Mapping stand-level forest biophysical variables for a mixedwood boreal forest using lidar: an examination of scanning density

2006 ◽  
Vol 36 (1) ◽  
pp. 34-47 ◽  
Author(s):  
V Thomas ◽  
P Treitz ◽  
J H McCaughey ◽  
I Morrison
Keyword(s):  
Aboveground Biomass ◽  
Basal Area ◽  
High Density ◽  
Lidar Data ◽  
Low Density ◽  
Entire Study ◽  
Dominant Height ◽  
Forested Areas ◽  
Mixedwood Boreal Forest ◽  
Crown Closure

Light detection and ranging (lidar) is becoming an increasingly popular technology among scientists for the development of predictive models of forest biophysical variables. However, before this technology can be adopted with confidence for long-term monitoring applications in Canada, robust models must be developed that can be applied and validated over large and complex forested areas. This will require "scaling-up" from current models developed from high-density lidar data to low-density data collected at higher altitudes. This paper investigates the effect of lowering the average point spacing of discrete lidar returns on models of forest biophysical variables. Validation of results revealed that high-density models are well correlated with mean dominant height, basal area, crown closure, and average aboveground biomass (R2 = 0.84, 0.89, 0.60, and 0.91, respectively). Low-density models could not accurately predict crown closure (R2 = 0.36). However, they did provide slightly improved estimates for mean dominant height, basal area, and average aboveground biomass (R2 = 0.90, 0.91, and 0.92, respectively). Maps were generated and validated for the entire study area from the low-density models. The ability of low-density models to accurately map key biophysical variables is a positive indicator for the utility of lidar data for monitoring large forested areas.

Crown efficiency in a loblolly pine (Pinus taeda) spacing experiment

1998 ◽  
Vol 28 (9) ◽  
pp. 1344-1351 ◽  
Author(s):  
Hubert Sterba ◽  
Ralph L Amateis
Keyword(s):  
Pinus Taeda ◽  
Loblolly Pine ◽  
Basal Area ◽  
Tree Height ◽  
Projection Area ◽  
Individual Tree ◽  
Dominant Height ◽  
Crown Projection Area ◽  
Pinus Taeda L ◽  
Crown Closure

Crown efficiency was first defined by Assmann (1961. Waldertragskunde. BLV, München) as individual tree volume increment per unit of crown projection area. He hypothesized that within a given crown class, smaller crowns are more efficient because their ratio between crown surface and horizontal crown projection is higher. Data from a loblolly pine (Pinus taeda L.) spacing experiment were used to test if this hypothesis also holds in young loblolly pine stands and, if so, to determine if it explains the increment differences between spacings in the spacing experiment. Using individual tree height relative to plot dominant height to describe crown class, within-plot regression showed that crown efficiency decreased with crown size for trees below dominant height. This relationship was much less pronounced than indicated from Assmann's examples, although the crown surface to crown projection ratio behaved in the same way as Assmann had hypothesized. Crown efficiency as well as the crown surface to crown projection area ratio decreased with increasing density. Basal area increment per hectare increased until total crown closure approached 130% and then stayed constant. This major impact of total crown coverage brings into question the usefullness of crown efficiency as an indicator for unit area growth.

scholarly journals Estimating forest aboveground biomass by low density lidar data in mixed broad-leaved forests in the Italian Pre-Alps

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Antonio Montagnoli ◽  
Sara Fusco ◽  
Mattia Terzaghi ◽  
Alan Kirschbaum ◽  
Dirk Pflugmacher ◽  
...  
Keyword(s):  
Aboveground Biomass ◽  
Lidar Data ◽  
Low Density ◽  
Forest Aboveground Biomass

scholarly journals Behaviour of Vitis vinifera L. cv. Albariño plants, produced by propagation in vitro, when using single bud cuttings

OENO One ◽  
1993 ◽  
Vol 27 (3) ◽  
pp. 159
Author(s):  
María-Carmen Martínez ◽  
José Luis González Mantilla
Keyword(s):  
Vitis Vinifera ◽  
Basal Area ◽  
High Density ◽  
First Year ◽  
Low Density ◽  
Intermediate Area ◽  
Total Absence ◽  
Mother Plants ◽  
Apical Area

<p style="text-align: justify;">Single bud cuttings were produced from cane taken from vines propagated <em>in vitro</em> which had been held for a year in pots. During this period we had observed, in the mother plants, that three areas appeared which showed a clearly different morphology. In the basal area the leaves were cordiform or pentagonal without sinuses, with high density of erect hairs, a low density or absence of horizontal hairs and a strong anthocyanic pigmentation. In the intermediate area the leaves were pentagonal, with deep sinuses, a high density of erect hairs and a strong anthocyanic pigmentation in the principal nerves. In the apical area the leaves were pentagonal, without sinuses, with a high density of horizontal hairs, total absence of erect hairs and absence of anthocyanic pigmentation in the principal nerves (typical of adult Albariño). The single bud cuttings were planted in pots and it was observed that during the first year all the plants, as much those taken from the basal area as those from the intermediate and apical areas, produced leaves having very deep sinuses (juvenile character). Three years more were allowed to pass, they were subjected to pruning as low down as possible on same year wood and then were restudied. It was seen that the vine produced from single bud cuttings taken from the basal area showed very juvenile characters, those taken from the intermediate area showed characters somewhere between the juvenile and adult stages, and those taken from the apical area showed adult characters.</p>

Beyond trees: Mapping total aboveground biomass density in the Brazilian savanna using high-density UAV-lidar data

2021 ◽  
Vol 491 ◽  
pp. 119155
Author(s):  
Máira Beatriz Teixeira da Costa ◽  
Carlos Alberto Silva ◽  
Eben North Broadbent ◽  
Rodrigo Vieira Leite ◽  
Midhun Mohan ◽  
...  
Keyword(s):  
Aboveground Biomass ◽  
High Density ◽  
Brazilian Savanna ◽  
Lidar Data ◽  
Biomass Density

scholarly journals Prediction of Aboveground Biomass from Low-Density LiDAR Data: Validation over P. radiata Data from a Region North of Spain

Forests ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 819 ◽  
Author(s):  
Tojal ◽  
Bastarrika ◽  
Barret ◽  
Espeso ◽  
Lopez-Guede ◽  
...  
Keyword(s):  
Aboveground Biomass ◽  
Tree Height ◽  
National Forest Inventory ◽  
Biomass Estimation ◽  
Lidar Data ◽  
Low Density ◽  
Cloud Data ◽  
Public Data ◽  
The Government ◽  
North Of Spain

Estimation of forestry aboveground biomass (AGB) by means of aerial Light Detection and Ranging (LiDAR) data uses high-density point sampling data obtained in dedicated flights, which are often too costly for available research budgets. In this paper we exploit already existing public low-density LiDAR data obtained for other purposes, such as cartography. The challenge is to show that such low-density data allows accurate biomass estimation. We demonstrate the approach on data available from plantations of Pinus radiata in the Arratia-Nervión region, located in Biscay province located in the North of Spain. We use public data gathered from the low-density (0.5 pulse/m2) LiDAR flight conducted by the Basque Government in 2012 for cartographic production. We propose a linear regression model based on explanatory variables obtained from the LiDAR point cloud data. We calibrate the model using field data from the Fourth National Forest Inventory (NFI4), including the selection of the optimal model variables. The results revealed that the best model depends on two variables extracted from LiDAR data: One directly related with tree height and a second parameter with the canopy density. The model explained 80% of its variability with a standard error of 0.25 ton/ha in logarithmic units. We validate the predictions against the biomass measurements provided by the government institutions, obtaining a difference of 8%. The proposed approach would allow the exploitation of the periodic available low-density LiDAR data, collected with territorial and cartographic purposes, for a more frequent and less expensive control of the forestry biomass.

Quantitative defect studies in semiconductor TEM samples prepared by low angle ion milling

1995 ◽  
Vol 53 ◽  
pp. 512-513
Author(s):  
L. Mulestagno ◽  
J.C. Holzer ◽  
P. Fraundorf
Keyword(s):  
Sample Preparation ◽  
Milling Time ◽  
High Density ◽  
Low Density ◽  
Ion Milling ◽  
High Quality ◽  
Variable Angle ◽  
Major Disadvantage ◽  
Induced Defects

Due to the wealth of information, both analytical and structural that can be obtained from it TEM always has been a favorite tool for the analysis of process-induced defects in semiconductor wafers. The only major disadvantage has always been, that the volume under study in the TEM is relatively small, making it difficult to locate low density defects, and sample preparation is a somewhat lengthy procedure. This problem has been somewhat alleviated by the availability of efficient low angle milling.Using a PIPS® variable angle ion -mill, manufactured by Gatan, we have been consistently obtaining planar specimens with a high quality thin area in excess of 5 × 104 μm2 in about half an hour (milling time), which has made it possible to locate defects at lower densities, or, for defects of relatively high density, obtain information which is statistically more significant (table 1).

Scanning Electron Microscopic and Electrophoretic Observations on Barium Sulphate Used to Adsorb Clotting Factors

1975 ◽  
Vol 33 (02) ◽  
pp. 256-270
Author(s):  
R. M Howell ◽  
S. L. M Deacon
Keyword(s):  
Electron Microscopy ◽  
Factor Xa ◽  
Barium Sulphate ◽  
High Density ◽  
Low Density ◽  
Factor X ◽  
Clotting Factors ◽  
Electron Microscopic ◽  
Complementary Techniques ◽  
Scanning Electron

SummaryElectron microscopy and particle electrophoresis were found to be complementary techniques with which to complete the physical data from an earlier study on barium sulphates used to adsorb clotting factors from serum. The differences revealed by scanning electron microscopy (S. E. M.) in the physical shape of low and high density grades of barium sulphate particles appear to be of greater significance than charge as expressed by electrophoretic mobility, in determining whether or not precursor or preformed factor Xa is eluted.This conclusion was based on the finding that at pH values close to 7, where the adsorption from serum occurs, all samples with the exception of natural barytes were uncharged. However as the high-density, or soil-grade, was found by S. E. M. to consist of large solid crystals it was suggested that this shape might induce activation of factor X as a result of partial denaturation and consequent unfolding of the adsorbed protein. In contrast, uptake of protein into the centre of the porous aggregates revealed by S. E. M. pictures of low-density or X-ray grade barium sulphate may afford protection against denaturation and exposure of the enzyme site.The porous nature of particles of low-density barium sulphate compared with the solid crystalline forms of other grades accounts not only for its lower bulk density but also for its greater surface/gram ratio which is reflected by an ability to adsorb more protein from serum.Neither technique produced evidence from any of the samples to indicate the presence of stabilising agents sometimes used to coat particles in barium meals.

scholarly journals A Dynamic Stand Growth Model System for Loblolly Pine Responding to Mid-Rotation Treatments

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 556
Author(s):  
Mauricio Zapata-Cuartas ◽  
Bronson P. Bullock ◽  
Cristian R. Montes ◽  
Michael B. Kane
Keyword(s):  
Growth Model ◽  
Loblolly Pine ◽  
Basal Area ◽  
Model System ◽  
Growth And Yield ◽  
Site Quality ◽  
Response To Treatment ◽  
Plantation Management ◽  
Vegetation Control ◽  
Dominant Height

Intensive loblolly pine (Pinus taeda L.) plantation management in the southeastern United States includes mid-rotation silvicultural practices (MRSP) like thinning, fertilization, competitive vegetation control, and their combinations. Consistent and well-designed long-term studies considering interactions of MRSP are required to produce accurate projections and evaluate management decisions. Here we use longitudinal data from the regional Mid-Rotation Treatment study established by the Plantation Management Research Cooperative (PMRC) at the University of Georgia across the southeast U.S. to fit and validate a new dynamic model system rooted in theoretical and biological principles. A Weibull pdf was used as a modifier function coupled with the basal area growth model. The growth model system and error projection functions were estimated simultaneously. The new formulation results in a compatible and consistent growth and yield system and provides temporal responses to treatment. The results indicated that the model projections reproduce the observed behavior of stand characteristics. The model has high predictive accuracy (the cross-validation variance explained was 96.2%, 99.7%, and 98.6%; and the prediction root mean square distance was 0.704 m, 19.1 trees ha−1, and 1.03 m2ha−1 for dominant height (DH), trees per hectare (N), and basal area (BA), respectively), and can be used to project the current stand attributes following combinations of MRSP and with different thinning intensities. Simulations across southern physiographic regions allow us to conclude that the most overall ranking of MRSP after thinning is fertilization + competitive vegetation control (Fert + CVC) > fertilization only (Fert) > competitive vegetation control only (CVC), and Fert + CVC show less than additive effect. Because of the model structure, the response to treatment changes with location, age of application, and dominant height growth as indicators of site quality. Therefore, the proposed model adequately represents regional growth conditions.

Sign in / Sign up

Export Citation Format

Share Document