Impact Of Vegetation Change Research Articles

Applicability of attribution methods for identifying runoff changes in changing environments

Under the dual impacts of global climate change and human activities, how to accurately and quantitatively assess and identify changes in watershed runoff is crucial to the rational development and utilization of water resources. Different methods of identifying runoff change attribution are applicable to different environments. In this study, we used five different methods, including the double mass curve (DMC), the soil and water assessment tool (SWAT), and the three Budyko hypotheses based on Fu, Choudhury‒Yang, and Milly‒Zhang formulas to explore the impact of human activities and climate change on runoff change in the Jinghe River basin (JRB). The results show that annual runoff of the JRB decreased considerably, and human activities accounted for more than 90%. Specifically, the results of the SWAT model and the three Budyko hypotheses are highly consistent except for the DMC method, which is not recommended in basins with significant changes in factors other than precipitation. More importantly, the Budyko hypothesis based on the Milly‒Zhang formula uses the vegetation water utilization coefficient to consider the impact of vegetation change on runoff, which is most consistent with the simulation results of the SWAT model and is recommended for the attribution analysis of changes in the Loess Plateau represented by the JRB.

Uncovering the impact of climate and vegetation changes on runoff in karstic regions of southwest China

The vegetation-runoff relationship remains unclear in karstic regions. The karst landform in southwest China is a focal area where significant changes in vegetation have occurred in the past few decades, which may substantially impact water resources. To date, the effects of these changes on runoff remain uncertain. This study employed statistical analysis, numerical simulation, and scenario analysis to investigate the temporal and spatial patterns of runoff, climate, and vegetation in 20 typical catchments. The study also evaluated the response of runoff to vegetation and climate changes and the underlying factors. The findings revealed precipitation changes dominated changes in runoff in these catchments (mean contribution of 53.03%), whereas the contributions of vegetation and potential evapotranspiration changes were 23.16% and 23.82%, respectively. The study also revealed that the impacts of vegetation changes on runoff were significantly dependent on vegetation and climate factors (R2 = 0.60, P < 0.01). Furthermore, under the same climate change conditions, a higher distribution of natural vegetation (such as forest) in the catchment resulted in a larger decreasing trend in runoff. The results provide guidelines for the prediction of runoff variation in southwest China, and benefits to decision-making on ecological restoration and water resources development.

Responses of hydrological processes to vegetation greening and climate change in subtropical watersheds

Study regionXiangjiang River Basin (XRB) in subtropical China. Study focusVegetation changes have a substantial impact on the water cycle in watersheds. However, the responses of hydrological processes to vegetation changes in subtropical regions have not yet been thoroughly clarified. The primary objectives of this study were to quantify the sensitivity of hydrological variables to vegetation changes and to elucidate the contributions of vegetation greening and climatic changes to alterations in hydrological variables in the Xiangjiang River Basin (XRB). New hydrological insights for the regionEvapotranspiration (ET) exhibits a significant positive sensitivity to alterations in Leaf Area Index (LAI) in the XRB, while soil water storage (SW) and flow depth (Q) showed a significant negative sensitivity to LAI changes. Changes in LAI primarily result in increased ET and reduced SW and Q, while increased in precipitation leads to augmented ET, SW, and Q. Alterations in potential evapotranspiration have been associated with heightened ET and reduced SW and Q. From the perspective of relative contributions, LAI predominantly influences alterations in ET within the XRB; P and PET are the primary driver of shifts in SW; and P chiefly governs the variations in Q. Our results highlight the important impact of vegetation changes on hydrological variables in subtropical watersheds.

Study on the impact of vegetation change on ecosystem services in the Loess Plateau, China

Vegetation change has a non-negligible role in the impact of ecosystem services (ESs). Quantitative assessment of vegetation ecosystem services is the basis for sustainable regional development. Using the Chinese Loess Plateau (LP) as the study area, this study firstly analysed the spatial and temporal characteristics of vegetation change and used a Geodetector model to reveal the driving mechanism. Next, this study applied the InVEST model to quantitatively assess the four services of carbon storage, habitat quality, soil conservation and water yield, and explored the vegetation ecosystem service balance through vegetation type transfer. The results showed that (1) there was a trend towards an increase in the area of all vegetation types, with sparse vegetation being the most pronounced. Areas of damaged vegetation were concentrated in urban and peripheral areas, as well as wasteland and bare ground. (2) Annual precipitation, soil types and cumulative afforestation area ratio were the main drivers of vegetation change on the LP. (3) Restoration of woodland enhanced carbon storage, habitat quality and soil retention services for vegetation on the LP, while water yield decreased by 31.66%. The restoration of vegetation area did not enhance all ecosystem services. This study may provide a reference and basis for the sustainable management of regional ecosystems.

Assessing the Impact of Vegetation Variation, Climate and Human Factors on the Streamflow Variation of Yarlung Zangbo River with the Corrected Budyko Equation

The Yarlung Zangbo River (YZR) is the largest river on the Qinghai Tibet Plateau, and changes in its meteorology, hydrology and vegetation will have a significant impact on the ecological environment of the basin. In order to deepen our understanding of the relationship of climate–vegetation–hydrological processes in YZR, the purpose of this study is to explore how vegetation growth in the YZR affects its runoff changes. We first identified the abrupt year of discharge in the YZR using a heuristic segmentation algorithm and cumulative anomaly mutation test approach. After that, the functional equation for NDVI and the Budyko parameter (n) was computed. Finally, the NDVI was introduced into the Budyko equation to evaluate the impact of vegetation changes on the streamflow in the YZR. Results showed that: (1) NDVI and discharge in the YZR both presented an increasing trend, and the mutation year of annual runoff in Nuxia station occurred in 1997. (2) n had a significant negative correlation with NDVI in the YZR (p &lt; 0.01). (3) The contributions of Pr, ET0, NDVI, and n on streamflow change in the S2 period (1998–2015) were 5.26%, 1.14%, 43.04%, and 50.06%. The results of this study can provide scientific guidance and support for the evaluation of the effects of ecological restoration measures, as well as the management and planning of water resources in the YZR.

Quantitative assessment of hydrological response to vegetation change in the upper reaches of Luanhe River with the modified Budyko framework

For assessing the influence of vegetation variation in upper reaches of Luanhe River (URLR) on streamflow, we first computed the equation between underlying surface parameter (ω) and the Normalized Difference Vegetation Index (NDVI). Then we introduced the vegetation information into the Budyko equation and established a modified Budyko equation. Finally, the impact of vegetation change on streamflow in URLR were estimated using the modified Budyko equation. Results showed that: (1) The NDVI in the URLR presented an increasing trend from 1982 to 2016, which is opposite to the runoff depth. The sudden change of NDVI occurred in 1998, and a simple linear model between ω and NDVI was obtained (p &amp;lt; 0.01). (2) The contribution rate of precipitation, potential evapotranspiration, NDVI, and anthropogenic factor on streamflow change during the changing period (1999–2016) are 44.99, 11.26, 29.45, and 17.30%, respectively. Although precipitation is still the main driver of runoff impact in the ULRB, with the increasing vegetation in the ULRB, vegetation has become the second driver of runoff impact followed by human activities and potential evapotranspiration. The mechanism of the effect of vegetation change on the water cycle needs to be further investigated. The results of this study can provide a theoretical basis for water use and conservation in the URLR.

Influence of vegetation change on water consumption in watersheds

AbstractEvapotranspiration is one of the hot issues of ecological hydrology. However, few studies have analysed the impact of vegetation changes on water consumption from the perspective of natural and artificial vegetation. Taking the Ziya River Basin as an example, the daily meteorological data from 2001 to 2015 were used to calculate the water consumption of vegetation based on the Penman–Monteith model. The results showed that the vegetation coverage increased. The total water consumption increased from 2001 (2.60 × 1,010 m3) to 2005 (2.65 × 1,010 m3) and decreased from 2005 (2.65 × 1,010 m3) to 2015 (2.40 × 1,010 m3). The water consumption per unit area in descending order was mixed forests (660 mm, annual average), croplands (640 mm), closed shrublands (581 mm), deciduous broadleaf forests (528 mm), grasslands (514 mm), savannas (459 mm), and woody savannas (454 mm). Finally, the regression equation between vegetation coverage change and water consumption was y = 0.377x + 84.516, which showed that there was a proportional relationship. Therefore, attention should be given to balancing local water allocation during vegetation restoration. The results can provide a reference for vegetation restoration policies

Vegetation Greening Enhanced the Regional Terrestrial Carbon Uptake in the Dongting Lake Basin of China

Terrestrial ecosystem carbon uptake is essential to achieving a regional carbon neutrality strategy, particularly in subtropical humid areas with dense vegetation. Due to the complex spatial and temporal heterogeneity of the carbon uptake of ecosystems, it is difficult to quantify the influence and contribution of different factors. With the aid of multisource remote sensing data, the spatiotemporal characteristics of carbon uptake and the impact of vegetation change were explored in the Dongting Lake Basin from 2001 to 2020. Based on the Conversion of Land Use and its Effects at Small regional extent (CLUE-S) model, we simulated the land use of the basin under different development scenarios in 2030. Our results showed that the basin has demonstrated a significant greening trend in the last 20 years, with a multiyear average NDVI (normalized difference vegetation index) of 0.60 and an increasing trend (y = 0.0048x − 9.069, R2 = 0.89, p &lt; 0.01). In this context, the multiyear mean of net ecosystem productivity (NEP) was 314.95 g C·m−2·a−1 and also showed a significant increasing trend (y = 1.8915x + 295.09, R2 = 0.23, p &lt; 0.05). Moreover, though the future carbon uptake might decrease because of the enhanced anthropogenic activities, the ecological conservation scenario might mitigate the reduction by 0.05 × 107 t. In conclusion, the greening trend enhanced the ecosystem carbon uptake in the Dongting lake basin. Considering the representativeness of the Dongting Lake Basin, the results of our study would provide useful clues for understanding the trend and pattern of terrestrial carbon uptake and for guiding the carbon neutrality strategy in the subtropical humid area.

Estimating hydrological consequences of vegetation greening

• LAI increased significantly up to 72.2% of the whole YRB area in 1981–2018. • Vegetation greening decreased SW and Q, but increased ET in selected catchments. • Sensitivities of the changes in Q and ET to the changes in LAI increased as LAI grows. • Sensitivity of ET and Q to LAI changes increased as the climate became drier. Large-scale afforestation program has alleviated environmental problems to some extent in China. However, the response of hydrological processes to vegetation greening at different catchments remains unclear. This study identified the impact of vegetation changes on runoff (Q), evapotranspiration (ET), and soil water storage (SW), as well as their relationships and sensitivities based on a coupled SWAT-PML model for 23 catchments from 2000 to 2018 in the Yellow River Basin (YRB). Results show that leaf area index (LAI) was significantly ( p < 0.05) increased in 72.2% of the YRB area. Vegetation greening decreased SW and Q, but increased ET in all catchments. The effects of vegetation greening on Q and ET were contrasting with axisymmetric fluctuation distribution. The changes in SW, ET, and Q were strongly correlated with the changes in LAI. Sensitivity of the changes in ET and Q to LAI changes increased when the climate becomes drier. Our study suggests that the vegetation greening followed by the afforestation policy implementation has caused gradually increasing impacts on Q and ET. However, such effects are spatially heterogeneous due to different degrees of increase in LAI and aridity conditions. Given the water crisis problem in the YRB, afforestation activity should be taken into consideration of the increasing water demand and the negative effects of vegetation greening on water resources in the future.

Retraction Note to: The impact of vegetation change and climate in coastal cities on public sports: the impact of urban heat island

The process of urbanization is the most important human activity since the twentieth century. Due to the unique environmental problems brought about by urbanization, urban heat islands not only affect regional economic development and regional climate but also bring comfort to urban residents and energy consumption. The negative impact is obvious, so the study of urban heat island effect is very important to monitor regional and even global climate change and guide urban development plans. First of all, this paper takes the coastal megacities along the Belt and Road as the research object, based on MODIS surface temperature products and Landsat land use classification data, and uses urban heat island intensity as an indicator to analyze the heat islands of 10 megacities from an interannual and seasonal perspective from 2004 to 2020. The effect of the spatio-temporal pattern changes; then, taking a city as an example, based on Landsat land use classification data, RS and GIS technology is used to analyze the land use cover change and urban expansion of a city in the past 30 years; finally, according to Landsat surface temperature data and land using classified data, the impact of land use and cover characteristics on urban heat islands in a city was investigated. Outdoor sports organizations and operators in SD coastal cities found that the outdoor sports organizations and operators in SD coastal cities did not make full use of the geographical environment, economic development, and cultural environment of coastal cities and fully analyzed the comprehensive and systematic problems in the organization and management of outdoor sports, so that outdoor sports organizations and operators in SD coastal cities can give full play to their advantages. Through this research, we will promote a more comprehensive understanding of the healthy and sustainable development of outdoor sports and promote the organization and development of outdoor sports. Management research provides a theoretical basis.

Increased Vegetation in Mountainous Headwaters Amplifies Water Stress During Dry Periods

AbstractThe dynamics of blue and green water partitioning under vegetation and climate change, as well as their different interactions during wet and dry periods, are poorly understood in the literature. We analyzed the impact of vegetation changes on blue water generation in a central Spanish Pyrenees basin undergoing intense afforestation. We found that vegetation change is a key driver of large decreases in blue water availability. The effect of vegetation increase is amplified during dry years, and mainly during the dry season, with streamflow reductions of more than 50%. This pattern can be attributed primarily to increased plant water consumption. Our findings highlight the importance of vegetation changes in reinforcing the decrease in water resource availability. With aridity expected to rise in southern Europe over the next few decades, interactions between climate and land management practices appear to be amplifying future hydrological drought risk in the region.

Response of soil respiration and Q10 to temperature and moisture in naturally regenerated and bare lands based on an 11-year observation period

Although correlations between soil respiration (Rs) and environmental factors in different ecosystems have been extensively investigated, results based on long-term experiments are limited. In this study, we analyzed the correlations between Rs and soil temperature (Ts), moisture (θ), the normalized difference vegetation index (NDVI), and soil organic matter (SOM) based on an 11-year field campaign in abandoned farmland (HD) and bare land (LD) areas with a Cambisol soil type in the eastern Loess Plateau of China. The results showed that the mean annual Rs and annual temperature sensitivity (Q10) values in HD were significantly larger than those in LD during the measurement period. Rs and the annual contribution ratio (Rratio) of root respiration (Rr) to Rs in HD increased significantly with vegetation recovery years. On the annual scale, Rs was controlled primarily by Ts at both sites. However, in the summer months, Rs was controlled by θ rather than Ts. A two-variable model, including Ts and θ, could more accurately predict the temporal variations in Rs at the annual and seasonal time scales than a single-variable model, and the explanatory power of the equations in HD was significantly larger than that in LD. On the interannual scale, variations in the annual Rs and Rr showed significant positive correlations with the annual θ and NDVI and SOM, and negative correlations with Ts in HD. Moreover, the annual Q10 was significantly positively related to θ in HD. In LD, the only significant relationship was between the annual Q10 and the annual θ. All differences between HD and LD in Rs, Ts, and θ and their correlations were attributed to differences in vegetation. Our findings highlight the importance of long-term observations for the accurate estimation of CO2 efflux in semiarid regions and the impact of vegetation changes on soil respiration.

RETRACTED ARTICLE:The impact of vegetation change and climate in coastal cities on public sports: the impact of urban heat island

The process of urbanization is the most important human activity since the twentieth century. Due to the unique environmental problems brought about by urbanization, urban heat islands not only affect regional economic development and regional climate but also bring comfort to urban residents and energy consumption. The negative impact is obvious, so the study of urban heat island effect is very important to monitor regional and even global climate change and guide urban development plans. First of all, this paper takes the coastal megacities along the Belt and Road as the research object, based on MODIS surface temperature products and Landsat land use classification data, and uses urban heat island intensity as an indicator to analyze the heat islands of 10 megacities from an interannual and seasonal perspective from 2004 to 2020. The effect of the spatio-temporal pattern changes; then, taking a city as an example, based on Landsat land use classification data, RS and GIS technology is used to analyze the land use cover change and urban expansion of a city in the past 30 years; finally, according to Landsat surface temperature data and land using classified data, the impact of land use and cover characteristics on urban heat islands in a city was investigated. Outdoor sports organizations and operators in SD coastal cities found that the outdoor sports organizations and operators in SD coastal cities did not make full use of the geographical environment, economic development, and cultural environment of coastal cities and fully analyzed the comprehensive and systematic problems in the organization and management of outdoor sports, so that outdoor sports organizations and operators in SD coastal cities can give full play to their advantages. Through this research, we will promote a more comprehensive understanding of the healthy and sustainable development of outdoor sports and promote the organization and development of outdoor sports. Management research provides a theoretical basis.

Surface Energy Flux Estimation in Two Boreal Settings in Alaska Using a Thermal-Based Remote Sensing Model

Recent Arctic warming has led to changes in the hydrological cycle. Circum-Arctic and circumboreal ecosystems are showing evidence of “greening” and “browning” due to temperature warming leading to shrub encroachment, tree mortality and deciduousness. Increases in latent heat flux from increased evapotranspiration rates associated with deciduous-dominated ecosystems may be significant, because deciduous vegetation has extremely high-water use and water storage capacity compared to coniferous and herbaceous plant species. Thus, the impact of vegetation change in boreal ecosystems on regional surface energy balance is a significant knowledge gap that must be addressed to better understand observed trends in water use/availability and tree mortality. To this end, output from a two-source energy balance model (TSEB) with modifications for high latitude boreal ecosystems was evaluated using flux tower measurements and Terra/Aqua MODIS remote sensing data collected over the two largest boreal forest types in Alaska (birch and black spruce). Data under clear and overcast days and from leaf-out to senescence from 2012 to 2016 were used for validation. Using flux tower observations and local model inputs, modifications to the model formulation for soil heat flux, net radiation partitioning, and canopy transpiration were required for the boreal forest. These improvements resulted in a mean absolute percent difference of around 23% for turbulent daytime fluxes when surface temperature from the flux towers was used, similar to errors reported in other studies conducted in warmer climates. Results when surface temperature from Terra/Aqua MODIS estimates were used as model input suggested that these model improvements are pertinent for regional scale applications. Vegetation indices and LAI time-series from the Terra/Aqua MODIS products were confirmed to be appropriate for energy flux estimation in the boreal forest to describe vegetation properties (LAI and green fraction) when field observations are not available. Model improvements for boreal settings identified in this study will be implemented operationally over North America to map surface energy fluxes at regional scales using long time series of remote sensing estimates as part of NOAA’s GOES Evapotranspiration and Drought Information System.

The role of unsaturated zone in estimating groundwater recharge in arid and semiarid areas as depicted by geochemical tracers

In arid and semiarid area, the recharge rate is relatively limited and the unsaturated zone (UZ) is commonly thick. The moisture in the UZ may represent the water infiltrating from precipitation during the past decades to thousands of years. Therefore, the multiple geochemical tracers in soil moisture, including Cl (chloride mass balance), 3H (tritium peak displacement), NO3, 2H, 18O, can be used to estimate diffuse recharge rate and related recharge characteristics. Based on 45 UZ profiles with maximum depth of 62 m in the Ordos Basin in NW China, a typical arid and semiarid area, we has used multiple geochemical tracers to study the following recharge informations: (1) reconstruction of groundwater recharge history, (2) determination of groundwater recharge mechanism, and (3) assessment of impact of vegetation changes on groundwater recharge. The results show that the soil texture (epically the shallow soil), vegetation and precipitation mainly control the recharge rate. This study also found that shallow groundwater in arid and semiarid areas is often not in equilibrium with near-surface boundary conditions. To estimate present recharge information, the UZ must be considered. The whole recharge process from precipitation to groundwater cannot be well understood unless the UZ have been included in arid and semiarid areas.

An Analytical Solution for the Impact of Vegetation Changes on Hydrological Partitioning Within the Budyko Framework

AbstractVegetation change is a critical factor that profoundly affects the terrestrial water cycle. Here we derive an analytical solution for the impact of vegetation changes on hydrological partitioning within the Budyko framework. This is achieved by deriving an analytical expression between leaf area index (LAI) change and the Budyko land surface parameter (n) change, through the combination of a steady state ecohydrological model with an analytical carbon cost‐benefit model for plant rooting depth. Using China where vegetation coverage has experienced dramatic changes over the past two decades as a study case, we quantify the impact of LAI changes on the hydrological partitioning during 1982–2010 and predict the future influence of these changes for the 21st century using climate model projections. Results show that LAI change exhibits an increasing importance on altering hydrological partitioning as climate becomes drier. In semiarid and arid China, increased LAI has led to substantial streamflow reductions over the past three decades (on average −8.5% in 1990s and −11.7% in 2000s compared to the 1980s baseline), and this decreasing trend in streamflow is projected to continue toward the end of this century due to predicted LAI increases. Our result calls for caution regarding the large‐scale revegetation activities currently being implemented in arid and semiarid China, which may result in serious future water scarcity issues here. The analytical model developed here is physically based and suitable for simultaneously assessing both vegetation changes and climate change induced changes to streamflow globally.

Vegetation changes and land surface feedbacks drive shifts in local temperatures over Central Asia

Vegetation changes play a vital role in modifying local temperatures although, until now, the climate feedback effects of vegetation changes are still poorly known and large uncertainties exist, especially over Central Asia. In this study, using remote sensing and re-analysis of existing data, we evaluated the impact of vegetation changes on local temperatures. Our results indicate that vegetation changes have a significant unidirectional causality relationship with regard to local temperature changes. We found that vegetation greening over Central Asia as a whole induced a cooling effect on the local temperatures. We also found that evapotranspiration (ET) exhibits greater sensitivity to the increases of the Normalized Difference Vegetation Index (NDVI) as compared to albedo in arid/semi-arid/semi-humid regions, potentially leading to a cooling effect. However, in humid regions, albedo warming completely surpasses ET cooling, causing a pronounced warming. Our findings suggest that using appropriate strategies to protect vulnerable dryland ecosystems from degradation, should lead to future benefits related to greening ecosystems and mitigation for rising temperatures.

Individual contributions of climate and vegetation change to soil moisture trends across multiple spatial scales.

Climate and vegetation change are two dominating factors for soil moisture trend. However, their individual contributions remain unknown due to their complex interaction. Here, I separated their contributions through a trajectory-based method across the global, regional and local scales. Our results demonstrated that climate change accounted for 98.78% and 114.64% of the global drying and wetting trend. Vegetation change exhibited a relatively weak influence (contributing 1.22% and −14.64% of the global drying and wetting) because it occurred in a limited area on land. Regionally, the impact of vegetation change cannot be neglected, which contributed −40.21% of the soil moisture change in the wetting zone. Locally, the contributions strongly correlated to the local environmental characteristics. Vegetation negatively affected soil moisture trends in the dry and sparsely vegetated regions and positively in the wet and densely vegetated regions. I conclude that individual contributions of climate and vegetation change vary at the global, regional and local scales. Climate change dominates the soil moisture trends, while vegetation change acts as a regulator to drying or wetting the soil under the changing climate.

The influence of Holocene vegetation changes on topography and erosion rates: a case study at Walnut Gulch Experimental Watershed, Arizona

Abstract. Quantifying how landscapes have responded and will respond to vegetation changes is an essential goal of geomorphology. The Walnut Gulch Experimental Watershed (WGEW) offers a unique opportunity to quantify the impact of vegetation changes on landscape evolution over geologic timescales. The WGEW is dominated by grasslands at high elevations and shrublands at low elevations. Paleovegetation data suggest that portions of WGEW higher than approximately 1430 m a.s.l. have been grasslands and/or woodlands throughout the late Quaternary, while elevations lower than 1430 m a.s.l. changed from a grassland/woodland to a shrubland ca. 2–4 ka. Elevations below 1430 m a.s.l. have decadal timescale erosion rates approximately 10 times higher, drainage densities approximately 3 times higher, and hillslope-scale relief approximately 3 times lower than elevations above 1430 m. We leverage the abundant geomorphic data collected at WGEW over the past several decades to calibrate a mathematical model that predicts the equilibrium drainage density in shrublands and grasslands/woodlands at WGEW. We use this model to test the hypothesis that the difference in drainage density between the shrublands and grassland/woodlands at WGEW is partly the result of a late Holocene vegetation change in the lower elevations of WGEW, using the upper elevations as a control. Model predictions for the increase in drainage density associated with the shift from grasslands/woodlands to shrublands are consistent with measured values. Using modern erosion rates and the magnitude of relief reduction associated with the transition from grasslands/woodlands to shrublands, we estimate the timing of the grassland-to-shrubland transition in the lower elevations of WGEW to be approximately 3 ka, i.e., broadly consistent with paleovegetation studies. Our results provide support for the hypothesis that common vegetation changes in semi-arid environments (e.g., from grassland to shrubland) can change erosion rates by more than an order of magnitude, with important consequences for landscape morphology.

Rainfall-runoff Investigation of Pine Forest Plantation in the Upstream Area of Gajah Mungkur Reservoir

Vegetation cover change has a profound influence on the hydrological cycle. A reduction in vegetative cover from forest harvesting generally increases the average surface runoff volume and total water yield for a given area of land. The differences of structure and land cover type are the main baseline in this research to understand the hydrological response of catchment. This research is using two catchment experiments, pine forest and mix-plant forest catchments. Plantation forest with clear cutting system in the mountain area is very sensitive with the changes of runoff and soil erosion. This study investigated the impact of vegetation changes on rainfall-runoff response in different type and periods of Pine forest plantation from their respective forestry treatments. The result shown that in the 7-year old mix-plant forest, direct runoff, peak discharge and runoff coefficient are dramatically increased than that in the 37-year old pine forest. 15 years after planting, direct runoff, peak discharge and runoff coefficient are decreased and reaching to the 37-year old pine forest responses. Implementation of a mix-plant forest method is effective in controlling the hydrological responses of direct runoff, peak discharge and runoff coefficient. The results showed that the magnitude of runoff during different forest treatments depend on interactions among rainfall, forest cover changes and surface disturbance. Forest management practices should consider and attempt to minimize disturbance during each plantation stage to control runoff response.