Language：English   Publishing type：Research paper (scientific journal)   Publisher：FORMATH Research Group  

DOI： 10.15684/formath.09.008

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Forest Planning  

Airborne laser profiling of mainland Ehime Prefecture, Japan was conducted to develop an entirely new method of land-cover classification, partly in preparation for the post-Kyoto national carbon budget accounting, and partly for correction of the existing government land-use statistics, which should constitute the very basis of the impending national carbon budget accounting of the Kyoto Protocol. The altimetry data was obtained by using NASA's Portable Airborne Laser System (PALS) along 23 parallel flight lines 4km apart from each other covering the whole mainland portion of the prefecture. Based on the resulting surface profile representing topography and structures on the ground with some reference to laser return intensity and nadir video images, land cover along the flight line was classified into "forest", "farmland", "residential and urban", and "others" using PALSA (PALS Analyzer), a software developed for this particular purpose. This line evaluation was then developed into area statistics by simply multiplying by the distance between the flight lines, i.e. 4km. The resultant land-cover estimates not only differed from the existing government statistics as much as the latter does within itself, but also helped to identify the causes and sources of discrepancy quantitatively. Thus it was concluded that coordinated use of this new method with the existing system of land-use statistics would improve the overall credibility of the land-use/land-cover statistics of the prefecture and the nation.

DOI： 10.20659/jfp.13.special_issue_245

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Forest Planning  

With an objective of evaluating forest habitability for wildlife in terms of forest structure, wildlife abundance was observed using automated infrared sensor cameras while forest structure of the habitat was quantified with airborne laser profiling in three study areas of 400ha each set up around Mt. Ishizuchi-san, Mt. Myoujin-ga-mori, and Mt. Takanawa-san in Ehime Prefecture, Japan. Two parameters derived from airborne laser profiling, i.e. mean and standard deviation of standing timber stock in each study area, were used as structural indexes of forests, while the richness of fauna was quantified as the number of inhabitant species and their frequency of being captured by the automated camera. Of the four possible combinations of the forest and faunal parameters, only the one between the photographic capture frequency and standard deviation of standing timber stock revealed strong negative correlation. Thus it was reasoned that the variability in timber stock has resulted from altitude variability within a given study area which tends to be more pronounced in higher and more remote areas, leading to a conclusion that what is really correlated with wildlife abundance is the proximity to the human domain.

DOI： 10.20659/jfp.13.special_issue_215

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Forest Planning  

The objective of the present study is to develop a transparent and verifiable model of volume estimation for conifer plantations using remote sensing. The model is to be independent from observation, that is, ground truths are not necessary for parameter fitting and model construction. To achieve it, the estimation process is divided into two steps: direct measurements of physical parameters of stand, and a stand volume estimation by an external model. As an external model, we adopt the stand density chart, which is a robust and general model of stand volume growth and estimation based on a semi-empirical growth model of even-aged stands. It can estimate a stand volume from a dominant height and a density, which can be directly measured by remote sensing. In the present study, firstly, the iso-height curves, a sub-model of the stand density chart, are created from the external inventory data. Then, the dominant heights and densities are directly observed by means of the airborne remote sensing. Finally stand volumes are estimated by the observed dominant heights and densities using the iso-height curves. We found that the new iso-height curves predicted the stand volume very well. The dominant height estimation was reasonably accurate, too. However, there was a room for improvement for the stand density estimation. This method will contribute the implication of the remote sensing technology to forest management by sharing the concept and values with foresters.

DOI： 10.20659/jfp.13.special_issue_295

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Forest Planning  

Most of Japanese young plantation forests have reached an age when thinning is needed, but they have not yet been cut, and stand density is often too high. An economical method is needed for selecting stands that should be cut. We are developing a method of stand density estimation using aerial photography. In previous work, we devised a method for high resolution color aerial-photographs. It divides images into a series of color bands, and estimates stand densities by the brightness in a combination of different band images. Ground truthing is needed to improve precision. In our earlier work, we used a set of 22 plots for ground truthing. Here, we present ground truthing of mono-color aerial photographs obtained for a growing stock investigation project in Ehime prefecture, Japan. The project is to estimate the CO_2 sink potential for all forests in the prefecture. Vegetation profiles are measured by airborne laser altimetry assisted by a consecutive series of ground truth surveys. Performance of mono-color aerial photography method was rather poor, indicating that manual contrast adjustment should be improved.

DOI： 10.20659/jfp.13.special_issue_141

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Forest Planning  

The timber stock of mainland Ehime prefecture was estimated using airborne laser profiling data. Our provisional analysis revealed that: 1) at 5,435km^2, the laser estimate of land area obtained as a simple product of flight path length and its 4km width was fairly consistent with the figure of 5,455km^2 by the Geographical Survey Institute, considered the most reliable of the government statistics; 2) on the other hand, at 176 million m^3 for the entire prefecture our estimate of standing timber stock turned out to be twice as much as the government figure of 87 million m^3; 3) judging from the precision in land-area estimation and results from other research, our estimate is considered more likely to represent the actual timber stock than the government figure; 4) thus airborne laser altimetry would provide more accurate national forest carbon budget for the Kyoto Protocol than does the existing national forest inventory; 5) at the present density of laser profiling transects, 4km apart from each other, however, no reasonable accuracy is expected at the municipality level.

DOI： 10.20659/jfp.13.special_issue_259

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE INC  

Forest dynamics are characterized by both continuous (i.e., growth) and discontinuous (i.e., disturbance) changes. Change detection techniques that use optical remotely sensed data to capture disturbance related changes are established and commonly applied; however, approaches for the capture of continuous forest changes are less mature. Optical remotely sensed imagery is well suited for capturing horizontally distributed conditions, structures, and changes, while Light Detection And Ranging (LIDAR) data are more appropriate for capturing vertically distributed elements of forest structure and change. The integration of optical remotely sensed imagery and LIDAR data provides improved opportunities to fully characterize forest canopy attributes and dynamics. The study described in this paper captures forest conditions along a corridor approximately 600 km long through the boreal forest of Canada. Two coincident LIDAR transects, representing 1997 and 2002 forest conditions respectively, are compared using image segments generated from Landsat ETM+ imagery. The image segments are used to provide a spatial framework within which the attributes and temporal dynamics of the forest canopy are estimated and compared. Segmented and classified Landsat imagery provides a context for the comparison of sufficiently spatially related LIDAR profiles and for the provision of categories to aid in the application of empirical models requiring knowledge of land cover. Global and local approaches were employed for characterizing changes in forest attributes over time. The global approach, emphasized the overall trend in forest change along the length of the entire transect, and indicated that key canopy attributes were stable, and transect characteristics, including forest canopy height, did not change significantly over the five-year period of this study (two sample t-test, p=0.08). The local approach analyzed segment-based changes in canopy attributes, providing spatially explicit indications of forest growth and depletion. The local approach identified that 84% of the Landsat segments intercepted by both LIDAR transects either have no change, or have a small average increase in canopy height (0.7 m), while the other 16% of segments have an average decrease in canopy height of 1.6 m. As expected, the difference in the magnitude of the changes was markedly greater for depletions than it was for growth, but was less spatially extensive. Growth tends to occur incrementally over broad areas; whereas, depletions are dramatic and spatially constrained. The approach presented holds potential for investigating the impacts of climate change across a latitudinal gradient of boreal forest. Crown Copyright (c) 2007 Published by Elsevier Inc. All rights reserved.

DOI： 10.1016/j.rse.2007.02.002

Web of Science

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Language：Japanese   Publisher：THE JAPANESE FORESTRY SOCIETY  

DOI： 10.11519/jfsc.118.0.2.0

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japanese Forestry Society  

Being the most extensively forested region of the world, the carbon budget of the Siberian boreal forest is one of the important subjects of global concern. This study was conducted to quantify leaf area index (LAI), one of the significant factors controlling terrestrial carbon budget, over an extensive range in Siberia as well as to propose an new method of LAI estimation using airborne laser altimetry. Along a 200-km transect set up along the Bakhta River, a tributary of the Yenisey in central Siberia, airborne laser altimetry was conducted to obtain a vegetation profile, from which the distribution of LAI all along the transect was estimated on the basis of allometric relationship among LAI, standing timber stock and vegetation profile area, using ground-truth measurements of LAI and timber stock at ten sample plots laid out directly beneath the flight track. It turned out that the distribution of LAI is controlled not only by temperature which in turn is dictated by the altitude down from the Central Siberian Plateau to the alluvial flat of the Yenisey, but also significantly by the thickness of active layer on permafrost, which varies considerably both regionally and locally depending upon the topography. With the capability of measuring vegetation characteristics and topographic features simultaneously, airborne laser profiling should turn out to be a powerful tool for monitoring in an integrated manner the Siberian boreal forest and its environment threatened by the impending global warming.

DOI： 10.4005/jjfs.88.21

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Other Link： https://jlc.jst.go.jp/DN/JALC/00274182785?from=CiNii

Publishing type：Research paper (scientific journal)  

DOI： 10.4005/jjfs.88.103

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Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

Recently, due to the increasing interest of climatic change, Leaf Area Index (LAI) has been estimated in the large scale using vegetation indices derived from satellite data. However, the relationship between LAI and vegetation indices used so far is nonlinear, and their relationship is usually expressed as the exponential function. This procedure results in the difficulty of estimating LAI where LAI is larger than 2.0. Considering this problem, this study proposes the new vegetation index named NHVI (Normalized Hotspot-signature Vegetation Index), which is derived from the index named HDS (Hotspot-Darkspot Signature) and NDVI. HDS is derived from the large reflectance of vegetation in the back scattering region (Hotspot) and small reflectance in the forward scattering region (Darkspot). NHVI is proposed as the multiple of NDVI (Normalized Difference Vegetation Index) and HDS. The relationship between the new index NHVI and LAI is linear in boreal forest. This result inplies that NHVI is superior to NDVI when estimating LAI larger than 2.0. in boreal forest.

DOI： 10.11520/jshwr.19.0.73.0

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Language：Japanese  

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Publisher：THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

The geometric structure of vegetation causes uneven scattering of sunlight,which is reproduced by BRDF.The purpose of this study is to estimate the effect of BRDF on vegetation indices.We investigated the vegetation in succession stages after forest fire in the northwestern part of Canada. In each site, the difference of NDVI of the value of 0.1-0.2 was caused by BRDF. The robustness of other vegetation indices to BRDF was compared. The reflectance of the near-infrared band normalized by the sum of other bands :nNIR, and Global Environmental Monitoring Index :GEMI were investigated along with NDVI. It is clarified that nNIR was most robust in the site where vegetation existed. GEMI was most robust in the sites of scarce vegetation, while NDVI was strongly affected by BRDF in such sites.

DOI： 10.11520/jshwr.18.0.41.0

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Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/s0378-1127(02)00567-4

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Forest Planning  

The free (unobstructed) sight through the foliage layer of forest canopy is expected to depend on the density of the foliage, i.e. dense foliage shortens the free sight while sparse one extends it. Conversely, it is possible to estimate foliage density from the free sight. Furthermore, it is possible to estimate from the free sight the amount of leaves in terms of leaf area or leaf area index (LAI) as a product of estimated foliage density and the thickness of the foliage layer. This paper presents a simple theory of estimating LAI from the free sight along with its verification using a set of field data from boreal forest of Canada. Free sight through the canopy was measured using airborne laser altimetry (ALA). Laser beams emitted vertically from an aircraft are reflected from different layers of the canopy, ranging from the uppermost canopy surface to the ground. The distance that a laser beam travels unimpeded into the canopy was assumed to be the free sight or more aptly, the free path, and the mean of a number of penetrations within the canopy as a good measure of the amount of leaf area. We assembled a set of field leaf area and mean free path data for 13 boreal forest sites in central Alberta, Canada. We related leaf area density with mean free path and found an inverse relationship between them. Furthermore, we verified that LAI can be estimated as a product of mean free path-based leaf area density and an estimate of canopy depth (D) obtained based on the relationships we found between D and mean tree height (H) and between H and mean laser vegetation height.

DOI： 10.20659/jfp.8.1_9

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Language：English  

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