森林范围的指标

森林损失

该指标旨在监视 森林每年在全球范围内丢失或删除。指标当前测量 树覆盖损失作为森林损失的最佳可用代理。树覆盖损失包括森林损失以及工业损失 树木种植园 农作物作物,通常不被视为森林。该指标中报告的统计数据捕获了“毛”树覆盖损失,这是全部损失 树盖增益那可能是同年发生的。

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每年在全球范围内损失多少树覆盖?

世界损失了4.37亿 公顷(MHA)的 树盖自本世纪之交以来,相当于2000年全球树木覆盖率的11%。最近的历史上的树木覆盖损失从2001年的13.4 MHA树覆盖损失到2021年的25.3 MHA。

较少的

树覆盖损失,森林损失和森林砍伐

本报告中使用的树封面数据基于Hansen等。(2013),,,, Hansen等。2013,https://doi.org/10.1126/science.1244693。他们将树覆盖定义为木质植被,高度至少为5米(M),在30 m分辨率下的冠层密度至少为30%。因此,树木覆盖的数据包括树木种植园和树作物,这不构成大多数定义的“森林”。树盖数据不包括稀疏树木覆盖的区域,例如在萨赫勒或塞拉多州,以及农业,郊区或城市景观中的单个树木。

树覆盖损失的定义是由于任何原因,包括人为引起的损失和自然事件,完全清除了树皮。树覆盖的损失可能是永久的或暂时的;例如,当收获树木以生产木材时,可能会发生临时树覆盖损失,然后将土地重新种植或自然再生。 森林砍伐另一方面,通常是指人类引起的,永久删除 天然林覆盖。该报告使用树覆盖损失数据,因为它可以在全球范围内始终如一地测量,但它也试图估计数据允许的森林损失和森林砍伐。有关这些估计值的更多信息可在数据和方法部分。

较少的

自2000年以来,全球树木覆盖率损失的年龄上升

较少的

树覆盖损失的主要原因是什么?

林业,商品驱动的森林砍伐,野火和农业转移是树覆盖损失的主要原因

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  • 林业与135 MHA的树覆盖损失有关:在未来再生的林木或林木种植园中进行的大规模林业运营。再生可能通过自然再生或植树。
  • 商品驱动的森林砍伐与117 MHA的树覆盖损失有关:永久转化森林以进行商品生产,包括农业,采矿或石油和天然气生产。
  • 野火与91 MHA的树覆盖损失有关:之后没有可见的人类conversion依或农业活动的植被燃烧。其中一些火灾自然发生,但另一些是由人类设定的。在潮湿的热带森林中,火灾对生态系统并不自然,几乎总是由人类设定,通常是为了清理土地以供农业供农业。
  • 转移农业与88 MHA的树覆盖损失有关:清理森林,用于农业生产的农业实践已有几年,然后暂时被遗弃以允许树木再生。转移农业涉及许多不同类型的小型农业习俗。
  • 城市化与3 MHA的树覆盖损失有关:将森林永久转换为人类定居点。
更多的

热带地区经历了更多与农业有关的树覆盖损失,而北方地区和温带地区经历了更多的林业和野火损失

更多的

永久性与临时性是多少树覆盖损失?

大约三分之一 请参阅数据和方法自2000年以来,树木覆盖损失可能是森林砍伐的,其特征是森林永久损失,导致了新的非洞穴土地使用,例如农业和人类定居点。

其余的三分之二的树覆盖损失本质上可能更暂时,通常与火或木材收获有关。在这些领域,森林可能会重生,但是森林再生和重新开发重要的生态系统功能所需的时间高度可变,并且可能很长。 Liebsch等。2008,https://doi.org/10.1016/j.biocon.2008.04.013。

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热带与温带和北方森林中损失了多少树覆盖?

尽管本世纪的全球树木覆盖损失只有一半(215 MHA)发生在热带生态中,但热带地区占全球森林砍伐的近97%(与城市化,农业和其他商品生产有关)。 请参阅数据和方法热带树覆盖率损失的年率从2001年的6.7 MHA增加了一倍,达到2021年的11.1 MHA。 请参阅数据和方法尽管巴西和印度尼西亚经历了本世纪的树木覆盖损失地区,但自2001年以来,随着所有其他热带国家合计的树木覆盖率损失的率增长了126%,这两个国家的占主导地位较低。 请参阅数据和方法

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在热带地区,树覆盖的损失稳步增加

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同时,自世纪之交以来,温带和北方森林经历了170 MHA的总树覆盖损失,近97%与临时因素(林业和野火)相关,可能会在树上覆盖。加拿大,俄罗斯和美国共同占与野火相关的树木覆盖损失的99%,在温带和北方森林中与林业有关的所有损失的66%。与野火和林业有关的树覆盖损失不一定是永久的,但森林需要花费时间才能再生。不可持续的林业实践,例如太短的林业周期,可能会影响森林的状况及其提供野生动植物栖息地和重要生态系统服务的能力 Peng等。2002,https://doi.org/10.1016/s0304-3800(02)00134-5。(请参阅森林降解指标)。

更多的

火势正在加剧吗?

在许多温带和北方森林中,火是景观的自然部分,促进了物种的营业额并释放重要的营养。尽管在过去的几十年中,全球烧毁的地区有所下降,这可能是由于草原向农业conversion依的结果 Voiland 2019,https://earthobservatory.nasa.gov/images/145421/building-a-long-term-term-record-fire。随着气候变化为世界部分地区带来越来越温暖和干燥的天气,森林大火变得越来越频繁和严重。必威官网是真的吗 Brändlin2017,https://www.dw.com/en/how-cl必威官网是真的吗imate-change-is-increasing-forest-forest-fires-around-the-world/a-19465490;Dickie 2017,https://www.upi.com/science_news/2017/07/12/c必威官网是真的吗limate-change-change-change-could-mean-mean-more-wildfires-in-wildfires-in-alaska-northwest-canada/2641499989893084/;Gillis and Fountain 2016,https://www.nytimes.com/2016/05/11/science/global-warming-cited-cited-cited-cited-as-wildfires-increase-increase-in-fragile-boreal-forest.html;威廉姆斯等人。2019,https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019EF001210。这些森林大火可能会对经济,人类生活和森林生态系统产生重大影响。除气候变化外,人类还通过抑制自必威官网是真的吗然燃烧,侵占野生区域并点燃新大火,加剧了这些景观中的大火。 Phillips 2019,https://www.weforum.org/agenda/2019/05/the-vicial-cl必威官网是真的吗imate-wildfire-cycle。

近年来,热带森林也受到火灾的严重影响, Weisse and Goldman 2017,//www.365bettiyuzaixian.net/blog/2017/10/global-tree-cover-loss-loss-loss-51-percent-2016。在巴西,印度尼西亚,玻利维亚和其他地方都有大量媒体的关注。在潮湿的热带森林(例如亚马逊)中的火灾并不自然 - 这些大火几乎总是由人类设置 Cochrane 2011,https://link.springer.com/chapter/10.1007%2F978-3-642-05383-2_7;Cochrane and Laurance 2008,https://www.nrem.iastate.edu/class/assets/nrem390-10/cochrane%26laurance_tropics_fire.pdf。- 尽管在干旱条件下,他们通常只会烧毁失控。由于这些生态系统不适合开火,因此在未来几年中,大火可能会对这些森林造成不利影响。 Rappaport等。2018,https://doi.org/10.1088/1748-9326/AAC331。这些热带森林大火也导致严重的气候损害排放,必威官网是真的吗 Harris等。2015年,//www.365bettiyuzaixian.net/blog/2015/10/indonesia-s-fire--fire-preambreasts-producing-more-daily-daily-emissions-emsions-entire-us-ceconomy。导致气候变化和火灾之间潜在的积极反馈回路。必威官网是真的吗 Le Page等。2017,https://www.earth-syst-dynam.net/8/1237/2017/esd-8-1237-2017.pdf。

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在温带森林中,城市扩张造成的树覆盖损失最高。在2001年至2021年之间,美国对城市化的树木覆盖率超过2.0 mha,比加拿大高约20倍,加拿大的森林砍伐率与城市扩张相关。在美国境内的城市地区,亚特兰大市由于城市蔓延而经历了最大的树木覆盖损失。 Miller 2012,https://doi.org/10.1016/j.apgeog.2011.11.010。

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森林已转变为美国东南部城市周围的城市土地

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局限性和未来的前景

树覆盖损失不等于森林的损失,因为某些形式的树木覆盖物(例如,诸如油棕之类的树作物)不包括在森林的大多数广泛接受的定义中。正在进行的努力,以开发更好的全球空间数据 天然林, 管理 半自然的森林 种植的森林, 和 农作物作物可以改善对森林损失的监测。2019年的研究 Harris等。2019年,//www.365bettiyuzaixian.net/pablication/planted-trees。从各种来源和时间段内的种植森林和农作物作物的汇总地图中,据估计,该数据库估计覆盖了全球大约75%(173 MHA)种植的森林和树木作物。在热带地区,数据库的覆盖范围最完整,种植的森林和农作物作物仅占树木覆盖的2%。在温带和北方生态中,这个数字可能更高。

关于树盖损失驱动因素的当前数据也有限。Curtis等人的10公里空间分辨率。(2018)此分析中使用的数据相对粗糙,导致土地利用动力学和不准确性的过分尺寸;例如,已知数据高估了 转移农业在非洲。 柯蒂斯等。2018,https://doi.org/10.1126/science.aau3445。这些数据的作者目前正在探索新的人工智能技术,以改善模型的空间分辨率。

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{“词汇表”:{“ 51”:{“名称”:“农业树作物”,“描述”:“为食物,文化或经济价值耕种的树木包括油棕,橡胶,可可,可可,腰果,芒果,芒果,橘子(柑橘),车前草,香蕉和椰子。\ r \ n“},“ 101”:{“ name”:“ abedo”,“ description”:“表面反射阳光的能力。\ u0026nbsp; light light- 彩色表面将大部分日光归还回到大气(高反照率)。黑暗表面吸收了来自太阳的光线(低反照率)。\ r \ n“},“ 94”:{“ name”:“生物多样性完整性”,“描述”:“保留的位置\ u0027s原始森林社区(物种和个人的数量)的比例和丰度。生物多样性意义”,“描述”:“一个区域基于稀有性的森林依赖物种的持久性的重要性。\ r \ n“},“ 98”:{“ name”:“二氧化碳(CO2E)“,”描述:“二氧化碳当量(CO2E)是一种措施,用于根据其100年的全球变暖潜力来汇总各种温室气体(GHG)的排放,这是通过将非CO2 GHG等同于同等量的CO2来汇总的。。\ r \ n“},“ 99”:{“ name”:“ co2e”,“ descript”:“二氧化碳等效(CO2E)是一种用于汇总各种温室气体(GHG)发射的措施他们的100年全球变暖潜力是通过将非CO2葡萄镀等于等效量的二氧化碳。另一种土地覆盖或土地使用,例如森林到种植园或森林到市区。覆盖或土地使用,例如森林或森林到市区。由于自然和人为的变化,执行生态系统服务,例如碳存储和水调节。\ r \ n“},“ 75”:{“ name”:“ degraded”,“ Description”:“森林的减少\由于自然和人为的变化,U2019S可以执行生态系统服务,例如碳存储和水调节。 that changes the structure of a forest ecosystem.\r\n"},"68":{"name":"disturbed","description":"A discrete event that changes the structure of a forest ecosystem.\r\n"},"65":{"name":"driver of tree cover loss","description":"The direct cause of forest disturbance.\r\n"},"70":{"name":"drivers of loss","description":"The direct cause of forest disturbance.\r\n"},"81":{"name":"drivers of tree cover loss","description":"The direct cause of forest disturbance.\r\n"},"102":{"name":"evapotranspiration","description":"When solar energy hitting a forest converts liquid water into water vapor (carrying energy as latent heat) through evaporation and transpiration.\r\n"},"2":{"name":"forest","description":"Forests include tree cover greater than 30 percent tree canopy density and greater than 5 meters in height as mapped at a 30-meter Landsat pixel scale.\r\n"},"3":{"name":"forest concession","description":"A legal agreement allowing an entity the right to manage a public forest for production purposes.\r\n"},"90":{"name":"forest concessions","description":"A legal agreement allowing an entity the right to manage a public forest for production purposes.\r\n"},"53":{"name":"forest degradation","description":"The reduction in a forest\u2019s ability to perform ecosystem services, such as carbon storage and water regulation, due to natural and anthropogenic changes.\r\n"},"54":{"name":"forest disturbance","description":"A discrete event that changes the structure of a forest ecosystem.\r\n"},"100":{"name":"forest disturbances","description":"A discrete event that changes the structure of a forest ecosystem.\r\n"},"5":{"name":"forest fragmentation","description":"The breaking of large, contiguous forests into smaller pieces, with other land cover types interspersed.\r\n"},"6":{"name":"forest management plan","description":"A plan that documents the stewardship and use of forests and other wooded land to meet environmental, economic, social, and cultural objectives. Such plans are typically implemented by companies in forest concessions.\r\n"},"62":{"name":"forests","description":"Forests include tree cover greater than 30 percent tree canopy density and greater than 5 meters in height as mapped at a 30-meter Landsat pixel scale.\r\n"},"69":{"name":"fragmentation","description":"The breaking of large, contiguous forests into smaller pieces, with other land cover types interspersed.\r\n"},"80":{"name":"fragmented","description":"The breaking of large, contiguous forests into smaller pieces, with other land cover types interspersed.\r\n"},"74":{"name":"gain","description":"The establishment of tree canopy in an area that previously had no tree cover. Tree cover gain may indicate a number of potential activities, including natural forest growth or the crop rotation cycle of tree plantations.\r\n"},"7":{"name":"hectare","description":"One hectare equals 100 square meters, 2.47 acres, or 0.01 square kilometers and is about the size of a rugby field. A football pitch is slightly smaller than a hectare (pitches are between 0.62 and 0.82 hectares).\r\n"},"66":{"name":"hectares","description":"One hectare equals 100 square meters, 2.47 acres, or 0.01 square kilometers and is about the size of a rugby field. A football pitch is slightly smaller than a hectare (pitches are between 0.62 and 0.82 hectares).\r\n"},"67":{"name":"intact","description":"A forest that contains no signs of human activity or habitat fragmentation as determined by remote sensing images and is large enough to maintain all native biological biodiversity.\r\n"},"78":{"name":"intact forest","description":"A forest that contains no signs of human activity or habitat fragmentation as determined by remote sensing images and is large enough to maintain all native biological biodiversity.\r\n"},"8":{"name":"intact forests","description":"A forest that contains no signs of human activity or habitat fragmentation as determined by remote sensing images and is large enough to maintain all native biological biodiversity.\r\n"},"55":{"name":"land and environmental defenders","description":"People who peacefully promote and protect rights related to land and\/or the environment.\r\n"},"9":{"name":"loss driver","description":"The direct cause of forest disturbance.\r\n"},"10":{"name":"low tree canopy density","description":"Less than 30 percent tree canopy density.\r\n"},"84":{"name":"managed forest concession","description":"Areas where governments have given rights to private companies to harvest timber and other wood products from natural forests on public lands.\r\n"},"83":{"name":"managed forest concession maps for nine countries","description":"Cameroon, Canada, Central African Republic, Democratic Republic of the Congo, Equatorial Guinea, Gabon, Indonesia, Liberia, and the Republic of the Congo\r\n"},"104":{"name":"managed natural forests","description":"Naturally regenerated forests with signs of management, including logging, clear cuts, etc.\r\n"},"91":{"name":"megacities","description":"A city with more than 10 million people.\r\n"},"57":{"name":"megacity","description":"A city with more than 10 million people."},"56":{"name":"mosaic restoration","description":"Restoration that integrates trees into mixed-use landscapes, such as agricultural lands and settlements, where trees can support people through improved water quality, increased soil fertility, and other ecosystem services. This type of restoration is more likely in deforested or degraded forest landscapes with moderate population density (10\u2013100 people per square kilometer). "},"86":{"name":"natural","description":"A forest that is grown without human intervention.\r\n"},"12":{"name":"natural forest","description":"A forest that is grown without human intervention.\r\n"},"63":{"name":"natural forests","description":"A forest that is grown without human intervention.\r\n"},"82":{"name":"persistent gain","description":"Forests that have experienced one gain event from 2001 to 2016.\r\n"},"13":{"name":"persistent loss and gain","description":"Forests that have experienced one loss or one gain event from 2001 to 2016."},"97":{"name":"plantation","description":"An area in which trees have been planted, generally for commercial purposes.\u0026nbsp;\r\n"},"93":{"name":"plantations","description":"An area in which trees have been planted, generally for commercial purposes.\u0026nbsp;\r\n"},"88":{"name":"planted","description":"A forest composed of trees that have been deliberately planted and\/or seeded by humans.\r\n"},"14":{"name":"planted forest","description":"A forest composed of trees that have been deliberately planted and\/or seeded by humans.\r\n"},"73":{"name":"planted forests","description":"A forest composed of trees that have been deliberately planted and\/or seeded by humans.\r\n"},"15":{"name":"primary forest","description":"Old-growth forests that are typically high in carbon stock and rich in biodiversity. The GFR uses a humid tropical primary rainforest data set, representing forests in the humid tropics that have not been cleared in recent years.\r\n"},"64":{"name":"primary forests","description":"Old-growth forests that are typically high in carbon stock and rich in biodiversity. The GFR uses a humid tropical primary rainforest data set, representing forests in the humid tropics that have not been cleared in recent years.\r\n"},"58":{"name":"production forest","description":"A forest where the primary management objective is to produce timber, pulp, fuelwood, and\/or nonwood forest products."},"89":{"name":"production forests","description":"A forest where the primary management objective is to produce timber, pulp, fuelwood, and\/or nonwood forest products.\r\n"},"87":{"name":"seminatural","description":"A managed forest modified by humans, which can have a different species composition from surrounding natural forests.\r\n"},"59":{"name":"seminatural forests","description":"A managed forest modified by humans, which can have a different species composition from surrounding natural forests. "},"96":{"name":"shifting agriculture","description":"Temporary loss or permanent deforestation due to small- and medium-scale agriculture.\r\n"},"103":{"name":"surface roughness","description":"Surface roughness of forests creates\u0026nbsp;turbulence that slows near-surface winds and cools the land as it lifts heat from low-albedo leaves and moisture from evapotranspiration high into the atmosphere and slows otherwise-drying winds. \r\n"},"17":{"name":"tree cover","description":"All vegetation greater than five meters in height and may take the form of natural forests or plantations across a range of canopy densities. Unless otherwise specified, the GFR uses greater than 30 percent tree canopy density for calculations.\r\n"},"71":{"name":"tree cover canopy density is low","description":"Less than 30 percent tree canopy density.\r\n"},"60":{"name":"tree cover gain","description":"The establishment of tree canopy in an area that previously had no tree cover. Tree cover gain may indicate a number of potential activities, including natural forest growth or the crop rotation cycle of tree plantations.\u0026nbsp;As such, tree cover gain does not equate to restoration.\r\n"},"18":{"name":"tree cover loss","description":"The removal or mortality of tree cover, which can be due to a variety of factors, including mechanical harvesting, fire, disease, or storm damage. As such, loss does not equate to deforestation.\r\n"},"19":{"name":"tree plantation","description":"An agricultural plantation of fast-growing tree species on short rotations for the production of timber, pulp, or fruit.\r\n"},"72":{"name":"tree plantations","description":"An agricultural plantation of fast-growing tree species on short rotations for the production of timber, pulp, or fruit.\r\n"},"85":{"name":"trees outside forests","description":"Trees found in urban areas, alongside roads, or within agricultural land\u0026nbsp;are often referred to as Trees Outside Forests (TOF).\u202f\r\n"},"105":{"name":"unmanaged natural forests","description":"Naturally regenerated forests without any signs of management, including primary forest.\r\n"}}}