5th, December, 2014
Cohen, W. B., Maiersperger, T. K., Turner, D. P., Ritts, W. D., Pflugmacher, D., Kennedy, R. E., ... & Gower, S. T. (2006). MODIS land cover and LAI collection 4 product quality across nine sites in the western hemisphere. Geoscience and Remote Sensing, IEEE Transactions on, 44(7), 1843-1857.
- This article said satellite based LAI (MODIS) has uncertainties as known, because MODIS offer 1km resolution, small patches of vegetation could be missed. Therefore, it would limited to use as reference values.
4th, December, 2014
Zou, X., Mõttus, M., Tammeorg, P., Torres, C. L., Takala, T., Pisek, J., ... & Pellikka, P. (2014). Photographic measurement of leaf angles in field crops. Agricultural and Forest Meteorology, 184, 137-146.
- This article (2014) found out that it is possible to measure leaf angle distribution not only in the canopy scale but also in the crop scale by photographic technique.
3rd, December, 2014
Graham, E. A., Yuen, E. M., Robertson, G. F., Kaiser, W. J., Hamilton, M. P., & Rundel, P. W. (2009). Budburst and leaf area expansion measured with a novel mobile camera system and simple color thresholding. Environmental and Experimental Botany, 65(2), 238-244.
- Methods for scaling up the ground based measurements are still lacking and the author said digital cameras would help to solve this point. However, not only digital camera but also other measurements are required (needed) to incorporate to scale up the satellite data.
2nd, December, 2014
Breda, N. J. (2003). Ground‐based measurements of leaf area index: a review of methods, instruments and current controversies. Journal of experimental botany, 54(392), 2403-2417.
- This article was easy to understand how to estimate leaf area index (LAI) in direct and indirect method. It showed the weakness of both methods and mentioned the methods should be improved in the future studies.
1st, December, 2014
Chianucci, F., Cutini, A., Corona, P. and Puletti, N., 2014. Estimation of leaf area index in understory deciduous trees using digital photography. Agricultural and Forest Meteorology, 198: 259-264.
- Estimate leaf area index about understory by nadir photography analyzed with JPGE format. The author recommended to increase sampling plot, use short focal length and to take multiple photos per site. Also mentioned the benefit of RAW format option needs further testing.
4th, November, 2014
Peng, S., Piao, S., Ciais, P., Friedlingstein, P., Ottle, C., Bréon, F. M., ... & Myneni, R. B. (2011). Surface urban heat island across 419 global big cities. Environmental science & technology, 46(2), 696-703.
- Reading the article(2011) I did not notice there were many different cases to think about urban heat island (seasonal , day time, night time, city size, population density, etc.)and realized that remote sensing (MODIS) provide convenience in analyzing in big scale.
3rd, November, 2014
McKinney, M.L., 2002. Urbanization, biodiversity, and conservation. Bioscience, 52(10): 883-890.
- This article (2002) shows human activity decreased the urban biodiversity by land change. It is said species richness tends to be higher in areas with low to moderate levels of human development. Especially species richness at the urban core is cut down in half the rural area. Author advice urban planners to find the way to protect urban biodiversity when city planning and try to expand the natural habitat.
2nd, November, 2014
Nasahara, K.N., Muraoka, H., Nagai, S. and Mikami, H., 2008. Vertical integration of leaf area index in a Japanese deciduous broad-leaved forest. Agricultural and forest meteorology, 148(6): 1136-1146.
- This article (2008) was useful to understand about the leaf mass per unit leaf area (LMA). However, I am curious about what is the reason LAI-2000 measurement is half of the value of the method in this study.
1st, November, 2014
Ryu, Y., Lee, G., Jeon, S., Song, Y. and Kimm, H., 2014. Monitoring multi-layer canopy spring phenology of temperate deciduous and evergreen forests using low-cost spectral sensors. Remote Sensing of Environment, 149: 227-238.
- This paper was interesting because it used different kinds of instrument (e.g. digital camera, LED, LAI-2200, MODIS satellite) to look phenology in multi later canopy. Also, the instruments were compared each other and looking over the relation was amusing.
4th, October, 2014
McCarthy, H.R., Pataki, D.E. and Jenerette, G.D., 2011. Plant water-use efficiency as a metric of urban ecosystem services. Ecological Applications, 21(8): 3115-3127.
-In this article, McCarthy and her colleagues (2011) studied about Atmospheric and soil moisture measurements about urban trees water use efficiency (WUE) in leaf scale, whole tree scale and temporal scale. The result was integrated leaf WUE did not match well with instantaneous leaf WUE and integrated whole tree WUE. Also suggest whole tree WUE is useful to measure the balance between costs and benefits of irrigated urban trees and finding which trees is more appropriate to maximize growth while conserving water.
3rd, October, 2014
Townsend‐Small, A., Pataki, D. E., Liu, H., Li, Z., Wu, Q., & Thomas, B. (2013). Increasing summer river discharge in southern California, USA, linked to urbanization. Geophysical Research Letters, 40(17), 4643-4647.
- I realized that the site climate was different from the Republic of Korea, since in summer Korea has a humid weather caused by summer monsoon. Therefore I wonder how the result would come up if we do the same experiment in Korea.
2nd, October, 2014
Edmondson, J.L., Davies, Z.G., McHugh, N., Gaston, K.J., & Leake, J.R. (2012). Organic carbon hidden in urban ecosystems. Scientific reports, 2
-In this article, Edmondson (2012) discussed that urban soil stored more organic carbon compared to agricultural land. It was interesting because in my knowledge urban surface is covered by many buildings. Because of this reason, I thought storing organic carbon could be limited. However, the reason why agricultural land has lower storage of organic carbon was that in urban, residents give fertilizer to the soil and agricultural land often turn over the soil so agricultural land had lower value.
1st, October, 2014
Mackey, C.W., Lee, X., & Smith, R.B. (2012). Remotely sensing the cooling effects of city scale efforts to reduce urban heat island. Building and Environment, 49, 348-358
-In this article, Mackey (2012) discussed how temperature change in a city scale was effected by the increase of Normalized difference vegetation index (NDVI) and albedo. Unlike what I learned in the landscape architecture course that planting vegetation would decrease the urban heat island effect, Mackey (2012) showed that increase of albedo decreased more temperature compared to the increased vegetation. Figure 5 compared eight sites of Chicago using Landsat, remote sensing, and data from year 1998 and 2010.was surprised by the results that a slight change of albedo could affect a big decrease in temperature. However, it was regrettable that Landsat could not detect the pixel under 30m pixel because it meant that green roof analysis was not credible when green roof was undetectable.
4th, September, 2014
Wild, M., Gilgen, H., Roesch, A., Ohmura, A., Long, C.N., Dutton, E.G., Forgan, B., Kallis, A., Russak, V., & Tsvetkov, A. (2005). From dimming to brightening: Decadal changes in solar radiation at Earth's surface. science, 308, 847-850
-In this article, Martin (2005) discussed the changes in solar radiation. Figure 2a illustrated the surface radiation changes from 1992 to 2002 at the three different latitude sites, which were high, mid, and low latitude. All sites show an increasing phenomenon therefore, the author assumed if there was any particular contribution in the sky conditions (clear sky or all sky). However as the Figure 2b showed there were no significant matters about the sky condition. Later the increasing brightening reason found to be the greenhouse signals which became stronger after the 1990s.
3rd, September, 2014
Omasa, K., Hosoi, F., Uenishi, T., Shimizu, Y., & Akiyama, Y. (2008). Three-dimensional modeling of an urban park and trees by combined airborne and portable on-ground scanning LIDAR remote sensing. Environmental modeling & assessment, 13, 473-481
-This article (Omasa, Hosoi, Uenishi, Shimzu, and Akiyama, 2008) was very interesting because it was about three-dimension modeling of trees measured by LIDAR sensor, which combined the two scanning methods, i.e., airborne and on-ground. The two scanning methods and the combination of the two methods were easily explained by the diagram (Figure2). The diagram also shortly explained what kind of information the method provided. Therefore, it was easy to understand the differences as well as the strengths and the weaknesses of the methods in the paragraph. The best way to make a three dimensional modeling is combining the airborne and on-ground scanning LIDAR data.
2nd, September, 2014
Chang, H., & Kwon, W.-T. (2007). Spatial variations of summer precipitation trends in South Korea, 1973–2005. Environmental Research Letters, 2, 045012
-In this article, Chang (2007) describes precipitation trends. I am looking forward to the future study findings related to the trend in the heavy precipitation and also some solutions of the urban areas. From this article, I learned that the climate change makes the late summer precipitation caused by the weaken of the Changma front. Also, it was interesting to find that monsoon can be related to the sea surface temperature, not just the Changma fronts.
1st, September, 2014
Bonan, G.B. (2008). Forests and climate change: forcings, feedbacks, and the climate benefits of forests. science, 320, 1444-144
-Before reading this paper I thought ‘forest’ has only positive effect in climate change, because I thought CO2 would decrease by the effect of the green. Also, I have never thought about forest in other location. In this article Bonan (2008) divided the forest into three kinds (tropical, temperate and boreal) of forests and explained each of the climate change effect. It was interesting that other location forest had complex and different correlation with biosphere and atmosphere than I thought for example albedo, evapotranspiration, human land use etc.
5th, August, 2014
Grimm, N.B., Faeth, S.H., Golubiewski, N.E., Redman, C.L., Wu, J., Bai, X., & Briggs, J.M. (2008). Global change and the ecology of cities. science, 319, 756-760
-In this paper covered five major types of global environmental change by urban ecosystems: changes in land use and cover, biogeochemical cycle, climate, hydro systems, and biodiversity. It was helpful to understand the urban ecology by reading the individual parts which were covered in the article. However, it could have been better if the author treated some of the results because the article did not cover any results how the farther urban ecology can be changed or what the humankind should do to make a better urban ecology.
4th, August, 2014
Ahl, D.E., Gower, S.T., Burrows, S.N., Shabanov, N.V., Myneni, R.B., & Knyazikhin, Y. (2006). Monitoring spring canopy phenology of a deciduous broadleaf forest using MODIS. Remote Sensing of Environment, 104, 88-95
-Measuring the understory was an interesting study because I recently had to find out when did the understory came out in the coniferous forest. This paper was similar to my research, I also had to use the logistic and find when did the leaf came out and got stable. This paper results were that the MODIS data is sensitive to track the general vegetation phenology trajectory during leaf expansion in deciduous forest.
3rd, August, 2014
Graham, E.A., Hamilton, M.P., Mishler, B.D., Rundel, P.W., & Hansen, M.H. (2006). Use of a Networked Digital Camera to Estimate Net CO2 Uptake of a Desiccation‐Tolerant Moss. International Journal of Plant Sciences, 167, 751-758
-It was interesting that MossCam could measurer various phenomenon, such as air temperature, wind speed, leaf wetness etc. Also I was surprised that there was a difference in hydrated/dry values for live and dead samples. Because I thought dead samples would not response. And the color index of green: red ratio chosen for this study provided the best signal of color change in the field compared to other methods investigated.
2nd, August, 2014
Majasalmi, T., Rautiainen, M., Stenberg, P., & Rita, H. (2012). Optimizing the sampling scheme for LAI-2000 measurements in a boreal forest. Agricultural and forest meteorology, 154, 38-43
-This paper studied how many sample would it need to measure LAI accurately by LAI-2000. And found out that using 12 sample measurement organized in across or square yields LAI estimates that have an average standard error less than 0.15 (0.06: forest with no a priori information on stand structure) units and a coefficients of variation (CV) less than 3%.
1st, August, 2014
Macfarlane, C., Arndt, S.K., Livesley, S.J., Edgar, A.C., White, D.A., Adams, M.A., & Eamus, D. (2007). Estimation of leaf area index in eucalypt forest with vertical foliage, using cover and fullframe fisheye photography. Forest ecology and management, 242, 756-763
-This paper have shown that errors in calculation of the foliage angle distribution are also significant and that, unexpectedly, foliage clumping can inadvertently improve Leaf area index estimation in stands with vertical foliage. Also conclude that cover photography should be the preferred method for routine indirect canopy LAI measurements.
4th, July, 2014
Macfarlane, C., Hoffman, M., Eamus, D., Kerp, N., Higginson, S., McMurtrie, R., & Adams, M. (2007). Estimation of leaf area index in eucalypt forest using digital photography. Agricultural and forest meteorology, 143, 176-188
3rd, July, 2014
Pisek, J., Ryu, Y., & Alikas, K. (2011). Estimating leaf inclination and G-function from leveled digital camera photography in broadleaf canopies. Trees, 25, 919-924
-There were lots of advantages using digital camera image to estimate leaf inclination and G-function. The camera had an affordable costs compared to other equipment and it could take pictures even in large distance. At last it could save the data image and see it on the computer. The most important results were well matched. Though the photography had an issue in needle leaf.
2nd, July, 2014
Lang, M., Kuusk, A., Mõttus, M., Rautiainen, M., & Nilson, T. (2010). Canopy gap fraction estimation from digital hemispherical images using sky radiance models and a linear conversion method. Agricultural and forest meteorology, 150, 20-29
- I though taking pictures in a sunny day, clear sky would be clearly to analyze the image but the overcast sky was more stable (overcast sky radiance decreases with increasing the view zenith angle) then clear sky. Also the comparison of transmittances and calculated PAIe values based on LAI-2000 data and hemispherical images (took below canopy) showed reasonably well.
1st, July, 2014
Cescatti, A. (2007). Indirect estimates of canopy gap fraction based on the linear conversion of hemispherical photographs: Methodology and comparison with standard thresholding techniques. Agricultural and forest meteorology, 143, 1-12
-Digital numbers are not linearly related to the brightness of the scene. Human eye and digital camera response to the light is logarithmic. Therefor the author used two synchronized images taken above and below the canopy and save the original sensor information in a raw file format. Next Manual, Ridler and Calvard, Side Look and Linear Ratio methods were evaluated by comparison with the LI-COR PCA DIFN (diffuse non-interceptance) and ePAL (effective plat area index). As a result Linear Ratio was the most accurate method among the others, those performed with hemispherical photographs.
4th, June, 2014
Macfarlane, C., Ryu, Y., Ogden, G.N., & Sonnentag, O. (2014). Digital canopy photography: Exposed and in the raw. Agricultural and forest meteorology
-This paper was interesting because it is related to my study, which I am working on.
Now I could understand why I was taking raw image by one stop of underexposure and saving DNG format, which I was told to do so. Also the paper showed that gap fraction (GF) was more stable in raw images compare to JPGE images.
3rd, June, 2014
Petach, A.R., Toomey, M., Aubrecht, D.M., & Richardson, A.D. (2014). Monitoring vegetation phenology using an infrared-enabled security camera. Agricultural and forest meteorology, 195, 143-151
-This paper tells that camera NDVI which method they have develop shows almost identical to NDVI measured using narrow-band radiometric instruments or MODIS platform. Also the author said the advantage of gcc is that it is sensitive to leaf color, while camera NDVI is a better for measuring LAI. So the use of both gcc and camera NDVI together give more information than using only one. I was interested with false-color images (XRG) obtained from an infrared-enabled security camera because it was more outstanding then RGB image.
2nd, June, 2014
Chapin III, F., Woodwell, G., Randerson, J.T., Rastetter, E.B., Lovett, G., Baldocchi, D.D., Clark, D., Harmon, M.E., Schimel, D.S., & Valentini, R. (2006). Reconciling carbon-cycle concepts, terminology, and methods. Ecosystems, 9, 1041-1050
-Reading this paper I realized it is important to define scientific terminology. There for in this paper NEP(Net ecosystem production) was define as GPP(gross primary production) minus ER(ecosystem respiration). Also NECB(Net ecosystem carbon balance) was more sensitive than NEP during fires(NEP is zero, NECB decreases dramatically).
1st, June. 2014
Macfarlane, C. (2011). Classification method of mixed pixels does not affect canopy metrics from digital images of forest overstorey. Agricultural and forest meteorology, 151, 833-840
- The author tested four different methods to classify mixed pixels (between canopy and sky pixels) in both cover and fisheye images. The results of these methods made little difference to estimate Leaf area index (LAI) even though fisheye had more mixed pixels then cover images. Although the results were similar LLX (LAI using Lang and Xiang method) form fisheye photography agreed best with LAI from DCP (Digital cover photography).
5th, May, 2014
T.F. Keenan1, B. Darby, E. Felts, O. Sonnentag, M. Friedl, K. Hufkens6, J. O’Keefe, S. Klosterman, J.W. Munger, M. Toomey, A.D. Richardson(2014). Tracking forest phenology and seasonal physiology using digital repeat photography: a critical assessment
4th, May. 2014
Fu, Y.S., Campioli, M., Vitasse, Y., De Boeck, H.J., Van den Berge, J., AbdElgawad, H., Asard, H., Piao, S., Deckmyn, G., & Janssens, I.A. (2014). Variation in leaf flushing date influences autumnal senescence and next year’s flushing date in two temperate tree species. Proceedings of the National Academy of Sciences, 201321727
- It was interesting that leaf flushing has a relation between the previous year temperatures (warm winter). The earlier the leaf flush the earlier it senescence. The author experiment with saplings, giving different temperatures for each of them, and exposed to similar ambient conditions for 1year.
3rd, May. 2014
Nagai, S., Maeda, T., Gamo, M., Muraoka, H., Suzuki, R., & Nasahara, K.N. (2011). Using digital camera images to detect canopy condition of deciduous broad-leaved trees. Plant Ecology & Diversity, 4, 79-89
- This paper suggest autumn detect better RGB digital numbers(DN) values compared with spring. In autumn it showed differences in leaf-colouring, leaf-fall patterns and timings between species. During leaf-expansion period LAI correlated positively with G values and negatively with R values. And during leaf-fall period SPAD (soil and plant analyser development) correlated positively with G values.
2nd, May. 2014
Sonnentag, O., Hufkens, K., Teshera-Sterne, C., Young, A.M., Friedl, M., Braswell, B.H., Milliman, T., O’Keefe, J., & Richardson, A.D. (2012). Digital repeat photography for phenological research in forest ecosystems. Agricultural and forest meteorology, 152, 159-177
- In this paper the author compared excess green (ExG=2G-[R+B]) and green chromatic coordinate (Gcc=G/[R+G+B]) to remove the scene illumination affect. The result of both descriptions of canopy greenness failed, but the author found out that Gcc was more effective then ExG. Also comparing ExG and Gcc with different cameras found out to be a secondary importance. It was interesting that changing RAW format to JPEG format do not loss its information about phenological relevant.
1st, May. 2014
Nagai, S., Nasahara, K.N., Muraoka, H., Akiyama, T., & Tsuchida, S. (2010). Field experiments to test the use of the normalized-difference vegetation index for phenology detection. Agricultural and forest meteorology, 150, 152-160
- In this paper the author examined the use of Normalized Difference Vegetation Index (NDVI) data to detect the dates of leaf expansion and defoliation. Using these data, the author investigated the monotonicity, uniqueness, and robustness of the relationship between NDVI and phenology in the spring and autumn. It was easy to understand the phenomenon because there was an images of canopy surface with the graph.
4th, Apr. 2014
Jonckheere, I., Fleck, S., Nackaerts, K., Muys, B., Coppin, P., Weiss, M., & Baret, F. (2004). Review of methods for in situ leaf area index determination: Part I. Theories, sensors and hemispherical photography. Agricultural and forest meteorology, 121, 19-35
- In this paper there was a definition about LAI and how to measure the LAI in direct and indirect methods. There were a lot of instruments to measure LAI but all the method had its specific problems and limitations. And the author recommended hemispherical photography, a powerful indirect method for measuring various components of canopy structure and under story light regime.
3rd, Apr. 2014
Peckham, S.D., Ahl, D.E., Serbin, S.P., & Gower, S.T. (2008). Fire-induced changes in green-up and leaf maturity of the Canadian boreal forest. Remote Sensing of Environment, 112, 3594-3603
- In this paper the author used the Canadian Large Fire Database(CLFD) and analyzed the impact fire had on the phenology dates.
I was interested that both NDVI (Normalized Difference Vegetation Index) and LAI (Leaf Area Index) increased while NDWI (Normalized Difference Water Index) was decreased, this meant NDVI and LAI begin to increase during snowmelt.