scholarly journals A system for estimating height and site index of western hemlock in the interior of British Columbia

1998 ◽  
Vol 74 (4) ◽  
pp. 588-596 ◽  
Author(s):  
Gordon D. Nigh
Keyword(s):  
British Columbia ◽  
Site Index ◽  
Tsuga Heterophylla ◽  
Western Hemlock ◽  
Index Model ◽  
Breast Height ◽  
Age Model ◽  
Site Index Model ◽  
Growth Intercept ◽  
Height Model

The focus of recent site productivity research in British Columbia has been to develop height-breast height age, growth intercept, and ecosystem-site index models. These models, together with a years-to-breast-height model, form a system for estimating site index and height. This system is described for western hemlock (Tsuga heterophylla (Raf.) Sarg.) in the interior of British Columbia. Forty-four western hemlock stem analysis plots were used in the construction of this system. As there are three models for estimating site index, the appropriate model for a given stand depends largely on the stand condition and the precision of the models. A graph of model precision against breast height age gives some assistance in deciding which model should be used to estimate site index. Key words: western hemlock, site index, height-age model, growth intercept model, years-to-breast-height model, ecosystem-site index model, model precision

scholarly journals Juvenile Height Development in Interior Spruce Stands of British Columbia

2000 ◽  
Vol 15 (3) ◽  
pp. 117-121 ◽  
Author(s):  
Gordon D. Nigh ◽  
Bobby A. Love
Keyword(s):  
Decision Making ◽  
British Columbia ◽  
Site Index ◽  
Timber Supply ◽  
Breast Height ◽  
Forest Region ◽  
Interior Spruce ◽  
Spruce Stands ◽  
Age Model ◽  
Height Model

Abstract Good estimates of juvenile heights are important for silviculture and timber supply decision-making. These height estimates are particularly important for estimating the number of years it takes a stand to reach green-up and breast height. Thirty-nine 0.04 ha plots were established in managed juvenile stands of interior spruce in the Prince Rupert Forest Region. Four sample trees in each plot were split longitudinally and height-age data were obtained from the exposed pith nodes or branch whorls. The height-age data were fit to a combined exponential and power function to create a juvenile height model for interior spruce. This model is a function of age and site index. Years to breast height and green-up age models were developed with data generated from the juvenile height model. Forecasts from these models indicate that the time to reach breast height and green-up age is less than previously expected. The juvenile height model, years to breast height model, and green-up age model should be used for site indices above 14.2 m. In addition, the height model should only be used up to total age 20. West. J. Appl. For. 15(3):117-121.

Growth intercept models for species without distinct annual branch whorls: western hemlock

1996 ◽  
Vol 26 (8) ◽  
pp. 1407-1415 ◽  
Author(s):  
Gordon D. Nigh
Keyword(s):  
Site Index ◽  
Fixed Number ◽  
Western Hemlock ◽  
Breast Height ◽  
Growth Intercept

A growth intercept model is presented that is designed to estimate site index for juvenile stands of species without distinct annual branch whorls. It is called a variable growth intercept model and is demonstrated on western hemlock (Tsugaheterophylla (Raf.) Sarg.). The growth intercept is calculated from all the growth above breast height (hence the name variable), not just a fixed number of years' growth above breast height as is traditionally done. This technique gives more flexibility in using growth intercepts to estimate site index. It can also lead to more accurate estimates of site index because it incorporates more growth information.

A height-growth and site-index model for interior spruce in the Sub-Boreal Spruce biogeoclimatic zone of British Columbia

2010 ◽  
Vol 40 (6) ◽  
pp. 1175-1183 ◽  
Author(s):  
Zhengjun Hu ◽  
Oscar García
Keyword(s):  
British Columbia ◽  
Full Range ◽  
Site Index ◽  
Height Growth ◽  
Site Quality ◽  
Growth Equation ◽  
Index Model ◽  
Interior Spruce ◽  
Height Prediction ◽  
Site Index Model

Height growth was modelled for spruce-dominated, even-aged stands in the Sub-Boreal Spruce biogeoclimatic zone of British Columbia, Canada, using both stem analysis (SA) and permanent sample plot (PSP) data. The model is based on a stochastic differential equation (SDE) formulation of the Bertalanffy–Richards growth equation. The SDE approach accounts for serial correlation and heterogeneous variance and makes hypothesis testing possible. Statistically significant differences in height–age trends between SA and PSP data were found that may be attributed to bias caused by dominance changes in SA trees. Error structure in SA and PSPs was also significantly different. Combining both data sources in a way that respects these different error structures reduced bias and increased precision. Four parametrizations were tested; the best was a polymorphic version. The final model fit the data well with no appreciable bias over the full range of ages and site qualities. The currently used spruce site-index model was found to underestimate growth and overestimate site index in young stands. The new model can be recommended for height prediction and site-quality assessment in interior spruce.

Climate sensitivity of trembling aspen radial growth along a productivity gradient in northeastern British Columbia, Canada

2008 ◽  
Vol 38 (5) ◽  
pp. 1211-1222 ◽  
Author(s):  
Giovanni Leonelli ◽  
Bernhard Denneler ◽  
Yves Bergeron
Keyword(s):  
British Columbia ◽  
Populus Tremuloides ◽  
Radial Growth ◽  
Site Index ◽  
Future Climate Change ◽  
Trembling Aspen ◽  
Tree Ring Chronology ◽  
Index Model ◽  
Productivity Gradient ◽  
Site Index Model

Growth–climate relationships were analyzed for 15 stands of trembling aspen ( Populus tremuloides Michx.) along a productivity gradient in northeastern British Columbia. Productivity was evaluated with a site index model whose values varied between 6.65 and 26.93 m height at age 50 years. To assess the role of climate on radial growth, we built a tree-ring chronology for each site and then performed a dendroclimatic analysis by means of bootstrapped correlation functions using monthly and annual climatic variables. We found that trembling aspen sensitivity to climate varied across stands with different productivities in the study area. At the more productive sites, trees were more sensitive to climate, and ring widths were positively correlated, particularly with summer month precipitation prior to the year of growth. The different responses to climate along the productivity gradient are likely related to the differences in substrate properties; substrates at the more productive sites are richer in nutrients and have a better water holding capacity than those of the less productive sites. Our study suggests that the effects of future climate change on tree growth may not only increase towards the limit of a species distribution, but also towards richer and wetter stands.

scholarly journals A Site Index Model for Lodgepole Pine in British Columbia

2014 ◽  
Vol 60 (5) ◽  
pp. 982-987 ◽  
Author(s):  
Adrian Batho ◽  
Oscar García
Keyword(s):  
British Columbia ◽  
Lodgepole Pine ◽  
Site Index ◽  
Index Model ◽  
Site Index Model ◽  
A Site

TOXICITY OF SMOKE FROM SPOROPHORES OF THE INDIAN PAINT FUNGUS AND WOOD FROM WESTERN HEMLOCK TO YELLOWFEVER MOSQUITOES

1987 ◽  
Vol 119 (12) ◽  
pp. 1109-1115
Author(s):  
W.P.L. Osborn ◽  
J.H. Borden
Keyword(s):  
British Columbia ◽  
Aedes Aegypti ◽  
Combustion Products ◽  
Tsuga Heterophylla ◽  
Water Soluble ◽  
Western Hemlock ◽  
Aqueous Extracts ◽  
Smoke Water

AbstractTo mitigate the effects of mosquitoes, settlers in the Revelstoke area of British Columbia reportedly burned the sporophores of the Indian paint fungus, Echinodontium tinctorium (Ell. & Ev.) Ell. & Ev., a pathogen of western hemlock, Tsuga heterophylla (Raf.) Sarg., and true firs, Abies spp. Larval and adult yellowfever mosquitoes, Aedes aegypti (L.), were exposed to aqueous extracts of smoke (smoke-waters) from E. tinctorium sporophores, and from western hemlock sapwood and heartwood. Smoke-waters were of approximately equal toxicity to larvae. Fungus smoke-water, but not sapwood or heartwood smoke-waters, lost 50% of its potency in 5 months. Vapors from fungus smoke-water were significantly more toxic to adult mosquitoes than those from sapwood or heartwood. Thus smoke from E. tinctorium sporophores and T. heterophylla wood apparently contain different water-soluble combustion products toxic to A. aegypti.

STUDIES IN FOREST PATHOLOGY: VII. DECAY IN WESTERN HEMLOCK AND FIR IN THE FRANKLIN RIVER AREA, BRITISH COLUMBIA

1949 ◽  
Vol 27c (6) ◽  
pp. 312-331 ◽  
Author(s):  
D. C. Buckland ◽  
R. E. Foster ◽  
V. J. Nordin
Keyword(s):  
British Columbia ◽  
Tsuga Heterophylla ◽  
Western Hemlock ◽  
Forest Pathology ◽  
Abies Amabilis ◽  
Armillaria Mellea ◽  
Forest Region ◽  
Volume Increment ◽  
Juan De Fuca

An investigation of decay in western hemlock (Tsuga heterophylla (Raf.) Sarg.) and fir (mainly Abies amabilis (Loud.) Forb.) in the Juan de Fuca forest region of British Columbia has shown that the major organisms causing root and butt rots are the same in both species. These are Poria subacida (Peck) Sacc., Fomes annosus (Fr.) Cke., Armillaria mellea Vahl ex Fr., Polyporus sulphureus Bull. ex Fr., and P. circinatus Fr. Those organisms causing trunk rots of western hemlock, in decreasing order of importance, are Fomes pinicola (Sw.) Cke., F. Pini (Thore) Lloyd, Stereum abietinum Pers., Fomes Hartigii (Allesch.) Sacc. and Trav., and Hydnum sp. (H. abietis). These same organisms causing trunk rots of fir, in decreasing order of importance, are Fomes pinicola, Stereum abietinum, Hydnum sp. (H. abietis), Fomes Pini, and Fomes Hartigii. The logs of 963 western hemlock were analyzed in detail. Maximum periodic volume increment was reached between 225 and 275 years of age. Maximum periodic volume increment was reached between 275 and 325 years of age in the 719 fir that were analyzed. Scars were the most frequent avenue of entrance for infection. In 59% of the cases of infection studied the fungus had entered through wounds.

STUDIES IN FOREST PATHOLOGY: XII. DECAY OF WESTERN HEMLOCK IN THE UPPER COLUMBIA REGION, BRITISH COLUMBIA

1954 ◽  
Vol 32 (1) ◽  
pp. 145-171 ◽  
Author(s):  
R. E. Foster ◽  
H. M. Craig ◽  
G. W. Wallis
Keyword(s):  
Site Index ◽  
Tsuga Heterophylla ◽  
Western Hemlock ◽  
Site Quality ◽  
Advanced Stage ◽  
Multiple Correlation ◽  
Relative Percentage ◽  
Total Incidence ◽  
Average Defect ◽  
Mature Stands

An investigation of western hemlock (Tsuga heterophylla (Raf.) Sarg.) in the Upper Columbia region has shown that decay losses are excessive, amounting to 52 and 74% in terms of cubic and board foot computations respectively. The logs of 833 hemlock on 36 sample plots located in mature timber were analyzed in detail. Twenty-six decay-producing fungi have been isolated. Sixty-two per cent of the total decay was attributed to Echinodontium tinctorium Ell. & Ever. and 25% to Fomes pini (Thore) Lloyd. Considerable variation in the fungi responsible for decay was encountered intraregionally. Stand defect losses varied from 38 to 71%. Some of this variation could be predicted on the basis of the site index determinations of hemlock. Relative to the total incidence and importance of decay, Echinodontium tinctorium decreased and Fomes pini increased in significance with increasing site quality. Sporophores, scars, dead tops, large rotten branches, swollen knots, frost cracks, forked trees, and trunk infections of mistletoe were classed as indicators of significance in relation to hidden defect. Living trees, classed as Suspect or Residual depending on the presence or absence of one or more reliable indicators of defect, were found to differ appreciably in average defect. Within each of the preceding classes decay increased progressively with increasing diameter and decreasing site quality. Immature hemlock was found to be susceptible to appreciable decay and mature stands reached an advanced stage of deterioration at 250 years. Multiple correlation analyses between percentage of decay, site, age, and the relative percentage of Residual trees weighted by volume permitted an estimate of total stand defect within ± 7%.

scholarly journals SITE QUALITY ESTIMATIONS BASED ON THE GENERALIZED ALGEBRAIC DIFFERENCE APPROACH: A CASE STUDY IN ÇANKIRI FORESTS

2018 ◽  
Vol 42 (3) ◽  
Author(s):  
Ugur Akbas ◽  
Muammer SENYURT
Keyword(s):  
Site Index ◽  
Site Quality ◽  
Model Parameters ◽  
Successful Model ◽  
Index Model ◽  
Prediction Technique ◽  
Algebraic Difference ◽  
Pine Stands ◽  
Site Index Model ◽  
Generalized Algebraic Difference Approach

ABSTRACT In this study, it is aimed that the dynamic site index models were developed for Crimean Pine stands in Sarikaya-Cankiri forests located in middle northern Turkey. The data for this study are 153 sample trees obtained from the Crimean Pine stands. In modeling relationships between height and age of dominant or co-dominant trees, some dynamic site index equations such as Chapman-Richards (M1, M2, M3), Lundqvist (M4 and M6), Hossfeld (M5), Weibull (M7) and Schumacher (M8) based on the Generalized Algebraic Difference Approach (GADA) were used. The estimations for these eight-dynamic site index model parameters with well as various statistical values were obtained using the nonlinear regression technique. Among these equations, the Chapman-Richards’s equation, M3, was determined to be the most successful model, with accounted for 89.03 % of the total variance in height-age relationships with MSE: 1.7633, RMSE: 1.3279, SSE: 1165.6, Bias: -0.0380. After determination of the best predictive model, ARMA (1, 1) autoregressive prediction technique was used to account autocorrelation problems for time-series height measurements. When ARMA autoregressive prediction technique was applied to the Chapman-Richards function for solving autocorrelation problem, these success statistics were improved as SSE: 868.7, MSE: 1.3183, RMSE: 1.1482, Bias: -0.06369, R2: 0.918. Also, Durbin-Watson statistics displayed that autocorrelation problem was solved by the use of ARMA autoregressive prediction technique; DW test value=1.99, DW<P=0.5622, DW>P=0.4378. The dynamic site index model that was developed has provided results compatible with the growth characteristics expected in the modeling of height-age relations, such as polymorphism, multiple asymptote, and base-age invariance.

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