An exploratory analysis of spectral indices to estimate vegetation water content using sensitivity function

Water is an important component of vegetation canopies and the timely monitoring of vegetation moisture status is very useful for agricultural drought assessment and forest fire prediction. Currently, the retrieval of vegetation water content (VWC) is mainly based on spectral indices. However, the different performances under varying conditions make the evaluation of spectral indices very necessary. In previous studies, the determination coefficient (R ²), mean square error (MSE) and root mean square error (RMSE) were widely used for the evaluation of spectral indices. However, using these constants as evaluation criteria, the performance of spectral indices was the same within a wide range and thus could not be precisely described. In this study, the sensitivity function was introduced to investigate the strength of the spectral indices to VWC estimation based on LOPEX (Leaf Optical Properties EXperiment) data set. Equivalent water thickness (EWT) and fuel moisture content (FMC), both FMC based on fresh weight (FMC_w) and FMC based on dry weight (FMC_d), were used to indicate vegetation moisture status. According to the results, the major conclusions are as follows: (1) the sensitivity of spectral indices to VWC is not a constant but a function of VWC; (2) for each VWC indicator, the spectral indices show varying performances at different moisture levels, which can provide reference for spectral index selection while monitoring the vegetation moisture status; and (3) besides, the sensitivity of the same spectral index to different vegetation moisture indicators is not the same and the comparative study indicates that spectral indices are much more sensitive to EWT than FMC_w and FMC_d.     

Estimation of volumetric surface soil moisture content using microwave-calibrated soil evaporative efficiency information

ABSTRACT

Soil moisture (SM) is a critical variable in energy and water partitioning at the interface between the land surface and atmosphere. In this study, we provided a robust method to retrieve soil moisture using optimal remotely sensed soil evaporative efficiency (SEE) information. Specifically, SEE was deduced from the triangle space constituted by remotely sensed land surface temperature (LST) and fractional vegetation cover (Fc). Theoretical solutions of the dry and wet boundaries were derived by annual-scale optimization and microwave SM calibration. The two limits of SM were obtained by linear fit function between SEE and microwave-based SM. The proposed method was validated at the Liaoning Province of China in the year 2011 by using MODerate Resolution Imaging Spectroradiometer (MODIS) and Soil Moisture and Ocean Salinity (SMOS) satellite images as input. Results indicated that the new method has not only bypassed the complex parametric scheme in the calculation of boundaries within the LST-Fc feature space but also performed superior in the estimation of soil moisture status at all-sky days. Besides, the optimal method has reproduced the spatial and temporal patterns of soil moisture reasonably well, with a root mean square error of 0.07 m³ m^?3. Therefore, the proposed method can be regarded as a suitable tool to provide accurate and continuous monitoring of soil moisture.     

Expanding the applicability of remotely sensed soil evaporation transfer coefficient to the estimation of soil moisture over bare soil and partially vegetated areas

Soil evaporation transfer coefficient (h_a) is an effective means of estimating surface soil moisture from moderate-resolution imaging spectroradiometer (MODIS) imagery. This coefficient is a function of three variables: air temperature, land surface temperature and dry soil temperature. The first two variables can easily be obtained from different sources, whereas dry soil temperature cannot be determined as easily as the other ones, particularly over partially vegetated areas. In this paper, to enhance the capability of h_a in estimating soil moisture, we propose to use the combination of land surface temperature (LST) and normalized difference vegetation index (NDVI) to estimate dry soil temperature over partially vegetated areas as well as bare soil areas; this combination is known as LST-NDVI feature space in the literature. The underlying assumption of the proposed method is that at any given pixel over partially vegetated or bare soil areas, dry soil temperature is approximately equivalent to the maximum LST derived from LST-NDVI triangle space. The results showed that calculating h_a using dry soil temperature derived from the triangle space can result in more reliable estimation of soil moisture over bare soil and partially vegetated areas.     

A new estimate of tundra-biome phytomass from trans-Arctic field data and AVHRR NDVI

It is often assumed that the Normalized Difference Vegetation Index (NDVI) can be equated to aboveground plant biomass, but such a relationship has never been quantified at a global biome scale. We sampled aboveground plant biomass (phytomass) at representative zonal sites along two trans-Arctic transects, one in North America and one in Eurasia, and compared these data to satellite-derived NDVI. The results showed a remarkably strong correlation between total aboveground phytomass sampled at the peak of summer and the maximum annual NDVI (R ²?=?0.94, p < 0.001). The relationship was almost identical for the North America and Eurasia transects. The NDVI–phytomass relationship was used to make an aboveground phytomass map of the tundra biome. The approach uses a new and more accurate NDVI data set for the Arctic (GIMMS3g) and a sampling protocol that employs consistent methods for site selection, clip harvest and sorting and weighing of plant material. Extrapolation of the results to zonal landscape-level phytomass estimates provides valuable data for monitoring and modelling tundra vegetation.     

Evaluation of simulated soil moisture from China Land Data Assimilation System (CLDAS) land surface models

ABSTRACT

This study evaluated the land surface model-simulated soil moisture (SM) product from the China Land Data Assimilation System (CLDAS). This was achieved using three densely instrumented in situ observation networks in China that have different environmental conditions, i.e., the Hebi, Naqu and Heihe sites. The European Space Agency Climate Change Initiative multi-satellite-retrieved SM product (CCI-SM) was also included for inter-comparison purposes. Standard validation scores indicated that the CLDAS-SM product has high correlation and low uncertainty with both surface and root-zone soil moisture observations. The target accuracy (0.04 m³ m^?3) was achieved over all three sites. Compared with the CCI-SM product, the CLDAS-SM product showed higher accuracy for the Hebi and Heihe sites but slightly lower accuracy for the Naqu site located at the centre of the Tibetan Plateau. Regionally, the unbiased root mean square difference between the CLDAS-SM and CCI-SM products was noticeably smaller within China than in neighbouring countries. Given that the performance of the CCI-SM product should be unaffected by country boundaries, the better performance of the CLDAS-SM product in China can be attributed primarily to the high-quality meteorological forcing data.     

Managing wood production from small grower acacia hybrid plantations on eroded soils in central Vietnam

An experiment in a second rotation acacia hybrid (Acacia mangium × A. auriculiformis) clonal plantation in central Vietnam examined factors determining total wood production and its apportionment to sawlog and pulpwood. Growth and stand characteristics were compared with those in nearby plantations owned by small growers. The experimental site was on sloping land damaged and eroded by war and previous land use. The soil was shallow, with 20–30% laterised stones by volume and had lost part of the A horizon. Mean annual increment (MAI, in standing merchantable volume over bark) of the first rotation at age 8.8 years was 17 m³ ha^?1 y^?1. In the second rotation at age 7.6 years it was 20 m³ ha^?1 y^?1. Application of P fertiliser at three rates ranging from 14 to 86 kg ha^?1 increased stem diameter over the second rotation although stand volume response to P was not significant by rotation end. Potassium (14 kg ha^?1) gave no growth response. Growth rate was similar under weed control by herbicide and manual means. MAI increased progressively from 16.5 m³ ha^?1 y^?1 at the hilltop to 25.0 m³ ha^?1 y^?1 at the lowest part of the experiment; slope position influenced growth more than management practices. Key soil properties, pH, N, Bray-1 P and organic C were maintained from the first to the second rotation. With simple management practices including conservation of site organic matter and early stand management, appropriate for local small growers, the second rotation yielded 46% of harvested volume as sawlogs and the balance as pulpwood. Although small growers achieved similar growth rates, their current management regime does not yield sawlogs. They can influence the log categories produced and stand value through changes to stocking rate, stand management and rotation age.     

Day-to-day variation in oxygen consumption and energy expenditure during submaximal treadmill walking in female adolescents

The day-to-day variation in oxygen consumption (V˙O ₂) and energy expenditure (EE) during horizontal treadmill walking was measured using indirect calorimetry in 20 female adolescents (mean age 17·3 years). Two different walking speeds were used: 5 km h^?1 and an individually convenient speed of 3·0 km h^?1 (mean). The two sets of measurements were performed on 2 consecutive days, and great care was taken to minimize possible disturbing factors. The mean V˙O ₂ was 919 ml min^?1 at 5 km h^?1 and 622 ml min^?1 at the individual speed, and the mean values of EE were 4·5 kcal min^?1 and 3·1 kcal min^?1 respectively. The individual day-to-day variation in V˙O ₂ (at 5 km h^?1) was between ?11·7% and +12·6% of the mean V˙O ₂. The coefficient of variation (CV) was 6·4% when values were calculated in ml min^?1 kg^?1. The energy expenditure varied somewhat less between the 2 days (CV = 5·7%). The corresponding value for EE when walking at the individual speed was 7·2%, and the mean day-to day variation in V˙O ₂ was 7·5% (CV). The rate of perceived exertion according to Borg's scale was lower on day 2 (11·9) compared with day 1 (13·0) when walking at 5 km h^?1. There was no difference in heart rate between the 2 days. It is concluded that EE varies somewhat less than V˙O ₂ on successive days, probably because of an interchangeable relationship between breathing gases, depending on which substrate is used for combustion. When using V˙O ₂ and EE for evaluation of physical capacity, the day-to-day variation in the measurements must be taken into consideration.     

Assessing vegetation cover on the date of satellite-derived start of spring

Time series of satellite imagery are commonly used to study and model phenology. To use these models, their results must be compared with time series of areal field data, and vegetation condition must be assessed relative to model predictions. Field data and Moderate Resolution Imaging Spectroradiometer (MODIS) data for corn fields in Illinois, USA, were collected throughout the growing season, including vegetation cover fraction (VCF) derived from kite aerial photography (KAP). The mean height of corn on the estimated start of spring (SOS) date was just over 2 cm and the mean VCF on SOS was nearly 10%, indicating that satellite models of phenology lag behind field-based measures of phenology like crop emergence. The relationships between MODIS Normalized Difference Vegetation Index (NDVI) and both KAP NDVI (coefficient of determination (R ²)?=?0.918, p < 0.000) and KAP VCF (R ²?=?0.920, p < 0.000) were strong, highlighting the importance of areal field data in phenology studies.     

Asymmetric NDVI trends of the two cropping seasons in the Huai River basin

In this study we investigate vegetation changes using the normalized difference vegetation index (NDVI) in the Huai River basin during 1982–2013, where double cropping (DC) systems are widespread. The seasonal cycle of NDVI shows a bimodal distribution with two obvious peaks in May and August, respectively. By contrast, both precipitation and temperature reach their maxima in July, which suggests that the seasonal vegetation cycle is dominated by the DC ecosystems. During 1982–2013, annual NDVI has a significant (p < 0.1) positive trend at the rate of 1.360 × 10^–3 year^?1. We define the winter and summer cropping seasons (WCS and SCS) as November to May and June to October based on the agriculture calendar. NDVI trends are found to be asymmetric in these two cropping seasons. NDVI shows a positive trend with an increase of 2.314 × 10^–3 year^?1 (p < 0.1) during WCS, but during SCS, NDVI does not show a significant trend. No significant trend is found in precipitation. Meanwhile, temperature increases significantly in both cropping seasons, and is suggested to cause the asymmetric trends in NDVI because warming stimulates growth in the WCS more than SCS. Our results highlight the stimulative effect of temperature on vegetation growth even in warm regions dominated by multiple cropping ecosystems.     

Assessing water quality in the northern Adriatic Sea from HICO™ data

This letter focuses on water-quality estimation in the northern Adriatic Sea using physically-based methods applied to image obtained with the Hyperspectral Imager for the Coastal Ocean (HICO?). Optical properties of atmosphere and water were synchronously measured to parameterise such methods. HICO?-derived maps of chlorophyll-a (chl-a) and suspended particulate matter (SPM) indicated low values, in the range of 0–3 mg m^?3 and 0–4 g m^?3, respectively, correlating significantly with field data (R² = 0.71 for chl-a and R² = 0.85 for SPM). The results, on analysis, identify clear waters in the open sea and moderately turbid waters near the coast due to river sediment discharge and organic matter from coastal lagoons. These findings support the use of HICO? data to assess water-quality parameters in coastal zones and suggest the feasibility of integrating them with future-generation space-borne hyperspectral images.     

Mortality of Eucalyptus marginata (jarrah) and E. calophylla (marri) trees following stem injection: effects of herbicide,dose, season,and spacing of injections

Mortalities of Eucalyptus marginata Donn ex Smith (jarrah) and E. calophylla R.Br, (marri) trees injected with Roundup^TM (360 g glyphosate l^?1 ) or Tordon Timber Control^TM (50 g picloram l^?1 and 100 g triclopyr l^?1 ) (P+T) were determined at doses of 5 to 80 grams of active ingredient (g.a.i.) m^?2 of stem basal area for glyphosate, and 2 to 40 g.a.i. m^?2 for P+T. The effect of spacing of injections around the tree bole was examined. Seasonal variation in mortality was examined in relation to atmospheric vapour pressure deficit (v.p.d.) and soil water deficits.

Glyphosate was more effective in killing E. marginata trees, whereas P+T tended to be more effective in killing E. calophylla trees. The optimum doses of glyphosate and P+T for E. marginata trees were 20 g.a.i. m^?2 and 15 g.a.i. m^?2 respectively, and for E. calophylla 80 g.a.i. m^?2 and 15 g.a.i. m^?2 respectively. Spacing of injections around the circumference of the tree did not have a significant effect on the mortality of E. marginata trees injected with glyphosate. However, mortality of E. calophylla trees injected with P+T declined from 89% at 10–15 cm spacing to 70% at 25–50 cm spacing.

There were strong seasonal effects with both herbicides and in both species, with mortality higher (70 - 90 % mortality) in seasons other than summer (30 - 50 % mortality). For E. marginata trees injected with glyphosate, mortality declined linearly with increasing v.p.d., from 95% at a v.p.d. of 0.5 kPa, to 25% at 4.5 kPa. For E. calophylla trees injected with P+T, mortality declined linearly with increasing v.p.d., from 85% mortality at a v.p.d. of 0.5 kPa, to 50% at 3.0 kPa. Stem injection of both species should only be carried out when the vapour pressure deficit on the day prior to stem injection is less than 1.5 kPa.     

Growth performance of selected taxa as candidate species for productive tree plantations in Borneo

ABSTRACT

The establishment of commercial tree plantations in Malaysian Borneo began with a progression of various species, including Pinus caribea, Acacia mangium, Gmelina arborea, Falcataria moluccana (formerly Albizia falcataria) and Eucalyptus deglupta. Ultimately, A. mangium, intended for the production of pulplogs, dominated the plantation landscape. However, recent widespread devastation of A. mangium by the Ceratocystis pathogen in Sabah has led to a shift in plantation species, which has also necessitated a review of downstream end products. This paper analyses growth data and estimates productivity for species in a taxa trial as well as a F. moluccana progeny trial in a single trial area in Sabah. A eucalyptus hybrid (Eucalyptus urophylla x Eucalyptus grandis (UG)), Eucalyptus pellita, F. moluccana, Acacia crassicarpa and A. mangium exhibited high productivity after three years, with an average mean annual increment of approximately 35 m³ ha^?1 y^?1 or better. Mean annual increment curves show that productivity declined slightly for the eucalypts and F. moluccana after three years. Acacia species experienced a sharper decline associated with disease-caused mortality, with A. mangium the most seriously affected. The mean basic density of the UG hybrid and F. moluccana was 560 kg m^?3 and 252 kg m^?3 at six and five years of age, respectively, and E. pellita had a mean basic density of 629 kg m^?3 at six years of age. The importance of growth and wood properties in the selection of species suitable for planted forest development in the wet tropics is discussed.     

The usability of a modified Åstrand bicycle test to assess the aerobic capacity in patients with musculoskeletal pain and healthy controls

Purpose.?The aim of this study was to assess the usability of a modified Åstrand bicycle test in subjects with musculoskeletal pain disorder (MSPD) and healthy controls.

Methods.?In a random cross-over design, 31 subjects with a MSPD who have been referred to rehabilitation medicine and 33 healthy subjects matched for age, gender, height and body weight, performed an Åstrand bicycle test and a modified test with a time interval of 7 days. Drop-out rates, VO₂max values (in mL/kg lean body mass (LBM) min^?1), intraclass correlation coefficients (ICCs) and critical difference (Bland-Altman plots) for both tests within each group of subjects were compared.

Results.?The drop-out rate in both tests for the MSPD group was comparable, and mainly caused by pain, fatigue or breathlessness. Compared with the modified version, the Åstrand test showed higher VO₂max-scores: 4.83?mL/kg LBM min^?1 (9.96%) in the MSPD group and 3.5?mL/kg LBM min^?1 (5.57%) in the healthy group. ICCs were 0.79 and 0.87 and the limits of agreement were 8.5?mL/kg LBM min^?1 (15.9%) and 10.2?mL/kg LBM min^?1 (18.1%), respectively.

Conclusion.?The usability of the modified test is acceptable, as well as in healthy individuals as subjects suffering from MSPD being referred to rehabilitation medicine. However, a slight under estimation of VO₂max with the modified test has to be taken into account.     

Accuracy diagrams: a novel way to illustrate uncertainty of estimated GFR

Most studies that validate GFR equations present accuracy results stratified by measured GFR (mGFR; diagnostic correctness) or by estimated GFR (eGFR; diagnostic predictiveness) only, without a clear distinction in interpretation. The accuracy of a GFR equation is normally reported in percent (e.g. P₃₀), but is often misinterpreted when stratified by eGFR. The aim of the study was to develop new accuracy measures and diagrams that allow straightforward interpretations and illustrations of the uncertainty in eGFR in clinical practice. We applied quantile regression to the distribution of estimation errors for two creatinine-based GFR equations, LM-REV and CKD-EPI, in a clinical cohort (n?=?3495) referred for GFR measurement (plasma clearance of iohexol). Measures of bias and precision and accuracy intervals (AIs) were expressed in mL/min/1.73?m². Diagrams with AIs were chosen as a novel way to present the error margin in eGFR at a pre-specified certainty level. It was shown that creatinine-based equations are still quite inaccurate in that large estimation errors could not be ruled out with satisfactory certainty. As an example, the 75% AI for the most accurate equation, LM-REV, was approximately?±10?mL/min/1.73?m² at eGFR?=?45?mL/min/1.73?m², whereas it ranged between ?13 and +20?mL/min/1.73?m² at eGFR?=?90?mL/min/1.73?m². Accuracy intervals presented in diagrams can be used to illustrate the uncertainty of eGFR. Future validation studies should assess the variability in the predictiveness of eGFR across populations and clinical settings using tools and performance measures that are easy to interpret.     

A new vegetation heavy metal pollution index for detecting the pollution degree of different varieties of maize under copper stress

This study proposed a new vegetation heavy metal pollution index VHMPI to detect the pollution degree of different varieties of maize under copper stress, which provides a new idea for the detection of heavy metal pollution in vegetation. In order to ensure the outdoor growth environment of maize, we put all maize into outdoor greenhouse. The spectral reflectance interval of 450 nm–850 nm of maize leaves was processed by the first order differential (D) and continuum removal (CR), and the DCR spectral curve was obtained. The Pearson correlation coefficient (R) was used to analyze the DCR data and the biochemical data and select characteristic bands that sensitive to heavy metal Cu. The calculated Pearson correlation coefficients suggested that the DCR value at 490 nm–520 nm and 680 nm–700 nm presented a linear positive correlation close to 1 with the Cu²⁺ contents in soil and leaves, and a linear negative correlation close to ?1 was present in the range of 630 nm–650 nm and 710 nm–750 nm. We selected the DCR value of wavelengths 505 nm, 640 nm, 690 nm and 730 nm to establish VHMPI, and compared it with conventional vegetation indices (VIs) by calculating Pearson correlation coefficient between them and Cu contents in soil and leaves, Vegetation indices include WBI (Water Band Index), PSNDa (Pigment Specific Normalized Difference a), PRI (Photochemical Reflectance Index), NDVI (Normalized Difference Vegetation Index). Maize leaf spectral data obtained from experiments in 2017 were used for verification, VHMPI was also compared with WBI, PSNDa, PRI and NDVI.The results suggested that VHMPI showed a significant correlation with Cu²⁺ stress concentration,and the correlation of VHMPI was much stronger than that of other vegetation indices. The proposed VHMPI detects the pollution degree of maize with different varieties and in different periods under copper stress has advantages of straightforward calculation, robustness, and high effectiveness. This study focused on the laboratory leaf scale, so it is expected that future work extends it to a wide range of field scale and image scale.     

A comparison of single plasma sample methods to estimate renal clearance using 99mTc‐ethylenedicysteine and 99mTc‐mercaptoacetyltriglycine

Several single sample methods for determination of ^99mTc‐mercaptoacetyltriglycine (MAG3) clearance are being used clinically. Kabasakal et al. proposed a similar formula for ^99mTc‐ethylenedicysteine (EC). This study was performed to compare his method with Bubeck et al. formula for ^99mTc‐MAG3 already in use. Twenty‐eight subjects divided in two groups were registered which included 22 patients with various renal diseases (group‐I) and six normal volunteers (group II). All subjects were studied twice using both the radiopharmaceuticals. The images and renogram parameters, that is T_MAX and T_1/2 of both the agents, were similar in all the subjects. The clearance of the ^99mTc‐EC was however considerably higher than ^99mTc‐MAG3 in both the groups (mean ± SEM =279 ± 14 ml min^?1/1·73 m² versus 177 ± 15 ml min^?1/1·73 m² in group‐I and 377 ± 11·90 ml min^?1/1·73 m² versus 238 ± 8·23 ml min^?1/1·73 m² in group II). This difference was more pronounced in cases with reduced renal functions. Among the Effective Renal Plasma Flow (ERPF) values determined from EC and MAG3 clearances in six normal volunteers, four cases only in MAG3 had ERPF below the lower limit. This study has demonstrated superiority of single sample method for ^99 mTc‐EC clearance over its analogous method for ^99mTc‐MAG3.     

Determinants of the reduction in B‐type natriuretic peptide after mitral valve replacement in patients with rheumatic mitral stenosis

Background: Plasma B‐type natriuretic peptide (BNP) levels are closely related to symptoms in left ventricle (LV) systolic heart failure, although marked regarding heterogeneity levels among subjects are reported. Aims: To assess the influence of right ventricle on plasma BNP in the patients with different grades of its overload secondary to severe mitral valve stenosis (MVS). Methods: Plasma BNP was evaluated in MVS patients (n = 27) before valve replacement and during follow‐up (FUV) 401 ± 42 days after operation. Results: Initial examination showed severe MVS (0.9 ± 0.2 cm²), left atrial enlargement (LAI 30 ± 4.5 mm m^?2), right ventricle diastolic dilatation (RVDI 16 ± 3.6 mm m^?2), normal LV size/function and elevated BNP levels (166 ± 137 pg ml^?1). FUV examination revealed a significant reduction in LAI (27 ± 2.2 mm m^?2), RVDI (14 ± 1.6 mm m^?2) and BNP levels (80 ± 35 pg ml^?1). The regression analysis of the initial parameters found RVDI to be the strongest predictor (R² = 0.61; P<0.0001) for BNP level, whereas RVDI reduction was the strongest factor for BNP decrease (R² = 0.65; P<0.0001) during FUV. Conclusions: Right ventricle should be taken into account as a potential important source of plasma BNP owing to the fact that LV size and function are well preserved in MVS patients. RVDI determines BNP plasma levels whereas after MVS removal, the RVDI reduction predicts BNP level decrease.     

Discrimination of areas infected with coffee leaf rust using a vegetation index

Coffee leaf rust is for the coffee industry potentially one of the causes of a sustainability crisis. Currently, on-site disease detection is the only effective method to fell coffee trees for prevention of the infection. However, accurate infection detection over wide areas is difficult when conducted by ground surveys. Here, we examine the application of a remote sensing method. The Normalized Difference Vegetation Index (NDVI) values of coffee farms were computed using satellite images and compared with the results of the ground truth. We found that the standard deviation of the NDVI value (σ_NDVI) in damaged farms increases as the average NDVI value decreases. This fact implies that the disease progresses in-homogeneously inside a damaged area. In the present analysis, up to 94.1% of the damaged farms were discriminated by combining the NDVI and σ_NDVI thresholds when 75.0% of the damaged farms had NDVI values under 0.732 and σ_NDVI over 0.044. Our monitoring method enabled us to take early-stage countermeasures against the infection, and it could be applied to other vegetation diseases.     

Nine year results from a Eucalyptus camaldulensis Dehnh. provenance trial in the Wellington catchment of Western Australia

Data for 20 provenances of Eucalyptus camaldulensis from the southern half of Australia including 14 provenances of variety camaldulensis and 6 provenances of variety obtusa were assessed for growth and form in the south west of Western Australia. Mean annual volume increment at age nine years was greater in variety camaldulensis (3.3 m³ ha^?1 yr^?1) than for variety obtusa (1.9 m³ ha^?1 yr^?1). No significant differences in forking or branching were found between the two varieties. Lake Albacutya (variety camaldulensis) was the most productive provenance yielding 5.3 m³ ha^?1 yr^?1 but was only average for form. Laura (variety camaldulensis) was the best all round performer yielding the third highest volume production (4.2 m³ ha^?1 yr^?1) and ranking in the top quartile for forking, branching and straightness. Within variety camaldulensis a weak correlation was found between height and mean annual rainfall, provenances from lower rainfall areas being more likely to produce taller trees. A trend for smaller numbers of persistent branches with decreasing rainfall was observed for the species as a whole.     

MODIS remote sensing approaches to monitoring soil moisture in Tibet,China

Satellite remote sensing from space offers a unique way to monitor surface soil moisture on a large geographical scale. In this work, the general approaches to monitoring surface soil moisture for Tibet area were developed using Moderate Resolution Imaging Spectroradiometer (MODIS) data and ground observations. The result shows that MODIS Vegetation Supply Water Index (VSWI) and band-7 reflectance are significantly correlated with ground measured soil moisture and MODIS band 7 is a simple and more effective method to monitor soil moisture in Tibet with higher spatial resolution at 500 m in comparison with VSWI at 1000 m resolution.