Use of a tree volume equation based on two lower-stem diameters to estimate forest volume from sample tree counts

1995 ◽  
Vol 25 (6) ◽  
pp. 871-877 ◽  
Author(s):  
Thomas B. Lynch
Keyword(s):  
Linear Equations ◽  
Stem Diameter ◽  
Linear Functions ◽  
Individual Tree ◽  
Point Sampling ◽  
Sample Tree ◽  
Fixed Radius ◽  
Volume Equation ◽  
The Individual ◽  
Lower Stem

A recently developed method of individual-tree volume prediction uses measurements of two lower-stem diameters, rather than the more traditional DBH and height measurements, to estimate stemwood. One form of the equation is linear with respect to volume between the two diameter measurements, as computed by Smalian's formula, and can be algebraically rearranged into the sum of two equations, one linear with respect to the square of the topmost lower-stem diameter, the other linear with respect to the square of the bottom lower-stem diameter. These two equations have the same form as local volume equations that are linear functions of the square of diameter. Because of this, a variation of horizontal point sampling can be used to select trees with probability exactly proportional to each of the equations. Forest volumes can be estimated from counts of trees obtained by comparing the point sampling gauge angle with individual tree diameters at the lower-stem diameter measurement points used by the individual-tree volume equation. To account for the negative intercept term in the linear equations, trees within a small fixed-radius plot are not included in the counts.

Stand volume estimation from tree counts in the context of vertical line sampling

1990 ◽  
Vol 20 (3) ◽  
pp. 274-279 ◽  
Author(s):  
Thomas B. Lynch
Keyword(s):  
Volume Estimation ◽  
Vertical Line ◽  
Individual Tree ◽  
Stand Volume ◽  
Variable Volume ◽  
Sample Tree ◽  
Line Sampling ◽  
Constant Form ◽  
Volume Equation ◽  
Line Sample

Stand volume estimators are developed in the context of vertical line sampling that depend on counts of sample trees only, rather than on measurements of sample tree dimensions. These estimators are based on three commonly used individual tree volume equations: the constant form factor volume equation, the combined variable volume equation with negative intercept, and the combined variable volume equation with positive intercept. Fieldwork for each of the estimators involves comparison of the squared dbh's of trees that would qualify for selection in an ordinary vertical line sample with numbers chosen randomly from the interval bounded by zero and a fixed maximum squared dbh. Two of the estimators choose sample trees with probability exactly proportional to an individual tree volume equation.

An Equation for Estimating Total Volume of Both Stands and Single Trees of Black Spruce

1983 ◽  
Vol 59 (1) ◽  
pp. 26-29 ◽  
Author(s):  
F. Evert
Keyword(s):  
Picea Mariana ◽  
Black Spruce ◽  
Direct Reference ◽  
Individual Tree ◽  
Stand Volume ◽  
Volume Equation ◽  
The Individual ◽  
Individual Trees

A stand volume equation is presented for black spruce (Picea mariana (Mill.)B.S.P.), based on a sample of 785 felled trees. To ensure that the equation will provide accurate estimates of the volume of both variously stocked stands and of individual trees, stand volume was expressed as the sum of individual tree volumes without direct reference to the size of the area that the trees occupy. The equation will reduce the problem of forecasting stand volume to the simpler problem of forecasting separately the individual components in the stand-volume equation.

Données LiDAR aériennes: pertinence de l'interprétation visuelle pour la foresterie

2017 ◽  
Vol 168 (3) ◽  
pp. 127-133
Author(s):  
Matthew Parkan
Keyword(s):  
Cross Sections ◽  
Forest Edge ◽  
Airborne Lidar ◽  
Visual Interpretation ◽  
Individual Tree ◽  
Small Areas ◽  
Interactive 3D ◽  
The Individual ◽  
Airborne Lidar Data ◽  
Stem Position

Airborne LiDAR data: relevance of visual interpretation for forestry Airborne LiDAR surveys are particularly well adapted to map, study and manage large forest extents. Products derived from this technology are increasingly used by managers to establish a general diagnosis of the condition of forests. Less common is the use of these products to conduct detailed analyses on small areas; for example creating detailed reference maps like inventories or timber marking to support field operations. In this context, the use of direct visual interpretation is interesting, because it is much easier to implement than automatic algorithms and allows a quick and reliable identification of zonal (e.g. forest edge, deciduous/persistent ratio), structural (stratification) and point (e.g. tree/stem position and height) features. This article examines three important points which determine the relevance of visual interpretation: acquisition parameters, interactive representation and identification of forest characteristics. It is shown that the use of thematic color maps within interactive 3D point cloud and/or cross-sections makes it possible to establish (for all strata) detailed and accurate maps of a parcel at the individual tree scale.

scholarly journals Crown Structure Explains the Discrepancy in Leaf Phenology Metrics Derived from Ground- and UAV-Based Observations in a Japanese Cool Temperate Deciduous Forest

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 425
Author(s):  
Noviana Budianti ◽  
Hiromi Mizunaga ◽  
Atsuhiro Iio
Keyword(s):  
Deciduous Forest ◽  
Leaf Expansion ◽  
Image Resolution ◽  
Leaf Phenology ◽  
Visual Interpretation ◽  
Temperate Deciduous Forest ◽  
Individual Tree ◽  
Crown Structure ◽  
Uav Images ◽  
The Individual

Unmanned aerial vehicles (UAV) provide a new platform for monitoring crown-level leaf phenology due to the ability to cover a vast area while offering branch-level image resolution. However, below-crown vegetation, e.g., understory vegetation, subcanopy trees, and the branches of neighboring trees, along with the multi-layered structure of the target crown may significantly reduce the accuracy of UAV-based estimates of crown leaf phenology. To test this hypothesis, we compared UAV-derived crown leaf phenology results against those based on ground observations at the individual tree scale for 19 deciduous broad-leaved species (55 individuals in total) characterized by different crown structures. The mean crown-level green chromatic coordinate derived from UAV images poorly explained inter- and intra-species variations in spring leaf phenology, most probably due to the consistently early leaf emergence in the below-crown vegetation. The start dates for leaf expansion and end dates for leaf falling could be estimated with an accuracy of <1-week when the influence of below-crown vegetation was removed from the UAV images through visual interpretation. However, a large discrepancy between the phenological metrics derived from UAV images and ground observations was still found for the end date of leaf expansion (EOE) and start date of leaf falling (SOF). Bayesian modeling revealed that the discrepancy for EOE increased as crown length and volume increased. The crown structure was not found to contribute to the discrepancy in SOF value. Our study provides evidence that crown structure is a pivotal factor to consider when using UAV photography to reliably estimate crown leaf phenology at the individual tree-scale.

Incorporating predictions into an annual forest inventory

1996 ◽  
Vol 26 (9) ◽  
pp. 1709-1713 ◽  
Author(s):  
Paul C. Van Deusen
Keyword(s):  
Forest Inventory ◽  
Variance Components ◽  
Growth Modeling ◽  
Estimation Procedure ◽  
Regression Estimator ◽  
Forest Types ◽  
Model Estimate ◽  
Individual Tree ◽  
Time Period ◽  
The Individual

Growth modeling of forests at the individual tree and stand levels is a highly refined procedure for many forest types. A method to incorporate predictions from such models into a forest inventory system is developed. Variance components from the actual measurements and from the predicted measurements are used to estimate the variance of the combined predicted value. The only assumption required to justify this method is that the model estimate has a bias that does not change from one time period to the next. The estimation procedure proposed here can also incorporate remotely sensed information via a regression estimator.

Variance reduction in Ueno's method and cylinder sampling for forest volume estimation

1995 ◽  
Vol 25 (11) ◽  
pp. 1783-1794 ◽  
Author(s):  
Thomas B. Lynch
Keyword(s):  
Computer Simulation ◽  
Variance Reduction ◽  
Volume Estimation ◽  
Critical Height ◽  
Volume Estimate ◽  
Individual Tree ◽  
Stand Volume ◽  
Reduction Techniques ◽  
Antithetic Variates ◽  
Volume Equation

Three basic techniques are proposed for reducing the variance of the stand volume estimate provided by cylinder sampling and Ueno's method. Ueno's method is based on critical height sampling but does not require measurement of critical heights. Instead, a count of trees whose critical heights are less than randomly generated heights is used to estimate stand volume. Cylinder sampling selects sample trees for which randomly generated heights fall within cylinders formed by tree heights and point sampling plot sizes. The methods proposed here for variance reduction in cylinder sampling and Ueno's method are antithetic variates, importance sampling, and control variates. Cylinder sampling without variance reduction was the most efficient of 12 methods compared in computer simulation that used estimated measurement times. However, cylinder sampling requires knowledge of a combined variable individual tree volume equation. Of the three variance reduction techniques applied to Ueno's method, antithetic variates performed best in computer simulation.

scholarly journals Estimation of Genetic and Phenotypic Parameters for Growth Traits in a Clonal Seed Orchard of Pinus kesiya in Malawi

ISRN Forestry ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Edward Missanjo ◽  
Gift Kamanga-Thole ◽  
Vidah Manda
Keyword(s):  
Growth Traits ◽  
Seed Orchard ◽  
Direct Selection ◽  
Tree Model ◽  
Individual Tree ◽  
Individual Level ◽  
Clonal Seed Orchard ◽  
Pinus Kesiya ◽  
Individual Tree Model ◽  
The Individual

Genetic and phenotypic parameters for height, diameter at breast height (dbh), and volume were estimated for Pinus kesiya Royle ex Gordon clonal seed orchard in Malawi using an ASReml program, fitting an individual tree model. The data were from 88 clones assessed at 18, 23, 30, 35, and 40 years of age. Heritability estimates for height, dbh, and volume were moderate to high ranging from 0.19 to 0.54, from 0.14 to 0.53, and from 0.20 to 0.59, respectively, suggesting a strong genetic control of the traits at the individual level, among families, and within families. The genetic and phenotypic correlations between the growth traits were significantly high and ranged from 0.69 to 0.97 and from 0.60 to 0.95, respectively. This suggests the possibility of indirect selection in trait with direct selection in another trait. The predicted genetic gains showed that the optimal rotational age of the Pinus kesiya clonal seed orchard is 30 years; therefore, it is recommended to establish a new Pinus kesiya clonal seed orchard. However, selective harvest of clones with high breeding values in the old seed orchard should be considered so that the best parents in the old orchard can continue to contribute until the new orchard is well established.

Assyrian sacred trees in the Brooklyn Museum

Iraq ◽  
1994 ◽  
Vol 56 ◽  
pp. 123-133 ◽  
Author(s):  
Pauline Albenda
Keyword(s):  
Present Author ◽  
Ninth Century ◽  
Palm Tree ◽  
The West ◽  
Individual Tree ◽  
Sacred Tree ◽  
The Individual ◽  
Individual Trees ◽  
Brooklyn Museum ◽  
Tree Type

The Brooklyn Museum houses twelve stone slabs with carved decoration from the Northwest Palace of Ashurnasirpal II. The motif of a stylized tree — the so-called Sacred Tree (see Figs. 1, 4, 6) — appears on seven of those slabs which come from rooms F, I, L, S, T of the ninth century palace at Nimrud. These tree renderings are representative of the sacred tree-type found in ten rooms of the royal residence and the west wing. Approximately 96 sacred trees, in two-register arrangement, appeared on the pictorial decorations in room I; the same motif occurred about 75 times in one-register arrangement on the reliefs of the other rooms. The abundance of the sacred tree motif on the wall decorations of the Northwest Palace attests to the significance of this plant. Its design deserves investigation; in Layard's words, “the tree, evidently a sacred symbol, is elaborately and tastefully formed.”In his study of the Ashurnasirpal II reliefs in American collections, Stearns did not attempt to list the sacred trees, because “variations in the sacred tree occur only in minor details,” and “the tree in itself is rarely useful in identifying the location of the reliefs.” These statements make clear Stearns' belief that the sacred trees were nearly alike. Other scholars, notably Weidner and Reade, have pointed out that on a number of slabs now in American and European museums are carvings of matching half trees, therefore indicating that when paired, these trees belonged to adjoining slabs originally. In trying to match half trees, one finds that individual sacred trees do differ in the rendering of specific details. Bleibtreu, in her analysis of the sacred tree-type, lists three variants of the flower found on the palmette-garland framing the individual tree on three sides. The present author, after examining the sacred trees carved on the slabs in The Brooklyn Museum, concludes that the design of the tree-type is more varied than heretofore presumed, and that its construction is more complex than indicated in previous descriptions of the subjects. An analysis of the Assyrian sacred tree-type may lead to possible conclusions regarding its intended image: a stylized palm tree, a cult object, an emblem of vegetation or “tree of life”, an imperial symbol, or a combination of those forms. In addition, one may consider to what extent the rendering of individual trees was the consequence of artistic inventiveness.

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