{"id":2836,"date":"2020-07-06T08:31:00","date_gmt":"2020-07-06T08:31:00","guid":{"rendered":"https:\/\/www.zavit.org.il\/intl\/?p=2836"},"modified":"2020-07-06T08:34:26","modified_gmt":"2020-07-06T08:34:26","slug":"israeli-scientists-strive-to-monitor-forest-health-with-drones","status":"publish","type":"post","link":"https:\/\/www.zavit.org.il\/intl\/en\/animal_plants\/israeli-scientists-strive-to-monitor-forest-health-with-drones\/","title":{"rendered":"Researchers strive to monitor forest health with drones"},"content":{"rendered":"\n<figure class=\"wp-block-embed-youtube wp-block-embed is-type-video is-provider-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe loading=\"lazy\" title=\"Forests and drones\" width=\"640\" height=\"360\" src=\"https:\/\/www.youtube.com\/embed\/XW4urEe0-S0?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen><\/iframe>\n<\/div><\/figure>\n\n\n\n<p>Although currently put on hold due to COVID-19, scientists from the Department of Geography and Human Environment at Tel Aviv University, in collaboration with, Keren Kayemet LeYisrael \u2013 Jewish National Fund (KKL \u2013 JNF), have been working for two years obtaining drone footage of designated forest plots throughout the country. <\/p>\n\n\n\n<p>\u201cAround ten years ago, KKL-JNF decided that in order to manage forests in Israel more efficiently, they need to establish research plots,\u201d says Moshe Mandelmilch, a PhD student at both the Department of Geology at the Porter School of the Environment and Earth Sciences at Tel Aviv University, and the Department of Plants Sciences and Genetics in Agriculture at the Hebrew University of Jerusalem.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" width=\"1024\" height=\"683\" src=\"https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/rural-explorer-oWS_3i0Y5sI-unsplash-1024x683.jpg\" alt=\"\" class=\"wp-image-2841\" srcset=\"https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/rural-explorer-oWS_3i0Y5sI-unsplash-1024x683.jpg 1024w, https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/rural-explorer-oWS_3i0Y5sI-unsplash-300x200.jpg 300w, https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/rural-explorer-oWS_3i0Y5sI-unsplash-768x512.jpg 768w, https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/rural-explorer-oWS_3i0Y5sI-unsplash-1536x1024.jpg 1536w, https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/rural-explorer-oWS_3i0Y5sI-unsplash-2048x1365.jpg 2048w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><figcaption><em>KKL-JNF decided that in order to manage forests in Israel more efficiently, they need to establish research plots. Photo by Rural Explorer<\/em><\/figcaption><\/figure>\n\n\n\n<p class=\"has-medium-font-size\"><strong>Measuring\nthe forest<\/strong><\/p>\n\n\n\n<p>\u201cTo that\nend, existing forested areas, primarily pine trees, were divided into\nindividual plots, from Metula, the country\u2019s northern-most town, all the way down\nto the city of Beer Sheba, located on the desert edge,\u201d Mandelmilch explains.<\/p>\n\n\n\n<p>\u201cSome of\nthe plots are very old. There is a plot from a forest in Beit Shemesh near\nJerusalem, which was planted during the British Mandate and is close to 100\nyears old\u201d, he adds.<\/p>\n\n\n\n<p>According\nto Mandelmilch, KKL-JNF\u2019s initial forest plots were each around 30&#215;30 meters in\nsize, which is equivalent to one LANDSAT satellite pixel (LANDSAT is a NASA satellite\nthat acquires earth images on a regular basis). For the satellite images, four of\nthese 30&#215;30 forest plots were added together to one larger plot, corresponding\nwith four satellite pixels. Inside each of these plots, JNF started measuring\nonly the pine trees and created a database with the aim to return to each plot\nabout every 5-7 years and compare the new measurements with the existing data.<\/p>\n\n\n\n<p>In some of the places,\ndepending on the amount of rain, there are not only pine trees but other types\nof trees, such as Israeli Oak <em>(Quercus\ncalliprinos)<\/em> and Mastik Tree <em>(Pistacia lentiscus)<\/em>, which are also being monitored.<\/p>\n\n\n\n<p>\u201cBecause we are talking about roughly 100 plots here, it is very hard to\ndo that manually in the field. It requires a lot of workforce and logistics.\nTherefore, two years ago, KKL-JNF created a research grant with the goal of using remote sensing deploying\ndrones,\u201d says Mandelmilch.<\/p>\n\n\n\n<p>The grant is managed by Professor Eyal Ben-Dor from the Department of\nGeography at Tel Aviv University and by Dr. Efrat\nSheffer from The Robert H. Smith Institute of Plant Sciences and\nGenetics in Agriculture&nbsp;at the Hebrew University of\nJerusalem, which are also both my PhD supervisors in this project.<\/p>\n\n\n\n<p>Remote\nsensing is a field in science where information of certain objects can be\nobtained from a distance, using their electromagnetic radiation signature. More\nspecifically, measuring sun radiation that is not absorbed by the object but reflected\nback into the atmosphere. Using remote sensors mounted on drones is a\nrelatively new way of obtaining data in the open field. <\/p>\n\n\n\n<p>\u201cBasically,\nwhat we do is fly our drone over those forest plots, obtain the trees&#8217; spectral\ndata, and then compare it to data that KKL-JNF collected in the field,\u201d\nMandelmilch explains.<\/p>\n\n\n\n<p>During the first one and half years of the research, Mandelmilch worked on two forest plots, where he monitored over 40 different plant individuals from four different species and classified the plots according to those species. The aim of the first phase of the research was to establish a protocol of how to use drones for monitoring.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" width=\"1024\" height=\"683\" src=\"https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/david-jusko-aq8hL1Jbm_c-unsplash-1024x683.jpg\" alt=\"\" class=\"wp-image-2849\" srcset=\"https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/david-jusko-aq8hL1Jbm_c-unsplash-1024x683.jpg 1024w, https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/david-jusko-aq8hL1Jbm_c-unsplash-300x200.jpg 300w, https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/david-jusko-aq8hL1Jbm_c-unsplash-768x512.jpg 768w, https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/david-jusko-aq8hL1Jbm_c-unsplash-1536x1024.jpg 1536w, https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/david-jusko-aq8hL1Jbm_c-unsplash-2048x1365.jpg 2048w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><figcaption><em>Most of the forest plots designated for the research project are pine trees. Photo by David Jusko on Unsplash<\/em><\/figcaption><\/figure>\n\n\n\n<p class=\"has-medium-font-size\"><strong>New\ntechnology; new problems<\/strong><\/p>\n\n\n\n<p>One of the issues\nwith drones, as opposed to satellites, is that drones are susceptible to wind,\nwhich makes it tricky to achieve the same accuracy. &nbsp;Satellites will always move in the same orbit,\npassing the same exact spot at the same exact time. Therefore, images taken of\nthe plots are perfectly accurate, and every tree will be photographed from the\nexact same angle. The scientific term used in this context is &nbsp;\u201cgeoreferencing,\u201d which \u201cis the name given to\nthe <a href=\"https:\/\/link.springer.com\/referenceworkentry\/10.1007%2F978-0-387-39940-9_181\">process of geospatially referencing\ndata<\/a>, and\ninformation objects \u2013 datasets, text documents, maps, photographs and imagery,\netc. \u2013 to their proper locations on Earth.\u201d<\/p>\n\n\n\n<p>\u201cI managed\nto overcome this issue by merging several drone images with computer software.\nEven though shifting due to wind is always a factor when using drones for\nremote sensing, our geometric correction is good enough to get accurate\nmaterial,\u201d says Mandelmilch. <\/p>\n\n\n\n<p>In addition, drones can only take images of smaller areas, while satellites are able to record large areas in one image. Due to rather short battery lives, drones also have a limited flying time, and thus, more flights are usually needed to capture all the footage needed in one forest plot.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" width=\"1024\" height=\"683\" src=\"https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/spacex-VBNb52J8Trk-unsplash-1-1024x683.jpg\" alt=\"\" class=\"wp-image-2845\" srcset=\"https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/spacex-VBNb52J8Trk-unsplash-1-1024x683.jpg 1024w, https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/spacex-VBNb52J8Trk-unsplash-1-300x200.jpg 300w, https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/spacex-VBNb52J8Trk-unsplash-1-768x512.jpg 768w, https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/spacex-VBNb52J8Trk-unsplash-1-1536x1024.jpg 1536w, https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/spacex-VBNb52J8Trk-unsplash-1-2048x1365.jpg 2048w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><figcaption><em>Satellites will always move in the same orbit, passing the same exact spot at the same exact time. Therefore, images taken of the plots are perfectly accurate, and every tree will be photographed from the exact same angle. Photo by SpaceX on Unsplash<\/em><\/figcaption><\/figure>\n\n\n\n<p class=\"has-medium-font-size\"><strong>Drone advantages<\/strong><strong><\/strong><\/p>\n\n\n\n<p>\u201cThe\noutstanding advantage of drone footage is that it is very detailed and has a\nvery high resolution, with pixel sizes of about 3.5 cm. Flying our drone at a\nheight of 50 meters, filming a person on the ground drinking a bottle of coke,\nyou\u2019d be able to read the label,\u201d Mandelmilch says.<\/p>\n\n\n\n<p>According to Mandelmilch, drones have the benefit of being deployable 24\nhours a day and can collect data also when it is overcast. In addition, the\nspatial resolution of drones is better than that of satellites.<\/p>\n\n\n\n<p>\u201cJNF rangers told us that tree height is an important parameter for them, and they wanted us to take measurements. So we went out with the laser gun and measures the height of several tree individuals, and then based on the drone images, we calculated a heightmap. After that, I did some statistical correlation, through which we got some very suitable results,\u201d Mandelmilch says. \u201cAnd even though the results weren\u2019t perfect due to the course of the flight of the drone, it showed us the importance of using drones as it was the first map to really predict the height of the trees,\u201d he adds.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" width=\"1024\" height=\"683\" src=\"https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/jason-blackeye-XYrjl3j7smo-unsplash-1-1024x683.jpg\" alt=\"\" class=\"wp-image-2857\" srcset=\"https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/jason-blackeye-XYrjl3j7smo-unsplash-1-1024x683.jpg 1024w, https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/jason-blackeye-XYrjl3j7smo-unsplash-1-300x200.jpg 300w, https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/jason-blackeye-XYrjl3j7smo-unsplash-1-768x512.jpg 768w, https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/jason-blackeye-XYrjl3j7smo-unsplash-1-1536x1024.jpg 1536w, https:\/\/www.zavit.org.il\/intl\/wp-content\/uploads\/2020\/07\/jason-blackeye-XYrjl3j7smo-unsplash-1-2048x1365.jpg 2048w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><figcaption><em>Drones have the benefit of being deployable 24 hours a day and able to collect data also when it is overcast. In addition, the spatial resolution of drones is better than that of satellites. Photo by Jason Blackeye on Unsplash<\/em><\/figcaption><\/figure>\n\n\n\n<p class=\"has-medium-font-size\"><strong>Future Goals<\/strong><\/p>\n\n\n\n<p>Although\nthe research is currently put on ice due to the COVID-19 crisis, Mandelmilch\nsays that the first stage of the study has been a success, and the protocol of\nhow to use drones in forest monitoring has been established.<\/p>\n\n\n\n<p>\u201cWe are far\nfrom being done yet, but we now know that drones have to be used at the height\nof 100 meters and not 50 meters as initially assumed, due to geometric issues.\nThe best flight time is at noon when the sun is at its peak. Sunny days are\nalso more advantageous, as cloud cover creates more shades on the ground (depending\non the scattering of the clouds and their percentage of coverage). We also know\nthat our drone can fly across the forest for a maximum of 35 minutes.\u201d<\/p>\n\n\n\n<p>\u201cOur\nobjective, for now, is to continually improve our protocol,\u201d Mandelmilch adds. <\/p>\n\n\n\n<p>\u201cIn the future, I believe this kind of work can be carried out solely by using drones, which would make everything a whole lot easier. The only limitation we see so far is of technological nature. More specifically, the battery life of the drone. However, as technology is constantly advancing, it\u2019s very likely that in the future, drones will replace the conventional monitoring methods entirely.\u201d Mandelmilch concludes.<\/p>\n\n\n\n<p><em>This ZAVIT article was also published in&nbsp;<a href=\"https:\/\/jewishjournal.com\/commentary\/blogs\/318379\/israeli-scientists-strive-monitor-forest-health-with-drones\/\">The Jewish Journal<\/a> on 07\/02\/2020.<\/em><br><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Although currently put on hold due to COVID-19, scientists from the Department of Geography and Human Environment at Tel Aviv &#8230;<\/p>\n","protected":false},"author":182,"featured_media":2837,"comment_status":"open","ping_status":"open","sticky":true,"template":"","format":"standard","meta":[],"categories":[11,10],"tags":[],"acf":[],"post-meta-fields":{"_edit_lock":["1594024344:11"],"_thumbnail_id":["2837"],"_oembed_8a83141869b38c2c4a67781afcacd98a":["<iframe title=\"Forests and drones\" width=\"640\" height=\"360\" src=\"https:\/\/www.youtube.com\/embed\/XW4urEe0-S0?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen><\/iframe>"],"_oembed_time_8a83141869b38c2c4a67781afcacd98a":["1594024255"],"_edit_last":["11"],"subtitle":["In the 1970s, Keren Kayemet LeYisrael \u2013 Jewish National Fund (KKL \u2013 JNF) began monitoring the health of Israeli forests. Five years ago, they started using satellite imagery. Today, scientists are deploying drones to find out if new technology can replace conventional monitoring methods"],"_subtitle":["field_59d3d36ea7fe1"],"_wpml_media_duplicate":["1"],"_wpml_media_featured":["1"]},"_links":{"self":[{"href":"https:\/\/www.zavit.org.il\/intl\/wp-json\/wp\/v2\/posts\/2836"}],"collection":[{"href":"https:\/\/www.zavit.org.il\/intl\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.zavit.org.il\/intl\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.zavit.org.il\/intl\/wp-json\/wp\/v2\/users\/182"}],"replies":[{"embeddable":true,"href":"https:\/\/www.zavit.org.il\/intl\/wp-json\/wp\/v2\/comments?post=2836"}],"version-history":[{"count":8,"href":"https:\/\/www.zavit.org.il\/intl\/wp-json\/wp\/v2\/posts\/2836\/revisions"}],"predecessor-version":[{"id":2868,"href":"https:\/\/www.zavit.org.il\/intl\/wp-json\/wp\/v2\/posts\/2836\/revisions\/2868"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.zavit.org.il\/intl\/wp-json\/wp\/v2\/media\/2837"}],"wp:attachment":[{"href":"https:\/\/www.zavit.org.il\/intl\/wp-json\/wp\/v2\/media?parent=2836"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.zavit.org.il\/intl\/wp-json\/wp\/v2\/categories?post=2836"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.zavit.org.il\/intl\/wp-json\/wp\/v2\/tags?post=2836"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}