Spiral waves in population density distributions of invasive pests in warm-temperate deciduous forest ecosystems

2021 ◽  
Author(s):  
Jian Gao ◽  
Changgui Gu ◽  
Chuansheng Shen ◽  
Huijie Yang
Keyword(s):  
Population Density ◽  
Forest Ecosystems ◽  
Deciduous Forest ◽  
Spiral Waves ◽  
Temperate Deciduous Forest ◽  
Invasive Pests ◽  
Density Distributions ◽  
Temperate Deciduous ◽  
Warm Temperate

scholarly journals Does NDVI explain spatial and temporal variability in sap velocity in temperate forest ecosystems?

2018 ◽  
Author(s):  
Anne J. Hoek van Dijke ◽  
Kaniska Mallick ◽  
Adriaan J. Teuling ◽  
Martin Schlerf ◽  
Miriam Machwitz ◽  
...  
Keyword(s):  
Temperate Forest ◽  
Vegetation Index ◽  
Forest Ecosystems ◽  
Normalized Difference Vegetation Index ◽  
Deciduous Forest ◽  
Significant Negative Correlation ◽  
Small Scale ◽  
Spatial And Temporal Variability ◽  
Temperate Deciduous Forest ◽  
Temperate Deciduous

Abstract. There is a need for a better understanding of the link between vegetation characteristics and tree transpiration to facilitate satellite derived transpiration estimation. Many studies use the normalized difference vegetation index (NDVI), a proxy for tree biophysical characteristics, to estimate evapotranspiration. In this study we investigated the link between sap velocity and 30 m resolution Landsat derived NDVI for twenty days during two contrasting precipitation years in a temperate deciduous forest catchment. Sap velocity was measured in the Attert catchment in Luxembourg in 25 plots of 20 × 20 m covering three geologies with sensors installed in 2–4 trees per plot. The results show that sap velocity and NDVI were significantly positively correlated in April, i.e., NDVI successfully captured the pattern of sap velocity during the phase of green-up. After green-up, a significant negative correlation was found during half of the studied days. During a dry period, sap velocity was uncorrelated to NDVI, but influenced by geology and aspect. In summary, in our study area, the correlation between sap velocity and NDVI was not constant, but varied with phenology and water availability. The same behaviour was found for the Enhanced Vegetation Index (EVI). This suggests that methods using NDVI or EVI to predict small-scale variability in (evapo)transpiration should be carefully applied and that NDVI and EVI cannot be used to scale sap velocity to stand level transpiration in temperate forest ecosystems.

Temperate Deciduous Forest Ecosystems of the World

1992 ◽  
Vol 19 (5) ◽  
pp. 584
Author(s):  
John R. Packham ◽  
E. Rohrig ◽  
B. Ulrich
Keyword(s):  
Forest Ecosystems ◽  
Deciduous Forest ◽  
Temperate Deciduous Forest ◽  
The World ◽  
Temperate Deciduous
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