Accuracy of partially visually assessed stand characteristics: a case study of Finnish forest inventory by compartments

2004 ◽  
Vol 34 (4) ◽  
pp. 916-930 ◽  
Author(s):  
Annika Kangas ◽  
Elina Heikkinen ◽  
Matti Maltamo
Keyword(s):  
Basal Area ◽  
Visual Assessment ◽  
Management Planning ◽  
Forest Management Planning ◽  
Mixed Regression ◽  
Final Error ◽  
Variance Estimates ◽  
Accuracy Assessments ◽  
Measurement Strategies ◽  
Visual Assessments

In Finland, forest management planning is based on standwise assessment of forest variables. The data is traditionally gathered partly by (subjective) sampling and partly by visual assessment, which makes the accuracy assessments difficult. This study consists of an experiment where the visual assessments of field technicians were compared with the accurately measured values. The data consists of assessments from 18 sample plots made by 19 technicians. Each technician assessed four forest characteristics from each stand, for each tree species and each tree class. Basal area was observed in all cases; the other three variables varied according to 18 different measurement strategies. From these observations, mixed models were estimated to analyze to what extent the assessment errors depend on forest characteristics. Variation among both sample plots and field technicians was also considered. The results show that some of the variables could be interpreted as Berkson cases. The assessment errors were also often highly hetero sce dastic. Therefore, variance was explicitly modeled, and the final error models were estimated with weighted mixed regression using the variance estimates as weights. The results show clear variation among technicians, especially in characteristics that include personal judgment. The effect of training could be detected from variation between the technician groups. Furthermore, the broad-leaved tree classes were generally more difficult to assess than conifers.

scholarly journals Forest management planning in the Terai: sharing experiences from Sabaiya, Parsa

1970 ◽  
Vol 16 (1) ◽  
pp. 32-34
Author(s):  
Y.B. Thapa ◽  
P.L. Shaha ◽  
B. Ghimire ◽  
K.C. Arjun ◽  
S. Karmacharya
Keyword(s):  
Forest Management ◽  
Soil Conservation ◽  
Technical Information ◽  
Basal Area ◽  
Management Planning ◽  
Forest Management Planning ◽  
Volume Table ◽  
Stand Parameters ◽  
Area And Volume ◽  
Future Management

The Ministry of Forests and Soil Conservation is in the process of developing operational forest management mechanisms for the Terai regions of Nepal. The Sabaiya pilot scheme in Parsa is under implementation, which witnessed experiences in several issues in the process. The paper aims to share technical experiences with wider audiences. It highlights anomalies in scheme estimation and final enumeration in basic stand parameters such as basal area and volume. It presents possible reasons and provide analysis and insights for future management planning of Terai forests. The paper concludes with a need for more technical information generation, analysis and utilisation approaches in forest management in Nepal. Key words: Forest management, stand parameters, volume table, Sabaiya Banko Janakari Vol.16(1) 2006 pp32-34

scholarly journals An analysis of the Modeling and Inventory Support Tool: Yield curves vary with Forest Ecosystem Classification

2012 ◽  
Vol 88 (02) ◽  
pp. 147-153
Author(s):  
Daniel Marina ◽  
Sean C. Thomas
Keyword(s):  
Forest Ecosystem ◽  
Basal Area ◽  
Site Index ◽  
Growth And Yield ◽  
Management Planning ◽  
Support Tool ◽  
Forest Management Planning ◽  
Stand Productivity ◽  
Ecosystem Classification ◽  
Definition Of

Stand-level growth and yield models are essential to assessing sustainable levels of forest harvest; such assessments are supported in Ontario by the Modeling and Inventory Support Tool (MIST), which combines updated yield estimates and predicted successional trajectories to improve yield forecasts in Ontario. Currently, forest management planning and MIST stratifies the landbase by the Standard Forest Unit (SFU), but not ecosite as defined under the Forest Ecosystem Classification (FEC) system. Here we examined variation in MIST's input and output parameters (site index, top height, and basal area) for ecosites that fall within the definition of the PW1 SFU in Central Ontario (white-pine-dominated sites). Ecosites showed significant differences in site index values and top height, but not basal area, results indicating systematic differences in productivity among ecosites within the SFU. These results show that fine-scale variation in edaphic factors, as indicated by ecosite information, correspond to differences in stand productivity, and suggest the importance of a more harmonized approach between yield modeling, SFUs, and the FEC system in Ontario.

Estimation of the carcass composition of different cattle breeds and crosses from fatness measurements and visual assessments

1986 ◽  
Vol 106 (2) ◽  
pp. 223-237 ◽  
Author(s):  
A. J. Kempster ◽  
J. P. Chadwick ◽  
D. D. Charles
Keyword(s):  
Subcutaneous Fat ◽  
Visual Assessment ◽  
Carcass Composition ◽  
Beef Breed ◽  
Percentage Unit ◽  
Wide Range ◽  
Fat Thickness ◽  
Substantial Bias ◽  
Visual Assessments ◽  
Thickness Measurements

SUMMARYCarcass data for 1053 steers from the Meat and Livestock Commission's beef breed evaluation programme were used to examine the relative precision of alternative fatness assessments for predicting carcass lean percentage. The data were from four trials and comprised both dairy-bred and suckler-bred cattle by a wide range of sire breeds.A visual assessment of carcass subcutaneous fat content to the nearest percentage unit (SFe) was the single most precise predictor both overall (residual S.d. = 2·28) and within breed (residual S.d. = 2·05). Precision was improved by the addition in multiple regression of the percentage perinephric and retroperitoneal fat (KKCF) in carcass, a visual score of the degree of marbling in the m. longissimus and selected fat thickness measurements taken by calipers on cut surfaces (residual S.d. = 2·11 (overall) and 1·90 (within breed)).When the best overall equation was applied to the breed means, there was substantial bias (predicted – actual carcass lean percentage). Biases ranged from +2·5 (purebred Canadian Holstein and Luing) to – 1·3 (Limousin crosses).Breeds differed significantly in carcass lean content when compared at equal levels of fatness measurements. The differences depended both on the precision with which the measurements predicted carcass lean content and the observed differences in carcass composition that existed before adjustments to equal fatness were made.The robustness of prediction equations was examined by applying them to independent sets of data (a total of 334 carcasses) from four other trials involving steers, heifers, cows and young bulls. Equations were stable for cattle of the same breed, sex and similar levels of fatness but important bias was found between more extreme types of cattle.

Developing and Implementing Multiple-Use Forest Management Planning in Turkey

2008 ◽  
Vol 42 (1) ◽  
pp. 37-48 ◽  
Author(s):  
Emin Zeki Baskent ◽  
Salih Terzioğlu ◽  
Şağdan Başkaya
Keyword(s):  
Forest Management ◽  
Multiple Use ◽  
Management Planning ◽  
Forest Management Planning

scholarly journals Opportunities for the application of linear program­ming in forest management planning

2013 ◽  
pp. 175-191
Author(s):  
Damjan Pantic ◽  
Bojan Tubic ◽  
Marko Marinkovic ◽  
Dragan Borota ◽  
Snezana Obradovic
Keyword(s):  
Linear Programming ◽  
Maximum Yield ◽  
Half Period ◽  
Management Planning ◽  
Forest Management Planning ◽  
Conflicting Interests ◽  
Poplar Plantations ◽  
The One ◽  
Forest Practice ◽  
The U.S

In situations where it is necessary to consider a variety of options when making decisions in forestry (and in general), with the choice influenced by hardly comparable criteria and a number of conflicting interests, a possible solution is to use multiple criteria methods. One of these methods, which can be applied in forestry, is mathematical programming (in particular, linear programming). Linear programming has a long tradition of being used in the U.S. and European forestry, whereas in the forestry of Serbia it still represents a theoretically and practically unknown tool. Therefore, in this paper we analyze the possibility of applying the methods of linear programming in developing a plan of regeneration cutting in the poplar plantations of FMU "Topolik" managed by PE "Vojvodinasume." Using the aimed function (linear programming) and the corresponding software package the maximum yield that can be achieved by cutting the plantation was obtained. The planned management period was from 2012 to 2021 and its volume was 155 852 m3. The preset condition that the yield in half-periods remains equal was fulfilled (half-period I 77,925 m3, half-period II 77,927 m3). The maximum yield obtained with this methodology was by 4,040 m3 lower than the theoretically possible yield that would be obtained if all stands were cut down at the end of the second half-period, i.e. higher by 8,430 m3 than the yield that would be obtained if cutting of the stands were performed at the start of the management period. The results obtained and foreign experience in this area clearly indicate that linear programming can successfully be used to solve this problem and even more complex problems (than the one presented in this paper) in our local forest practice (multidimensional planning with a series of constraints).

scholarly journals Small Area Estimation of Postfire Tree Density Using Continuous Forest Inventory Data

2021 ◽  
Vol 4 ◽  
Author(s):  
George C. Gaines ◽  
David L. R. Affleck
Keyword(s):  
Forest Inventory ◽  
Mean Squared Error ◽  
Tree Density ◽  
Standard Errors ◽  
Sample Sizes ◽  
Management Planning ◽  
Forest Management Planning ◽  
Continuous Forest ◽  
Sample Data ◽  
Regional Forest

Wildfire activity in the western United States is expanding and many western forests are struggling to regenerate postfire. Accurate estimates of forest regeneration following wildfire are critical for postfire forest management planning and monitoring forest dynamics. National or regional forest inventory programs can provide vegetation data for direct spatiotemporal domain estimation of postfire tree density, but samples within domains of administrative utility may be small (or empty). Indirect domain expansion estimators, which borrow extra-domain sample data to increase precision of domain estimates, offer a possible alternative. This research evaluates domain sample sizes and direct estimates in domains spanning large geographic extents and ranging from 1 to 10 years in temporal scope. In aggregate, domain sample sizes prove too small and standard errors of direct estimates too high. We subsequently compare two indirect estimators—one generated by averaging over observations that are proximate in space, the other by averaging over observations that are proximate in time—on the basis of estimated standard error. We also present a new estimator of the mean squared error (MSE) of indirect domain estimators which accounts for covariance between direct and indirect domain estimates. Borrowing sample data from within the geographic extents of our domains, but from an expanded set of measurement years, proves to be the superior strategy for augmenting domain sample sizes to reduce domain standard errors in this application. However, MSE estimates prove too frequently negative and highly variable for operational utility in this context, even when averaged over multiple proximate domains.

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