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1
Koch, Barbara. "Stand und Perspektiven der Nutzung neuer Fernerkundungstechnologien im Waldbereich | Status and perspectives of the application of new remote sensing technologies in forestry." Schweizerische Zeitschrift fur Forstwesen 162, no. 6 (June 1, 2011): 156–63. http://dx.doi.org/10.3188/szf.2011.0156.
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Remote sensing has been used in forestry for a long time. Aerial photography has mainly been used to support national and operational inventories and medium resolution satellite data for large area inventories. Today through the availability of new technologies there are greatly extended possibilities for remote sensing in the forestry sector. The major change is the better availability of 3-D information, which allows a much better modelling of forests and forest attributes. The paper presents an overview of the newest remote sensing technologies, such as the systems carried by satellite which can be used to record changes or degradation in the area covered by forest for the global forestry resources assessment of the UN World Food and Agriculture Organisation or are examined in connection with the United Nations REDD program. Besides these, other small scale applications are presented based on optical or laser systems carried by aircraft. The article finishes with an outlook on expected developments in the near future. It is expected that the future of forestry remote sensing will be characterized above all by the combination of information obtained from diverse sources, such as data based on terrestrial and on remotely sensed sources.
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Martin, Maxence, Nicole J. Fenton, and Hubert Morin. "Boreal old-growth forest structural diversity challenges aerial photographic survey accuracy." Canadian Journal of Forest Research 50, no. 2 (February 2020): 155–69. http://dx.doi.org/10.1139/cjfr-2019-0177.
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The erosion of old-growth forests in boreal managed landscapes is a major issue currently faced by forest managers; however, resolving this problem requires accurate surveys. The intention of our study was to determine if historic operational aerial forest surveys accurately identified boreal old-growth forests in Quebec, Canada. We first compared stand successional stages (even-aged vs. old-growth) in two aerial surveys performed in 1968 (preindustrial aerial survey) and 2007 (modern aerial survey) on the same 2200 km2 territory. Second, we evaluated the accuracy of the modern aerial survey by comparing its results with those of 74 field plots sampled in the study territory between 2014 and 2016. The two aerial surveys differed significantly; 80.8% of the undisturbed stands that were identified as “old-growth” in the preindustrial survey were classified as “even-aged” in the modern survey, and 60% of the stands identified as “old-growth” by field sampling were also erroneously identified as “even-aged” by the modern aerial survey. The scarcity of obvious old-growth attributes in boreal old-growth forests, as well as poorly adapted modern aerial survey criteria (i.e., criteria requiring high vertical stratification and significant changes in tree species composition along forest succession), were the main factors explaining these errors. It is therefore likely that most of Quebec’s boreal old-growth forests are currently not recognized as such in forest inventories, challenging the efficacy of sustainable forest management policies.
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BERGEN, KATHLEEN, ZHENZHEN ZHANG, GERALD TYRRELL, KAREN VON KLUGE, and JACOB RUMSCHLAG. "Mapping Forest and Surrounding Landscape Changes 1949-2015 at the University of Michigan's Historic Forestry Education Properties." Michigan Academician 45, no. 2 (January 1, 2018): 241–64. http://dx.doi.org/10.7245/0026-2005-45.2.241.
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ABSTRACT Three forested properties owned by the University of Michigan and near to Ann Arbor were the sites of some of the earliest forestry field education in the USA. No longer managed solely for this purpose after the mid-1960s, and at the same time nested within a rapidly developing area of Michigan, current planning for the properties focuses on melding their historic legacy with renewed ecologically and sustainably sound uses. We developed new maps and knowledge of forest and land change within and surrounding the properties between 1949 and 2015. We acquired aerial photography at 5-10 year intervals, created land-cover/land-use and change data, and identified key trajectories of change. Results within Saginaw Forest (established 1904) showed a consistent amount of forest area, but transitions in some observed overstory composition from coniferous to mixed forest between 1949 and 2015. Within the present-day extent of Stinchfield Woods and the Newcomb Tract (established 1925-1955), forest area increased from 68% to 98% and 51% to 93% respectively between 1949 and 2015, as forest plantations and other regrowth replaced former cleared lands. In 0.5 km-wide buffer areas surrounding the properties, agriculture decreased, and urban uses increased dramatically between 1949 and 2015 for all three sites. Forested land cover has also increased on the surrounding landscapes, again replacing agriculture and grassland. The properties today still display the legacies of their historic forestry education and research, and are living laboratories of natural succession in planted forests. The properties now also represent some of the most protected local lands while the landscapes surrounding them continue to change.
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Gillis, Mark D., and Donald G. Leckie. "Forest inventory update in Canada." Forestry Chronicle 72, no. 2 (April 1, 1996): 138–56. http://dx.doi.org/10.5558/tfc72138-2.
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Modern forest management presents ever increasing demands for accurate and up-to-date forest inventory information. The process of inventory update is critical. Inventory update in Canada is examined including update for harvest, burns, insect and disease, silviculture, roads and other changes. The magnitude and requirements of the update task are documented. The procedures used are described and summarized by province in table form. Usage, advantages and disadvantages of current methods (e.g. conventional 9 × 9 aerial photography, supplemental aerial photography, satellite imagery, and aerial reconnaissance) are examined, new methods discussed and trends highlighted. Also outlined are issues related to the incorporation of silviculture and insect and disease information into inventories and the structure and responsibilities for update. Key words: forest inventory, inventory update, harvest, burns, insect and disease, blowdown, silviculture, aerial photography, satellite imagery, Global Positioning System, aerial reconnaissance, video
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Spencer, Ray D. "Small format aerial photography: methods and achievements in Australian forestry." Australian Forestry 61, no. 4 (January 1998): 267–74. http://dx.doi.org/10.1080/00049158.1998.10674751.
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Morgan, Jessica L., and Sarah E. Gergel. "Automated analysis of aerial photographs and potential for historic forest mapping." Canadian Journal of Forest Research 43, no. 8 (August 2013): 699–710. http://dx.doi.org/10.1139/cjfr-2012-0492.
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Historic information regarding forest status is essential to management and conservation. Manual interpretation of aerial photography has long been the standard for forest inventory; however, manual interpretation can be subjective, inconsistent, and labor-intensive. This research compares automated techniques with manual interpretation results. First, we used an automated process (called segmentation) to delineate homogeneous stands of forests (or objects), analogous to the goal of manually delineating of polygons. Second, we used classification and regression tree (CART) analysis to classify polygons into the forest and terrain schemes used in British Columbia. Most characteristics of objects created via segmentation were similar to manually delineated polygons, as >70% of attributes were statistically similar across local, polygon, and landscape-level comparisons. Using manual interpretations for comparative reference, automated classifications produced overall accuracies ranging from 62% to 86% with per-class accuracies ranging from 0% to 96%. Automated methods yielded classifications meeting provincial overlap accuracy targets and helped identify classifications most suited to automation. Automated procedures have potential for aiding swift utilization of extensive historical photography archives with several caveats for future consideration. While automated techniques may never replicate all aspects of forest inventory classification, automated techniques may be valuable in assisting different phases of the process.
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Kamioka, Hisaaki, and Nobuyuki Abe. "Estimating Stand Structure Using Digitalized Aerial Photography." Journal of Forest Research 4, no. 2 (May 1999): 75–78. http://dx.doi.org/10.1007/bf02762229.
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Gering, Lawrence R., and Dennis M. May. "Point-Sampling of Tree Crowns Using Aerial Photographs for Forest Inventory." Southern Journal of Applied Forestry 21, no. 1 (February 1, 1997): 28–36. http://dx.doi.org/10.1093/sjaf/21.1.28.
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Abstract Aerial-photo angle-gauges were designed and constructed for developing a procedure for using variable-radius plot sampling for forest inventory of natural stands in Hardin and Wayne Counties, Tennessee. Data were obtained during the 1989 USDA Southern Forest Experiment Station survey of the forests of Tennessee, with supplemental aerial photographic measurements. Photo-based cruises of the two counties were made on 9 x 9 in. color aerial photographs (with a nominal scale of 1:4,800) taken during the fall color season. Photo cruises were compared to traditional ground-based cruises, and great differences were observed in number of trees, basal area, and merchantable volume. Evaluation of empirical diameter distributions revealed that the photo-based inventory failed to tally many of the smaller diameter trees. The development of the angle-gauge is theoretically sound, but results from its use are questionable due to differences with corresponding ground-based inventories. South. J. Appl. For. 21(1):28-36.
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Lister, Andrew J., Hans Andersen, Tracey Frescino, Demetrios Gatziolis, Sean Healey, Linda S. Heath, Greg C. Liknes, et al. "Use of Remote Sensing Data to Improve the Efficiency of National Forest Inventories: A Case Study from the United States National Forest Inventory." Forests 11, no. 12 (December 19, 2020): 1364. http://dx.doi.org/10.3390/f11121364.
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Globally, forests are a crucial natural resource, and their sound management is critical for human and ecosystem health and well-being. Efforts to manage forests depend upon reliable data on the status of and trends in forest resources. When these data come from well-designed natural resource monitoring (NRM) systems, decision makers can make science-informed decisions. National forest inventories (NFIs) are a cornerstone of NRM systems, but require capacity and skills to implement. Efficiencies can be gained by incorporating auxiliary information derived from remote sensing (RS) into ground-based forest inventories. However, it can be difficult for countries embarking on NFI development to choose among the various RS integration options, and to develop a harmonized vision of how NFI and RS data can work together to meet monitoring needs. The NFI of the United States, which has been conducted by the USDA Forest Service’s (USFS) Forest Inventory and Analysis (FIA) program for nearly a century, uses RS technology extensively. Here we review the history of the use of RS in FIA, beginning with general background on NFI, FIA, and sampling statistics, followed by a description of the evolution of RS technology usage, beginning with paper aerial photography and ending with present day applications and future directions. The goal of this review is to offer FIA’s experience with NFI-RS integration as a case study for other countries wishing to improve the efficiency of their NFI programs.
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Blinn, Charles R., Al Lyons, and Edward R. Buckner. "Color Aerial Photography for Assessing the Need for Fertilizers in Loblolly Pine Plantations." Southern Journal of Applied Forestry 12, no. 4 (November 1, 1988): 270–73. http://dx.doi.org/10.1093/sjaf/12.4.270.
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Abstract Color aerial photography was used to assess crown color classes in loblolly pine (Pinus taeda L.) plantations. Three distinct Munsell color classes were delineated on the resulting photographs. Foliar N levels and, to a lesser degree, foliar K levels were directly related to color. Significant relationships between color and site index and color and basal area were shown. Application of color aerial photography, combined with Munsell color coding, could expedite land classification and also make possible more efficient use of fertilizers. South J. Appl. For. 12(4):270-273.
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Hall, R. J., and A. H. Aldred. "Forest regeneration appraisal with large-scale aerial photographs." Forestry Chronicle 68, no. 1 (February 1, 1992): 142–50. http://dx.doi.org/10.5558/tfc68142-1.
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The operational feasibility of using large-scale aerial photographs to quantify coniferous forest stocking and regeneration density, was assessed over 6 cutovers with a 1,700 ha total area. The project involved two stages: one to pre-stratify cutover stocking levels using 1:10,000 general-coverage, colour photos; and the second to sample intensively, stocking and density using 1:500 large-scale photos. The accuracy, cost and practical problems in using large-scale sampling photos for regeneration assessment were determined. Accuracy assessment included detectability of young trees, species interpretation, and reliability of stocking and density measurements. Stocking estimates were on average, only five percent lower than field survey results but could be calibrated using regression techniques. Large differences between field survey and photo estimates of density in stems/ha suggested such counts should not be made from large-scale photos. Density count differences were attributable to seedlings occurring in dense patches or clumps where field counts were also difficult. If survey objectives and methods are carefully planned, large-scale photos can be a suitable tool for assessing and monitoring the stocking and survival rates of coniferous forest regeneration. Key words: Forest regeneration appraisal, silviculture, inventory, sampling, large-scale photography.
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Leckie, Donald G. "Advances in remote sensing technologies for forest surveys and management." Canadian Journal of Forest Research 20, no. 4 (April 1, 1990): 464–83. http://dx.doi.org/10.1139/x90-063.
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Canadian forest management has had a long history of developing and implementing remote sensing technology and is a major user of remote sensing. Despite difficulties in developing and implementing new digital remote sensing techniques, several key developments in Canadian forest management and in remote sensing and computer technology make the development and implementation of new remote sensing techniques at this time feasible and appropriate. Integration of different remote sensing technologies, remote sensing data with other information sources through geographic information systems, and remote sensing interpretations with forest management systems and practices are critical. Current capabilities and new advances in remote sensing technology for forest survey (excluding forest damage assessment) are discussed. Satellite imagery is a cost-effective tool for broad forest type mapping. New satellite systems improve this capability, but their major impact will be in inventories for new clear-cut and burned areas. Advances in linear array imager technology and lidar systems may lead to development of an end to end inventory mapping system. This system would provide an alternative to aerial photography and current mapping methods and could revolutionize the way forests are inventoried. Imaging spectrometry is a new technology with applications in damage assessment, but as yet has limited potential for assisting in other forest surveys. Spaceborne imaging radar systems are being developed for the 1990s. These systems can produce imagery under cloudy conditions. Their major impact on forestry will be to provide an alternative to visible-infrared satellite data for inventory update.
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Laquerre, Simon, Brian D. Harvey, and Alain Leduc. "Spatial analysis of response of trembling aspen patches to clearcutting in black spruce-dominated stands." Forestry Chronicle 87, no. 1 (February 1, 2011): 77–85. http://dx.doi.org/10.5558/tfc87077-1.
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While expansion of intolerant hardwoods, including trembling aspen, has been recognized as a problem by boreal forestmanagers in eastern Canada, the problem has mostly been associated with the boreal mixedwood and, with a few exceptions,the spatial aspects of the phenomenon have not been well documented in the scientific literature. The objective ofthis study is to evaluate how the density and size of aspen patches influence the change in density, size and persistence ofpatches following clearcutting of black spruce forests in the claybelt region of northwestern Quebec. To do this, we finelyinterpreted: 1) aerial photos taken between 1970 and 1979 of 12 mature black spruce-dominated stands containing varyingsizes and densities of aspen patches prior to being clearcut harvested and 2) aerial photos taken between 1992 and1995 of the 12 resulting clearcuts, 11 to 18 years after harvesting. Sketch maps of pre- and post-harvest aspen presencewere rasterized and changes in aspen patch size and cover were determined. As well, the probabilities of aspen colonizationwith increasing distance from pre-harvest patches were calculated for each site. Black spruce forests of the claybeltcontaining no aspen prior to harvesting are relatively resistant to aspen invasion. However, when forests do contain aspenpatches with cover values ≤25%, almost 60% of these patches increase to a higher density class. Aspen patches less than 2ha in area had about a 50% probability of disappearing following clearcutting whereas larger patches had about a 96%chance of persisting as a result of clearcutting. In the black spruce forest of the claybelt, thick organic layers appear to havea negative effect on aspen recruitment. Distances of regenerating aspen from pre-harvest patches suggest that recruitmentfrom seed is more important than previously thought. Key words: encroachment, trembling aspen, clearcutting, black spruce, claybelt, aerial photography
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Smith, James L., Shepard M. Zedaker, and Richard C. Heer. "Estimating Pine Density and Competition Condition in Young Pine Plantations Using 35mm Aerial Photography." Southern Journal of Applied Forestry 13, no. 3 (August 1, 1989): 107–12. http://dx.doi.org/10.1093/sjaf/13.3.107.
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Abstract A prediction system was developed that estimated pine density and hardwood competition levels in young plantations using simple measurements made on 35mm aerial photographs. The precision of the prediction system was found to be moderate to good. The use of these photo-based modelsin a decision-making situation was examined. Ground-based decisions regarding replanting, spraying for competition control, or no treatment were compared to similar decisions reached strictly from the aerial photographic measurements. Approximately 80% of all decisions agreed, and 90% of theno-treatment decisions agreed. While aerial photographs do not totally eliminate the need for field work, it is clear that photographic information can often produce reliable decisions with reduced field efforts. South. J. Appl. For. 13(3):107-112.
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Düggelin, Christoph, and Meinrad Abegg. "Modelle zur Biomasse- und Holzvolumenschätzung im Schweizer Gebüschwald | Modelling of biomass and wood volume in Swiss shrub forest." Schweizerische Zeitschrift fur Forstwesen 162, no. 2 (February 1, 2011): 32–40. http://dx.doi.org/10.3188/szf.2011.0032.
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The results of the third National Forest Inventory indicate that shrub forest accounts for 5% of the total forest area in Switzerland. It grows almost exclusively in the subalpine zone and is dominated by the woody species Alnus viridis and Pinus mugo prostrata. As a consequence of global warming and the increasing demand for sustainable energy, there is a national and international interest to quantify wood volume and biomass in shrub forests. Therefore representative coppice shoots were measured in detail to establish allometric volume and biomass functions for Alnus viridis, Pinus mugo prostrata and Salix sp. For each coppice shoot the wood volume, the wet weight, the dry weight and the carbon mass was determined as a function of the base diameter. In the next step all coppice shoots of 49 sample plot areas were measured. A regression analysis shows the relationship between the degree of cover and wood volume, and hence the biomass, in a shrub forest stand. Shrub forest stands which consist of Alnus viridis and which have a degree of cover of 100% contain on average 74 m3/ha of above-ground wood volume. More than twice of that volume, namely 166 m3/ha, is contained in corresponding Pinus mugo prostrata shrub forest stands. In Swiss shrub forests, the average aboveground wood volume amounts to 66 m3/ha, corresponding to around 2 million tons of biomass. Based on the presented volume functions it will be possible to estimate the aboveground wood volume and biomass of shrub forest stands dominated by Alnus viridis and Pinus mugo prostrata with good results. Input variable is the degree of cover of the present woody species, which can be determined efficiently on aerial photography by image interpretation.
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Fensham, R. J., and R. J. Fairfax. "Assessing woody vegetation cover change in north-west Australian savanna using aerial photography." International Journal of Wildland Fire 12, no. 4 (2003): 359. http://dx.doi.org/10.1071/wf03022.
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Models to calibrate tree and shrub cover assessed from aerial photography with field measurements were developed for a range of vegetation types in north-western Australia. The models verify previous studies indicating that woody cover can be successfully determined from aerial photography. The calibration models were applied to estimates of woody vegetation cover determined for 279 randomly located sample areas in the Ord–Victoria Rivers region using aerial photography from 1948 to 1950 and 1988 to 1997. Overstorey cover increased from a regional average of 11.5% to 13.5% and understorey cover increased from 1.3% to 2.0%. Downs, Limestone Hills and Alluvia land-types showed the most substantial increases in overstorey cover while overstorey cover in the Limestone plains land-type decreased. Relatively open structured vegetation is most susceptible to thickening. Rainfall records reveal an extreme multi-year rainfall deficit in the study area in the 1930s and relatively wet times in the 1970s and 1980s. Interpretation of a limited set of aerial photographs taken between 1964 and 1972 suggests that most of the increases in cover have occurred since this time. The study highlights the possibility that the average trend of vegetation thickening represents recovery during the relatively wet times after the 1970s. There was no relationship between structural change and a grazing intensity surrogate (distance of sample points to stock watering-points). However, the causes of structural change are undoubtedly multi-factored and the relative contributions of climate, fire and grazing vary for different landscapes and tree species.
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Fairfax, R. J., and R. J. Fensham. "Corrigendum to: Assessing woody vegetation cover change in north-west Australian savanna using aerial photography." International Journal of Wildland Fire 13, no. 1 (2004): 131. http://dx.doi.org/10.1071/wf03022_co.
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Models to calibrate tree and shrub cover assessed from aerial photography with field measurements were developed for a range of vegetation types in north-western Australia. The models verify previous studies indicating that woody cover can be successfully determined from aerial photography. The calibration models were applied to estimates of woody vegetation cover determined for 279 randomly located sample areas in the Ord–Victoria Rivers region using aerial photography from 1948 to 1950 and 1988 to 1997. Overstorey cover increased from a regional average of 11.5% to 13.5% and understorey cover increased from 1.3% to 2.0%. Downs, Limestone Hills and Alluvia land-types showed the most substantial increases in overstorey cover while overstorey cover in the Limestone plains land-type decreased. Relatively open structured vegetation is most susceptible to thickening. Rainfall records reveal an extreme multi-year rainfall deficit in the study area in the 1930s and relatively wet times in the 1970s and 1980s. Interpretation of a limited set of aerial photographs taken between 1964 and 1972 suggests that most of the increases in cover have occurred since this time. The study highlights the possibility that the average trend of vegetation thickening represents recovery during the relatively wet times after the 1970s. There was no relationship between structural change and a grazing intensity surrogate (distance of sample points to stock watering-points). However, the causes of structural change are undoubtedly multi-factored and the relative contributions of climate, fire and grazing vary for different landscapes and tree species.
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Tiwari, A. K., J. S. Mehta, O. P. Goel, and J. S. Singh. "Geo-forestry of Landslide-affected Areas in a Part of Central Himalaya." Environmental Conservation 13, no. 4 (1986): 299–309. http://dx.doi.org/10.1017/s0376892900035347.
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Black-and-white aerial photographs were used to map the lithology, land-use/forest types, and landslide zones (namely old, active, or potential) in a part of Central Himalaya. The landslide and land-use/forest type maps were simultaneously studied, and the frequency distribution of the landslide zones in different land-uses and forest types was estimated. The correlation between the maps indicated the following: In old landslide-affected sites, agriculture was the predominant land-use, followed by Pinus roxburghii forest (≤ 40% crown cover), scrub vegetation, and wasteland (including grassland). The presence of other forests (e.g. forests dominated by climax species such as Shorea robusta at low elevations and Quercus spp. at higher elevations) indicates a high potentiality of recovery of the ecosystems involved, provided biotic (especially anthropic) factors are not too intensive.The active and potential landslide zones were concentrated along geologically active planes, namely thrusts and faults, and/or in the vicinity of toe-erosion of hill-slopes. These two were dominated by P.roxburghii forest (≤ 40% crown cover). The broadleaf forests showed minimal signs of active and potential landslides, perhaps because of their multistratal character which is conducive to minimizing soil-loss compared with the mostly single-storeyed Chir Pine forest. It is, therefore, suggested that the sites should be maintained under a multistratal broadleaf canopy to conserve the soil. Where, however, the Chir Pine forest is already developed, appropriate silvicultural measures may be taken to increase its crown cover to more than 40%.
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Rimal, R. K., R. Maharjan, K. Khanal, S. Koirala, B. Karki, S. M. Nepal, and H. L. Shrestha. "Detection, assessment, and updating the maps of encroached forest areas: a case study from Bara district, Nepal." Banko Janakari 27, no. 1 (November 7, 2017): 65–71. http://dx.doi.org/10.3126/banko.v27i1.18554.
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Forest encroachment is an illegal expansion of cultivable land and settlements within the jurisdiction of forests. It has been the key threat to forest management for the last several years in Nepal. The Department of Forests (DoF) is the responsible authority for detection and assessment of forest encroachment throughout the nation and updating the forest maps accordingly. Detection and preparing the updated maps of encroached forest areas is necessary for sustainable management of forests. Traditionally, the extent of forest encroachment is assessed through estimation by the front-line forestry staff. The new approach combines the aerial photographs, the cadastral maps prepared by the Department of Survey and the Google Earth Imagery to spatially locate the encroachment. This method will work as a desktop tool for the forest manager such that appropriate strategic actions can be taken immediately. Additionally, it will bring a transparency on the forest governance to identify the location of areas of interest like point location for forest-based industries or proposed sites for development of infrastructures on the ground. The local communities may use the tool to identify the actual location of the forest boundaries, and exert social pressure to relinquish the encroached forests, if any. The result showed that 8,540 ha of the forest area in Bara district was found to be encroached during the period of last 50 years, between 1964 and 2014, of which 71% (6,038 ha) happened to be encroached in the first three decades, indicating the retarding trend of encroachment in the later years. The methodology used to assess the encroachment of forest in Bara district can be easily scaled up to other districts too, and will eventually help to assess the country’s overall forest encroachment. Since the boundary delineation will be done on the basis of the cadastral maps, the output will be used as a robust evidence to defend the forest-related cased in the court during the legal arbitrations.Banko Janakari, Vol. 27, No. 1, Page: 65-71
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Gering, Lawrence R., and Dennis M. May. "The Relationship of Diameter at Breast Height and Crown Diameter for Four Species Groups in Hardin County, Tennessee." Southern Journal of Applied Forestry 19, no. 4 (November 1, 1995): 177–81. http://dx.doi.org/10.1093/sjaf/19.4.177.
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Abstract A set of simple linear regression models for predicting diameter at breast height (dbh) from crown diameter and a set of similar models for predicting crown diameter from dbh were developed for four species groups in Hardin County, TN. Data were obtained from 557 trees measured during the 1989 USDA Southern Forest Experiment Station survey of the forests of Tennessee, with supplemental aerial photographic observations. Estimates of individual tree crown diameter were obtained from ground measurements and from measurements made on 9 X 9 in. color aerial photographs (with nominal scale of 1:4,800) taken during the fall color season. In practice, users of aerial photographs can estimate dbh by measuring crown diameter, converting it to feet using the photo scale, and applying the appropriate equation. Similarly, crown diameter can be estimated from a ground measurement of dbh. This procedure may be useful in reducing the time required for field measurements. It may also be used to calculate crown diameters for datasets that include dbh but no direct measurement of crown attributes. South. J. Appl. For. 19(4):177-181.
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Zagalikis, G., A. D. Cameron, and D. R. Miller. "The application of digital photogrammetry and image analysis techniques to derive tree and stand characteristics." Canadian Journal of Forest Research 35, no. 5 (May 1, 2005): 1224–37. http://dx.doi.org/10.1139/x05-030.
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Ground-based forest inventory surveys can provide highly accurate measurements of tree and stand characteristics, but these are expensive to carry out. Aerial photography has been used for several decades as a tool in forest management and inventory. However, conventional methods of interpretation are both time-consuming and costly, with results varying among interpreters. With continuing development of personal computer technology, aerial photographs have become more accessible for digital analysis. This paper presents the potential operational use of digitized aerial photographs for the estimation of tree and stand characteristics of two forest plantations of Sitka spruce (Picea sitchensis (Bong.) Carrière) in Scotland. The digitized aerial photographs were processed using softcopy photogrammetry, and image analysis techniques were used for individual tree crown delineation. For the first site the estimations of stand top height, basal area, volume, biomass, and density (23.7%) were similar to the ground-measured stand characteristics (±10%), whereas for the second site the estimations were less accurate mainly because of the nonoptimal illumination conditions during the acquisition of the aerial photographs.
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Barbezat, Vincent. "Analyse semi-automatisée de photos aériennes numérisées pour l'étude de la dynamique de peuplements arborescents | Semi-Automatised Analysis of Digitised Aerial Photographs for the Study of Arborescent Population Dynamics." Schweizerische Zeitschrift fur Forstwesen 151, no. 7 (July 1, 2000): 238–42. http://dx.doi.org/10.3188/szf.2000.0238.
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At the present time, landscape inventories, the third National Forest Inventory (NFI), permanent research plots in the forests,cantonal inventories, regional forest planning, the redefinition of useful farm land, a new inventory of standard tree orchards but also the protection of peat bog and alluvial areas are daily business. Therefore, the development of a software for automated aerial photograph analysis is of greatest interest to the Swiss Confederation and its cantons as well as to forest owners, research institutes and certain industries (private engineering enterprises, software producers). In answer to these expectations, the Antenne Romande WSL, together with the Institute of Production in Microengineering of the Swiss Federal Institute of Technology Lausanne(EPFL), proposes to develop a software for user-friendly, neutral and rapid image-processing, the working precision of which will suit forest and landscape managers. Moreover, the software will provide scientists with basic data for the modelling of various ecosystem processes.
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Mustonen, Jukka, Petteri Packalén, and Annika Kangas. "Automatic segmentation of forest stands using a canopy height model and aerial photography." Scandinavian Journal of Forest Research 23, no. 6 (December 2008): 534–45. http://dx.doi.org/10.1080/02827580802552446.
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Cumming, Steve, Mariana Trindade, David Greene, and S. Ellen Macdonald. "Canopy and emergent white spruce in “pure” broadleaf stands: frequency, predictive models, and ecological importance." Canadian Journal of Forest Research 39, no. 10 (October 2009): 1997–2004. http://dx.doi.org/10.1139/x09-094.
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In mixedwood boreal forests of western Canada, stands classified as “pure deciduous” by forest inventories sometimes contain a few large white spruce (Picea glauca (Moench) Voss) trees among or emerging from the canopy. These trees are important as regeneration seed sources and for habitat structure. Neither their abundance nor the characteristics of stands in which they occur have previously been quantified. Of 275 “pure aspen” stands in northeastern Alberta, 19.6% contained at least one such spruce detectable in an aerial photograph. These trees were found in stands across the range of sampled canopy heights, densities, age classes, and stand sizes and were often present in the interior of stands, not just on the perimeter. The frequency of 3 ha cells containing at least one spruce was related to (i) stand shape and size, (ii) amount of mature white spruce in adjacent forest, (iii) canopy height, (iv) stand age, and (v) stand density. We conclude that such trees are relatively abundant and widely distributed within the boreal mixedwood forests of Alberta. There is presently no provision to maintain this landscape element within managed forests. More information is needed to determine if or how they should be considered in forest management planning.
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Kimambo and Naughton-Treves. "The Role of Woodlots in Forest Regeneration outside Protected Areas: Lessons from Tanzania." Forests 10, no. 8 (July 25, 2019): 621. http://dx.doi.org/10.3390/f10080621.
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Promoting forest regeneration outside protected forests is an urgent challenge in densely settled, biodiverse areas like the East African Rift. Regenerating forests entails managing complex processes of ecological recovery as well as understanding the needs and motivations of local land users. Here, we evaluate pathways for attaining native tree regeneration across variable site conditions. We investigate two common strategies for attaining native tree regeneration—setting aside land for forest regeneration (‘Protect and Wait’) and native tree planting (‘Native Tree Planting’)—and a possible third, smallholder exotic tree-planting (‘Woodlots’). We measured native seedling regeneration patterns for each of the three strategies, all underway at a single site in Southern Tanzania. We also used historical aerial photograph analysis and interviews with smallholder farmers to understand past and present land use. Our results show that forest regeneration has been arrested for decades on land under ‘Protect and Wait’, and seedling survival appears to be limited under ‘Native Tree Planting’. In contrast, we found saplings of 28 native species growing spontaneously within pine, eucalyptus, and cypress woodlots planted <400 meters from native forest boundaries. Interviews showed that the citizens most likely to plant woodlots near the protected forest were those who owned additional land parcels elsewhere. Some saw woodlots as a means to avoid losing crops to wildlife at the forest edge. Our findings suggest: 1) Simply setting aside land for regeneration does not guarantee forest regrowth, even if it is adjacent to natural forest, 2) native seedlings will be more likely to survive if planted near shade trees, and 3) smallholders’ woodlots could hasten native tree regeneration at forest park edges if farmers have incentives to protect the native tree seedlings in their woodlots and they can find land elsewhere to plant food crops.
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St-Onge, Benoît, Julien Jumelet, Mario Cobello, and Cédric Véga. "Measuring individual tree height using a combination of stereophotogrammetry and lidar." Canadian Journal of Forest Research 34, no. 10 (October 1, 2004): 2122–30. http://dx.doi.org/10.1139/x04-093.
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Photogrammetric methods using parallaxes can be employed to measure tree heights on aerial photographs. Because it is often impossible to measure ground elevation near trees growing in dense forests, such height measurements remain prone to error. Our objective was to solve this problem by combining a stereomodel and a digital terrain model (DTM) produced by an airborne-scanning system that uses light detection and ranging (lidar). A stereopair of scanned aerial photographs was first registered to a lidar DTM. The elevation of the apex of 202 Thuja occidentalis (L.) individuals was measured by an observer on a digital photogrammetric workstation. The tree base elevations were read from the lidar DTM and subtracted from the corresponding apex elevations to calculate individual tree heights. These were then compared with the heights measured in the field. The average photo-lidar bias was 0.59 m, and the average deviation of 1.01 m decreased to 0.88 m when the bias was removed. It was demonstrated that the photographic clearness of the tree apices influences the height error, while the density of the lidar echoes under the forest canopy does not. Using this method, retrospective studies of changes in tree height become feasible by using archived aerial photographs and recent lidar DTMs.
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Rhemtulla, Jeanine M., Ronald J. Hall, Eric S. Higgs, and S. Ellen Macdonald. "Eighty years of change: vegetation in the montane ecoregion of Jasper National Park, Alberta, Canada." Canadian Journal of Forest Research 32, no. 11 (November 1, 2002): 2010–21. http://dx.doi.org/10.1139/x02-112.
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Repeat ground photographs (taken in 1915 and 1997) from a series of topographical survey stations and repeat aerial photographs (flown in 1949 and 1991) were analysed to assess changes in vegetation composition and distribution in the montane ecoregion of Jasper National Park, in the Rocky Mountains of Alberta, Canada. A quantitative approach for assessing relative vegetation change in repeat ground photographs was developed and tested. The results indicated a shift towards late-successional vegetation types and an increase in crown closure in coniferous stands. Grasslands, shrub, juvenile forest, and open forests decreased in extent, and closed-canopy forests became more prevalent. The majority of forest stands succeeded to dominance by coniferous species. Changes in vegetation patterns were likely largely attributable to shifts in the fire regime over the last century, although climatic conditions and human activity may also have been contributing factors. Implications of observed changes include decreased habitat diversity, increased possibility of insect outbreaks, and potential for future high-intensity fire events. Results of the study increase knowledge of historical reference conditions and may help to establish restoration goals for the montane ecoregion of the park.
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Biggs, P. H., and R. D. Spencer. "New approaches to extensive forest inventory in Western Australia using large-scale aerial photography." Australian Forestry 53, no. 3 (January 1990): 182–93. http://dx.doi.org/10.1080/00049158.1990.10676076.
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Pitt, Douglas G., Robert G. Wagner, Ronald J. Hall, Douglas J. King, Donald G. Leckie, and Ulf Runesson. "Use of remote sensing for forest vegetation management: A problem analysis." Forestry Chronicle 73, no. 4 (August 1, 1997): 459–77. http://dx.doi.org/10.5558/tfc73459-4.
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Forest managers require accurate and timely data that describe vegetation conditions on cutover areas to assess vegetation development and prescribe actions necessary to achieve forest regeneration objectives. Needs for such data are increasing with current emphasis on ecosystem management, escalating silvicultural treatment costs, evolving computer-based decision support tools, and demands for greater accountability. Deficiencies associated with field survey methods of data acquisition (e.g. high costs, subjectivity, and low spatial and temporal coverage) frequently limit decision-making effectiveness. The potential for remotely sensed data to supplement field-collected forest vegetation management data was evaluated in a problem analysis consisting of a comprehensive literature review and consultation with remote sensing and vegetation management experts at a national workshop. Among curently available sensors, aerial photographs appear to offer the most suitable combination of characteristics, including high spatial resolution, stereo coverage, a range of image scales, a variety of film, lens, and camera options, capability for geometric correction, versatility, and moderate cost. A flexible strategy that employs a sequence of 1:10,000-, 1:5,000-, and 1:500-scale aerial photographs is proposed to: 1) accurately map cutover areas, 2) facilitate location-specific prescriptions for silvicultural treatments, sampling, buffer zones, wildlife areas, etc., and 3) monitor and document conditions and activities at specific points during the regeneration period. Surveys that require very detailed information on smaller plants (<0.5-m tall) and/or individual or rare plant species are not likely to be supported by current remote sensing technologies. Recommended areas for research include : 1) digital frame cameras, or other cost-effective digital imagers, as replacements for conventional cameras, 2) computer-based classification and interpretation algorithms for digital image data, 3) relationships between image measures and physical measures, such as leaf-area index and biomass, 4) imaging standards, 5) airborne video, laser altimeters, and radar as complementary sensors, and 6) remote sensing applications in partial cutting systems. Key words: forest vegetation management, regeneration, remote sensing, aerial photography
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Zörner, Jan, John Dymond, James Shepherd, Susan Wiser, and Ben Jolly. "LiDAR-Based Regional Inventory of Tall Trees—Wellington, New Zealand." Forests 9, no. 11 (November 13, 2018): 702. http://dx.doi.org/10.3390/f9110702.
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Indigenous forests cover 23.9% of New Zealand’s land area and provide highly valued ecosystem services, including climate regulation, habitat for native biota, regulation of soil erosion and recreation. Despite their importance, information on the number of tall trees and the tree height distribution across different forest classes is scarce. We present the first region-wide spatial inventory of tall trees (>30 m) based on airborne LiDAR (Light Detection and Ranging) measurements in New Zealand—covering the Greater Wellington region. This region has 159,000 ha of indigenous forest, primarily on steep mountainous land. We implement a high-performance tree mapping algorithm that uses local maxima in a canopy height model (CHM) as initial tree locations and accurately identifies the tree top positions by combining a raster-based tree crown delineation approach with information from the digital surface and terrain models. Our algorithm includes a check and correction for over-estimated heights of trees on very steep terrain such as on cliff edges. The number of tall trees (>30 m) occurring in indigenous forest in the Wellington Region is estimated to be 286,041 (±1%) and the number of giant trees (>40 m tall) is estimated to be 7340 (±1%). Stereo-analysis of aerial photographs was used to determine the accuracy of the automated tree mapping. The giant trees are mainly in the beech-broadleaved-podocarp and broadleaved-podocarp forests, with density being 0.04 and 0.12 (trees per hectare) respectively. The inventory of tall trees in the Wellington Region established here improves the characterization of indigenous forests for management and provides a useful baseline for long-term monitoring of forest conditions. Our tree top detection scheme provides a simple and fast method to accurately map overstory trees in flat as well as mountainous areas and can be directly applied to improve existing and build new tree inventories in regions where LiDAR data is available.
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Maltamo, M., J. Malinen, P. Packalén, A. Suvanto, and J. Kangas. "Nonparametric estimation of stem volume using airborne laser scanning, aerial photography, and stand-register data." Canadian Journal of Forest Research 36, no. 2 (February 1, 2006): 426–36. http://dx.doi.org/10.1139/x05-246.
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In forest management planning and forestry decision-making there is a continuous need for higher quality information on forest resources. The aim of this study was to improve the quality of forest resource information acquired by airborne laser scanning by combining it with aerial images and current stand-register data. A k-MSN (most similar neighbor) application was constructed for the prediction of the plot and stand volumes of standing trees. The application constructed used various data sources, including laser scanner data, aerial digital photographs, class variables describing a stand, and updated old stand volumes. The ability of these data sources to predict stem volume was tested together and separately. In the airborne laser scanner data based k-MSN application, characteristics of canopy quantiles were used as independent variables. The results show that with respect to individual plot and stand volume estimation approaches, the laser-based technique is a superior one. The results were improved further when other information sources were used together with the laser scanner data. Using a combination of laser scanner data, aerial images, and class variables (on the grounds of the current forest database) improved the root mean square error (RMSE) of the estimated plot volume by 15% (from 16% to 13%) as compared to using laser scanner data on their own. When the results were averaged at the stand level, the accuracy improved considerably, but the use of other information sources together with airborne laser scanner data did not further improve the results as it did at the plot level. The RMSE of stand volume was about 6% in all data combinations where airborne laser scanning information was used. One conclusion is that making use of additional available data sources together with laser material improves the reliability of plot volume estimates. As these additional data typically mean no extra material costs (since they are available in any case), making combined use of these data and laser scanner data improves the cost efficiency of a forest inventory.
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Massada, Avi Bar, Yohay Carmel, Gilad Even Tzur, José M. Grünzweig, and Dan Yakir. "Assessment of temporal changes in aboveground forest tree biomass using aerial photographs and allometric equations." Canadian Journal of Forest Research 36, no. 10 (October 1, 2006): 2585–94. http://dx.doi.org/10.1139/x06-152.
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Studies of forest biomass dynamics typically use long-term forest inventory data, available in only a few places around the world. We present a method that uses photogrammetric measurements from aerial photographs as an alternative to time-series field measurements. We used photogrammetric methods to measure tree height and crown diameter, using four aerial photographs of Yatir Forest, a semi-arid forest in southern Israel, taken between 1978 and 2003. Height and crown-diameter measurements were transformed to biomass using an allometric equation generated from 28 harvested Aleppo pine (Pinus halepensis Mill.) trees. Mean tree biomass increased from 6.37 kg in 1978 to 97.01 kg in 2003. Mean plot biomass in 2003 was 2.48 kg/m2 and aboveground primary productivity over the study period ranged between 0.14 and 0.21 kg/m2 per year. There was systematic overestimation of tree height and systematic underestimation of crown diameter, which was corrected for at all time points between 1978 and 2003. The estimated biomass was significantly related to field-measured biomass, with an R2 value of 0.78. This method may serve as an alternative to field sampling for studies of forest biomass dynamics, assuming that there is sufficient spatial and temporal coverage of the investigated area using high-quality aerial photography, and that the tree tops are distinguishable in the photographs.
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Iqbal, I. A., J. Osborn, C. Stone, A. Lucieer, M. Dell, and C. McCoull. "Evaluating the robustness of point clouds from small format aerial photography over a Pinus radiata plantation." Australian Forestry 81, no. 3 (July 3, 2018): 162–76. http://dx.doi.org/10.1080/00049158.2018.1482799.
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Pearson, Audrey F. "Natural and logging disturbances in the temperate rain forests of the Central Coast, British Columbia." Canadian Journal of Forest Research 40, no. 10 (October 2010): 1970–84. http://dx.doi.org/10.1139/x10-137.
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Natural disturbances frame the spatial and temporal processes of ecosystems and are the foundation for ecosystem-based management. In the coastal temperate rain forests of British Columbia, landscape patterns of natural disturbances and their contrasts with logging are not well documented. Stand-replacing disturbances over the past 140 years were investigated for the Central Coast (1.5 million ha) at regional and local scales using a combination of aerial photograph interpretation and forest management GIS databases. At the regional scale, stand-replacing natural disturbances affected 3.1% of the forested area. The extent of natural disturbances was not strongly affected by the scale of analysis. In contrast, spatial pattern and scale were essential for discerning the full impact of logging. At the regional scale, logging affected 5.4% of the forested area. Within watersheds, however, logging occurred primarily in valley bottoms (81% ± 4%) with 59% ± 10% of valley bottom areas logged, 10 times the area of natural disturbances. Watershed size strongly affected riparian zones, with active floodplains comprising 53% ± 5% of valley bottom area in large (>20 000 ha) watersheds. In physiographically diverse landscapes, geomorphic features (such as watersheds, valley bottoms, and fluvial landforms) are crucial for determining disturbance processes and effects of logging at ecologically relevant scales.
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Zimmerman, Gregory, F. Wayne Bell, John Woodcock, Aaron Palmer, and Jorma Paloniemi. "Response of Breeding Songbirds to Vegetation Management in Conifer Plantations Established in Boreal Mixedwoods." Forestry Chronicle 87, no. 02 (April 2011): 217–24. http://dx.doi.org/10.5558/tfc2011-009.
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We examined the response of breeding songbird communities 11 years after four vegetation management treatments were applied. Post-treatment vegetation was characterized by manually interpreting large-scale aerial photography and estimating proportional cover of eight vegetation classes. Songbird abundance was assessed by territory mapping. Using GIS layers, number of registrations and average vegetation proportions were compared among treatments. Ordination of the relative abundance of the 11 most frequent bird species suggested differences between Vision® and untreated areas. These results show that effects of vegetation management on songbirds may be more persistent than previous studies suggest and that monitoring should continue.
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Alemdag, I. S. "Estimating ovendry mass of trembling aspen and white birch using measurements from aerial photographs." Canadian Journal of Forest Research 16, no. 1 (February 1, 1986): 163–65. http://dx.doi.org/10.1139/x86-030.
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A pilot study tested the estimation of stem, crown, and whole-tree biomass of single trees from measurements of total tree height and crown area taken from large-scale aerial photographs. The results indicated the feasibility of this method, provided that time of photography is optimal. More extensive testing is required to confirm these encouraging preliminary results.
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Yang, Huijuan, Yongning Li, Zhidong Zhang, Zhongqi Xu, and Xuanrui Huang. "GIS-Based Multi-Criteria Assessment and Seasonal Impact on Plantation Forest Landscape Visual Sensitivity." Forests 10, no. 4 (March 30, 2019): 297. http://dx.doi.org/10.3390/f10040297.
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Visual sensitivity assessments identify the location of the high-sensitivity areas in terms of visual change. Studying the visual sensitivity of plantation forest landscapes and their seasonal changes can help resolve increasingly frequent conflicts between tourism and forest management activities, in the context of the multi-functional management of plantation forests. In this study, we used the geographic information system (GIS) and multi-criteria evaluation (MCE) methods combined with the analytic hierarchy process (AHP) to perform a visual sensitivity evaluation. Nine map-based criteria were selected, and the visual sensitivity of summer and autumn values were calculated, using data from sources including inventory data for forest management planning and design, digital elevation model (DEM), and aerial photographs. Vegetation uniformity (VU) and color diversity (CD) indices were constructed using three patch-level-based landscape indices, including area (AREA), fractal dimension index (FRAC), and proximity (PROX), to visualize the summer and autumn vegetation characteristics of a plantation forest landscape. We conducted a case study on the Saihanba Mechanical Forest Plantation, China’s largest forest plantation. The results were evaluated by experts, confirming the method to be reliable. This study provides an accurate, objective, and visualized evaluation method for the visual sensitivity of plantations for forest management units at the landscape scale. In analyzing the visual sensitivity of plantation forest landscapes, appropriate criteria, e.g., uniformity or diversity should be selected based on forest vegetation characteristics. When identifying high-sensitivity regions, it is necessary to simultaneously analyze areas with high visual sensitivity in different seasons and then superimpose the results.
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McTague, John Paul. "Estimation of Stand Density with Probability Proportional to Size from Aerial Photography." Western Journal of Applied Forestry 3, no. 3 (July 1, 1988): 89–92. http://dx.doi.org/10.1093/wjaf/3.3.89.
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Biggs, P. H. "Aerial tree volume functions for eucalypts in Western Australia." Canadian Journal of Forest Research 21, no. 12 (December 1, 1991): 1823–28. http://dx.doi.org/10.1139/x91-251.
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Large-scale, fixed-base aerial photography is being used together with ground sampling in a major inventory of eucalypt forest in Western Australia. This paper describes the aerial tree volume functions derived for that inventory, covering species in the jarrah (Eucalyptusmarginata) forest. The equations, derived from ground measurements, predict gross bole volume from estimates of total height and vary with the site quality of the forest. They are used to predict volume from photomeasurements of total height that have been corrected for measurement error. The functions appear suitable for this forest type, although the volumes of veteran trees with severely damaged crowns are underestimated.
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Smith, Alistair M. S., and Andrew T. Hudak. "Estimating combustion of large downed woody debris from residual white ash." International Journal of Wildland Fire 14, no. 3 (2005): 245. http://dx.doi.org/10.1071/wf05011.
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The production of residual white ash patches within wildfires represents near-complete combustion of the available fuel and releases a considerable quantity of gases to the atmosphere. These patches are generally produced from combustion of large downed woody debris (LDWD) such as fallen trees and snags. However, LDWD are generally ignored in calculations of fuel combusted within environments where surface fires dominate (e.g. southern African savannas). To assess the potential of fractional white ash cover as a remotely sensed measure of LDWD combustion, both the proportion of the surface covered by white ash and the combustion completeness required to produce white ash must be quantified. An aerial photograph of woodland savanna fires in north-western Zimbabwe was analysed to estimate the proportion of white ash cover within a typical satellite sensor pixel. The proportion loss on ignition (LOI) of wood samples from the study area was measured and combined with previous estimates of mean tree biomass. The proportion of white ash within the aerial photographs was 0.2% (± 0.06), which corresponded to an additional 67 320 kg ha−1 of biomass combusted above that typically recorded as combusted from a surface fire in this environment (~7000 kg ha−1). This analysis should be repeated in other savannas and forests, where pre-fire fuel loads and post-fire fractional white ash cover may be higher.
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Dell, M., C. Stone, J. Osborn, M. Glen, C. McCoull, A. Rimbawanto, B. Tjahyono, and C. Mohammed. "Detection of necrotic foliage in a young Eucalyptus pellita plantation using unmanned aerial vehicle RGB photography – a demonstration of concept." Australian Forestry 82, no. 2 (April 3, 2019): 79–88. http://dx.doi.org/10.1080/00049158.2019.1621588.
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Arkin, Jeremy, Nicholas C. Coops, Txomin Hermosilla, Lori D. Daniels, and Andrew Plowright. "Integrated fire severity–land cover mapping using very-high-spatial-resolution aerial imagery and point clouds." International Journal of Wildland Fire 28, no. 11 (2019): 840. http://dx.doi.org/10.1071/wf19008.
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Fire severity mapping is conventionally accomplished through the interpretation of aerial photography or the analysis of moderate- to coarse-spatial-resolution pre- and post-fire satellite imagery. Although these methods are well established, there is a demand from both forest managers and fire scientists for higher-spatial-resolution fire severity maps. This study examines the utility of high-spatial-resolution post-fire imagery and digital aerial photogrammetric point clouds acquired from an unmanned aerial vehicle (UAV) to produce integrated fire severity–land cover maps. To accomplish this, a suite of spectral, structural and textural variables was extracted from the UAV-acquired data. Correlation-based feature selection was used to select subsets of variables to be included in random forest classifiers. These classifiers were then used to produce disturbance-based land cover maps at 5- and 1-m spatial resolutions. By analysing maps produced using different variables, the highest-performing spectral, structural and textural variables were identified. The maps were produced with high overall accuracies (5m, 89.5±1.4%; 1m, 85.4±1.5%), with the 1-m classification produced at slightly lower accuracies. This reduction was attributed to the inclusion of four additional classes, which increased the thematic detail enough to outweigh the differences in accuracy.
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Lowell, Kim. "Evaluation of a moving-window algorithm for detecting individual tree stems from scanned aerial photographs in Victoria's eucalypt forests." Australian Forestry 61, no. 3 (January 1998): 226–34. http://dx.doi.org/10.1080/00049158.1998.10674745.
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Jaworek-Jakubska, Justyna, Maciej Filipiak, and Anna Napierała-Filipiak. "Understanding of Forest Cover Dynamics in Traditional Landscapes: Mapping Trajectories of Changes in Mountain Territories (1824–2016), on the Example of Jeleniogórska Basin, Poland." Forests 11, no. 8 (August 8, 2020): 867. http://dx.doi.org/10.3390/f11080867.
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Though on a global scale, for ecological reasons, increased forest cover is universally regarded as positive, on a local scale, the reforestation of arable land may pose threats to cultural landscapes by removing characteristic landscape features. Particularly vulnerable are marginal rural areas, e.g., mountain regions, where most traditional land use systems have survived and which are subject to the most spectacular land use change. The purpose of this article is to draw attention to the issue of the management of forest cover in historical cultural landscapes in mountain territories in Poland within the context of widespread land use change in Eastern Europe. Land cover data were obtained from historical and contemporary aerial photographs, as well as topographic maps from five time points between 1824 and 2016. The study was conducted by means of spatio-temporal forest cover trajectory analysis (LCTA), transition and time–depth analysis, and land cover change calculations that were made by means of ArcGIS. Our research indicates that the rate of change has risen considerably in the last two decades, and the current share of forest cover is much bigger than that reflected in the official data. Eight principal forest cover trajectory types were identified. The biggest area is occupied by woodland of long-term stability. Another large group is constituted by forests created on the basis of arable land and grassland as a result of simple conversion at one point in time, mainly in the years 1824–1886 and 1939–1994. At the same time, a sizeable group is made up by areas that have been subject to unplanned cyclical or dynamic changes during various periods. A very important group is comprised new forests that were created in 1994–2016, predominantly as a result of natural succession, that are often not included in official land classifications. The constant expansion of woodlands has led to a shrinking of historical former coppice woodlands. This indicates that the current landscape management mechanisms in Poland are inadequate for protecting the cultural landscape. The barriers include the lack of intersectoral cooperation and the overlooking of the historical context of landscapes. The present situation calls not only for verification of the existing forest policy but also for increasing the role and engagement of local communities, as well as making comprehensive local development plans, all of which may be helped by the findings of our study and of similar research.
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Rodrigues-Eklund, Gabriela, Matthew C. Hansen, Alexandra Tyukavina, Stephen V. Stehman, Klaus Hubacek, and Giovanni Baiocchi. "Sample-Based Estimation of Tree Cover Change in Haiti Using Aerial Photography: Substantial Increase in Tree Cover between 2002 and 2010." Forests 12, no. 9 (September 14, 2021): 1243. http://dx.doi.org/10.3390/f12091243.
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Recent studies have used high resolution imagery to estimate tree cover and changes in natural forest cover in Haiti. However, there is still no rigorous quantification of tree cover change accounting for planted or managed trees, which are very important in Haiti’s farming systems. We estimated net tree cover change, gross loss, and gross gain in Haiti between 2002 and 2010 from a stratified random sample of 400 pixels with a systematic sub-sample of 25 points. Using 30 cm and 1 m resolution images, we classified land cover at each point, with any point touching a woody plant higher than 5 m classified as tree crown. We found a net increase in tree crown cover equivalent to 5.0 ± 2.3% (95% confidence interval) of Haiti’s land area. Gross gains and losses amounted to 9.0 ± 2.1% and 4.0 ± 1.3% of the territory, respectively. These results challenge, for the first time with empirical evidence, the predominant narrative that portrays Haiti as experiencing ongoing forest or tree cover loss. The net gain in tree cover quantified here represents a 35% increase from 2002 to 2010. Further research is needed to determine the drivers of this substantial net gain in tree cover at the national scale.
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Anttila, Perttu. "Nonparametric estimation of stand volume using spectral and spatial features of aerial photographs and old inventory data." Canadian Journal of Forest Research 32, no. 10 (October 1, 2002): 1849–57. http://dx.doi.org/10.1139/x02-108.
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The forest management planning inventories for private forests in Finland are currently carried out in stand-level field inventories. To decrease the amount of fieldwork, aerial photographs and old inventory data could be utilized. The main objectives were to test the accuracy of a method based on these data sources and the effect of stand shape on the accuracy. Median pixel values, semivariances, and old inventory data were extracted for each of the 577 stands in the study. These data were applied as indicator attributes in k-nearest-neighbor estimation of stand volume. Stand-level estimates were computed as weighted means of k most similar neighbors. When all the stands were used, a root mean square error of 29.9% was obtained. Old inventory data proved to be valuable auxiliary information. It was also found that exclusion of stands with tortuous boundaries and small area decreased the error. The accuracy of mean volume estimation just met the requirements for stand-level inventory, but the method still needs further research before the final conclusion of the applicability for management planning.
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Moe, Kyaw, Toshiaki Owari, Naoyuki Furuya, and Takuya Hiroshima. "Comparing Individual Tree Height Information Derived from Field Surveys, LiDAR and UAV-DAP for High-Value Timber Species in Northern Japan." Forests 11, no. 2 (February 15, 2020): 223. http://dx.doi.org/10.3390/f11020223.
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High-value timber species such as monarch birch (Betula maximowicziana Regel), castor aralia (Kalopanax septemlobus (Thunb.) Koidz), and Japanese oak (Quercus crispula Blume) play important ecological and economic roles in forest management in the cool temperate mixed forests in northern Japan. The accurate measurement of their tree height is necessary for both practical management and scientific reasons such as estimation of biomass and site index. In this study, we investigated the similarity of individual tree heights derived from conventional field survey, digital aerial photographs derived from unmanned aerial vehicle (UAV-DAP) data and light detection and ranging (LiDAR) data. We aimed to assess the applicability of UAV-DAP in obtaining individual tree height information for large-sized high-value broadleaf species. The spatial position, tree height, and diameter at breast height (DBH) were measured in the field for 178 trees of high-value broadleaf species. In addition, we manually derived individual tree height information from UAV-DAP and LiDAR data with the aid of spatial position data and high resolution orthophotographs. Tree heights from three different sources were cross-compared statistically through paired sample t-test, correlation coefficient, and height-diameter model. We found that UAV-DAP derived tree heights were highly correlated with LiDAR tree height and field measured tree height. The performance of individual tree height measurement using traditional field survey is likely to be influenced by individual species. Overall mean height difference between LiDAR and UAV-DAP derived tree height indicates that UAV-DAP could underestimate individual tree height for target high-value timber species. The height-diameter models revealed that tree height derived from LiDAR and UAV-DAP could be better explained by DBH with lower prediction errors than field measured tree height. We confirmed the applicability of UAV-DAP data for obtaining the individual tree height of large-size high-value broadleaf species with comparable accuracy to LiDAR and field survey. The result of this study will be useful for the species-specific forest management of economically high-value timber species.
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Berg, Edward E., Kacy McDonnell Hillman, Roman Dial, and Allana DeRuwe. "Recent woody invasion of wetlands on the Kenai Peninsula Lowlands, south-central Alaska: a major regime shift after 18 000 years of wet Sphagnum–sedge peat recruitment." Canadian Journal of Forest Research 39, no. 11 (November 2009): 2033–46. http://dx.doi.org/10.1139/x09-121.
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We document accelerating invasion of woody vegetation into wetlands on the western Kenai Peninsula lowlands. Historical aerial photography for 11 wetland sites showed that herbaceous area shrank 6.2%/decade from 1951 to 1968, and 11.1%/decade from 1968 to 1996. Corresponding rates for converting herbaceous area to shrubland were 11.5% and 13.7%/decade, respectively, and, for converting nonforest to forest, were 7.8% and 8.3%/decade, respectively. Black spruce ( Picea mariana (Mill.) BSP) forests on three wetland perimeters established since the Little Ice Age concluded in the 1850s. Dwarf birch shrubs at three wetland sites showed median apparent tree-ring age of 13 years, indicating recent shrub colonization at these sites. Peat cores at 24 wetland sites (basal peat ages 1840 – 18 740 calibrated years before present) indicated that these peatlands originated as wet Sphagnum –sedge fens with very little woody vegetation. Local meteorological records show a 55% decline in available water since 1968, of which one-third is due to higher summer temperatures and increased evapotranspiration and two-thirds is due to lower annual precipitation. These results suggest that wet Sphagnum–sedge fens initiating since the end of the Wisconsin glaciation began to dry in the 1850s and that this drying has greatly accelerated since the 1970s.
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Parker, William H., Annette van Niejenhuis, and Laird Van Damme. "Base-line selection of black spruce by large-scale aerial photography." Canadian Journal of Forest Research 18, no. 3 (March 1, 1988): 380–83. http://dx.doi.org/10.1139/x88-056.
Full textAbstract:
Following selection of black spruce (Piceamariana (Mill.) B.S.P.) for growing space efficiency using a base line of basal area increment vs. crown length × crown radius, the corresponding crown data were determined by large-scale (1:1250) aerial photography for 174 ground-measured trees to determine whether aerial photography would provide a more accurate and cost-effective alternative for plus-tree selection. Values obtained for ground- and photo-measured tree heights and crown lengths corresponded closely, but values of crown radii measured from the ground by a right-angle prism did not correspond in the same manner to values derived from crown horizontal projection areas on the photos. Nonetheless, the different base lines of basal area increments vs. various ground- and photo-measured crown parameters generally identified the same trees as having the greatest growing space efficiency. The inclusion of crown length together with crown radius did not improve the goodness of fit for regressions of basal area increments vs. crown parameters. Apparently, the two horizontal dimensions are adequate to describe growing space for black spruce, perhaps because its crown form is relatively constant. Our results indicate that large-scale aerial photography is well suited to plus-tree selections of black spruce if ground mesurements are not also required to establish base lines; the extra cost of the photos is offset by the greater speed in measuring tree heights or crown horizontal projection areas. Thus, while the technique is sufficiently accurate, it is not cost effective for establishing growing space efficiency base lines where the basal area increment is determined directly from increment cores.
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Scharvogel, Daniel, Melanie Brandmeier, and Manuel Weis. "A Deep Learning Approach for Calamity Assessment Using Sentinel-2 Data." Forests 11, no. 12 (November 24, 2020): 1239. http://dx.doi.org/10.3390/f11121239.
Full textAbstract:
The number of severe storm events has increased in recent decades due to climate change. These storms are one of the main causes for timber loss in European forests and damaged areas are prone to further degradation by, for example, bark beetle infestations. Usually, manual mapping of damaged areas based on aerial photographs is conducted by forest departments. This is very time-consuming and therefore automatic detection of windthrows based on active and passive remote sensing data is an ongoing research topic. In this study we evaluated state-of-the-art Convolutional Neural Networks (CNNs) in combination with Geographic Information Systems (GIS) for calamity assessment. The study area is in in the northern part of Hesse (Germany) and was covered by twelve Sentinel-2 scenes from 2018. Labels of damaged areas from the Friedericke storm (18 January 2018) were provided by HessenForst. We conducted several experiments based on a custom U-Net setup to derive the optimal architecture and input data as well as to assess the transferability of the model. Results highlight the possibility to detect damaged forest areas using Sentinel-2 data. Using a binary classification, accuracies of more than 92% were achieved with an Intersection over Union (IoU) score of 46.6%. The proposed workflow was integrated into ArcGIS and is suitable for fast detection of damaged areas directly after a storm and for disaster management but is limited by the deca-meter spatial resolution of the Sentinel-2 data.