The total number of military and civilian casualties in World War I is estimated to be about 40 million: estimates range from 20.5 to 22 million deaths and about 20 to 22 million wounded military personnel, ranking it among the deadliest conflicts in human history. The total number of deaths includes about 9 to 11 million military personnel; the civilian death toll was about 11 million, including about 8 million of them which were due to war-related famine and disease and 3 million due to military actions and war crimes. The Triple Entente lost about 6 million military personnel while the Central Powers lost about 4 million. At least 2 million died from diseases and 6 million went missing, presumed dead. About three-quarters of military deaths in World War I were in battle, unlike the conflicts that took place in the 19th century, in which the majority of deaths were due to disease. Disease, including the 1918 flu pandemic, POW deaths still caused about one quarter of total military deaths for all belligerents.

Out of all the belligerents of the war, the Ottoman Empire suffered the highest death toll with over 4 million dead, or around 20 percent of its prewar population. The Russian Empire suffered the second highest number of fatalities, with over 3.6 million dead. The British Empire, Italy, Austria-Hungary and neutral Persia lost over one million dead during the war. Casualty statistics for World War I vary to a great extent. Military casualties reported in official sources list deaths due to all causes, including an estimated 7 to 8 million combat related deaths and another two to three million military deaths caused by accidents and deaths while prisoners of war. Official government reports listing casualty statistics were published by the United States and Great Britain; these secondary sources published during the 1920s, are the source of the statistics in reference works listing casualties in World War I. This article summarizes the casualty statistics published in the official government reports of the United States and Great Britain as well as France, Belgium, Germany and Russia.

More the research of the Commonwealth War Graves Commission has revised the military casualty statistics of the UK and its allies. The casualties of these support personnel recruited outside of Europe were not included with British war dead, however the casualties of the Labour Corps recruited from the British Isles were included in the rolls of British war dead published in 1921; the methodology used by each nation to record and classify casualties was not uniform, thus a general caveat regarding casualty figures is that they cannot be considered comparable in all cases. First World War civilian deaths are "hazardous to estimate" according to Michael Clodfelter who maintains that "the accepted figure of noncombatant deaths is 6.5 million." The figures listed below include about 8 million excess civilian deaths due to war related privations, which are omitted from other compilations of World War I casualties. The war brought about increased malnutrition and disease caused by the Central Powers U-boat Campaign against the Allies, the Allied blockades of the Central Powers, both of which disrupted trade and resulted in food shortages.

The civilian deaths in the Ottoman Empire include the Armenian Genocide, Assyrian Genocide, Greek Genocide, deaths due to Allied strategic bombing, deaths due to famine and disease. Civilian deaths due to the Spanish flu have been excluded from these figures, whenever possible; the figures do not include deaths during the Balkan Wars, the Russian Civil War, the Turkish War of Independence, the Finnish Kinship Wars, the German Revolution, the Irish War of Independence, or any of the various wars and revolutions that took place in the aftermath of World War I. The source of population data for the major belligerents is: Haythornthwaite, Philip J; the World War One Source Book pp. 382–383 The war involved multi-ethnic empires such as the British Empire, the French Empire, the German Empire, the Russian Empire, the Austro-Hungarian Empire, the Ottoman Empire. Many ethnic groups in these territories were conscripted for military service; the casualties listed by modern borders are included in the above table of figures for the countries that existed in 1914.

The casualty figures by 1924 post war borders are rough estimates by Russian historian Vadim Erlikman in a 2004 handbook of human losses in the 20th century, the sources of his figures were published in the Soviet era and in post-Soviet Russia. According to the 1914–1918 Online Encyclopedia "In addition to losses suffered by African military personnel and the laborers supporting their operations large, but unknown numbers of African civilians perished during the war." They made an estimate of civilian losses in Africa of 750,000 based on the study by the Vadim Erlikman. They noted that Erlikman's figures are based on the work of the Russian demographer Boris Urlanis, they noted that these estimates were "imprecise" and "could be used to provide a frame of reference for further inquiry"; the Oxford History of World War One notes that "In east and central Africa the harshness of the war resulted in acute shortages of food with famine in some areas, a weakening of populations, epidemic diseases which killed hundreds of thousands of people and cattle."

AustriaThe following estimates of Austrian deaths, within contemporary borders, were made by a Russia

Hubbard Brook Experimental Forest is an area of land in the towns of Woodstock and Thornton in the White Mountains of New Hampshire that functions as an outdoor laboratory for ecological studies. It was established in 1955 by the United States Forest Service for the study of the relationship between forest cover and water quality and supply. In 1955 the first tract was dedicated in the Hubbard Brook watershed, just west of the village of West Thornton, New Hampshire; the first stream in the forest was fitted with monitoring devices in 1956. Subsequently, seven additional headwater streams and their associated watersheds were delimited for study; each such zone functions as a closed environmental system. Since efflux of water and water-bound organisms leaving each watershed can be monitored, the effects of changes experimentally introduced into the system can be measured. For the first five or six years after its establishment the HBEF was used for research in forestry but soon its value for study of the forest ecosystem was recognized and it attracted the interest of researchers from major universities.

The work at Hubbard Brook has led researchers there and elsewhere to try to model or better understand the complex forest ecosystem, including its interaction with humans. HBEF research teams have succeeded in elucidating a number of vexing environmental problems, most notably the harmful effects of acid rain; the forest preservation the research promotes helps to protect watershed chemistry, ambient humidity, seasonal temperature fluctuations, wildlife habitats. The idea for using the small watershed approach being used at Hubbard Brook for studies of elemental budgets and cycles was born with Professor F. Herbert Bormann of Dartmouth College, who began taking his botany classes for field trips to this area of the White Mountain National Forest in the early 1950s, Forest Service scientist Robert Pierce. Bormann proposed to Pierce that the area set aside by the Forest Service for watershed studies be used for closed-system ecological studies. In 1960, soon after the establishment of HBEF, ecologist Gene Likens and geologist Noye Johnson, both from Dartmouth, joined the research team.

In 1963, the group received a $60,000 grant from the National Science Foundation to study "Hydrological-Mineral Cycle Interaction in a Small Watershed". This study evolved into the series of longitudinal studies now referred to as the "Hubbard Brook Ecosystem Study", or HBES; the early ecosystem monitoring was aimed at studying the effects of forest management practices on water flow and quality. These data have been helpful as baselines for the sophisticated areas of ongoing research in the forest. HBES has spawned over 2000 scientific papers most important a 1968 study that documented the widespread presence of "acid rain". HBRF was designated as a Long-Term Ecological Research site in 1988 and has some of the longest on-going ecological datasets; the study comprises researchers from multiple universities, including Dartmouth College, Yale University, Cornell University, Syracuse University, SUNY ESF, the University of New Hampshire, Keene State College and the University of Vermont. The Hubbard Brook Research Foundation provides housing for research assistants at nearby Pleasant View Farm and completed the purchase of cottages for visiting and resident scientists around Mirror Lake, the point at which Hubbard Brook exits the experimental forest.

Hubbard Brook Experimental Forest is the most added research forest under USFS jurisdiction for hydrologic studies in the eastern and southern United States. Located in the White Mountain National Forest in central New Hampshire, within the town of Woodstock, the 31-square-kilometer bowl-shaped forested valley has hilly terrain, ranging from 222 to 1,015 meters in altitude; the forest comprises nine individual watersheds, each of which drains into Hubbard Brook which flows eastward into the Pemigewasset River near West Thornton. The outlet from Mirror Lake, a much-studied pond and recreation site, flows south into Hubbard Brook just before the brook passes under Interstate 93; the forest is a "second-growth" mix of northern hardwoods and red spruce-balsam fir. Beech, yellow birch, sugar maple experience their greatest importance at 570 meters, 570 to 650 meters, 720 meters with paper birch and spruce at 720m to treeline. Mountain maple, striped maple, mountain ash characterize the understory at various elevations, with mountain maple being ubiquitous.

Five of the seven canopy species are valued for various reasons. Harsh winter conditions do not allow for rapid recovery, unlike more humid climates that recover net primary productivity within years, the northeastern version needs decades and in the case of the forest floor centuries to recover; the forest was cleared for agriculture starting in the late 18th century and was logged. By 1920 over 200 million board feet of timber had been harvested from the valley. Soil is predominantly well-drained spodosol derived from glacial till, with sandy loam textures, combining to produce an evident, but narrow E horizon; the forest floor is characterized by the complete suite of taxonomic subhorizons, has been classified as mor type humus, with mull occurring beneath maple stands at lower elevations. It is acidic and infertile for agricultural purposes. Aluminum and iron are preferentially leached from the upper soil horizons to an underlying layer, characteristic of the soil order. Hence, silica is retained and at times mi

Jonathan Bird is an American photographer, cinematographer and television host. He is best known for his role as the host of Jonathan Bird's Blue World, a family-friendly underwater exploration program on public television in the United States, his work is underwater in nature. Bird learned to scuba dive while in college at Worcester Polytechnic Institute and combined his interest in photography with diving, his first underwater photographs were made in the waters of Massachusetts. He worked as an electrical engineer for several years until leaving his position to pursue underwater photography full-time in 1993, he became a freelance underwater photographer, working for magazines including Sport Diver and Skin Diver. His first book, Beneath the North Atlantic, a collection of his favorite images from the waters of New England, was published in 1997 by Tide-mark Press, he is the author of 7 books and his images have appeared in top nature publications including National Geographic Magazine, National Wildlife Magazine and BBC Wildlife Magazine.

Bird formed Oceanic Research Inc. in 1991 to produce educational ocean-related materials. Oceanic Research Group became a 501 non-profit organization in 1993. Oceanic Research Group's first underwater film was produced in 1992 for the educational market and was distributed by AIMS Media, which has since been acquired by Discovery Education. Bird and Oceanic Research Group have made 13 educational films for use in schools about ocean topics since the most recent being Sharks: Predators with a Purpose in 2007, his first television film, Sharks: The Real Story, co-produced with longtime collaborator Art Cohen, was completed in 1995 and aired on PBS. Bird has made 5 films about sharks. In 2005, Bird completed his first film for National Geographic Channel, called Sharks: Deep Trouble, his broadcast work has earned Bird 2 CINE Golden Eagle awards. He cites Howard Hall as a major influence in his cinematography; the pilot for Jonathan Bird's Blue World was completed in 2001 and shopped around without success for several years.

The project was dropped. In 2007, without a television buyer, the first few episodes were put on the web. After gaining a fan base there, NETA offered Jonathan Bird’s Blue World distribution to U. S. public television. The fourth season began airing in 2014; the series is distributed abroad as well. Each episode is broken up into individual segments for release on the Internet. Bird lives in Massachusetts with two children, he plays guitar in The Wetsuits, a rock band made up of all professional underwater photographers including Michel Gilbert, Danielle Alary, Michael Lawrence, Paul Cater Deaton. He is a member of the Wyland Ocean Artist Society and a 2019 inductee of the International Scuba Diving Hall of fame. Jonathan Bird's Curriculum Vitae Oceanic Research Group