scholarly journals Development of height to crown base models for thirteen tree species of the North American Acadian Region

2012 ◽  
Vol 88 (1) ◽  
pp. 60-73 ◽  
Author(s):  
Baburam Rijal ◽  
Aaron R. Weiskittel ◽  
John A. Kershaw
Keyword(s):  
Tree Species ◽  
Basal Area ◽  
Logistic Equation ◽  
Growth And Yield ◽  
Suitable Model ◽  
Breast Height ◽  
The North ◽  
Model Predictions ◽  
Important Input ◽  
Growth And Yield Models

Height to live crown base (HCB) is an important input variable for several growth and yield models. Since HCB is rarely measured in the field, it is often predicted using static models. Instead of predicting HCB, the Forest Vegetation Simulator Northeastern Variant (FVS-NE) uses an equation that predicts crown ratio (CR), which has not been well validated. The main goal of the present study was to construct a regional HCB model for thirteen selected tree species of the Acadian Region of North America. The specific objectives were to: 1) evaluate FVS-NE model predictions, 2) compare suitable model forms, and 3) assess influence of various covariates to improve predictions. We evaluated three model forms, namely Holdaway (1986), logistic, and exponential. The findings indicated that FVS-NE models were significantly biased for all species as the overall mean bias and root mean square error (RMSE) were 0.11 m and 1.80 m, respectively. A logistic equation with size (diameter at breast height [DBH], total height [HT] and ratio of DBH to HT), and competition (crown competition factor [CCF] and basal area larger than subject tree [BAL]) gave the best predictions for all species in this analysis. This model had an overall mean bias <0.01 m and an RMSE of 1.59 m, which represents a significant improvement in predictions compared to FVS-NE. Despite the range of species and observed variation in the data, the equations worked well and can be easily calibrated to new stands with a few local observations.

scholarly journals SPATIAL DISTRIBUTION AND STRUCTURAL VARIATION OF Copaifera arenicola IN A CAATINGA FRAGMENT

FLORESTA ◽  
2020 ◽  
Vol 50 (3) ◽  
pp. 1660
Author(s):  
Dráuzio Correia Gama ◽  
Robério Anastácio Ferreira ◽  
Janisson Batista de Jesus ◽  
José Monteiro do Nascimento Júnior
Keyword(s):  
Spatial Distribution ◽  
Tree Species ◽  
Structural Variation ◽  
Basal Area ◽  
Stable Population ◽  
Distribution Analysis ◽  
Expansion Phase ◽  
Breast Height ◽  
Absolute Density ◽  
Univariate Function

The study of spatial distribution of tree populations has proven to be important for revealing how individuals are horizontally organized in the environment, facilitating the structural understanding and forms of colonization and dispersion of propagules. The present work aimed at studying the pattern of spatial distribution of tree species Copaiferaarenicola [(Ducke) J. Costa e L.P.Queiroz] and its structural relation with the altimetric profile in a Caatinga fragment in Ribeira do Pombal municipality, Bahia. Census of all individuals in the area with circumference at breast height (CBH) ≥ 6 cm was performed. The spatial distribution analysis was conducted for the whole population using Ripley K univariate function, with maximum search radius (h) of 128 m. 409 individuals were found, corresponding to absolute density of 89.49 ind. ha-1 and 0.681 m². ha-1 of basal area. The group of C. arenicola individuals corresponds to a stable population in expansion phase, presenting higher number of young and medium individuals. The pattern of spatial distribution of individuals in the area under study was the uniform arrangement. None of the altimetric classes of the area had a different influence on the structure and distribution of arboreal individuals.

scholarly journals Testing the Accuracy of Growth and Yield Models for Southern Hardwood Forests

2000 ◽  
Vol 24 (3) ◽  
pp. 176-185 ◽  
Author(s):  
H. Michael Rauscher ◽  
Michael J. Young ◽  
Charles D. Webb ◽  
Daniel J. Robison
Keyword(s):  
Test Data ◽  
Basal Area ◽  
Hardwood Forests ◽  
Growth And Yield ◽  
Bottomland Hardwoods ◽  
Average Error ◽  
Yellow Poplar ◽  
Data Set ◽  
Southern Appalachian ◽  
Growth And Yield Models

Abstract The accuracy of ten growth and yield models for Southern Appalachian upland hardwood forests and southern bottomland forests was evaluated. In technical applications, accuracy is the composite of both bias (average error) and precision. Results indicate that GHAT, NATPIS, and a locally calibrated version of NETWIGS may be regarded as being operationally valid growth and yield models for Southern Appalachian yellow-poplar (Liriodendron tulipifera) and mixed oak (Quercus spp.) forests that fall within the range of characteristics of the test data set. No publicly available growth and yield models specifically developed for southern bottomland hardwood forests exist. Four general models that contain most of the applicable species to predict growth of these forests were tested. SETWIGS was found to be the most accurate of the four models tested and is recommended for use if the reported level of accuracy is acceptable and the target stand characteristics fall within the range of our test data set. Results indicate that the growth and density dynamics of dense, young stands of both upland and bottomland hardwoods were poorly predicted by the models. Models predicted basal area and density changes in yellow-poplar stands more accurately than mixed hardwoods. Predictions for upland hardwoods were more accurate than those for bottomland hardwoods. Model accuracy uniformly decreases with increasing length of the projection period. South. J. Appl. For. 24(3):176-185.

scholarly journals StandsSIM-MD: a Management Driven forest SIMulator

2016 ◽  
Vol 25 (2) ◽  
pp. eRC07 ◽  
Author(s):  
Susana Barreiro ◽  
João Rua ◽  
Margarida Tomé
Keyword(s):  
Forest Management ◽  
Tree Species ◽  
Growth Models ◽  
Planning Horizon ◽  
Md Simulations ◽  
Forest Growth ◽  
Growth And Yield ◽  
Management Approaches ◽  
User Friendly ◽  
Growth And Yield Models

Aim of the study: The existing stand level forest simulators available in Portugal were not developed with the aim of including up-to-date model versions and were limited in terms of accounting for forest management. The simulators’ platform, sIMfLOR was recently created to implement different growth models with a common philosophy. The objective was developing one easily-updatable, user-friendly, forest management and climate change sensitive simulator capable of projecting growth for the main tree species in Portugal.Area of the study: Portugal.Material and methods: The new simulator was programmed in a modular form consisting of several modules. The growth module integrates different forest growth and yield models (empirical and process-based) for the main wood production tree species in Portugal (eucalypt, umbrella and maritime pines); whereas the management module drives the growth projections along the planning horizon according to a range of forest management approaches and climate (at present only available for eucalypt).Main results: The main result is the StandsSIM-MD Management Driven simulator that overcomes the limitations of the existing stand level simulators. It is a step forward when compared to the models currently available in the sIMfLOR platform covering more tree species, stand structures and stand compositions. It is focused on end-users and it is based on similar concepts regarding the generation of required inputs and generated outputs.Research highlights:-          Forest Management Driven simulations approach-          Multiple Prescriptions-Per-Stand functionality-          StandsSIM-MD can be used to support landowners decisions on stand forest management-          StandsSIM-MD simulations at regional level can be combined with optimization routinesKeywords: Forest simulator, Forest Management Approaches; StandsSIM-MD; forest management.

Crown and basal area relationships of open-grown southern pines for modeling competition and growth

1992 ◽  
Vol 22 (3) ◽  
pp. 341-347 ◽  
Author(s):  
W.R. Smith ◽  
R.M. Farrar Jr. ◽  
P.A. Murphy ◽  
J.L. Yeiser ◽  
R.S. Meldahl ◽  
...  
Keyword(s):  
Loblolly Pine ◽  
Longleaf Pine ◽  
Basal Area ◽  
Growth And Yield ◽  
Predictive Equations ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Crown Width ◽  
Basal Area Growth ◽  
Area Growth

Data were collected on open-grown loblolly pine (Pinustaeda L.), longleaf pine (Pinuspalustris Mill.), and shortleaf pine (Pinusechinata Mill.) and analyzed to provide predictive equations of crown width and maximum potential basal area growth for crown competition and growth and yield models. The measurements were taken on 115 open-grown loblolly pine trees and 76 shortleaf pines in southeastern Arkansas. The longleaf pine data consisted of 81 open-grown trees from southern Alabama, Georgia, and Florida. A circle and an ellipse were tested as geometric models of the vertically projected crown. No significant differences between the tree shapes were found based on analyses of length and azimuth of the largest crown diameter, and the circle was chosen as an appropriate model. This indicated that only the distance between trees, not their orientation to one another, need be included in models of crown competition based on crown contact. Predictive equations of mean crown width based on diameter at breast height were fitted for each species for use in models of crown competition. A Chapman–Richards growth rate function with an intercept term was fit to periodic annual inside-bark basal area growth based on initial inside-bark basal area to provide empirical estimates of maximum basal area growth rates for growth and yield modeling of the given species. Additionally, equations to predict double bark thickness as a function of diameter at breast height were fit for each species to facilitate the use of the equations with outside-bark measurements of diameter.

scholarly journals Floristic Structure of Fire Experimental Plots of Olokemeji Forest Reserve, Ogun State, Nigeria

2020 ◽  
Vol 24 (11) ◽  
pp. 1861-1865
Author(s):  
DM Taiwo ◽  
OR Olatidoye ◽  
OR Jeminiwa ◽  
TO Oyebola ◽  
C Omonu
Keyword(s):  
Tree Species ◽  
Basal Area ◽  
Relative Importance ◽  
Importance Value ◽  
Forest Reserve ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Ogun State ◽  
Mean Diameter ◽  
Floristic Structure

Total enumeration of tree species was carried out fire experimental plot of Olokemeji forest reserve for relative importance value (RIV) mean heights, mean diameter at breast height and mean basal area. Three investigative plot (Plot A, B and C) were established. Plot A which represents Early Burn is burnt annually during the dry season while Plot B was burnt annually during the rainy season when the trees are still wet and Plot C serves as the protected area. Gmelina arborea had the highest relative importance value (28.31), this is followed by Dalbergia sissoo which had RIV of 10.94. Plot C recorded the highest frequency of trees with the highest tree heights, this is closely followed by Plot A and Plot B being the plot with the lowest mean height. Plot C has the highest mean diameter at breast height (DBH) of trees and it is followed by Plot B and Plot A with very close mean DBH. The highest mean basal area was also recorded in Plot C, the highest total basal area and tree volume was also recorded at Plot C as 32.2 m2 ha-1 and 188.8 m3. The size distribution of tree species depicts that Plot C has been protected just as expected Keywords: Forest, Structure, Flora, Dynamics, Fire

scholarly journals A preliminary growth and yield model for Eucalyptus globoidea Blakely plantations in New Zealand

2020 ◽  
Vol 50 ◽  
Author(s):  
Serajis Salekin ◽  
Euan G. Mason ◽  
Justin Morgenroth ◽  
Dean F. Meason
Keyword(s):  
New Zealand ◽  
Basal Area ◽  
Growth And Yield ◽  
Maximum Diameter ◽  
Forest Industry ◽  
Eucalyptus Species ◽  
Plantation Forest ◽  
Yield Model ◽  
Growth And Yield Model ◽  
Growth And Yield Models

Background: New Zealand’s plantation forest industry is dominated by the exotic species radiata pine (Pinus radiata D.Don), which comprises approximately 90% of the net stocked area. However, there is interest in introducing new species to: (a) provide wood that is naturally decay-resistant as a substitute for wood treated with preservatives; (b) match species to the wide variety of environmental conditions in New Zealand; and (c) reduce reliance on P. radiata. Some Eucalyptus species are considered as potential alternatives to P. radiata, specifically those that can survive in resource-limited conditions and produce high quality wood. While Eucalyptus species are grown in plantations in many regions of the world, limited information is available on their growth in New Zealand. Eucalyptus globoidea Blakley is of particular interest and has been planted in trials throughout New Zealand. A complete set of preliminary growth and yield models for this species will satisfy the initial information requirements for diversifying New Zealand’s plantation forest industry. Methods: A set of growth and yield models was developed and validated, based on data from 29 E. globoidea permanent sample plots (PSPs) located mostly in North Island and a few in South Island of New Zealand. Trees were measured at different time intervals in these plots, with height and diameter at breast height (DBH) ranging from 0.1–39.8 m and 0.1–62.3 cm, respectively. An algebraic difference approach (ADA) was applied to model mean top height, basal area, maximum diameter, and standard deviation of DBH. Non-linear regression equations were used to project stand volume and height-diameter relationship, and Reineke’s stand density index (SDI) approach was employed to model mortality. Results: Mean top height, maximum diameter, and standard deviation of DBH were best fitted by Von Bertalanffy-Richards (SE=1.1 m), Hossfeld (SE=2.4 cm), and Schumacher polymorphic (SE=1.6 cm) difference equations, respectively. Basal area data were modelled with high precision (SE=6.9 m2 ha-1) by the Schumacher anamorphic difference equation. Reineke’s SDI approach was able to explain the self-thinning as a reduction in the number of stems per hectare. Stand-level volume per hectare and height-diameter relationship models were precise when including site-specific variables with standard errors of 40.5 m3 ha-1 and 3.1 m, respectively. Conclusion: This study presents a set of preliminary growth and yield models for E. globoidea to project plot-level growth attributes. The models were path invariant and satisfied basic traditional mensurational-statistical growth and yield model assumptions. These models will provide forest growers and managers with important fundamental information about the growth and yield of E. globoidea.

Improving growth and yield estimates with a process model derived growth index

2004 ◽  
Vol 34 (6) ◽  
pp. 1274-1282 ◽  
Author(s):  
Jason G Henning ◽  
Thomas E Burk
Keyword(s):  
Process Model ◽  
Environmental Variability ◽  
Growth Index ◽  
Process Models ◽  
Growth And Yield ◽  
Yield Model ◽  
Forest Inventories ◽  
Model Predictions ◽  
Growth And Yield Models ◽  
Empirical Growth

Forest managers have long made use of the regular and predictable nature of tree growth by using empirical growth and yield models to update forest inventories. Updated inventories support better decision making without requiring on the ground reassessment of the forest resource. Growth and yield model predictions can suffer from inaccuracies due to the influence of climate and environmental variability on the growth of trees. Researchers have been attempting to assess and predict the effect of this variation by developing mechanistic process models that often do not generate outputs applicable to inventory update. Here we create a growth index dependent on process model outputs to improve growth and yield estimates. Estimate accuracy was modestly improved over the basic growth and yield estimates and was comparable to previous efforts to account for environmental variability in growth and yield estimates. Using a process model we are nominally considering the entire environment, and by adjusting the growth and yield estimates external to both model types we have avoided difficulties involved with refitting or recreating either model. These are key differences from previous efforts to include environmental variability in growth and yield estimates.

scholarly journals Diameter-height models for the Terai tree species

2015 ◽  
Vol 25 (1) ◽  
pp. 50-54 ◽  
Author(s):  
A. Khadka ◽  
T. Subedi ◽  
M. Ghimire ◽  
B. P. Dhakal ◽  
H. Parikka
Keyword(s):  
Tree Species ◽  
Linear Models ◽  
Resource Assessment ◽  
Forest Growth ◽  
Growth And Yield ◽  
Forest Resource ◽  
Linear Mixed Effects ◽  
Shorea Robusta ◽  
Non Linear ◽  
Growth And Yield Models

Tree diameter-height relationship can be used as a key input component in forest growth and yield models, and description of stand dynamics. Various models of stem diameter and height relation were developed. Those were formulated and implemented during Terai forest inventory data calculations in the Forest Resource Assessment (FRA) Nepal Project. The field inventory was conducted from December, 2010 to March, 2011. The Concentric Circular Sample Plot was designed where the diameters at breast height of all the tallied trees and the heights of the sampled trees were measured. The data were handled with R-script in R Programme to generate non-linear mixed effects models in ‘lmfor’ package of forest biometrics functions of Mehtatalo. Different non-linear models were used to fit the diameter-height relation, which performed well in describing the relationships between the diameters and the heights of the Terai tree species depending on the sample size. The models were selected as the best fitted based on the statistical results such as standard error, Adjusted R2, RMSE and residuals. The best models for Shorea robusta and Terminalia alata were generated using Wykoff’s and Naslund’s functions, respectively.Banko Janakari, A Journal of Forestry Information for NepalVol. 25, No. 1Page: 50-54

Floristic Variation of Tree Communities and Their Association with Soil Properties in Pulau Jerejak, Penang, Peninsular Malaysia

2020 ◽  
Vol 14 (1) ◽  
pp. 34
Author(s):  
Faezah Pardi
Keyword(s):  
Tree Species ◽  
Diversity Index ◽  
Basal Area ◽  
Peninsular Malaysia ◽  
Importance Value ◽  
Conservation Action ◽  
Endangered Tree ◽  
Endangered Tree Species ◽  
Tree Communities ◽  
Floristic Variation

This study was conducted at Pulau Jerejak, Penang to determine the floristic variation of its tree communities. A 0.5-hectare study plot was established and divided into 11 subplots. A total of 587 trees with diameter at breast height (DBH) of 5 cm and above were measured, identified and recorded. The tree communities comprised of 84 species, 63 genera and 32 families. The Myrtaceae was the most speciose family with 10 recorded species while Syzgium glaucum (Myrtaceae) was the most frequent species. The Myrtaceae recorded the highest density of 306 individuals while Syzgium glaucum (Myrtaceae) had the highest species density of 182 individuals. Total tree basal area (BA) was 21.47 m2/ha and family with the highest BA was Myrtaceae with 5.81 m2/ha while at species level, Syzgium glaucum (Myrtaceae) was the species with the highest total BA in the plot with value of 4.95 m2/ha. The Shannon˗Weiner Diversity Index of tree communities showed a value of 3.60 (H'max = 4.43) and Evenness Index of 0.81 which indicates high uniformity of tree species. The Margalef Richness Index (R') revealed that the tree species richness was 13.02. Myrtaceae had the highest Importance Value of 20.4%. The Canonical Correspondence Analysis (CCA) showed that Diospyros buxifolia (Ebenaceae) and Pouteria malaccensis (Sapotaceae) were strongly correlated to low pH. Dysoxylum cauliflorum (Meliaceae) and Eriobotrya bengalensis (Rosaceae) were correlated to phosphorus (P) and calcium ion (Ca2+), respectively. Therefore, the trees species composition at Pulau Jerejak showed that the biodiversity is high and conservation action should be implemented to protect endangered tree species. Keywords: Floristic variation; Tree communities; Trees composition; Pulau Jerejak; Species diversity

Live tree species basal area of the contiguous United States (2000-2009)

2013 ◽  
Author(s):  
Barry T. Wilson ◽  
Andrew J. Lister ◽  
Rachel I. Riemann ◽  
Douglas M. Griffith
Keyword(s):  
United States ◽  
Tree Species ◽  
Basal Area ◽  
Live Tree
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