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1
Smith, V. G., M. Watts, and D. F. James. "Mechanical stability of black spruce in the clay belt region of northern Ontario." Canadian Journal of Forest Research 17, no. 9 (September 1, 1987): 1080–91. http://dx.doi.org/10.1139/x87-166.
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Black spruce (Piceamariana (Mill.) B.S.P.) is an important pulpwood species that grows on peatland sites in the clay belt region of northern Ontario. The mechanical stability of spruce found on these sites is crucial in determining how tall a stand can grow before losses due to windthrow become excessive. In this study, the stability of a sample of 58 black spruce trees, in stands of various height and density classes, was measured by winching them over and determining their critical turning moment. Regression analysis was used to express critical turning moment as a function of tree height, dominant stand height, and stand stocking. An analysis was carried out to estimate turning moments due to static wind action on the sample trees and predicting the wind speeds required to produce the static force needed to cause windthrow. A comparison of the measured critical turning moments to the estimated wind-generated critical turning moments was used to identify the wind speeds that have enough static force to cause windthrow. A table of critical wind speeds, based on a reference wind, is given for black spruce stands of various heights and densities. Based on these wind speeds and winds associated with periodic storms, black spruce stands can be expected to become susceptible to windthrow once dominant stand height reaches 20 to 21 m. Stand stability increases with stand density owing to the greater ability of dense stands to dissipate incoming winds and the added stability of interlocking root systems. These results suggest that the black spruce stands growing on peatland sites in the clay belt should be harvested before dominant stand height reaches a maximum of 20 to 21 m to avoid excessive losses due to windthrow.
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Hynynen, Jari. "Predicting tree crown ratio for unthinned and thinned Scots pine stands." Canadian Journal of Forest Research 25, no. 1 (January 1, 1995): 57–62. http://dx.doi.org/10.1139/x95-007.
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A nonlinear model that yields logical predictions for tree crown ratio is presented. The model is based on data from permanent experimental plots located in even-aged Scots pine (Pinussylvestris L.) stands in southern and central Finland. Regressor variables in the model are stand dominant height, stand basal area, tree diameter, and tree height. The effect of thinning on tree crown ratio is modelled by incorporating a thinning response variable into the model. Thinning effect is dependent on thinning intensity and time elapsed from thinning, the latter of which is represented by the difference between current stand dominant height and dominant height at the time of thinning.
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Eerikäinen, Kalle, Danaza Mabvurira, Ladislaus Nshubemuki, and Jussi Saramäki. "A calibrateable site index model for Pinus kesiya plantations in southeastern Africa." Canadian Journal of Forest Research 32, no. 11 (November 1, 2002): 1916–28. http://dx.doi.org/10.1139/x02-106.
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The aim of the study was to develop a site index model for Pinus kesiya Royle ex Gordon plantations in southeastern Africa based on the relationship between the dominant height and stand age. Conversely, analysis of dominant height and age data showed that the growth patterns of plantations were different. In addition, the asymptotes and forms of standwise dominant height curves varied within plantations. In developing a common site index model, instead of using the more common approach of estimating separate dominant heightage models for different plantations or sites, a mean curve approach based on a linear random parameter model with fixed and random parameters was applied. The random parameter model of this study was calibrated by predicting random parameters for the plantation and stand effects, in accordance with the standard linear prediction theory. The analyses showed that the calibration of the dominant height model was an efficient method to obtain reliable dominant height predictions of a stand, particularly when several dominant heightage observations from different stands of a plantation and at least one measured dominant height and stand age of a target stand are available. This is the case in many forest inventories based on temporary samples, i.e., cross-sectional data. The new site index model is a useful tool for use in different mensurational applications, and its properties can efficiently be utilized for example in forest inventories of P. kesiya plantations in southeastern Africa.
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Tarmu, Toomas, Diana Laarmann, and Andres Kiviste. "Mean height or dominant height – what to prefer for modelling the site index of Estonian forests?" Forestry Studies 72, no. 1 (September 18, 2020): 121–38. http://dx.doi.org/10.2478/fsmu-2020-0010.
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AbstractThe availability of a large amount of data from reliable sources is important for forest growth modelling. A permanent plot where trees are repeatedly measured provides a clearer picture of stand alterations. Various factors, including forest management, affect forest growth and accuracy of its assessment. In Estonia, mean height as a regression height prediction at mean square diameter is commonly used in forest management practice. Alternatively, dominant height can be used. The main advantage of using dominant height instead of mean height is that the growth of dominant trees is not so strongly affected by stand density (thinning). The aim of our research was to investigate the difference between mean height and dominant height when used as stand height. The research was based on the Estonian Network of Forest Research Plots (ENFRP). As a result, we found that the average mean height change was significantly greater in the case of thinning when compared to undisturbed stand development, whereas, the average dominant height change in the case of thinning compared to undisturbed development was less significant. As a side result, we developed a regression model that can be used for calculating the dominant height of the main tree species using stand attributes (mean height, quadratic mean diameter and density) with a residual standard deviation of 0.466 m.
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MacFarlane, David W., Edwin J. Green, and Harold E. Burkhart. "Population density influences assessment and application of site index." Canadian Journal of Forest Research 30, no. 9 (September 1, 2000): 1472–75. http://dx.doi.org/10.1139/x00-079.
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The height growth of dominant trees in plantations is often assumed to be independent of initial planting density. This assumption allows for the use of dominant tree height as an index of site quality. We found that this assumption was false for the seven tallest trees in 184 even-aged loblolly pine (Pinus taeda L.) stands, planted at nine initial planting densities, at four different geographic locations. A strong, highly significant negative correlation was found between dominant height and initial planting density for stands 14 and 16 years of age. This leads to large differences in predicted site index for stands with different initial planting densities planted at the same geographic location. Use of these site indices to predict yield produced large differences in predicted yield (m3/ha) at age 25. These results provide strong evidence for density-dependent height growth, even for dominant trees in the stand, and suggest that site index, used as a measurement of site quality, is confounded with stand density.
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Lauer, Dwight K., and Glenn R. Glover. "Stand level pine response to occupancy of woody shrub and herbaceous vegetation." Canadian Journal of Forest Research 29, no. 7 (August 1, 1999): 979–84. http://dx.doi.org/10.1139/x99-068.
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The relationship between age-5 pine height and vegetation cover was estimated for loblolly pine (Pinus taeda L.) and slash pine (Pinus elliottii Engelm.) stands using regression analysis. This paper utilizes results from four locations of a vegetation control study that included herbicide treatments to control woody shrub and herbaceous vegetation. Age-5 average dominant height was predicted from first-year herbaceous cover, untreated first-year shrub cover, and fifth-year shrub cover. Dominant height increased 0.5 m for each decrease of about 30% in either first year herbaceous cover, untreated first-year shrub cover, or year-5 shrub cover. Lack of vegetation control on beds where vegetation was allowed to recolonize before planting reduced dominant height an additional 0.5 m. A competition index was constructed that estimates the difference between "potential" and actual age-5 pine height. Stand-level models were developed to link age-5 pine height and occupancy of competing vegetation to quadratic mean DBH, specific DBH percentiles, and stand basal area. The effects of interspecific competition on stand basal area and diameter percentiles could be accounted for through the effects of competing vegetation on dominant height except for treatments that did not control woody shrubs.
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Ouzennou, Hakim, David Pothier, and Frédéric Raulier. "Adjustment of the age–height relationship for uneven-aged black spruce stands." Canadian Journal of Forest Research 38, no. 7 (July 2008): 2003–12. http://dx.doi.org/10.1139/x08-044.
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Site index (SI) is commonly used in natural stands, even when their diameter distribution deviates from that of the monospecific, even-aged, fully stocked stands used to develop basic age–height relationships. Since deviations from basic age–height trajectories can be reflected in deviations of stand diameter distribution from a bell shape, we incorporated different diameter diversity indices into an age–height equation to help improve height predictions and determine which index is best related to stand dominant height. This procedure was performed using black spruce ( Picea mariana (Mill.) BSP) stands from a large network of permanent sample plots established across the province of Quebec, Canada. The age–height model that minimized the Akaike’s information criterion used the Shannon evenness index (ESh) as an equation modifier accounting for the diameter diversity variable. The model showed that for stands established on relatively poor sites (SI = 9), no substantial differences in dominant height were found between two contrasting ESh values. For SI = 15, however, the larger ESh value increased the dominant height by as much as 1 m at 80 years. These results suggest that introduction of ESh into an age–height model can improve calculation of site index, particularly in regions characterized by the presence of numerous uneven-aged stands.
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Pothier, David, René Doucet, and Jocelyn Boily. "The effect of advance regeneration height on future yield of black spruce stands." Canadian Journal of Forest Research 25, no. 4 (April 1, 1995): 536–44. http://dx.doi.org/10.1139/x95-061.
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The advance regeneration often present following clear-cutting in black spruce (Piceamariana (Mill.) B.S.P.) stands is generally composed of individuals of various heights. This initial height difference is hypothesized to affect the yield of the future stand. Height of the advance regeneration at time of release was determined on several black spruce trees within 33 stands distributed across the boreal forest of the province of Quebec, Canada. From these data, a regeneration structure index was developed and used to explain a part of the variation in subsequent stand yield. Dominant trees of stands developing for 38 to 65 years since clear-cutting generally originated from the tallest advance regeneration at time of release. Stands with the tallest regeneration at time of release produced the largest yields for a given site quality and number of years since harvesting. A 3-m increase in advance-regeneration height resulted in a similar yield gain as a 3-m increase in site index. Site indices calculated from age-height relationships of dominant trees originating from tall advance regeneration were less than those calculated from trees that have undergone a relatively short period of suppression. These results suggest that traditional management tools developed for fire-origin black spruce stands, i.e., stands mainly composed of seed-origin trees established after perturbation, should be adjusted for clearcut-origin stands that largely develop from advance regeneration.
9
Ritchie, Martin, Jianwei Zhang, and Todd Hamilton. "Effects of Stand Density on Top Height Estimation for Ponderosa Pine." Western Journal of Applied Forestry 27, no. 1 (January 1, 2012): 18–24. http://dx.doi.org/10.1093/wjaf/27.1.18.
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Abstract Site index, estimated as a function of dominant-tree height and age, is often used as an expression of site quality. This expression is assumed to be effectively independent of stand density. Observation of dominant height at two different ponderosa pine levels-of-growing-stock studies revealed that top height stability with respect to stand density depends on the definition of the dominant height. Dominant height estimates calculated from a fixed number of trees per acre (ranging from 10 to 60 of the tallest trees per acre) were less affected by density than those calculated from a proportion (with the cutoff ranging from 95th to the 70th percentile) of the largest trees in the stand.
10
Ung, Chhun-Huor, and Denis Ouellet. "Stand volume tables: Application to black spruce stands of Lebel-sur-Quévillon." Forestry Chronicle 67, no. 6 (December 1, 1991): 712–15. http://dx.doi.org/10.5558/tfc67712-6.
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Within the framework of large-scale forest management, the application of Eichhorn's law, which employs dominant height or mean height exclusively to predict tree volumes per hectare, is certainly rapid, but high accuracy is not guaranteed. Substantial error occurred when this method was used in a study of boreal black spruce stands (Picea mariana (Mill.) B.S.P.). Use of both basal area per hectare and dominant height, however, permitted estimation of total volume per hectare and volume to 9 cm top with only 11 and 12% error, respectively. The form factors for total volume and volume to 9 cm top showed great stability. For this reason, use of the simple conventional formula (V = G.H.F.) to estimate standing volumes is justified. Key words: Stand volume table, Eichhorn's law, stand form factor
11
Mailly, Daniel, Sylvain Turbis, Isabelle Auger, and David Pothier. "The influence of site tree selection method on site index determination and yield prediction in black spruce stands in northeastern Québec." Forestry Chronicle 80, no. 1 (February 1, 2004): 134–40. http://dx.doi.org/10.5558/tfc80134-1.
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Site index is a common and convenient indicator of forest site productivity. The concept is well suited for growth and yield predictions, although there appears to be no universal consensus on the type or number of site trees needed for its application. We compared four methods for assessing site quality using data from black spruce (Picea mariana (Mill.) BSP) stands of northeastern Québec. Data were analysed with a univariate repeated measures analysis of variance design using the MIXED procedure of the SAS system. Significant differences were found between the method based on the mean height of the 100 largest trees per hectare and three other methods that calculate site index using information from average site trees (codominants and dominants) and an equation to estimate top height from stand level data. We concur with many others that using the mean height of the 100 largest trees per hectare is a more standard procedure than simple averages of codominant and dominant tree heights for site quality assessment and growth modelling. We recommend that the next yield table system developed in the province should be based on top height trees, instead of using average codominants and dominants and an equation to estimate dominant height. Key words: site index, top height, yield table, site trees
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Kim, Jeonghwan, Joo-Hoon Lim, Moonhyun Shin, Seung-Hyun Han, and Wonseok Kang. "Oak Resprouting Survival and Competition for 19 Years after Wildfire in the Republic of Korea." Forests 11, no. 5 (May 3, 2020): 515. http://dx.doi.org/10.3390/f11050515.
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In the Republic of Korea, forest fire occurred at a rate of more than 400 events yr−1 from 2000 to 2016, and the burned areas are concentrated in the eastern coastal region. In this region, pine forest is extensively distributed, and pine forest is converted to oak forest through natural succession or stump-sprout regeneration following forest fires. However, there is a lack of research on oak competition and survival during the regeneration process in burned areas. Therefore, this research was carried out to evaluate the effects of oak survival ratio of Quercus serrata (glandbearing oak), Q. variabilis (oriental oak), and Q. mongolica (Mongolian oak) in burned areas. The investigation plots were set to survey tree height, diameter at breast height, sprout survival, and composition in Goseong-gun, Kangwon province, Republic of Korea. The mean tree heights of Q. serrata and Q. variabilis were approximately 9.8 m and 9.1 m, respectively, which were higher than the approximately 5.8 m heights of Q. mongolica stands 18 years after a forest fire, and the trend for tree diameter at breast height was the same for all three species stands. In the early stage of regeneration after the forest fire, the survival probability of the Q. serrata sprouts decreased at a rate of 1.7–2.0 times higher than that of other oak species in the Q. serrata-dominant stands, and this tendency was found to the survival probability in Q. variabilis-dominant stands as well. The median survival time of Q. variabilis sprouts in the Q. variabilis-dominant stands was approximately 10.1 years, which was similar to Q. serrata-dominant stands. However, the dominant stand of Q. mongolica was different from that of other dominant stands since the stand mostly located in the ridge and the upper part of the mountain where topography and soil conditions were considerably dissimilar from the other stands. The decision of dominant species seems to be determined by the survival and occurrence of sprouts during the early stage in post-fire regenerated oak forests. Therefore, it would be more desirable to coppice sprout for dominant species productivity and rapid dominance after a forest fire.
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Marangon, Gabriel Paes, Emanuel Arnoni Costa, César Augusto Guimarães Finger, Paulo Renato Schneider, and Matheus Teixeira Martins. "DENSITY MANAGEMENT DIAGRAM FOR Eucalyptus grandis W. Hill. ex Maiden STANDS CONTROLLED BY DOMINANT HEIGHT." FLORESTA 51, no. 1 (December 29, 2020): 240. http://dx.doi.org/10.5380/rf.v51i1.68373.
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Density management diagram for eucalyptus stands controlled by dominant height. The present study aimed to elaborate Density Management Diagrams (DMD) for Eucalyptus grandis W. Hill. ex Maiden stands including the dominant height. Data were obtained from permanent plots installed in the Centro Oriental Riograndense region and the Porto Alegre Metropolitan area, both located in the state of Rio Grande do Sul. The models to describe the relationships between average volume, number of trees per hectare, mean diameter, and dominant height were assessed by the statistical criteria of coefficient of determination (R²), standard error of the estimate in percentage (Syx%), and graphical analysis of residuals. The developed DMD allows for a better control of stocks in the management of stands due to the strong relationship of dominant height with stand development site and forest yield.Keywords: Growth, Site index, Forest regulation, Yield.
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Sharma, Mahadev, and John Parton. "Modelling the effects of climate on site productivity of white pine plantations." Canadian Journal of Forest Research 49, no. 10 (October 2019): 1289–97. http://dx.doi.org/10.1139/cjfr-2019-0165.
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Ninety-three dominant or co-dominant white pine (Pinus strobus L.) trees were sampled from 93 plots (one tree per plot) in even-aged monospecific plantations at 31 sites (three plots per site) across Ontario, Canada. Stem analysis data collected from these trees were used to develop and evaluate stand height models. The effects of site and climate on site productivity were examined by incorporating site and climate variables into a stand height model. Including climate variables improved the fit statistics of the stand height model for white pine. A covariance structure (AR(1)) was used to address autocorrelation in the data. Similarly, a variance function was used to account for heteroscedasticity. Stand heights were predicted for four areas (middle, easternmost, westernmost, and southernmost parts of Ontario where white pine were sampled) for the period 2021 to 2080 under two emissions trajectories known as representative concentration pathways (RCPs), with each reflecting different levels of heat at the end of the century (i.e., 2.6 and 8.5 W·m–2). At the end of the 2021 to 2080 growth period, projected heights were shorter by 7% for the southern parts and taller by 9.8% for the middle parts of Ontario under both climate change scenarios compared with those under a no change scenario. However, there was no pronounced difference in projected heights under both climate change scenarios and the no change scenario for the other two areas evaluated. The resulting height growth models can be used to estimate stand heights for white pine plantations in a changing climate. Using the same model, the site index of a plot or stand can be estimated by calculating height at a given base (index) age. In the absence of climatic data, the model fitted without climate variables can be used to estimate stand heights and site indices.
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Vasiliauskas, Stan, and Han YH Chen. "How long do trees take to reach breast height after fire in northeastern Ontario?" Canadian Journal of Forest Research 32, no. 10 (October 1, 2002): 1889–92. http://dx.doi.org/10.1139/x02-104.
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Accurate determination of stand establishment ages is important in developing growth and yield models and in studying stand dynamics of fire-origin stands. The study objective was to determine time to reach breast height for black spruce (Picea mariana (Mill.) BSP), jack pine (Pinus banksiana Lamb.), trembling aspen (Populus tremuloides Michx.), and white birch (Betula papyrifera Marsh.) from fire origin stands under different site conditions in northeastern Ontario. Stands were randomly selected from burns with known fire dates. In each stand, three to six dominant and codominant trees of a selected species were cored at breast height (1.3 m above the ground level) to determine time to reach breast height. Trembling aspen and white birch did not differ for time to reach breast height after fire, taking 6 or 7 years, jack pine took marginally longer (8 years), whereas black spruce took the longest (18 years). While time to reach breast height did not vary among site conditions as described by soil texture and moisture regime, it was positively related to time since fire. The results of this study indicate that stand establishment dates and total tree ages can be substantially underestimated if breast height age is used as the stand age, resulting in misinterpretations of growth and yield and forest succession.
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Shataee, Sh, and J. Mohammadi. "INVISTIGATION ON CANOPY HEIGHT AND DENSITY DIFFERENTIATIONS IN THE MANAGED AND UNMANAGED FOREST STANDS USING LIDAR DATA (CASE STUDY: SHASTKALATEH FOREST, GORGAN)." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-1-W5 (December 11, 2015): 775–79. http://dx.doi.org/10.5194/isprsarchives-xl-1-w5-775-2015.
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Forest management plans are interesting to keep the forest stand natural composite and structure after silvicultural and management treatments. In order to investigate on stand differences made by management treatments, comparing of these stands with unmanaged stands as natural forests is necessary. Aerial laser scanners are providing suitable 3D information to map the horizontal and vertical characteristics of forest structures. In this study, different of canopy height and canopy cover variances between managed and unmanaged forest stands as well as in two dominant forest types were investigated using Lidar data in Dr. Bahramnia forest, Northern Iran. The in-situ information was gathered from 308 circular plots by a random systematic sampling designs. The low lidar cloud point data were used to generate accurate DEM and DSM models and plot-based height statistics metrics and canopy cover characteristics. The significant analyses were done by independent T-test between two stands in same dominant forest types. Results showed that there are no significant differences between canopy cover mean in two stands as well as forest types. Result of statistically analysis on height characteristics showed that there are a decreasing the forest height and its variance in the managed forest compared to unmanaged stands. In addition, there is a significant difference between maximum, range, and mean heights of two stands in 99 percent confidence level. However, there is no significant difference between standard deviation and canopy height variance of managed and unmanged stands. These results showd that accomplished management treatments and cuttings could lead to reducing of height variances and converting multi-layers stands to two or single layers. Results are also showed that the canopy cover densities in the managed forest stands are changing from high dense cover to dense cover.
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Harrison, Wade C., Thomas E. Burk, and Donald E. Beck. "Individual Tree Basal Area Increment and Total Height Equations for Appalachian Mixed Hardwoods After Thinning." Southern Journal of Applied Forestry 10, no. 2 (May 1, 1986): 99–104. http://dx.doi.org/10.1093/sjaf/10.2.99.
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Abstract Growth response of various species to thinning in even-aged stands of Appalachian mixed hardwoods was predicted with species-specific regression equations. Periodic annual increment over a five-year period was expressed as a linear function of original tree basal area divided by breast height age and a thinning or competition index based on stand basal area. For most species, a combination of stand basal area before and after thinning served as the thinning index; for the five oak species studied, the index was simply stand basal area after thinning. Nonlinear regression equations were formulated to express total tree height as a function of dbh and average height of dominant and codominant white oak. The equations for tree basal area increment and total height may be applied to predict growth after thinning in Appalachian mixed hardwood stands. South J. Appl. For. 10:99-104, May 1986
18
Mehtätalo, Lauri. "A longitudinal height–diameter model for Norway spruce in Finland." Canadian Journal of Forest Research 34, no. 1 (January 1, 2004): 131–40. http://dx.doi.org/10.1139/x03-207.
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A height–diameter (HD) model for Norway spruce (Picea abies (L.) Karst.) was estimated from longitudinal data. The Korf growth curve was used as the HD curve. Firstly, HD curves for each stand at each measurement time were fitted, and the trends in the parameters of the HD curve were modeled. Secondly, the trends were included in the HD model to estimate the whole model at once. To take the hierarchy of the data into account, a mixed-model approach was used. This makes it possible to calibrate the model for a new stand at a given point in time using sample tree height(s). The heights may be from different points in time and need not be from the point in time being predicted. The trends in the parameters of the HD curve were not estimated as a function of stand age but as a function of the median diameter of basal area weighted diameter distribution (dGm). This approach was chosen because the stand ages may differ substantially among stands with similar current growth patterns. This is true especially with shade-tolerant tree species, which can regenerate and survive for several years beneath the dominant canopy layer and start rapid growth later. The growth patterns in stands with a given dGm, on the other hand, seem not to vary much. This finding indicates that the growth pattern of a stand does not depend on stand age but on mean tree size in the stand.
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Suliman, Tammam, Uta Berger, Marieke Van der Maaten-Theunissen, Ernst Van der Maaten, and Wael Ali. "Modeling dominant height growth using permanent plot data for Pinus brutia stands in the Eastern Mediterranean region." Forest Systems 30, no. 1 (March 31, 2021): eSC03. http://dx.doi.org/10.5424/fs/2021301-17687.
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Aim of the study: At current, forest management in the Eastern Mediterranean region is largely based on experience rather than on management plans. To support the development of such plans, this study develops and compares site index equations for pure even-aged Pinus brutia stands in Syria using base-age invariant techniques that realistically describe dominant height growth.Materials and methods: Data on top height and stand age were obtained in 2008 and 2016 from 80 permanent plots capturing the whole range of variation in site conditions, stand age and stand density. Both the Algebraic Difference Approach (ADA) and the Generalized Algebraic Difference Approach (GADA) were used to fit eight generalized algebraic difference equations in order to identify the one which describes the data best. For this, 61 permanent plots were used for model calibration and 19 plots for validation.Main results: According to both biological plausibility and model accuracy, the so-called Sloboda equation based on the GADA approach showed the best performance.Research highlights: The study provides a solid classification and comparison of Pinus brutia stands growing in the Eastern Mediterranean region and can thus be used to support sustainable forest management planning.Keywords: site index; Generalized Algebraic Difference Approach (GADA); Sloboda equation.
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Sharma, Mahadev, and S. Y. Zhang. "Stand Density Management Diagram for Jack Pine Stands in Eastern Canada." Northern Journal of Applied Forestry 24, no. 1 (March 1, 2007): 22–29. http://dx.doi.org/10.1093/njaf/24.1.22.
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Abstract A stand density management diagram was developed for jack pine (Pinus banksiana Lamb.) stands using the data obtained from 125 permanent sample plots (PSPs) established in Ontario and 232 PSPs in Quebec, Canada. The diagram was evaluated using data from 40 PSPs established in Ontario. Recently developed and efficient models have been used in constructing the diagram to estimate diameters and heights for the trees for which no diameters or heights were recorded at the time of stand inventory. Relative density indices of 0.15, 0.40, and 0.55 were used, corresponding to the line of approximate crown closure, the limit of productive zone, and the lower limit of competition-related mortality, respectively. If two stand characteristics are known, including mean total tree volume, quadratic mean diameter, trees per hectare, and average dominant height, the others can be readily obtained using the diagram. The consequences of various thinning scenarios can be plotted and visualized in the field without the need for computer simulation.
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Pérez-Rodríguez, Fernando, Luis Nunes, Ângelo Sil, and João Azevedo. "FlorNExT®, a cloud computing application to estimate growth and yield of maritime pine (Pinus pinaster Ait.) stands in Northeastern Portugal." Forest Systems 25, no. 2 (July 20, 2016): eRC08. http://dx.doi.org/10.5424/fs/2016252-08975.
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Aim of the study: To introduce and describe FlorNExT®, a free cloud computing application to estimate growth and yield of maritime pine (Pinus pinaster Ait.) even-aged stands in the Northeast of Portugal (NE Portugal).Area of study: NE Portugal.Material and methods: FlorNExT® implements a dynamic growth and yield modelling framework which integrates transition functions for dominant height (site index curves) and basal area, as well as output functions for tree and stand volume, biomass, and carbon content.Main results: FlorNExT® is freely available from any device with an Internet connection at: http://flornext.esa.ipb.pt/.Research highlights: This application has been designed to make it possible for any stakeholder to easily estimate standing volume, biomass, and carbon content in maritime pine stands from stand data, as well as to estimate growth and yield based on four stand variables: age, density, dominant height, and basal area. FlorNExT® allows planning thinning treatments. FlorNExT® is a fundamental tool to support forest mobilization at local and regional scales in NE Portugal.Keywords: forest management; maritime pine; forest modelling; knowledge transfer tool.
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Palik, Brian J., and Kurt S. Pregitzer. "The age and height structure of red maple (Acerrubrum) populations in northern Michigan bigtooth aspen (Populusgrandidentata) forests." Canadian Journal of Forest Research 22, no. 10 (October 1, 1992): 1449–62. http://dx.doi.org/10.1139/x92-195.
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Red maple (Acerrubrum L.) is often the most abundant later successional tree species recruiting in the understories of aspen and oak dominated forests on dry–mesic sites in eastern North America. Limited evidence suggests that this species is capable of recruiting to dominant canopy positions on these sites. Given the potential for increasing overstory importance of red maple in these forests, detailed population-level examinations are warranted. In this study we examined the age and height structures of red maple populations in a bigtooth aspen (Populusgrandidentata Michx.) dominated landscape in northern lower Michigan, United States. Stem analysis was used to examine relationships between establishment times, heights, and height growth rates for overstory and understory red maple from 20 replicate plots in five stands located within a 18-km2 area. Red maple was a minor overstory component in the forests of the study area. The understories of all stands were overwhelmingly dominated by red maple. The populations were composed of two clearly defined age cohorts. The first cohort contained mostly sprout-origin individuals that established concurrently with bigtooth aspen within a 10-year period, beginning 70 years prior to the time of sampling. Mean age of the sprout-origin red maple cohort was not significantly different among stands, nor did it differ from the mean age of bigtooth aspen. Mean height of the red maple sprout-origin cohort was not significantly different among stands. Within each stand, height growth rates of these individuals were highly variable. The variability was not related to differences in stem age. Recent height growth increment of the sprout-origin stems was weakly related to position of an individual in the overstory, suggesting that most red maple were competitively suppressed by taller bigtooth aspen. Some sprout-origin red maple in all stands did approach the dominant bigtooth aspen in height growth rate. These were likely stems that were never competitively suppressed. The second red maple cohort contained seedling-origin individuals that began establishing 30–35 years after stand initiation, immediately after culmination of height increment in dominant overstory bigtooth aspen and red maple. This suggests that increasing resource availability, as a result of declining overstory vigor and canopy closure, may be a factor triggering understory reinitiation in these even-aged forests. In general, heights of seedling-origin red maple were more dependent on stem age compared with sprout-origin individuals. However, height growth rates for similar-aged individuals within the seedling cohort were still highly variable. The tallest individuals generally had the greatest rates of recent height increment, and thus were at a competitive advantage within the understory environment, but these were not always the oldest stems. There was, in fact, a trend of increasing initial height growth rate over time for the fastest growing seedling-origin individuals, again suggesting that resource availability in the understory was increasing over the course of stand development. Red maple's overwhelming understory dominance and ability to reach dominant canopy positions in the stands examined suggests a potential for increasing overstory importance on dry–mesic sites. Life history attributes, including shade tolerance, vigorous resprouting potential, and the ability to respond with increased growth upon release, may foster the development and maintenance of a red maple dominated cover type in the Great Lakes region.
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Kulla, Ladislav, Ivan Sačkov, and Miroslav Juriš. "Test of airborne laser scanning ability to refine and streamline growing stock estimations by yield tables in different stand structures." Forestry Journal 62, no. 1 (March 1, 2016): 39–47. http://dx.doi.org/10.1515/forj-2016-0005.
Full textAbstract:
Abstract Even if stand inventories based on growth tables have been widely discussed over the last years, this method of forest mensuration is still widely applied due to favourable ratio between costs and achievable precision of stand growing stock estimation. The aim of the study was to verify the potential of airborne laser scanning data (ALS) for direct estimation of mean stand height and mean stand density (stocking) as fundamental inputs for forest mensuration based on yield tables. The material from two reference plots with substantially different stand structure was processed by REFLEX software, and confronted with the results of the precise terrestrial inventory. The number of detected tree tops decreased from 100% in the case of super-dominant trees to 30% and 5% in the case of supressed trees at the homogeneous and heterogeneous plot, respectively. The correlation of ALS heights with terrestrially measured heights was R = 0.88 at the homogenous plot, and R = 0.77 at the heterogeneous plot. The tendency to underestimate dominant and to overestimate suppressed trees was revealed at both plots, but was more pronounced at the heterogeneous one. Nevertheless we justified that the mean ALS height calculated from the heights of the detected trees represented the biometric mean stand height linked to the stem with the mean basal area quite well. The stocking estimated by REFLEX software according to delineated crowns´ area was also closer to the real value of stocking than the one obtained by the routine mensuration procedure. The results indicate promising potential of the ALS data processed by REFLEX software to rationalise forest mensuration based on yield tables in even-aged forest structures.
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Larson, Bruce C. "Development and growth of even-aged stands of Douglas-fir and grand fir." Canadian Journal of Forest Research 16, no. 2 (April 1, 1986): 367–72. http://dx.doi.org/10.1139/x86-063.
Full textAbstract:
Stand development patterns and growth rates of even-aged mixed stands of Douglas-fir (Pseudotsugamensiesii Mirb. Franco) and grand fir (Abiesgrandis Dougl. Lindl.) were investigated by stand reconstruction in eastern Washington. Although Douglas-fir dominated the stands early, grand fir of the same age eventually overtook the tallest Douglas-firs. Dominant trees of both species were found to have highly variable taper form (based on basal area to height ratios), although a linear relationship existed in other crown classes. Stem volume growth rates were determined by reconstructing past diameters and heights and were found comparable to site class IV Douglas-fir in western Washington. Intensive management, especially planting and thinning, could improve upon the observed mean annual increments of 800 board feet per acre at 80 years of age.
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Raulier, Frédéric, Chhun-Huor Ung, and Denis Ouellet. "Influence of social status on crown geometry and volume increment in regular and irregular black spruce stands." Canadian Journal of Forest Research 26, no. 10 (October 1, 1996): 1742–53. http://dx.doi.org/10.1139/x26-198.
Full textAbstract:
A model of bole volume increment based on crown dimensions and tree social status is analyzed for its ability to predict bole volume increment independently of stand structure. Data were collected in two boreal black spruce (Piceamariana (Mill.) BSP) stands in Quebec. One stand is even-aged and of seed origin, and the other stand is uneven-aged and of layer origin. A varying parameter approach is taken to show that the crown profile of black spruce depends on competition. Formal expressions for crown surface area and volume are developed from the crown profile and are used to derive a potential growth function for bole volume. Three social status indices are considered to characterize competition experienced by a subject tree: a distance-dependent competition index relating differences of height between the tree and its neighbors to the distance separating them, and two distance-independent indices, one based on tree height relative to dominant stand height and one based on height growth relative to potential height growth of a competition-free tree. These indices are combined with the potential growth function to successfully model bole volume increment. Both stands have an equal weight in the unexplained residual variance. Furthermore, all three social status indices perform equally well at predicting bole volume increment. The use of a potential growth function with crown parameters is further discussed.
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Kaźmierczak, Katarzyna, and Bogna Zawieja. "Tree crown size as a measure of tree biosocial position in 135-year-old oak (Quercus L.) stand." Folia Forestalia Polonica 58, no. 1 (March 1, 2016): 31–42. http://dx.doi.org/10.1515/ffp-2016-0004.
Full textAbstract:
AbstractThe paper presents an attempt to apply measurable traits of a tree – crown projection area, crown length, diameter at breast height and tree height for classification of 135-year-old oak (QuercusL.) trees into Kraft classes. Statistical multivariate analysis was applied to reach the aim. Empirical material was collected on sample plot area of 0.75 ha, located in 135-year-old oak stand. Analysis of dimensional traits of oaks from 135-year-old stand allows quite certain classification of trees into three groups: pre-dominant, dominant and co-dominant and dominated ones. This seems to be quite promising, providing a tool for the approximation of the biosocial position of tree with no need for assessment in forest. Applied analyses do not allow distinguishing trees belonging to II and III Kraft classes. Unless the eye-estimation-based classification is completed, principal component analysis (PCA) method provided simple, provisional solution for grouping trees from 135-year-old stand into three over-mentioned groups. Discriminant analysis gives more precise results compared with PCA. In the analysed stand, the most important traits for the evaluation of biosocial position were diameter at breast height, crown projection area and height.
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Paquin, Raynald, and René Doucet. "Productivité de pessières noires boréales régénérées par marcottage à la suite de vieilles coupes totales au Québec." Canadian Journal of Forest Research 22, no. 4 (April 1, 1992): 601–12. http://dx.doi.org/10.1139/x92-080.
Full textAbstract:
Five black spruce (Piceamariana (Mill.) B.S.P.) stands originating from clear-cutting between 1924 and 1941 in the Baie-Comeau area of Quebec were studied to determine post-harvest growth. The analysis revealed that most stems originated from layers released by clear-cutting of the main stand. Present stem height is closely related to height at time of release: stems that were taller at release are now generally dominant or codominant in the main canopy and tend to contribute more to merchantable stand volume. Volume production of these stands is comparable to that of better sites of normal yield tables for black spruce. This means that black spruce layers occupying the understory, including stems a few meters high, can lead to the etablishment of productive stands when released by clear-cutting of the main stand. Despite the relatively advanced age of stems, decay does not seem to be more prevalent in these stands than in stands originating from seed, whose total age would be equivalent to release age of the stands studied.
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Bailey, R. L., and Stacey W. Martin. "Predicting Dominant Height from Plantation Age and the Diameter Distributions—Site-Prepared Loblolly Pine." Southern Journal of Applied Forestry 20, no. 3 (August 1, 1996): 148–50. http://dx.doi.org/10.1093/sjaf/20.3.148.
Full textAbstract:
Abstract With over 1,300 observations from plots in mechanically site-prepared loblolly pine plantations, regression equations are fitted that predict average height of dominant and codominant trees (i.e., site index trees)from stand age and diameter distribution characteristics. The equations can be used to avoid measuring heights and thus reduce costs of volume inventories in loblolly pine plantations. South. J. Appl. For. 20(3):148-150.
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Paquin, Raynald, and René Doucet. "Croissance en hauteur à long terme de la régénération préétablie dans des pessières noires boréales régénérées par marcottage, au Québec." Canadian Journal of Forest Research 22, no. 4 (April 1, 1992): 613–21. http://dx.doi.org/10.1139/x92-081.
Full textAbstract:
Height-growth patterns of black spruce (Piceamariana (Mill.) B.S.P.) in the boreal forest were studied in layer-origin stands released by clear-cutting in the first half of this century. Most stems responded to release brought about by clear-cutting of the main stand. Initially, small stems responded more rapidly and more strongly, but their height-growth rate culminated between 20 and 30 years following release, the same period when height-growth rate culminated for the taller, older stems. After the culmination period, growth rates were independent of height at the time of release. Consequently, the taller stems at time of release were able to maintain their dominant position. Height growth over the recent years indicates that this position could be maintained in the years to come, and even indefinitely. It seems that second-growth black spruce stands behave like even-aged stands despite their uneven-aged structure. Consequently, years since release and stem height are more accurate measures of stem effective age than total age. Moreover, the taller stems in the understory, which are usually considerably older, should be considered to be as valuable as smaller regeneration when a stand is cut.
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Li, Tie Hua, Shi Zhi Wen, Gong Xiu He, Liang Chen, and Shi Jia Huang. "Study on Superior Tree Selection Methods of Phoebe Hui in Hunan." Advanced Materials Research 1010-1012 (August 2014): 1198–201. http://dx.doi.org/10.4028/www.scientific.net/amr.1010-1012.1198.
Full textAbstract:
Phoebe hui is a precious timber tree species. In order to get excellent seedlings and stands with good genes and develop Phoebe hui better, it is necessary to select superior trees. The dominant trees comparative method and small sample plot method were used to evaluate and select Phoebe hui superior trees in Longshan county, Hunan province, and the evaluation factors included diameter at breast height (DBH), tree height, timber volume and other quality factors. The results showed that, using the dominant trees comparative method, the DBH, tree height and timber volume values of the superior tree were more than 1.12, 1.06 and 1.23 times of the mean values of 5 dominant trees respectively, and 6 superior trees were selected in two stands. Using small sample plot method, the DBH, tree height and timber volume of the superior tree were more than the mean value and 1 times standard deviation value of the stand, and 4 trees were selected as superior tree. These 2 methods can be used for superior tree selection of Phoebe hui in Hunan, and the dominant trees comparative method is more simple and easier for operation.
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Maguire, Douglas A., and William S. Bennett. "Patterns in vertical distribution of foliage in young coastal Douglas-fir." Canadian Journal of Forest Research 26, no. 11 (November 1, 1996): 1991–2005. http://dx.doi.org/10.1139/x26-225.
Full textAbstract:
Total amount and vertical distribution of foliage represent important aspects of forest stand structure and its influence on dry matter productivity, forest microclimate, watershed properties, and habitat structure. Variation in foliage distribution was analyzed on trees and plots in a series of even-aged Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stands scheduled for management under a wide range of silvicultural regimes. Branch-level foliage mass and foliage area equations were developed from a sample of 138 branches. These equations were applied to 27 trees on which the diameter and height of all live primary branches were measured, allowing estimation of both the total amount of foliage and its vertical distribution. A β-distribution was fitted to data describing the vertical distribution of foliage on each tree, and the resulting parameter estimates were modelled as functions of tree height, diameter at breast height, crown length, and relative height in the stand. Foliage area distribution tended to be shifted downward relative to foliage mass because of the expected increase in specific leaf area with depth into the crown. Similarly, the relative foliage distribution in terms of both mass and area was shifted downward as the tree became more dominant, or as relative height in the stand increased. In contrast, foliage on trees of similar relative height was shifted upward in response to the lower stand densities imposed by precommercial thinning. On the stand level, relative vertical distribution of foliage in the canopy was more peaked than would be implied by assuming a constant leaf area/sapwood area ratio throughout the composite tree crowns. Between-stand variation in vertical foliage distribution was dictated by differences in stand top height, height to crown base, and number of trees per hectare.
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Rossi, Sergio, Marie-Josée Tremblay, Hubert Morin, and Valérie Levasseur. "Stand structure and dynamics of Picea mariana on the northern border of the natural closed boreal forest in Quebec, Canada." Canadian Journal of Forest Research 39, no. 12 (December 2009): 2307–18. http://dx.doi.org/10.1139/x09-152.
Full textAbstract:
The boreal forest of higher latitudes constitutes a reservoir of trees of great ecological importance and unknown economic potential, but the stand dynamics in these regions still remain essentially unexplored. This paper examines the change in age and size structures during stand development on the northern border of the natural closed boreal forest in Quebec, Canada. Height, diameter, and age of trees were measured in 18 plots with stand ages between 77 and 340 years. The occurrence, size, and origin (layer or seed) of seedlings and saplings were assessed in subplots. Tree density ranged from 600 to 3750 trees·ha–1. Picea mariana (Mill.) BSP was the dominant species, mainly originating by layering. A cluster analysis segregated plots into even-aged and uneven-aged stands according to tree age, but size distribution of trees, saplings, and seedlings did not differ statistically between the two groups. Even-aged stands exhibited a 60% probability of assuming an uneven-aged structure between 120 and 200 years after stand initiation. At high latitudes, the closed boreal forest of P. mariana appears homogeneously sized, with similar distributions of diameter and height across all stages of stand development.
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Harding, R. Bruce. "Terminal leader failure in white spruce plantations in northern Minnesota." Canadian Journal of Forest Research 16, no. 3 (June 1, 1986): 648–50. http://dx.doi.org/10.1139/x86-111.
Full textAbstract:
Terminal leader failure from bud mortality occurred in 46% of plantation white spruce (Piceaglauca (Moench) Voss) trees, 19–43 years old. Frost damage was identified as the causal factor of bud mortality, with all plantations being established from seed sources of local origin. Large differences in terminal bud failure rates were noted between year of observation, tree size class, and stand age-class. Dominant trees, 33–43 years old, had a 3 year failure rate ranging from 16 to 51 %. For dominant trees, an 18% (9 cm) height growth reduction per year of incidence was noted. The lateral replacement process could account for greater than a 2 m height reduction for dominants at age 50 years, confounding estimates of potential site quality. The height growth of overtopped trees responded differently to frost damage than dominants, with replacement laterals averaging 38% (8 cm) greater height growth than apical terminals of undamaged trees.
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Han, Yangang, Zeyong Lei, Albert Ciceu, Yanping Zhou, Fengyan Zhou, and Dapao Yu. "Determining an Accurate and Cost-Effective Individual Height-Diameter Model for Mongolian Pine on Sandy Land." Forests 12, no. 9 (August 24, 2021): 1144. http://dx.doi.org/10.3390/f12091144.
Full textAbstract:
Height-diameter (H-D) models are important tools for forest management practice. Sandy Mongolian pine plantations (Pinus sylvestris var. mongolica) are a major component of the Three-North Afforestation Shelterbelt in Northern China. However, few H-D models are available for Mongolian pine plantations. In this paper we compared different equations found in the literature for predicting tree height, using diameter at breast height and additional stand-level predictor variables. We tested if the additional stand-level predictor variable is necessary to produce more accurate results. The dominant height was used as a stand-level predictor variable to describe the variation of the H-D relationship among plots. We found that the basic mixed-effects H-D model provided a similar predictive accuracy as the generalized mixed-effects H-D model. Moreover, it had the advantage of reducing the sampling effort. The basic mixed-effects H-D model calibration, in which the heights of the two thickest trees in the plot were included to calibrate the random effects, resulted in accurate and reliable individual tree height estimations. Thus, the basic mixed-effects H-D model with the above-described calibration design can be an accurate and cost-effective solution for estimating the heights of Mongolian pine trees in northern China.
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Clatterbuck, Wayne K., and John D. Hodges. "Development of cherrybark oak and sweet gum in mixed, even-aged bottomland stands in central Mississippi, U.S.A." Canadian Journal of Forest Research 18, no. 1 (January 1, 1988): 12–18. http://dx.doi.org/10.1139/x88-003.
Full textAbstract:
Development of even-aged mixed cherrybark oak (Quercusfalcata var. pagodifolia Ell.) and sweet gum (Liquidambarstyraciflua L.) stands was examined over a range of stand densities and ages in minor river bottoms of central Mississippi, U.S.A. Two stand development patterns were documented based on average spacing between dominant and codominant trees during the pole stage of development: a "restricted" pattern and an "unrestricted" pattern. The restricted pattern occurred at average spacings of less than 5.5 m. Here cherrybark oak was initially shorter than sweet gum but was able to outgrow and stratify above sweet gum when the stand was 20 to 25 years of age. Dominant and codominant cherrybark oaks averaged 61 cm in diameter, 34 m in height, and had 15 m of merchantable height at 58 years. The unrestricted pattern was found where cherrybark oak was either a few years older than sweet gum or was essentially open grown, with dominant and codominant trees of either species being more than 5.5 m apart. The unrestricted pattern resulted in cherrybark oak attaining less than 8 m of clear merchantable length and diameters of 56 cm in 40 years. The spacing of interacting trees appears to be responsible for the differences between the two development patterns in the timing and rate of cherrybark oak crown expansion, diameter growth, and length of the merchantable bole.
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Pienaar, L. V., and J. W. Rheney. "Yield Prediction for Mechanically Site-Prepared Slash Pine Plantations in the Southeastern Coastal Plain." Southern Journal of Applied Forestry 17, no. 4 (November 1, 1993): 163–73. http://dx.doi.org/10.1093/sjaf/17.4.163.
Full textAbstract:
Abstract Yield prediction equations with different input requirements, and intended for stand-level management planning, are presented in four separate sections: (1) Unthinned plantations with site index and planting survival at age 2 as input. Per-acre basal area and volume prediction equations are presented. (2) Thinned or unthinned plantations with age, surviving trees per acre, and average dominant/codominant height or site index as input; (3) A Weibull distribution-based yield prediction system for existing unthinned plantations with age, surviving trees per acre, and average dominant/codominant height as input. Tree volume and height prediction equations, developed for this plantation resource, are presented. (4) Future yield for thinned and unthinned plantations when an initial stand table is available. Survival and per-acre basal area projection equations of Section 2 are required to project the stand table. South. J. Appl. For. 17(4):163-173.
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Harms, William R., Dean S. DeBell, and Craig D. Whitesell. "Stand and tree characteristics and stockability in Pinustaeda plantations in Hawaii and South Carolina." Canadian Journal of Forest Research 24, no. 3 (March 1, 1994): 511–21. http://dx.doi.org/10.1139/x94-068.
Full textAbstract:
Stand structure and crown architecture of loblolly pine (Pinustaeda L.) spacing trials in Hawaii and South Carolina were examined for attributes that would explain markedly different stockabilities (stand density per mean stand DBH), respectively, 1740 and 850 trees/ha at a quadratic mean stand DBH of 25 cm. In plots spaced at 2.4 × 2.4 m, these stockabilities produced 604 m3/ha at age 25 in Hawaii, and 297 m3/ha in South Carolina. Data collected in these stands indicate that stockability differences were associated with differences in tree size-class structure, crown length, and leaf area. Both stands were characterized by a two-tiered height structure, but the crown bases of trees in the subdominant class in Hawaii extended 1–2 m below the bases of the crowns of the dominant height class. In the South Carolina stands the crown bases of both height classes were at the same level. Green crown lengths in Hawaii were 4–7 m longer than in South Carolina, and the associated crown leaf area of 63.9 m2 was five times greater. The differences in stockability was attributed to the Hawaiian site and climate, which provide a long growing season, high solar radiation, high sun angle, favorable temperatures, and a favorable soil moisture regime and foliage nutrient status, and to a lack of significant insect and disease pests. The influence of genotype on stockability was not testable with these data.
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Bravo-Oviedo, Andrés, Clemente Gallardo-Andrés, Miren del Río, and Gregorio Montero. "Regional changes of Pinus pinaster site index in Spain using a climate-based dominant height model." Canadian Journal of Forest Research 40, no. 10 (October 2010): 2036–48. http://dx.doi.org/10.1139/x10-143.
Full textAbstract:
This study compares two site index estimations for Mediterranean maritime pine ( Pinus pinaster Ait.) stands in the Iberian Peninsula. The first prediction was performed under the assumption of constant climate conditions, whereas the second one used foreseen climate according to an energy-use increment and high population growth (IPCC’s A2 emission scenario). We used an existing climate-based dominant height model that incorporates temperature, seasonal precipitation in winter and autumn, and drought length as driver variables for dominant height growth. Climate attributes were retrieved from eight regional climate models nested in the same atmospheric–ocean global circulation model. Forest stand data from 188 experimental plots in four natural regions were used to compare regional climate change trends. Results indicated a climate-related diminishing trend of site index values, although some regional differences were evident. In the northern stands, the negative effects were not observed, and in some cases, forest productivity increased on low site index classes. Conversely, in the southernmost stands, there is a significant decrease in the site index across all productivity classes. Western and eastern stands also showed a decreasing trend but to a lesser extent. Our results confirm the vulnerability of stands to warmer and drier climate conditions in the southern Mediterranean region in relation to wood productivity.
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Légaré, Sonia, David Paré, and Yves Bergeron. "The responses of black spruce growth to an increased proportion of aspen in mixed stands." Canadian Journal of Forest Research 34, no. 2 (February 1, 2004): 405–16. http://dx.doi.org/10.1139/x03-251.
Full textAbstract:
In the southeastern boreal forest of Canada, the presence of mixed stands of black spruce (Picea mariana (Mill.) BSP) and trembling aspen (Populus tremuloides Michx.) growing in similar abiotic conditions offers the opportunity to study the influence of aspen on stand volume and spruce growth. A regression analysis performed on field data from the ministère des Ressources naturelles du Québec showed a significant relationship between the relative basal area of aspen (aspen relative basal area was determined by the ratio of aspen basal area to total basal area of the stand) and the total stand merchantable volume after accounting for stand density. However, the relationship between total black spruce volume and relative basal area of aspen was not significant, implying that the volume gain was, in fact, aspen fibre. The positive effects of aspen on black spruce DBH and height were only present when the proportion of aspen in the stand ranged between 0% and 41% of the total stand basal area. These results suggest that aspen uses a different niche than black spruce. Furthermore, the significant increase in black spruce dominant height along the aspen gradient suggests that aspen enhances soil fertility by its influence on nutrient availability. The management of mixed stands, which make up an important proportion on the landscape, offers an example as to how commercial management of the forest can be in agreement with ecosystem management.
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Dussault, Christian, Réhaume Courtois, Jean Huot, and Jean-Pierre Ouellet. "The use of forest maps for the description of wildlife habitats: limits and recommendations." Canadian Journal of Forest Research 31, no. 7 (July 1, 2001): 1227–34. http://dx.doi.org/10.1139/x01-038.
Full textAbstract:
We evaluated the reliability of forest maps for describing wildlife habitats. During the summer of 1997, we sampled 186 boreal forest stands located in Jacques-Cartier Park, Quebec. In each stand, we measured slope, crown closure, basal area, as well as tree height and age. We determined if map classifications, with regard to dominant species composition, density, tree height, tree age, and slope, correlated with field observations. We also measured lateral cover and deciduous browse availability, variables that are considered useful for the characterization of wildlife habitats, to examine how these habitat features were related to map classification. Age (57% of the sites correctly classified) and density (34%) were the variables for which map classification had the best and worst correspondence with field measurements, respectively. Dominant species on maps were correctly identified in <74, <55, and <40% of the sites in coniferous, mixed, and deciduous stands, respectively. The use of a simple classification method based on cover type alone resulted in improved correlations, since 94, 60, and 29% of the coniferous, mixed, and deciduous stands, respectively, were properly identified on maps. We related lateral cover and food availability to stand categories using the most reliable map variables. We conclude that forest maps are useful for describing major habitats at the stand level. When forest resource maps are to be used for studying habitat suitability, we recommend sampling a subset of stands to assess if important wildlife habitat features, which reflect species requirements, can be related to habitat characteristics as determined by the maps.
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Coble, Dean W., and Young-Jin Lee. "A Mixed-Effects Height—Diameter Model for Individual Loblolly and Slash Pine Trees in East Texas." Southern Journal of Applied Forestry 35, no. 1 (February 1, 2011): 12–17. http://dx.doi.org/10.1093/sjaf/35.1.12.
Full textAbstract:
Abstract A new mixed-effects model was developed that predicts individual-tree total height for loblolly (Pinus taeda) and slash pine (Pinus elliottii) as a function of individual-tree diameter (in.), dominant height (ft), quadratic mean diameter (in.), and maximum stand diameter (in.). Data from 119,983 loblolly pine and 42,697 slash pine height–diameter observations collected on 185 loblolly pine and 84 slash pine permanent plots located in plantations throughout East Texas were used for model fitting. This new model is an improvement over earlier models fit with ordinary least squares, in that it can be calibrated to a new stand with observed height–diameter pairs, thus improving height prediction. An example is provided that describes how to calibrate the model to a new stand with observed data.
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Thomson, Alan J. "Comparison of lodgepole pine yield tables." Canadian Journal of Forest Research 17, no. 9 (September 1, 1987): 1110–14. http://dx.doi.org/10.1139/x87-169.
Full textAbstract:
Iterative solution of equations from Johnstone's variable-density yield tables for lodgepole pine permitted estimates of stand development index (DI) and productivity index (PI) from the volume, quadratic mean of diameter at breast height, basal area, or dominant–condominant height associated with a particular stand density at a particular age. Using such estimates, the yield tables of Smithers were compared with those of Johnstone. PI values associated with each of Smithers' site indices were calculated for British Columbia and Alberta. Results suggested that Johnstone's equations could be used in lodgepole pine stands in both British Columbia and Alberta, for PI values from 0.7 to 1.2, for densities up to 2500 stems acre−1 at age 70, and for ages up to 120. This considerably extends the range of application of these equations.
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Kabzems, Richard, and Oscar García. "Structure and dynamics of trembling aspen white spruce mixed stands near Fort Nelson, B.C." Canadian Journal of Forest Research 34, no. 2 (February 1, 2004): 384–95. http://dx.doi.org/10.1139/x03-254.
Full textAbstract:
The trembling aspen (Populus tremuloides Michx.) white spruce (Picea glauca (Moench) Voss) mixed woods near Fort Nelson are distinguished by the large size of individual trees, longevity, and the low occurrence of internal decay in trembling aspen. The development of these forest ecosystems has had limited documentation and may be significantly different than those described in other portions of the boreal forest. At five study stands, stem analysis techniques were used to examine the patterns of height and radial growth over time according to species and structure type. There were two patterns of species establishment that were consistent with the stand structure. In codominant stands, recruitment periods for trembling aspen and white spruce overlapped. The stratified stands were consistently associated with a 29- to 58-year lag in white spruce recruitment. Spruce that were codominant with aspen at the time of sampling had sustained periods of rapid height and diameter growth. White spruce that were later to establish on site had slower rates of height and diameter growth. White spruce ages indicated that a dominant recruitment episode was more common than continuous recruitment. Height and diameter growth of trembling aspen were similar in both stand types. The differences in trembling aspen growth patterns between stands were due to site quality. The white spruce in codominant stands did not appear to go through a period of suppression and then release associated with stand-level trembling aspen mortality, as commonly described for other boreal mixedwoods. The vigor and longevity of trembling aspen in Fort Nelson appear to prolong the period of trembling aspen domination of mixed stands well beyond the time periods observed in other boreal ecosystems.
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Boily, Jocelyn, and René Doucet. "Croissance juvénile de marcottes d'épinette noire en régénération après récolte du couvert dominant." Canadian Journal of Forest Research 23, no. 7 (July 1, 1993): 1396–401. http://dx.doi.org/10.1139/x93-176.
Full textAbstract:
Annual height growth of natural regeneration was measured in 18- to 21-year-old clear-cuts of black spruce stands growing on sites of contrasted drainage, in two ecological regions of the Haute-Gatineau-et-Cabonga management unit in western Quebec. Most regeneration was established by layering and was growing slowly on all sites at time of release by clear-cutting of the main stand. Height growth rates increased rapidly thereafter on mesic sites: about 7 to 8 years after release, it reached 15 cm or more per year, and 32 to 45 cm per year 20 years after harvest. On moist sites, growth rates of 15 cm per year were attained only 10 to 15 years after release, and did not exceed 25 cm at age 20. These results show that growth of black spruce natural regeneration is controlled more by site quality than by the mechanism responsible for reproduction.
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Deal, Robert L., Chadwick Dearing Oliver, and Bernard T. Bormann. "Reconstruction of mixed hemlock–spruce stands in coastal southeast Alaska." Canadian Journal of Forest Research 21, no. 5 (May 1, 1991): 643–54. http://dx.doi.org/10.1139/x91-088.
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Stands of western hemlock (Tsugaheterophylla (Raf.) Sarg.) and Sitka spruce (Piceasitchensis (Bong.) Carr.) on low-elevation, upland sites in coastal southeast Alaska develop as single-generation stands after stand-replacing disturbances and as multiple-generation stands after minor disturbances. Both stand types were studied. Spruce grew rapidly after major and minor windthrow events and reached the mid to upper canopy of the stand. Hemlock showed variable growth patterns and occupied both upper and lower canopy positions. Unlike forested regions containing more tree species, the species compositions and stand structures were similar among both the single- and multiple-generation stands. Hemlock and spruce occupied unique yet similar canopy and stand structural positions in both single- and multiple-generation stands because they had distinctly different regeneration and development patterns. Regardless of the frequency or intensity of the disturbance, spruce usually regenerated on mineral or mixed-soil microsites created by wind-throw events, and hemlock usually regenerated on organic substrates. Hemlock regeneration was prolific and tended to dominate sites by sheer number. Mortality rates were extremely high, but the large number of hemlock seedlings guaranteed many surviving stems. Spruce regeneration was much lower, but this species had higher survival rates and generally more rapid height growth. An important stand component was the advance hemlock regeneration that existed prior to the new stand; they formed a significant and dominant position in the future stand.
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Hökkä, Hannu, and Risto Ojansuu. "Height development of Scots pine on peatlands: describing change in site productivity with a site index model." Canadian Journal of Forest Research 34, no. 5 (May 1, 2004): 1081–92. http://dx.doi.org/10.1139/x03-275.
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The effect of site properties and forest drainage on the dominant height development of Scots pine (Pinus sylvestris L.) stands in peatland sites was studied using data from permanent sample plots located in natural and drained sites in northern Finland. The Korf model was used to describe the height development of dominant trees in natural sites. The effect of drainage on height development was accounted for by a term giving a nonlinear height increase for drained sites as a function of the time elapsed since drainage. The variance component model was applied to account for the hierarchical data structure. Natural height development after 30 years of age at DBH was significantly slower in PF sites (sparsely forested pine fens) than in PS sites (genuine forested pine swamps). Within PF sites, there were further differences in relation to nutrient availability. Temperature sum explained the variation in the intercept. In PS sites, drainage resulted in a moderate increase in the maximum attainable height, while in PF sites, drainage improved site productivity by 80%85% in terms of the attainable height. The asymptote for drained stands was dependent on stand age at the time of drainage. Differences between the two major groups were assumed to be due to initial differences in site water regime.
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Téo, Saulo Jorge, Sebastião do Amaral Machado, Afonso Figueiredo Filho, and Margarida Tomé. "GENERAL HEIGHT-DIAMETER EQUATION WITH BIOLOGICAL ATTRIBUTES FOR Pinus taeda L. STANDS." CERNE 23, no. 4 (December 2017): 403–11. http://dx.doi.org/10.1590/01047760201723042414.
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ABSTRACT The aim of this study was to develop an equation with biological attributes and general applicability, to represent the height-diameter relationship for Pinus taeda L. stands, with and without thinning, in the Middle West region of Santa Catarina state, Brazil. The data came from 652 permanent plots, with 428 to 740 m2, located in forest stands with ages ranging from 4.6 to 35.2 years, in which the total heights of about 20% of the trees were measured, in addition to the dominant trees. The functions developed by Harrison, Michailoff, Prodan and Stoffels & Van Soest were fitted with their parameters linear function of stand variables, based on the Gauss-Newton algorithm. In general, the Harrison model, fitted with the parameter linear function of age (t), site index (S), coefficient of variation of the tree diameters in the plot (CV d ) and basal area of the plot (G), showed the best statistical performance to represent the height-diameter relationship, biological consistency and general applicability for stands of Pinus taeda.
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Amateis, Ralph L., Jiping Liu, Mark J. Ducey, and H. Lee Allen. "Modeling Response to Midrotation Nitrogen and Phosphorus Fertilization in Loblolly Pine Plantations." Southern Journal of Applied Forestry 24, no. 4 (November 1, 2000): 207–12. http://dx.doi.org/10.1093/sjaf/24.4.207.
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Abstract Data from a fertilizer response study in loblolly pine (Pinus taeda L.) plantations at different sites in the southeastern United States were used to develop response models for dominant height and basal area following midrotation nitrogen (N) and phosphorus (P) fertilization. Nonlinear regression models developed from the data predict total cumulative response as a function of the interaction of N and P application rates, drainage class of the site, stand conditions when fertilized, and time since fertilization. Stand variables that were found to be significant predictors of response included site index, age, basal area, number of surviving trees, and dominant height at fertilization. Dominant height response was significantly greater on poorly drained sites than on other sites. Basal area response to P was significantly less on poorly drained sites and significantly greater on well drained sites. These models can be coupled with unfertilized baseline models to estimate volume response to midrotation fertilization. South. J. Appl. For. 24(4):207-212.
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Dobrowolska, D. "Growth and development of silver fir (Abies alba Mill.) regeneration and restoration of the species in the Karkonosze Mountains." Journal of Forest Science 54, No. 9 (September 24, 2008): 398–408. http://dx.doi.org/10.17221/29/2008-jfs.
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The main task of the study was to investigate the growth conditions of silver fir natural regeneration in the Karkonosze Mts. (Poland). The paper examines the quantity and quality of light reaching the forest floor in stands of different canopies. The aim of the study was also to define the optimal site conditions for silver fir planting under stand canopy. Data on the natural regeneration and stand structure of each investigated stand were collected on circular plots in a grid of 15 × 15 m in 1999 and 2000. Biometric measurements of fir plants planted under various stand canopies were done three times (May 1999, autumn 2000 and 2001). It was found that the fir was not a dominant tree in all size classes from seedlings to saplings. Seedlings (both phases) of spruce, beech, sycamore and rowan occurred in all studied stands. The optimal conditions for fir development were found under larch canopy. That was demonstrated by the highest increment of height, diameter and offshoots. The worst conditions for fir growth were under beech and spruce canopy, which was indicated by the lowest diameter and height. The highest PAR was recorded under pine canopy, whereas the lowest one under beech canopy. Beech stand induced a lower R:FR ratio than the other tree species both on sunny and cloudy days. The highest R:FR ratio was found under the canopy of larch and pine stands.
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Hipler, Sandra-Maria, Heinrich Spiecker, and Shuirong Wu. "Dynamic Top Height Growth Models for Eight Native Tree Species in a Cool-Temperate Region in Northeast China." Forests 12, no. 8 (July 21, 2021): 965. http://dx.doi.org/10.3390/f12080965.
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In this study, we developed dynamic top height growth models for the eight important Chinese tree species Larix gmelinii var. principis-rupprechtii, Pinus tabuliformis Carr., Pinus sylvestris var. mongolica Litv., Picea asperata Mast., Quercus mongolica Fisch. ex Ledeb, Betula platyphylla Suk., Betula dahurica Pall. and Populus davidiana Dode based on age-height relationships. For this purpose, commonly growth data from long-term observations of permanent experimental plots are used, which ideally cover all development stages from stand establishment to final harvest. As such data were not available in the research area of Hebei Province in Northeast China, we used stem analysis data as well as tree height and annual shoot length measurements. The dataset consisted of 72 stands, 233 dominant trees and 10,195 observations of stem discs and annual shoot length measurements. Five dynamic base-age invariant top height growth models were derived from four base models with the generalized algebraic difference approach and fitted to our age-height data using nested regression techniques. According to biological plausibility and model accuracy the Chapman–Richards model showed the best performance for Picea asperata. This selected model accounted for 99% of the total variance in age-height relationship with average absolute bias of 0.2322 m, root mean square error of 0.3337 m and Radj2 of 0.9979, respectively. The distribution of the residuals was scattered around 0 and without visible trends, indicating that the fitness of the models was good. All developed models are able to generate top height growth curves representing the analyzed height growth data and can be utilized for predicting height growth on the base of current height and age of dominant trees. Additionally, they are the base for calculating the development of other relevant stand attributes such as basal area and volume growth. The determination of potential site productivity by the use of top height growth curves is a practical and convenient method for a simplified presentation of complex growth processes in stands and helps to create growth models, which facilitate implementing sustainable forest management practices in Mulan Forest.