A methodology to estimate carbon storage and flux in forestland using existing forest and soils databases

Sequestration of carbon through expansion and management offorestland can assist in reducing greenhouse gas concentrationsin the atmosphere. Quantification of the amount of carbonpresents an ongoing challenge that calls for new approaches.These new approaches must seek to simplify the science-basedaccounting of carbon storage and flux, while adhering to generalprinciples of greenhous gas accounting. Quantifying change incarbon storage and carbon flux consists of two steps: developinga baseline of carbon storage, and measuring resulting storageand flux following a change of conditions. A methodology isproposed that accomplishes both steps, applicable to anaggregate-level analysis using the state of Iowa (U.S.A.) as a case study. The method combines existing databasesfrom the U.S. Forest Service (USFS) and U.S. Department ofAgriculture (USDA), and merges these with the methods of Birdsey(USDA, 1992, 1995; IPCC, 1997; EIIP, 1999) for partitioningcarbon stocks into storage pools. Forested ecosystems in the study area contain approximately 137.3 metric tons organiccarbon per hectare, or 114 million metric tons of carbon inaggregate. Of this total, 44.7 million tons are stored inbiomass tissue, and 69.2 million tons of carbon are contained insoils. Carbon flux due to forests in the state of Iowa isestimated to be a net annual sequestration (removal from theatmosphere) of 4.3 million metric tons of CO₂-equivalent,approximately 5% of the net annual CO₂-equivalentemissions from the state (Ney et al., 1996).     

Floristics, performance and prognosis of historical trees in the urban forest of Guangzhou City (China)

Outstanding historical trees embedded in cities constitute pertinent environmental assets, yet they are widely threatened in third-world cities. Inadequate understanding of this valuable natural-cum-cultural heritage hinders proper conservation. A case study of Guangzhou in south China evaluated floristic composition, age profile and biomass structure of historical trees, assessed their performance in major habitats (institutional, park and roadside), and established a prognosis for future growth and management. The 348 historical trees examined belonged to only 25 species, vis-à -vis 254 trees in the entire urban forest, dominated by five species and native members. Roadside had more trees, followed by institutional and park, with merely the most common four species shared by all habitats. The limited commonality reflected tree-performance differentiation by habitats exerting selection pressure on species. The institutional growth-regime was more conducive to nurturing high-caliber specimens, whereas park is less capable. Individual species achievement by habitats, derived from tree-count ranking and relative-abundance indices, could inform species choice and tree conservation. Few trees exceeded 300 years of age in the millennium-old city, echoing a history of intense tree—city conflicts. Potential life-span, trunk and crown diameters indicated ample opportunities for further expansion of biomass and landscape impacts, which would be straitjacketed by the tightening urban fabric.     

塔里木河地区胡杨—柽柳混交林的结构与功能

在调查塔里木河地区不同混交模式林分生产力、生物量及其分配状况、林分土壤养分分配状况、混交距离对胡杨生长的影响与不同林分土壤水源涵养能力的基础上,研究不同混交模式的结构与功能关系.结果表明,胡杨—柽柳块状混交林的生产力、生物量及其分配状况均好于胡杨—柽柳带状混交林与胡杨纯林.胡杨—柽柳块状混交林林下枯落物分解速度较快,积累量明显少于胡杨—柽柳带状混交林与胡杨纯林,说明胡杨—柽柳块状混交林具有较好的改良土壤作用,胡杨—柽柳块状混交林的土壤物理、化学性质及其涵养水源功能好于胡杨—柽柳混交林与胡杨纯林.此外,25 a胡杨—柽柳混交林混交距离应大于900 cm;混交方式采用块状混交能起到较好的效果.     

A habitat-based microscale forest classification system for zoning wood production areas to conserve a rare species threatened by logging operations in south-eastern Australia

The production of timber from native forests is presently one of the most controversial land management issues in Australia. Part of this controversy results from the potential impacts of forestry practices on forest-dependent fauna, particularly those that are rare and endangered, such as Leadbeater's Possum Gymnobelideus leadbeateri McCoy, in the forests of central Victoria, south-eastern Australia. A significant proportion of the highly limited distribution of this species overlaps with some of the most valuable wood production forests in Australia within which extensive clearfelling operations are employed to produce timber and pulpwood. These operations can destroy the habitat of G. leadbeateri. The Victoria government agency that is responsible for forest and wildlife management has devised a forest zoning system as part of the management strategies to conserve G. leadbeateri within timber production areas. This is designed to partition the forest into three types of areas: (1) where the conservation of G. leadbeateri is a priority, (2) where wood production is a priority, and, (3) where both land uses are a joint priority. The classification of areas of forest where the conservation of G. leadbeateri is the primary land use is based on an understanding of the habitat requirements of the species. The results of recent field studies, where statistical models of the habitat requirements of G. leadbeateri have been developed and their performance subsequently tested using a new dataset, highlights the need for a new basis to guide the classification of areas for the conservation of the species within wood production forests. We describe a method for devising a forest management zoning system that is based on a statistical model of the habitat requirements of G. leadbeateri and which will better integrate wood production and the conservation of the species. This procedure accounts for the uncertainty in the statistical model and, in turn, reduces the risk that areas where G. leadbeateri occurs are logged, whilst ensuring that other areas are not unnecessarily excluded from timber harvesting.     

Large-scale carbon stock assessment of woody vegetation in tropical dry deciduous forest of Sathanur reserve forest,Eastern Ghats,India

Tropical dry forests are one of the most widely distributed ecosystems in tropics, which remain neglected in research, especially in the Eastern Ghats. Therefore, the present study was aimed to quantify the carbon storage in woody vegetation (trees and lianas) on large scale (30, 1 ha plots) in the dry deciduous forest of Sathanur reserve forest of Eastern Ghats. Biomass of adult (≥10 cm DBH) trees was estimated by species-specific allometric equations using diameter and wood density of species whereas in juvenile tree population and lianas, their respective general allometric equations were used to estimate the biomass. The fractional value 0.4453 was used to convert dry biomass into carbon in woody vegetation of tropical dry forest. The mean aboveground biomass value of juvenile tree population was 1.86 Mg/ha. The aboveground biomass of adult trees ranged from 64.81 to 624.96 Mg/ha with a mean of 245.90 Mg/ha. The mean aboveground biomass value of lianas was 7.98 Mg/ha. The total biomass of woody vegetation (adult trees + juvenile population of trees + lianas) ranged from 85.02 to 723.46 Mg/ha, with a mean value of 295.04 Mg/ha. Total carbon accumulated in woody vegetation in tropical dry deciduous forest ranged from 37.86 to 322.16 Mg/ha with a mean value of 131.38 Mg/ha. Adult trees accumulated 94.81% of woody biomass carbon followed by lianas (3.99%) and juvenile population of trees (1.20%). Albizia amara has the greatest biomass and carbon stock (58.31%) among trees except for two plots (24 and 25) where Chloroxylon swietenia contributed more to biomass and carbon stock. Similarly, Albizia amara (52.4%) showed greater carbon storage in juvenile population of trees followed by Chloroxylon swietenia (21.9%). Pterolobium hexapetalum (38.86%) showed a greater accumulation of carbon in liana species followed by Combretum albidum (33.04%). Even though, all the study plots are located within 10 km radius, they show a significant spatial variation among them in terms of biomass and carbon stocks which could be attributed to variation in anthropogenic pressures among the plots as well as to changes in tree density across landscapes. Total basal area of woody vegetation showed a significant positive (R ² = 0.978; P = 0.000) relationship with carbon storage while juvenile tree basal area showed the negative relationship (R ² = 0.4804; P = 0.000) with woody carbon storage. The present study generates a large-scale baseline data of dry deciduous forest carbon stock, which would facilitate carbon stock assessment at a national level as well as to understand its contribution on a global scale.     

Community Based Interventions as a Strategy to Combat Desertification in the Arid and Semi-Arid Rangelands of Kajiado District, Kenya

Vegetation degradation, especially the disappearance of woody vegetation and a diminished grass cover, has aroused the concern of the Maasai community (semi-nomadic pastoralists) of Kajiado District, Kenya. The district is one of Kenya’s arid and semi-arid districts. Over recent years, they have observed their land resources deteriorate due to the desertification process caused by the land use practices of man. They have identified indicators of desertification such as increase of bare lands, which have been invaded by previously unknown grasses and weeds that are of no economic value, and also the disappearance of some useful plant species. It is due to the above concerns that a group of 30 farmers have been very keen to participate in on-farm research to strategize on ways to halt and even reverse the desertification process. The participatory research has identified useful trees that the farmers have been planting around homesteads, as woodlots on their farms to provide woodfuel, shade, and to act as windbreaks. They have also identified species for planting as live fences instead of using thorny tree branches as fencing material, which contributes further to the desertification process. Due to the termite menace on young tree seedlings, the farmers use indigenous knowledge to prepare concoctions using locally available materials, which they apply to planting holes and on seedlings. During awareness campaigns, the farmer research group highlights the need to conserve vegetation resources and also expounds on the concept of planting two trees after one is felled.     

Conservation practices in U.S. agriculture and their impact on carbon sequestration

Increase in the use of conservation practices byagriculture in the United States will enhance soilorganic carbon and potentially increase carbonsequestration. This, in turn, will decrease the netemission of carbon dioxide. A number of studies existthat calibrate the contribution of various individual,site-specific conservation practices on changes insoil organic carbon. There is a general absence,however, of a comprehensive effort to measureobjectively the contribution of these practicesincluding conservation tillage, the ConservationReserve Program, and conservation buffer strips to anchange in soil organic carbon. This paper fills thatvoid. After recounting the evolution of the use ofthe various conservation practices, it is estimatedthat organic carbon in the soil in 1998 in the UnitedStates attributable to these practices was about 12.2million metric tons. By 2008, there will be anincrease of about 25%. Given that there is asignificant potential for conservation practices tolead to an increase in carbon sequestration, there area number of policy options that can be pursued.     

Biofuel use assessments in Africa: Implications for greenhouse gas emissions and mitigation strategies

The energy balances of most African countries suggest that biofuels (woodfuel, crop and wood residues, and dung) constitute the largest share of total energy consumption (up to 97% in some sub-Saharan Africa countries). There is, however, an increasing scarcity of woodfuel (fuelwood and charcoal), the major biofuel, and a feared increase in greenhouse gas (GHG) emissions associated with biofuel combustion. The extent of GHG emissions is estimated from biofuel consumption levels that are in turn based on methodologies that might be inaccurate. A questionnaire, supplemented by informal interviews, are used to collect data, yielding information regarding end-uses, technologies used, scale of consumption, determinants of fuel consumption, and interfuel substitution (among other parameters). The survey revealed that cooking is the major end-use, with other common uses, such as space and water heating. Improved stoves that provide better combustion efficiency and, thus, reduce woodfuel consumption have not been widely disseminated and are associated with higher methane emissions than open fires. More than 90% of the households in Africa use open fires. Consumption is presented as per capita for households and as products and quantity of fuel in the small scale industries, commercial, and public sectors. Among the determinants for biofuel consumption are affordability, availability of the fuel, and interfuel substitutions. Flaws in estimating biofuel consumption yield large uncertainties in GHG emissions, with implications for the development of policies on energy planning and environmental protection. However, the application of scenarios can guide policy formulation.     

Double sampling for stratification for the monitoring of sparse tree populations: the example of Populus euphratica Oliv. forests at the lower reaches of Tarim River, Southern Xinjiang, China

Desertification is a pressing issue in the dry Tarim River basin, which is under anthropogenic stresses. In this study, double sampling for stratification (DSS) is employed to inventory Populus euphratica Oliv. forests in the lower reaches of the Tarim River Basin in Xinjiang, China. The two objectives were evaluating DSS as a sampling technique for monitoring desertification and generating baseline information for permanent observation. Here, DSS consists of two phases: in phase 1, crown cover is observed on a large sample of plots on a high resolution satellite image, and these photo-plots are stratified into five crown cover strata. Phase 2 is a stratified random sample from these photo-plots and the sampled plots are field observed. Approximately 32% of the study area is without P. euphratica trees. As expected, estimated mean poplar tree density and basal area increase with crown cover. DSS takes advantages of stratification (fieldwork efficiency and statistical precision) without the need for a priori strata delineation. It proves feasible for inventory the sparse poplar population and holds promise for the assessment of trees outside the forest, where density varies considerably and pre-stratification is intractable. It can be integrated into permanent observation systems for monitoring vegetation changes.     

A new method for detecting individual trees in aerial LiDAR point clouds using absolute height maxima

Data acquired from aerial laser scanner systems are increasingly used for detecting individual trees in operational inventories. In conventional analyses, tree detection is often performed on raster models that use local height maxima filters; an option that is likely to accumulate important errors. In order to reduce errors and improve the detection of individual trees, a new method is proposed that uses an Absolute Height Maxima (AHM) filter applied on the original point clouds obtained from Aerial Laser Scanning (ALS). ALS point clouds at a density of 2 to 4 points per square meter were acquired over forest stands in Hyrcanian forests. In the new method, false trees and commission errors were automatically found and excluded. To evaluate the efficiency of this new method, 121 sample trees in the field were located, with a DGPS and a mapping camera. The height and crown radius of the sample trees were also measured. The field-surveyed variables were compared to the closest detected tree, with an overall detection accuracy of 75.2%. The initial results of this analysis allowed us to hypothesize that a higher detection of tree may be expected with larger densities.     

Towards the harmonization between National Forest Inventory and Forest Condition Monitoring. Consistency of plot allocation and effect of tree selection methods on sample statistics in Italy

In the frame of a process aiming at harmonizing National Forest Inventory (NFI) and ICP Forests Level I Forest Condition Monitoring (FCM) in Italy, we investigated (a) the long-term consistency between FCM sample points (a subsample of the first NFI, 1985, NFI_1) and recent forest area estimates (after the second NFI, 2005, NFI_2) and (b) the effect of tree selection method (tree-based or plot-based) on sample composition and defoliation statistics. The two investigations were carried out on 261 and 252 FCM sites, respectively. Results show that some individual forest categories (larch and stone pine, Norway spruce, other coniferous, beech, temperate oaks and cork oak forests) are over-represented and others (hornbeam and hophornbeam, other deciduous broadleaved and holm oak forests) are under-represented in the FCM sample. This is probably due to a change in forest cover, which has increased by 1,559,200 ha from 1985 to 2005. In case of shift from a tree-based to a plot-based selection method, 3,130 (46.7 %) of the original 6,703 sample trees will be abandoned, and 1,473 new trees will be selected. The balance between exclusion of former sample trees and inclusion of new ones will be particularly unfavourable for conifers (with only 16.4 % of excluded trees replaced by new ones) and less for deciduous broadleaves (with 63.5 % of excluded trees replaced). The total number of tree species surveyed will not be impacted, while the number of trees per species will, and the resulting (plot-based) sample composition will have a much larger frequency of deciduous broadleaved trees. The newly selected trees have—in general—smaller diameter at breast height (DBH) and defoliation scores. Given the larger rate of turnover, the deciduous broadleaved part of the sample will be more impacted. Our results suggest that both a revision of FCM network to account for forest area change and a plot-based approach to permit statistical inference and avoid bias in the tree sample composition in terms of DBH (and likely age and structure) are desirable in Italy. As the adoption of a plot-based approach will keep a large share of the trees formerly selected, direct tree-by-tree comparison will remain possible, thus limiting the impact on the time series comparability. In addition, the plot-based design will favour the integration with NFI_2.     

Effect of 30 years of road traffic abandonment on epiphytic moss diversity

Road traffic emits a cocktail of pollutants that can influence the vegetation and plant diversity in neighboring areas. However, the recovery potential of bryophytes after traffic abandonment is still little explored. In addition, the effects of the main pollutants of road verges, such as metals and salinity, on moss flora need to be investigated. In our study, we compared the moss richness and diversity in two closely related veteran tree allees of high conservation importance. The allees in Gry?ów and Lubrza, Poland, were chosen because of their similarity in age, geographical location, type of surrounding areas, and tree species. The only difference was that the trees in Gry?ów had not been exposed to direct road pollution for almost 30 years. The moss richness and diversity differed significantly between the sites. Altogether, 20 moss species were recorded on 229 trees, 17 species in Gry?ów (abandoned road), and 13 in Lubrza (busy road). We found considerable differences between moss cover on the road-facing and opposite sides of tree trunks. In Lubrza, mosses on the road-facing side were very scarce. The moss cover in Gry?ów was highly balanced between trunk sides as well as among trunk heights. Typical epiphytic species such as Bryum moravicum, Dicranoweisia cirrata, Leskea polycarpa, and Orthodicranum tauricum preferred the Gry?ów tree stands, where they were present in numbers almost twice as high as that at Lubrza. The study shows that constructing a bypass road could be an effective conservation measure for veteran tree protection with their epiphytic moss flora.     

Accuracy assessment of a small-area method for estimating the spatial distribution of the degree of tree damage

Tree damage, gauged by the amount of defoliation, is one of the basic criteria used to determine treatments for protected and economic forests. Monitoring should include an assessment of the degree of tree damage in different spatial scales. Therefore, in addition to the commonly applied large-area methods, small-area methods should be used. The aim of the paper is to present the results of the accuracy assessment of a small-area method, proposed by Podlaski (2005) [Podlaski, R. (2005). Inventory of the degree of tree defoliation in small areas. Forest Ecology and Management, 215, 361–377], for monitoring the degree of tree damage. The degree of tree damage was shown in sub-blocks P₃ of the system of information on natural environment (SINUS). To estimate the spatial distribution of the degree of tree defoliation, survey sampling, based on simple random sampling with replacement (SRSWR), was used. The degree of damage to fir (Abies alba Mill.) and beech (Fagus sylvatica L.) was analysed in the Święty Krzyż forest section in the Świętokrzyski National Park. The maximum total estimation errors for the proportion of trees with a degree zero of damage, and with second and third degrees of damage together (for α = 0.05) were at most 30.8% for fir and 24.3% for beech trees. For standard, small-area evaluations, these are satisfactory values. In the Święty Krzyż forest section, the number of P₃ sub-blocks with 0.00–5.00% of undamaged trees and with 80.01–100.00% of moderately- or severely-damaged trees was significantly greater for fir than for beech. These results indicate that the fir population was unhealthier than the beech group in the study area. P₃ sub-blocks of the SINUS system, in which the proportion of the healthiest trees was highest, were situated at the forest margin, bordering on meadows and arable fields (in the case of fir) and forming dense patches consisting of several sub-blocks, or occurring singly in the whole study area (in the case of beech). The results show the significant differentiation of forest tree health in small areas.     

伊犁低山丘陵区小流域水土保持措施优化配置研究

在调查分析伊犁低山丘陵区水土流失特点的基础上，研究了该区小流域水土保持措施的空间配置。结果表明：伊犁低山丘陵区水土流失主要表现为以水力侵蚀为主的多种土壤侵蚀类型作用下的坡面侵蚀和沟道侵蚀。针对其水土流失特点，伊犁低山丘陵区小流域水土保持措施优化配置为：以生态修复为主，上游地区封禁保护；中游地区种植水保林和经济林带，建立生态缓冲带；下游水平沟种草。通过综合治理开展水土保持生态环境建设，至2012年底，伊犁低山丘陵区治理程度达到77．33％，林草覆盖率48％，改善了当地生态环境。     

Biological monitoring of atmospheric trace metal deposition in North-Eastern Nigeria

The epiphytic moss Polytrichum juniperinum and the tree bark of Azardirachta indica were used to determine the atmospheric Cd, Cu, Pb, Mn, Fe, Ni and Zn levels in the North-East region of Nigeria. A good correlation exists between levels in the moss and the tree barks. The Pb, Zn and Fe levels in both sample types were higher than other metals in most sites. There was no significant difference in the levels of Cd, Cu, Ni and Mn recorded for inhabited and forest sites. The area derives its atmospheric metal contamination from vehicular, urban, industrial and agricultural sources.     

Permanent sample plots for natural tropical forests: A rationale with special emphasis on Central Africa

Permanent sample plots (PSP), where trees are individually and permanently marked, have received increased interest in Central Africa as a tool to monitor vegetation changes. Although techniques for mounting PSP in tropical forests are well known, their planning still deserves attention. This study aims at defining a rationale for determining the size and number of replicates for setting up PSP in mixed tropical forests. It considers PSP as a sampling plan to estimate a target quantity with its associated margin of error. The target quantity considered here is the stock recovery rate, which is a key parameter for forest management in Central Africa. It is computed separately for each commercial species. The number of trees to monitor for each species defines the margin of error on the stock recovery rate. The size and number of replicated plots is obtained as the solution of an optimization problem that consists in minimizing the margin of error for every species while ensuring that the mounting cost remains below a given threshold. This rationale was applied using the data from the M’Baïki experimental site in the Central African Republic. It showed that the stock recovery rate is a highly variable quantity, and that the typical cost that forest managers are prone to devote to PSP leads to high margins of error. It also showed that the size and number of replicated plots is related to the spatial pattern of trees: clustered or spatially heterogeneous patterns favor many small plots, whereas regular or spatially homogeneous patterns favor few large plots.     

Changes in forest biomass carbon stock in Northern Turkey between 1973 and 2006

New forest management and planning approaches are designed to optimize forest structure. Optimal forest structure was determined using newly established growth models while considering primary timber production objectives as well as non-timber objectives for inaccessible areas and social and political pressures on land management. With currently planned management the forests of the Ormanüstü Planning Unit (OPU) in the Black Sea region of northern Turkey are likely to become an important C sink. To quantify this potential C sink and understand its implication to the regional carbon budget and future forest management, we estimated the changes in the OPU between 1973 and 2006. Based on four periods of data for the OPU forests obtained from the Forest Management and Planning Office of Turkey, we used allometric biomass and C regression equations along with biomass expansion factors to estimate the forest biomass carbon pool for each of four inventory years 1973, 1984, 1997, and 2006. Since 1973, OPU forests have accumulated 110.2?×?10³ tons of C as a result of forest expansion and the growth of extant forests, increasing by 50.8 % from 217?×?10³ tons in 1973 to 327.2?×?10³ tons C in 2006. Hardwood and softwood forests accounted for 44 and 56 % of carbon accumulation during this period, respectively. From 1973 through 2006, forest C accumulated at a rate of 3.3?×?10³ tons C year^?1. Carbon density of the OPU forests in the Black Sea region increased by 48.2 % from 5,679 to 8,419 tons/ha.     

Evaluating forest management practices using a GIS-based cellular automata modeling approach with multispectral imagery

The objective of this study was to develop an integrated geographic information system (GIS) cellular automata (CA) model for simulating insect-induced tree mortality patterns in order to evaluate the influence of different forest management activities to control insect outbreaks. High-resolution multispectral images were used to determine susceptibility of trees to attack, whereas the GIS-based CA model simulated the effectiveness of clear-cuts and thinning practices for reducing insect-induced tree mortality. The results indicate that thinning susceptible forests should be more effective than clear-cutting for reducing tree loss to insect outbreaks. This study demonstrates the benefits of an integrated approach for understanding and evaluating forest management activities and expresses the need for spatial analysis and modeling for improving forest management practices.     

Relation between individual tree mortality and tree characteristics in a polluted and non-polluted environment

Data on individual tree mortality in relatively healthy (Berezinskiy biosphere reserve) and damaged (surroundings of the mineral fertilizer plant 'Achema') even-aged Scots pine (Pinus sylvestris L.) stands are presented. Tree size and competition intensity were found to be the most significant predictors of individual tree mortality in all age groups of the relatively healthy Scots pine stands, however, an essential reduction in the closeness of relations between the tree mortality rate and these variables was determined with the aging of stands. An exponential decrease in tree mortality probability with an increase of tree size is characteristic for trees suffering different competition intensity, however, this decrease becomes much more pronounced as the competition pressure increases. The relations of different tree and stand variables with tree mortality probability have been found to become much weaker in the polluted environment. An exponential increase in tree mortality probability with an increase of crown defoliation was characteristic of damaged Scots pine stands, however, the rate of the increase was different in different age and diameter classes. The impact of crown defoliation on tree mortality rate increased with the aging of stands. At the same defoliation level, individual tree mortality probability was much higher for smaller suppressed trees, however, a relative increase in tree mortality probability along with an increase of crown defoliation was more pronounced for dominant trees. Conclusion: a higher mortality of damaged (defoliated) trees should be considered while assessing losses in forest productivity in a polluted environment.     

Mapping trees outside forests using high-resolution aerial imagery: a comparison of pixel- and object-based classification approaches

Discrete trees and small groups of trees in nonforest settings are considered an essential resource around the world and are collectively referred to as trees outside forests (ToF). ToF provide important functions across the landscape, such as protecting soil and water resources, providing wildlife habitat, and improving farmstead energy efficiency and aesthetics. Despite the significance of ToF, forest and other natural resource inventory programs and geospatial land cover datasets that are available at a national scale do not include comprehensive information regarding ToF in the United States. Additional ground-based data collection and acquisition of specialized imagery to inventory these resources are expensive alternatives. As a potential solution, we identified two remote sensing-based approaches that use free high-resolution aerial imagery from the National Agriculture Imagery Program (NAIP) to map all tree cover in an agriculturally dominant landscape. We compared the results obtained using an unsupervised per-pixel classifier (independent component analysis—[ICA]) and an object-based image analysis (OBIA) procedure in Steele County, Minnesota, USA. Three types of accuracy assessments were used to evaluate how each method performed in terms of: (1) producing a county-level estimate of total tree-covered area, (2) correctly locating tree cover on the ground, and (3) how tree cover patch metrics computed from the classified outputs compared to those delineated by a human photo interpreter. Both approaches were found to be viable for mapping tree cover over a broad spatial extent and could serve to supplement ground-based inventory data. The ICA approach produced an estimate of total tree cover more similar to the photo-interpreted result, but the output from the OBIA method was more realistic in terms of describing the actual observed spatial pattern of tree cover.