基于MODIS时序数据的黑龙江流域火烧迹地提取

火烧迹地信息是研究火灾的重要参数和基础数据,也是研究全球生态系统和碳循环扰动的重要依据之一。以受森林火灾影响较为严重的黑龙江流域为研究区,以MODIS时间序列数据为数据源建立了一个分为两阶段的火烧基地提取算法(即首先设定较为严格的提取条件对最有可能发生火灾的像元——核心像元进行提取,然后设定较为宽松的阈值提取距离核心像元一定范围内的火烧像元),对2000—2011年的火烧迹地信息进行了提取,生成了研究区长时间序列火烧迹地分布图,并对其时空分布特征进行了分析。选择黑龙江省为典型验证区对算法精度进行了验证,结果显示算法的整体精度较之以往的算法有了一定程度的提高。     

Loss of habitats,naturalness and species diversity in Eurasian forest landscapes

Man has exploited land and forests in Western and Central Europe longer and more intensively than in Northern Europe and further east in Eurasia. We estimated forest naturalness and modelled expected biodiversity loss in seven different landscapes (2500 km² each) in the Netherlands, Sweden, Finland, Poland, St. Petersburg (Western European Russia), Perm (Eastern European Russia), and Irkutsk (Central Siberia) across the distribution of Pinus sylvestris L. in Eurasia. Field inventories showed that the mean living tree volumes were relatively similar in the studied sites, but the volumes of dead wood differed greatly. In Irkutsk and Perm the volume of dead trees per ha was about 5–10 times larger than in Central and Western European regions. The studied forests were generally young in all regions except for Irkutsk, where about half of the study plots had trees older than 120 years. Signs of recent forest fires were found almost exclusively on Russian sites. According to Landsat satellite image-based land-cover classifications the amount of remaining forest habitat in the studied landscapes varied from 25% in the Netherlands to 93% in Irkutsk. Estimated by forest patch size and density of cut stumps, forests were also more fragmented and heavily managed in the western study landscapes compared to eastern ones. Based on species–area relationship functions, we calculated that the proportion of forest-dwelling species already extinct or expected to become extinct due to habitat loss ranges from 1–2% in Irkutsk to 13–24% in the Netherlands study landscape. For saproxylic species, which depend on dead wood, the extinction estimates were calculated based on remaining dead wood volume in the landscape. The modelled expected loss of saproxylic species ranged from 7–14% in Irkutsk to 35–58% in the Netherlands.     

Estimation of forest cover extent over peatlands and paludified shallow-peat lands in Russia

On the basis of the geoinformational system “Peatland ecosystems of Russia”, developed at the Institute of Forest Science (Russian Academy of Sciences), and the Map of Forests of Russia (2004), the areas of forest cover on peatlands (139 mln ha) and on paludified shallow-peat lands (230 mln ha) were estimated. Trees are present on 38% of the peatland area, of which more than half (21%) is sparsely treed. Forests (peatland forests) cover only 17% (24 mln ha). The majority of peatlands (over 62%) are open. More than half of the paludified shallow-peat habitats are also open, and the remainder (23 and 24%) are almost equally divided between forested and sparsely forested types.     

Climate change and wildfires in Russia

The effect of climate change on the distribution, intensity, and transforming role of wild fires is considered. A general overview of the current wild fire regimes (WRs) and impacts on forest ecosystems and environment is provided. One distinctive feature of WRs is the increasing frequency of disastrous wild fires. The application of various remote sensing instruments has shown that the average vegetation wild fire area in Russia for 1998–2010 accounted for 8.2 ± 0.8 × 10⁶ ha, with about two-thirds of wildfires occurring on forest lands and half on the forested lands. The average annual fire carbon balance during the above period was 121 ± 28 Tg C yr^?1, including 92 ± 18 Tg C yr^?1 emitted from the forested land. The forecasts based on the General Circulation Models suggest the dramatic acceleration of fire regimes by the end of the 21st century. Taking into account the increase in the dryness of the climate and the thawing of permafrost, this will likely lead to a dramatic loss of forested area and the impoverishment of the forest cover over a major part of the forest zone. A transition to adaptive forestry would allow a substantial decrease of the expected losses. This paper takes a brief look at the general principals of adapting forest fire protection system to climate change, which is considered an integral part of the transition to sustainable forest management in Russia.     

Spatial distribution of young forests and carbon fluxes within recent disturbances in Russia

Forest stand age plays a major role in regulating carbon fluxes in boreal and temperate ecosystems. Young boreal forests represent a relatively small but persistent source of carbon to the atmosphere over 30 years after disturbance, while temperate forests switch from a substantial source over the first 10 years to a notable sink until they reach maturity. Russian forests are the largest contiguous forest belt in the world that accounts for 17% of the global forest cover; however, despite its critical role in controlling global carbon cycle, little is known about spatial patterns of young forest distribution across Russia as a whole, particularly before the year 2000. Here, we present a map of young (0–27 years of age) forests, where 12‐ to 27‐year‐old forests were modeled from the single‐date 500 m satellite record and augmented with the 0‐ to 11‐year‐old forest map aggregated from the 30 m resolution contemporary record between 2001 and 2012. The map captures the distribution of forests with the overall accuracy exceeding 85% within three largest bioclimatic vegetation zones (northern, middle, and southern taiga), although mapping accuracy for disturbed classes was generally low (the highest of 31% for user's and producer's accuracy for the 12–27 age class and the maximum of 74% for user's and 32% for producer's accuracy for the 0–11 age class). The results show that 75.5 ± 17.6 Mha (roughly 9%) of Russian forests were younger than 30 years of age at the end of 2012. The majority of these 47 ± 4.7 Mha (62%) were distributed across the middle taiga bioclimatic zone. Based on the published estimates of net ecosystem production (NEP) and the produced map of young forests, this study estimates that young Russian forests represent a total sink of carbon at the rate of 1.26 Tg C yr^?1.     

Land cover change and carbon emissions over 100 years in an African biodiversity hotspot

Agricultural expansion has resulted in both land use and land cover change (LULCC) across the tropics. However, the spatial and temporal patterns of such change and their resulting impacts are poorly understood, particularly for the presatellite era. Here, we quantify the LULCC history across the 33.9 million ha watershed of Tanzania's Eastern Arc Mountains, using geo‐referenced and digitized historical land cover maps (dated 1908, 1923, 1949 and 2000). Our time series from this biodiversity hotspot shows that forest and savanna area both declined, by 74% (2.8 million ha) and 10% (2.9 million ha), respectively, between 1908 and 2000. This vegetation was replaced by a fivefold increase in cropland, from 1.2 million ha to 6.7 million ha. This LULCC implies a committed release of 0.9 Pg C (95% CI: 0.4–1.5) across the watershed for the same period, equivalent to 0.3 Mg C ha^?1 yr^?1. This is at least threefold higher than previous estimates from global models for the same study area. We then used the LULCC data from before and after protected area creation, as well as from areas where no protection was established, to analyse the effectiveness of legal protection on land cover change despite the underlying spatial variation in protected areas. We found that, between 1949 and 2000, forest expanded within legally protected areas, resulting in carbon uptake of 4.8 (3.8–5.7) Mg C ha^?1, compared to a committed loss of 11.9 (7.2–16.6) Mg C ha^?1 within areas lacking such protection. Furthermore, for nine protected areas where LULCC data are available prior to and following establishment, we show that protection reduces deforestation rates by 150% relative to unprotected portions of the watershed. Our results highlight that considerable LULCC occurred prior to the satellite era, thus other data sources are required to better understand long‐term land cover trends in the tropics.     

Spatial and temporal variability of fires in relation to ecosystems,land tenure and rainfall in savannas of northern South America

Fire is a predominant factor forcing global terrestrial biomass dynamics, with more than 30% of the land surface showing frequent burning, particularly in the tropics, where it mostly affects savannas ecosystems annually. Savannas, which cover approximately 269 million ha in South America, play a major role in the global carbon cycle. They are affected by increasing human pressures and global climate change. Using satellite data, this study quantifies vegetation burning in the Colombian Llanos savannas for the period 2000–2008, and analyzes how fire spatial pattern, frequency and extent vary with ecosystem type, land tenure and rainfall. On average 2.75±0.5 million ha (24±4.2%) of the savannas burn each year. Burned area is highly variable, with 3.4 million ha burned in 2002–2003 and <1.9 million ha in 2005–2006. However, during the 2000–2008 period near of 3.7 million ha (33.5%) of the savannas never burned. Compared with the average 8–10 years of fire return time for the tropics and subtropics, these savannas burn twice as often. In addition, the average burn size figure for tropical and subtropical grassland savannas (with <5% trees) of 7000 ha (median 5000 ha), is about seven times the average burned patch size we found in our study. Fires predominate in the well‐drained high plain savannas, lowest figures occurring along the Andean foothills, in forested areas and in pasture and croplands. Annual proportion burned varies with land tenure, being highest in National Parks. This study is the first complete regional map of fire disturbance in a South American savanna. This detailed regional data provides a unique opportunity for increasing the accuracy of global carbon emission calculations.     

Carbon cost of collective farming collapse in Russia

The collapse of collective farming in Russia after 1990 and the subsequent economic crisis led to the abandonment of more than 45 million ha of arable lands (23% of the agricultural area). This was the most widespread and abrupt land use change in the 20th century in the northern hemisphere. The withdrawal of land area from cultivation led to several benefits including carbon (C) sequestration. Here, we provide a geographically complete and spatially detailed analysis of C sequestered in these abandoned lands. The average C accumulation rate in the upper 20 cm of mineral soil was 0.96 ± 0.08 Mg C ha^?1 yr^?1 for the first 20 years after abandonment and 0.19 ± 0.10 Mg C ha^?1 yr^?1 during the next 30 years of postagrogenic evolution and natural vegetation establishment. The amount of C sequestered over the period 1990–2009 accounts to 42.6 ± 3.8 Tg C per year. This C sequestration rate is equivalent to ca. 10% of the annual C sink in all Russian forests. Furthermore, it compensates all fire and postfire CO₂ emissions in Russia and covers about 4% of the global CO₂ release due to deforestation and other land use changes. Our assessment shows a significant mitigation of increasing atmospheric CO₂ by prolonged C accumulation in Russian soils caused by collective farming collapse.     

Correction of phenology-induced effects in forest canopy height models based on airborne laser scanning data. Insights from the deciduous mountain forests in Picos de Europa National Park in Spain

The comparison of ALS time-series is an important element of modern landscape conservation planning, especially to monitor forest ecosystems. Modellers must evaluate phenology when comparing ALS-based maps of ground elevation or canopy height between years. We showcase the scenario using a National Park in the North-West of Spain where bi-temporal ALS has been used to map deciduous mountain forests. We compare the 2010 and 2021 surveys using the same algorithms to interpret ALS data and to generate actionable products for managers, mainly digital terrain models and canopy height models. We implemented a hybrid approach to correct the discrepancies between the surveys, showing the problems arising from differences in phenology or the selection of the scaling. We quantified around 5% of the area suffered from >1 m difference in DTM and higher impact on CHM values. With the hybrid method, modellers can highly reduce the uncertainty when comparing two ALS surveys and derivable products. We provided a solid graphical and analytical diagnosis of these emerging problems in the context of multi-temporal ALS surveys testing the hybrid approach at two resolutions: 1 and 2 m, fine-grained scales. The assessment of phenology-induced effects is important under the context of nationwide ALS survey programmes currently in operation and on high-demand. Finally, we discuss and frame the hybrid-approach as a well-suited vector of canopy gap detection methods to support conservation planning and enforce species-specific habitat improvements.     

Sex-specific differences and long-term trends in habitat selection of American woodcock

Effective wildlife management requires an understanding of how individuals select environmental factors, although few studies assess how habitat selection may differ over time or between sexes. During the post-breeding period (15 May to 1 Sep), we tracked 146 male American woodcock (Scolopax minor) in Rhode Island, USA, from 2010–2021 to assess how habitat selection varied over time, and 17 females and 51 males during the final 2 years of the study to document sex-specific differences in habitat selection. Males generally had smaller home ranges (35.0 ± 10.7 [margin of error] ha) and preferred habitat mosaics that consisted of forested wetlands, young forest patches, areas of deciduous forest, moist soils with gentle slopes, and riparian corridors. We detected subtle differences between sexes in selection for wetland young forest, upland young forest, percent slope, distance to upland young forest, distance to streams, and distance to moist soils. During 2020–2021, females tended to have larger home ranges (78.7 ± 46.4 ha) than males (35.0 ± 10.7 ha) and more strongly selected sites closer to riparian corridors, while males selected areas that were closer to upland young forest with flatter slopes than the available surrounding landscape. Such sex-specific differences in habitat selection may be related to males and females prospecting for potential breeding sites during this post-breeding period for the following spring. We used the top-ranked habitat selection models for males and females to produce a spatially explicit state-wide map that identifies low-to-high likelihood of use areas that can be used to guide forest management decisions in southern New England to maximize benefits for American woodcock.     

Disparate Geography of Consumption,Production, and Environmental Impacts

International trade transfers social and environmental impacts across national borders. The consumption of forest products often takes place far away from industrial production sites, and mills procure raw material from remote forests. Finland produces about 10% of forest products that are traded internationally, with the majority of its exports destined for other European countries. Here we report and analyze data that demonstrate that international leakage, in relative terms, increased faster than the production of commodities. The international consumption of products made in Finland increased, and an increase in wood imports from Russia provided the raw material for most of the incremental production. The international consumption‐production system translated the increasing global demand for Finnish products into increased harvests in Russia, until the Russian customs duties started to increase in 2007. We argue that national and regional policies for the promotion of sustainable consumption and production must be analyzed and assessed from an international, holistic perspective.     

Monitoring Landscape‐Scale Ponderosa Pine Restoration Treatment Implementation and Effectiveness

We evaluated landscape‐scale forest restoration treatment implementation and effectiveness in meeting objectives in a ponderosa pine forest at Mt. Trumbull, Arizona, U.S.A. The goal of the project was to alter forest structure by thinning and burning to more closely resemble forest conditions prior to Euro‐American settlement in 1870. We measured 117 permanent plots before (1996/1997) and after (2003) treatments. The plots were evenly distributed across the landscape (approximately 1,200 ha), about half of which was an untreated control. We evaluated treatment implementation and effectiveness based on 1870 structure and/or goals outlined by managers. The success of treatment implementation varied: about 94% of the area originally planned for restoration was treated in some manner by 2003, but only 70% received the full planned treatment (thin and burn). Although density of ponderosa pines >2.5 cm was reduced significantly by 66% from approximately 429 pines/ha to approximately 146 pines/ha in the treated area, the targeted residual density was exceeded by 111–256% (all plots) or 10–85% (thinned and burned plots). Thirteen percent of the pre‐settlement pines died in the treated area by 2003, but 9% percent also died in the control, indicating that pre‐settlement pines in untreated areas were nearly as vulnerable as those exposed to restoration treatments. Large snags increased 45%, and 65% of logs >50 cm were retained, achieving implementation goals. Although restoration treatments were not implemented totally to specifications, they were effective in attaining the overall project goal of restoring more open forest structure while preserving more than 75% of the pre‐settlement pines. Canopy fuel loads were substantially reduced, allowing for the reintroduction of surface fires.     

Estimation of Soil Erosion Dynamics in the Koshi Basin Using GIS and Remote Sensing to Assess Priority Areas for Conservation

High levels of water-induced erosion in the transboundary Himalayan river basins are contributing to substantial changes in basin hydrology and inundation. Basin-wide information on erosion dynamics is needed for conservation planning, but field-based studies are limited. This study used remote sensing (RS) data and a geographic information system (GIS) to estimate the spatial distribution of soil erosion across the entire Koshi basin, to identify changes between 1990 and 2010, and to develop a conservation priority map. The revised universal soil loss equation (RUSLE) was used in an ArcGIS environment with rainfall erosivity, soil erodibility, slope length and steepness, cover-management, and support practice factors as primary parameters. The estimated annual erosion from the basin was around 40 million tonnes (40 million tonnes in 1990 and 42 million tonnes in 2010). The results were within the range of reported levels derived from isolated plot measurements and model estimates. Erosion risk was divided into eight classes from very low to extremely high and mapped to show the spatial pattern of soil erosion risk in the basin in 1990 and 2010. The erosion risk class remained unchanged between 1990 and 2010 in close to 87% of the study area, but increased over 9.0% of the area and decreased over 3.8%, indicating an overall worsening of the situation. Areas with a high and increasing risk of erosion were identified as priority areas for conservation. The study provides the first assessment of erosion dynamics at the basin level and provides a basis for identifying conservation priorities across the Koshi basin. The model has a good potential for application in similar river basins in the Himalayan region.     

Impact of silkmoth outbreak on taiga wildfires

We provide a quantitative analysis of postoutbreak wildfire frequency within the confluence of the Yenisei and Angara rivers affected by the Siberian Silkmoth (Dendrolimus sibiricus Tschetv.). A catastrophic outbreak was observed in 1993–1996. It expanded to about 1 million ha and caused stand mortality on an area of about 460000 ha. For the outbreak area, the fire frequency was about 7 times higher when compared to the reference area; on the burned area, it was 20 times higher. The peak of fire activity within outbreak areas occurs in May–June, while that for undamaged coniferous stands is in July. The number of fires is correlated with the mean monthly air temperature (r = 0.65) of June. The area of fires displays a negative correlation with moisture conditions: precipitation (r =–0.53), drought index (SPEI: r =–0.57), and ground-cover moisture content (r =–0.57). Extensive fires prevail within outbreak areas (S > 1000 ha), while within the control there is a smaller area of fires. Multiple (reoccurring) wildfires are typical for pest outbreak areas. The area of these fires is related to their reoccurrence by logarithmic dependence (17% of the territory twice burned by forests fires, 5% on that burned three times, and 0.5% on that burned four times). Wildfires in the outbreak areas surpress the initial forest recovery by destroying the regeneration of conifers: 20 years after the outbreak, >90% of disturbed areas are occupied by grass–bush and small-leaved cenoses.     

Strategies to estimate national forest carbon stocks from inventory data: the 1990 New Zealand baseline

An estimate of live tree carbon stored in New Zealand forests at 1990 was made to partially satisfy New Zealand's international obligations under the Framework Convention for Climate Change. A national database was compiled of 4956 forest inventory plots measured as recently as possible to 1990. Plot biomass estimates were obtained by applying species allometric relationships derived from harvested stands. Forest areas and classes were taken from a 1987 national map of vegetation cover. Regularly spaced grids, based on an initial 1 km × 1 km grid, were overlaid on the total forest area and plots were tested for bias against site characteristics at the grid points. As grid point density and sample size increased, bias was minimal in regional sampling intensity and in total annual precipitation. Differences in mean elevation and annual temperature remained stable as grid point density increased, and showed little correlation with stem biomass. This sampling method gave a measure of precision not available from previous estimates. An efficient sample size to estimate the mean within a 5% level of precision (at 95% probability) required a sample of 574 plots selected from a 4‐km grid. This strategy generated a mean estimate for the 1990 New Zealand forest carbon biomass of 179.3 ± 4.9 Mg ha^?1 (± SE), totalling 919.1 ± 25.1 Mt for the 5.1 million ha mapped forest area. The mean was 6–10% lower than previous estimates, and was within the range reported for other countries. Within forest classes, mean carbon biomass ranged from 105 Mg ha^?1 in pure podocarp forest to 215 Mg ha^?1 in mixed lowland podocarp–broadleaved–beech forest. Of the major taxa groups throughout the forest estate, beech (Nothofagus) contributed 60% of the national forest carbon biomass reservoir, 26.7% was in other hardwoods, 13.2% in conifers, and 0.1% in other taxa (e.g. tree ferns).     

Isolation,patch size and matrix effects on bird assemblages in forest reserves

Habitat fragmentation is one of the most studied topics in ecology but our knowledge is still limited particularly concerning matrix effects on species distribution in a human-dominated landscape. We tested the ability of random sampling hypothesis, colonization–extinction dynamics and matrix-related concepts to explain the variation in species richness, total bird density and community composition in old-forest bird assemblages in two contrasting landscapes. We collected data on breeding bird abundances from 66 old-growth forest reserves in NE Finland and six larger areas in adjacent Russian Karelia using the line transect method. In Finland, protected old-forest patches are embedded in a matrix dominated by young regeneration stands. In Russia, study areas were situated in continuous, old forest dominated landscapes. Bird assemblages in old-forest patches embedded in human-modified matrix in Finland were not random samples from Russian bird assemblages. In the Finnish assemblages, species richness was lower and total bird density higher. Species richness declined with increasing distance (isolation) to Russia. Bird assemblages in large forest reserves in Finland close to Russia were structurally more similar to assemblages in the continuous reference landscape than those in small and more distant reserves. The results support the idea that several mechanisms related to colonisation–extinction dynamics and to matrix resource availability influence species distribution in fragmented landscapes but in species-specific ways. We conclude that even though small and isolated protected areas may foster high relative bird species density their ecological integrity is compromised, and therefore, improving matrix quality around reserves may lead to considerable conservation benefits.     

The Environmental Control of Near-Surface Thermoclines in Boreal Lakes

We report on the effect of lake size, water transparency, and wind on the frequency of transient near-surface thermoclines in 39 boreal lakes from the Experimental Lakes Area (ELA) and Northwest Ontario Lake Size Series (NOLSS). This study was based on more than 3000 archived temperature profiles amassed over a 25-year period for lakes ranging from 2 ha to 8 million ha in surface area. The incidence of transient thermoclines decreased with increasing lake size from 90% of all summer days in small lakes (less than 4 ha) to 40% or less in the larger NOLSS lakes (up to 34,700 ha). No transient near-surface thermoclines were detected in Lake Superior. Forest fires and climatic variability were also found to affect the frequency of near-surface thermoclines. Long-term trends indicate an increase in average annual wind velocity in the area, possibly as the result of extensive forest fires and clearcutting. The subsequent decrease in the frequency of shallow secondary thermoclines in aquatic ecosystems has possible consequences for the lake biota, as the result of changes in radiation, turbulence, and the nutrient regime. Received 8 November 2000; accepted 30 April 2001.     

Recent areal changes in US forested wetlands

This study summarizes US Forest Service Resource Bulletin data to estimate forested wetlands areal changes. The Forest Resource Bulletins used field-data surveys to estimate the area of different forest land plant associations, including those that are typically defined as forested wetlands. The information includes changes since 1940 on national and state levels. These figures may help judge the success of some recent efforts by private and public agencies to protect wetlands.Forested wetland area decreased by about 3 million ha from 1960 to 1990. The percentage of forested wetlands lost (13%) was greater than for forest land (7%) for the past three decades. In the 1980s, Louisiana and North Carolina experienced the greatest losses (178,000 ha and 203,000 ha, respectively). In the same period, Maine, Montana, and South Carolina experienced the largest increases. The area of forested wetlands in the United States decreased over 700,000 ha (0.3%/yr) between 1980 and 1990.Corresponding Editor: R.E. Turner     

基于人工神经网络的天然林生物量遥感估测

基于Landsat TM遥感图像, 以吉林省汪清天然林区为例, 应用B-P神经网络建立了森林生物量非线性遥感模型系统. 除采用遥感数据外, 该系统还引入了地形因子(海拔、坡度、坡向、立地类型等)作为模型自变量. 通过压缩输入数据和增强网络训练学习算法等措施, 对标准B-P神经网络进行了增强. 模型仿真结果表明：增强型B-P神经网络具有收敛速度快和自学习、自适应功能强的特点, 能最大限度地利用样本集的先验知识, 自动提取合理的模型, 模型预测结果能真实合理地反映实际情况. 针叶林、阔叶林和针阔混交林的生物量遥感模型系统仿真结果的平均相对误差分别为-1.47%、2.38%和3.56%, 平均相对误差绝对值分别为6.33%、8.46%和8.91%, 预估效果较理想. 应用该模型系统生成了研究区的森林生物量定量分布图, 其总体精度为88.04%.     

Remote sensing of forest gas exchange: Considerations derived from a tomographic perspective

The global exchange of gas (CO₂, H₂O) and energy (sensible and latent heat) between forest ecosystems and the atmosphere is often assessed using remote sensing (RS) products. Although these products are essential in quantifying the spatial variability of forest–atmosphere exchanges, large uncertainties remain from a measurement bias towards top of canopy fluxes since optical RS data are not sensitive for the vertically integrated forest canopy. We hypothesize that a tomographic perspective opens new pathways to advance upscaling gas exchange processes from leaf to forest stands and larger scales. We suggest a 3D modelling environment comprising principles of ecohydrology and radiative transfer modelling with measurements of micrometeorological variables, leaf optical properties and forest structure, and assess 3D fields of net CO₂ assimilation (A_n) and transpiration (T) in a Swiss temperate forest canopy. 3D simulations were used to quantify uncertainties in gas exchange estimates inherent to RS approaches and model assumptions (i.e. a big‐leaf approximation in modelling approaches). Our results reveal substantial 3D heterogeneity of forest gas exchange with top of canopy A_n and T being reduced by up to 98% at the bottom of the canopy. We show that a simplified use of RS causes uncertainties in estimated vertical gas exchange of up to 300% and that the spatial variation of gas exchange in the footprint of flux towers can exceed diurnal dynamics. We also demonstrate that big‐leaf assumptions can cause uncertainties up to a factor of 10 for estimates of A_n and T. Concluding, we acknowledge the large potential of 3D assessments of gas exchange to unravelling the role of vertical variability and canopy structure in regulating forest–atmosphere gas and energy exchange. Such information allows to systematically link canopy with global scale controls on forest functioning and eventually enables advanced understanding of forest responses to environmental change.