the available-water-to-available-energy ratio (WER) by improving upon the Budyko framework, which evaluates climate variation and vegetation change. Moreover, the impact of vegetation greening on WER is quantified in 34 catchments under different climatic conditions. The results show that the normalized difference vegetation index (NDVI) increased at all the catchments, which indicates that there was a vegetation greening trend in the study area. There are negative relationships between the NDVI and runoff at both water-limited and energy-limited catchments, which demonstrates that both types of catchments became drier due to vegetation greening. Four numerical experiments were executed to quantify the contribution of vegetation greening and climate variations to WER changes. The results show that the calculated WER trends by numerical tests fit well with the observed WER trends (R² = 0.96). Vegetation greening has positive influences on WER changes under energy-limited conditions, which indicates that residual energy decreases faster than water availability, resulting in less energy for sensible heat, i.e., a cooling effect. Nevertheless, vegetation greening has negative influences on WER under water-limited conditions, which indicates that water availability decreases faster than residual energy, resulting in more energy for sensible heat. Notably, the WER decrease in water-limited catchments is dominated by potential evapotranspiration and NDVI variation, whereas the WER change in energy-limited catchments is dominated by climate variation. This study provides a comprehensive understanding of the relationships among water, energy and vegetation greening under different climatic conditions, which is important for land-atmosphere-vegetation modeling and designing strategies for ecological conservation and local water resource management. Full article

(This article belongs to the Special Issue Afforestation and Reforestation: Drivers, Dynamics, and Impacts)

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17 pages, 5053 KiB

Open AccessArticle

Assessing the Driving Forces in Vegetation Dynamics Using Net Primary Productivity as the Indicator: A Case Study in Jinghe River Basin in the Loess Plateau

by Hao Wang, Guohua Liu, Zongshan Li, Pengtao Wang and Zhuangzhuang Wang

Forests 2018, 9(7), 374; https://doi.org/10.3390/f9070374 - 21 Jun 2018

Cited by 22 | Viewed by 3521

Abstract

An objective and effective method to distinguish the influence of climate change and human activities on vegetation dynamics has great significance in the design and implementation of ecosystem restoration projects. Based on the Moderate Resolution Imaging Spectroradiometer (MODIS) remote data and the Miami and Carnegie–Ames–Stanford Approach (CASA) model, this study simulated and used net primary productivity (NPP) as an indicator to identify vegetation dynamics and their driving forces in the Jinghe River basin from 2000 to 2014. The results showed that: (1) The vegetation in the Jinghe River basin, which accounted for 84.4% of the study area, showed an increasing trend in NPP; (2) Human activities contributed most to vegetation restoration, which accounted for 54.5% of the areas; 24.0% of the areas showed an increasing trend in the NPP that was dominated by climate factors. Degradation dominated by human activities accounted for 4.3% of the study area, and degradation dominated by climate factors resulted in 17.2%; (3) The rate of vegetation degradation in areas dominated by climate factors rose with increased slope, where the arid climate caused shortages of water resources, and the human-dominated vegetation restoration activities exacerbated the vegetation’s water demand further, which surpassed the carrying capacity of regional water resources and led ultimately to vegetation degradation. We recommend that future ecological restoration programs pay more attention to maintaining the balance between ecosystem restoration and water resource demand to maximize the benefits of human activities and ensure the vegetation restoration is ecologically sustainable. Full article

(This article belongs to the Special Issue Afforestation and Reforestation: Drivers, Dynamics, and Impacts)

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14 pages, 2650 KiB

Open AccessArticle

Contrast Effects of Vegetation Cover Change on Evapotranspiration during a Revegetation Period in the Poyang Lake Basin, China

by Ying Wang, Yuanbo Liu and Jiaxin Jin

Forests 2018, 9(4), 217; https://doi.org/10.3390/f9040217 - 19 Apr 2018

Cited by 27 | Viewed by 4687

Abstract

It is known that evapotranspiration (ET) differs before and after vegetation change in watersheds. However, impacts of vegetation change on ET remain incompletely understood. In this paper, we investigated the process-specific, nonclimatic contribution (mainly vegetation coverage changes) to ET at grid, sub-basin, and basin scales using observation and remote sensing data. The Poyang Lake Basin was selected as the study area, which experienced a fast vegetation restoration from 1983 to 2014. Our results showed that vegetation cover change produced contrasting effects on annual ET in magnitude and direction during shifts from a less covered to a more covered stage. At the early stage (1983–1990), with vegetation cover of 30%, vegetation cover change produced negative effects on ET over the basin. At the middle stage (1990–2000), the vegetation coverage increased at a fast pace and the negative effects gradually shifted to positive. At the late stage (2000–2014), the vegetation coverage remained high (over 60%) and maintained a positive relationship with ET. In summary, the vegetation effects are collaboratively influenced by both vegetation coverage and its change rate. Our findings should be helpful for a comprehensive understanding of complicated hydrological responses to anthropogenic revegetation. Full article

(This article belongs to the Special Issue Afforestation and Reforestation: Drivers, Dynamics, and Impacts)

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21 pages, 10877 KiB

Open AccessArticle

Improved Water Consumption Estimates of Black Locust Plantations in China’s Loess Plateau

by Kai Schwärzel, Lulu Zhang, Andreas Strecker and Christian Podlasly

Forests 2018, 9(4), 201; https://doi.org/10.3390/f9040201 - 11 Apr 2018

Cited by 13 | Viewed by 5640

Abstract

Black locust (Robinia pseudoacacia L.) is a major tree species in China’s large-scale afforestation. Despite its significance, black locust is underrepresented in sap flow literature; moreover, the published water consumption data might be biased. We applied two field methods to estimate water consumption of black locust during the growing seasons in 2012 and 2013. The application of Granier’s original sap flow method produced a very low transpiration rate (0.08 mm d⁻¹) while the soil water balance method yielded a much higher rate (1.4 mm d⁻¹). A dye experiment to determine the active sapwood area showed that only the outermost annual ring is responsible for conducting water, which was not considered in many previous studies. Moreover, an in situ calibration experiment was conducted to improve the reliability of Granier’s method. Validation showed a good agreement in estimates of the transpiration rate between the different methods. It is known from many studies that black locust plantations contribute to the significant decline of discharge in the Yellow River basin. Our estimate of tree transpiration at stand scale confirms these results. This study provides a basis for and advances the argument for the development of more sustainable forest management strategies, which better balance forest-related ecosystem services such as soil conservation and water supply. Full article

(This article belongs to the Special Issue Afforestation and Reforestation: Drivers, Dynamics, and Impacts)

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17 pages, 31368 KiB

Open AccessArticle

Seasonal Changes in Photosynthetic Energy Utilization in a Desert Shrub (Artemisia ordosica Krasch.) during Its Different Phenophases

by Cai Ren, Yajuan Wu, Tianshan Zha, Xin Jia, Yun Tian, Yujie Bai, Charles P.-A. Bourque, Jingyong Ma and Wei Feng

Forests 2018, 9(4), 176; https://doi.org/10.3390/f9040176 - 30 Mar 2018

Cited by 11 | Viewed by 3717

Abstract

Our understanding of the mechanisms of plant response to environment fluctuations during plants’ phenological phases (phenophases) remains incomplete. Continuous chlorophyll fluorescence (ChlF) measurements were acquired from the field to quantify the responses in a desert shrub species (i.e., Artemesia ordosica Krasch. (A. ordosica)) to environmental factors by assessing variation in several ChlF-linked parameters and to understand plant acclimation to environmental stresses. Maximal quantum yield of PSII photochemistry (F_v/F_m) was shown to be reduced by environmental stressors and to be positively correlated to air temperature (T_a) during the early and late plant-growing stages, indicating a low temperature-induced inhibition during the leaf expansion and coloration phases. Effective quantum yield of PSII photochemistry (Φ_PSII) was negatively correlated to incident photosynthetically active radiation (PAR) irrespective of phenophase, suggesting excessive radiation-induced inhibition at all phenophases. The main mechanism for acclimating to environmental stress was the regulatory thermal dissipation (Φ_NPQ) and the long-term regulation of relative changes in Chl a to Chl b. The relative changes in photosynthetic energy utilization and dissipation in energy partitioning meant A. ordosica could acclimatize dynamically to environmental changes. This mechanism may enable plants in arid and semi-arid environments to acclimatize to increasingly extreme environmental conditions under future projected climate change. Full article

(This article belongs to the Special Issue Afforestation and Reforestation: Drivers, Dynamics, and Impacts)

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15 pages, 1252 KiB

Open AccessArticle

Relationship between Soil Characteristics and Stand Structure of Robinia pseudoacacia L. and Pinus tabulaeformis Carr. Mixed Plantations in the Caijiachuan Watershed: An Application of Structural Equation Modeling

by Xi Wei, Huaxing Bi, Wenjun Liang, Guirong Hou, Lingxiao Kong and Qiaozhi Zhou

Forests 2018, 9(3), 124; https://doi.org/10.3390/f9030124 - 06 Mar 2018

Cited by 23 | Viewed by 4271

Abstract

In order to study the multi-factor coupling relationships between typical Robinia pseudoacacia L. and Pinus tabulaeformis Carr. mixed plantations in the Caijiachuan basin of the Loess Plateau of Shanxi Province, West China, 136 sample plots were selected for building a structural equation model (SEM) of three potential variables: terrain, stand structure, and soil characteristics. Additionally, the indicators (also known as observed variables) were studied in this paper, including slope, altitude, diameter at breast height (DBH), tree height (TH), tree crown area, canopy density, stand density, leaf area index (LAI), soil moisture content, soil maximum water holding capacity (WHC), soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), ammonia-nitrogen (NH₃-N), nitrate-nitrogen (NO₃-N), and available phosphorus (AP). The results showed that terrain was the most important factor influencing soil moisture and nutrients, with a total impact coefficient of 1.303 and a direct path coefficient of 0.03, which represented mainly positive impacts; while correspondingly stand structure had a smaller negative impact on soil characteristics, with a total impact coefficient of −0.585 and a direct path coefficient of −0.01. The terrain also had a positive impact on the stand structure, with a total impact coefficient of 0.487 and a direct path coefficient of 0.63, indicating that the topography factors were more suitable for site conditions and both the stand structure and the soil moisture and nutrient conditions were relatively superior. By affecting the stand structure, terrain could restrict some soil, water, and nutrient functions of soil and water conservation. The influence coefficients of the four observed variables of DBH, stand density, soil water content, and organic matter, and potential variable topography reached 0.686, −0.119, 1.117, and 0.732, respectively; and the influence coefficients of soil moisture, organic matter and stand structure were −0.502 and −0.329, respectively. Therefore, besides observing the corresponding latent variables, the observed variables had a considerable indirect influence on other related latent variables. These relationships showed that the measures, such as changing micro-topography and adjusting stand density, should effectively maintain or enhance soil moisture and nutrient content so as to achieve improved soil and water conservation benefits in the ecologically important Loess Area. Full article

(This article belongs to the Special Issue Afforestation and Reforestation: Drivers, Dynamics, and Impacts)

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