Testing a new competition index for Maritime pine in northwestern Spain

1999 ◽  
Vol 29 (2) ◽  
pp. 280-283 ◽  
Author(s):  
Jörg Schröder ◽  
Klaus von Gadow
Keyword(s):  
Basal Area ◽  
Stand Density ◽  
Maritime Pine ◽  
Competition Index ◽  
Potential Growth ◽  
Relative Spacing ◽  
Pine Trees ◽  
Northwestern Spain ◽  
Naturally Regenerated Stands ◽  
Individual Trees

A distance-independent competition index is derived from the basal area in larger trees (BAL) index combining individual tree's basal area percentiles with a relative-spacing stand-density measure. Empirical increment data from Maritime pine trees (Pinus pinaster Ait.) sampled from regular, naturally regenerated stands in the province of Pontevedra, northwestern Spain, are used to compare the performance of the two competition indices in the context of basal area growth modelling. The basal area increment of individual trees was first predicted exclusively as a response to competition using a two-parameter exponential function and then as a function of potential growth reduced by competition. For the criteria evaluated in this paper, the new competition index has shown superior qualities. The main improvement over BAL is the incorporation of the relative spacing measure.

An age-independent basal area increment model for maritime pine trees in northwestern Spain

2002 ◽  
Vol 157 (1-3) ◽  
pp. 55-64 ◽  
Author(s):  
Jörg Schröder ◽  
Roque Rodrı́guez Soalleiro ◽  
Guillermo Vega Alonso
Keyword(s):  
Basal Area ◽  
Maritime Pine ◽  
Basal Area Increment ◽  
Pine Trees ◽  
Northwestern Spain ◽  
Age Independent

Incorporating intertree competition into an ecosystem model

1995 ◽  
Vol 25 (3) ◽  
pp. 413-424 ◽  
Author(s):  
R.L. Korol ◽  
S.W. Running ◽  
K.S. Milner
Keyword(s):  
Process Model ◽  
Basal Area ◽  
Stand Density ◽  
Tree Height ◽  
Ecosystem Model ◽  
Growth And Yield ◽  
Maintenance Respiration ◽  
Tree Diameter ◽  
Diameter Increment ◽  
Individual Trees

Current research suggests that projected climate change may influence the growth of individual trees. Therefore, growth and yield models that can respond to potential changes in climate must be developed, TREE-BGC, a variant of the ecosystem process model FOREST-BGC, calculates the cycling of carbon, water, and nitrogen in and through forested ecosystems. TREE-BGC allocates stand-level estimates of photosynthesis to "each tree using a competition algorithm that incorporates tree height, relative radiation-use efficiency, and absorbed photosynthetically active radiation, TREE-BGC simulated the growth of trees grown in a dense and an open stand of interior Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) near Kamloops, B.C. The competition algorithm dynamically allocated stand estimates of photosynthesis to individual trees, and the trees were grown using an allometric relationship between biomass increment and height and diameter increment. Asymptotic height growth and the changes in the height–diameter relationship with competition were also incorporated in the model algorithms. Sapwood and phloem volume were used to calculate maintenance respiration. Predicted reductions in diameter growth with stand density were similar to those observed in the study stands. Although the carbon balance of individual trees was not tested, simulated tree diameter increments and height increments were correlated with the actual measurements of tree diameter increment (r2 = 0.89) and tree height increment (r2 = 0.78) for the 5-year period (n = 352). Although the model did not work well with trees that had diameters <5 cm, the model would be appropriate for a user who required an accuracy of ± 0.03 m3•ha−1 for volume, ± 0.02 m2•ha−1 for basal area, or ± 0.4 m for tree height over a 5-year period.

scholarly journals Effects of Permanent and Temporary Edges on Pinus clausa (sand pine) Architecture and Stand Conditions

2021 ◽  
Author(s):  
Colin Brownell Smith ◽  
Francis Putz
Keyword(s):  
Edge Effects ◽  
Forest Type ◽  
Basal Area ◽  
Stand Density ◽  
Canopy Tree ◽  
Pine Trees ◽  
North And South ◽  
Stand Conditions ◽  
Sand Pine ◽  
Pinus Clausa

Effects of permanent (i.e., maintained) and temporary edges with north- and south-facing exposures were studied in sand pine (Pinus clausa var. clausa) scrub, an open-canopied forest type in Ocala National Forest, Florida. On edges and interiors of four stands of each type, we measured canopy tree architecture in 5 x 100 m plots and stand density and basal area in 5 x 200 m plots. Edge effects were modest but often stronger on south- than north-facing edges and along permanent forest roads than temporary edges of clearcuts that were allowed to regrow. Compared to interior trees, those on edges were typically shorter, retained branches lower on their boles, oriented their first branches more towards the edge, and produced more asymmetrical crowns with the long axis extending into the opening; these trends were greater on south- than north-facing edges and along permanent than temporary edges. Contrary to expectations, there were no edge effects on total basal area, dead tree densities, proportions of sand pine trees with leaning trunks, directions of lean, or angles of lean. Instead of an edge effect, most trees leaned southwesterly, which seems related to the northeastern origin of prevailing winds and wind gusts.

Stand structure and growing space efficiency following thinning in an even-aged Douglas-fir stand

1988 ◽  
Vol 18 (7) ◽  
pp. 859-866 ◽  
Author(s):  
K. L. O'Hara
Keyword(s):  
Stand Structure ◽  
Volume Growth ◽  
Basal Area ◽  
Stand Density ◽  
Douglas Fir ◽  
Stem Volume ◽  
Projection Area ◽  
Individual Tree ◽  
Space Efficiency ◽  
Individual Trees

The growth of individual trees from four thinning treatments in a 64-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stand was analyzed to determine desirable residual stand structures after thinning. Dominant and codominant trees had the highest individual tree stem volume growth rates over the previous 5 years, and accounted for most stand volume growth in thinned and unthinned stands. Two measures of growing space, crown projection area and sapwood basal area (a surrogate for leaf area), were used to measure how efficiently individual trees used their growing space. Crown classes were useful in characterizing growing space efficiency (volume growth per unit of growing space) only in the unthinned treatment. In thinned treatments, tall trees with medium-sized crowns were most efficient, while in the unthinned treatment, tall trees with relatively large crowns were most efficient. A large crown in an unthinned stand was comparable in size to a medium-sized crown in a thinned stand. Results suggest growing space is not limiting individual tree growth in thinned stands and that thinning to a particular stand structure is more appropriate than thinning to a particular level of stand density.

Competition-induced changes in developmental features of planted Douglas-fir in southwestern British Columbia

1986 ◽  
Vol 16 (2) ◽  
pp. 191-196 ◽  
Author(s):  
David G. Brand
Keyword(s):  
Basal Area ◽  
Douglas Fir ◽  
Developmental Expression ◽  
Competition Index ◽  
Resource Limitations ◽  
Developmental Characteristics ◽  
Individual Trees ◽  
Induced Changes ◽  
Relationship Of ◽  
Developmental Features

One- to five-year-old Douglas-fir, planted operationally, were measured for various developmental characteristics indicative of competition-induced acclimation to resource limitations. Characteristics were tested against a competition index based on measures of the brush canopy surrounding individual trees. The most promising developmental characteristics for assessing competition stress were the specific leaf area of foliage, the allometric relationship of height to basal area, and bud production on nodal shoots. Measures of foliar nitrogen status and leaf internode length were less well correlated with the competition index. Comparing these results with those of controlled laboratory studies gives an indication that on the sites studied, brush competition effects on planted trees are expressed through developmental acclimation to reduced light intensity. Developmental expression of changing nutrient or moisture availability was less evident, but may be confounded by reduced demand or secondary brush canopy effects.

scholarly journals Effect of Hardwoods and Pine Density on Natural Loblolly Pine Yields and Product Distribution

1996 ◽  
Vol 20 (2) ◽  
pp. 99-102
Author(s):  
Barry D. Shiver ◽  
Graham H. Brister
Keyword(s):  
Loblolly Pine ◽  
Total Yield ◽  
Basal Area ◽  
Stand Density ◽  
Product Distribution ◽  
Yield Function ◽  
Variable Threshold ◽  
Pine Trees ◽  
Pinus Taeda L ◽  
Georgia Piedmont

Abstract Data from 75 yield plots in natural loblolly pine (Pinus taeda L.) stands from the Georgia Piedmont were used to investigate the effects of hardwood and pine stand density on pine yields and product distribution. A yield function incorporating percentage of total basal area in hardwoods and the number of pine trees per acre, and a modifying equation to estimate merchantable volume to any top diameter limit above variable threshold diameters, were developed and used to evaluate these effects. There was a slight decrease in total yield as pine trees per acre increased, but the percentage of total yield in sawtimber decreased dramatically above 100 trees/ac. Hardwoods also decreased yields with virtually all of the decrease coming from sawtimber. South. J. Appl. For. 20(2):99-102.

Six-Year Response of Northern Hardwoods to the Selection System

1984 ◽  
Vol 1 (4) ◽  
pp. 87-91 ◽  
Author(s):  
Stephen F. Mader ◽  
Ralph D. Nyland
Keyword(s):  
Basal Area ◽  
Stand Density ◽  
Diameter Distribution ◽  
Northern Hardwoods ◽  
Selection System ◽  
Northern Hardwood ◽  
Selection Cutting ◽  
Optimum Diameter ◽  
Commercial Species ◽  
Individual Trees

Abstract During 6 years following selection cutting, three northern hardwood stands grew 2.8 to 3.3 square feet in basal area and 316 to 332 board feet (Int.) per acre per year. Over two-thirds of the volume accrued on trees at least 16 inches dbh. Individual trees grew most rapidly at lowest residual basal areas, with growth of small trees most sensitive to differences in stand density. Irregularities in the diameter distribution became less distinct during the 6 years. About 60 to 70% of the regeneration was of commercial species, and more than 316 seedlings per acre grew to heights of at least 6 feet. Most plots with 6-foot regeneration had advance seedlings at least 1 foot tall at the time of cutting. Results confirm the validity of the selection system, and indicate that uneven-aged northern hardwood stands with a reasonably well-balanced diameter distribution can be repeatedly cut at 12- to 15-year intervals to a constant, optimum diameter distribution. North. J. Appl. For. 1:87-91, Dec. 1984.

Incorporating stand density effects in modeling the taper of red pine plantations

2020 ◽  
Vol 50 (8) ◽  
pp. 751-759
Author(s):  
Mahadev Sharma
Keyword(s):  
Basal Area ◽  
Stand Density ◽  
Red Pine ◽  
Pine Plantations ◽  
Individual Tree ◽  
Stem Taper ◽  
System Of Units ◽  
Pine Trees ◽  
Parameter Values ◽  
Taper Models

Taper models are used to estimate the diameter at any height along the bole of a tree. Individual tree volume can then be calculated based on these diameters and corresponding heights. As tree diameters are affected by stand density, inside- and outside-bark taper models that incorporate stand density information were developed for trees in red pine (Pinus resinosa Aiton) plantations. Data used in this study came from stem analysis on 150 red pine trees sampled from 30 even-aged, monospecific plantations across Ontario, Canada. A nonlinear mixed-effects approach was applied in fitting these taper models. Several forms of stand density were evaluated for both inside- and outside-bark diameters. A combination of stand densities expressed as [Formula: see text] (BA, basal area; TPH, trees per hectare) explained the most variation in stem taper of trees grown in red pine plantations in Ontario. This variable was highly significant in the regression and improved the predictive accuracies of both inside- and outside-bark taper models. The taper models presented here are dimensionally compatible. Therefore, these models are applicable for data using any system of units without adjusting parameter values.

Ten-year tree mortality following a jack pine budworm outbreak in Saskatchewan

1998 ◽  
Vol 28 (12) ◽  
pp. 1784-1793 ◽  
Author(s):  
W Jan A Volney
Keyword(s):  
Pinus Banksiana ◽  
Tree Mortality ◽  
Proportional Hazards ◽  
Proportional Hazards Model ◽  
Basal Area ◽  
Stand Density ◽  
Tree Height ◽  
Jack Pine ◽  
Jack Pine Budworm ◽  
Individual Trees

The fate of jack pine (Pinus banksiana Lamb.) trees growing in a variety of stand conditions was assessed annually for a decade following an outbreak of jack pine budworm (Choristoneura pinus Freeman) in central Saskatchewan. Mortality was clearly associated with the severity and damage sustained by the trees during the second year of the defoliation episode. The pattern of mortality was remarkably similar among stands that originated in decades that spanned 60 years. Mortality rates were highest in stands that originated in the 1890s and were lowest in stands of the most recent origin (1940s). Defoliation severity, the length of dead top, diameter at breast height, and relative tree height expressed as a standard normal variable accounted for 94% of the variability in survival time. A nonparametric proportional hazards model was developed to evaluate the relative risk of individual trees dying. Defoliation is an important process in determining stand density, basal area, and volume after juvenile stand development is complete. The results presented suggest a novel method to determine the hazard of trees in stands and thus assess the vulnerability of stands to future budworm attack.

Development of a basal area growth system for maritime pine in northwestern Spain using the generalized algebraic difference approach

2006 ◽  
Vol 36 (6) ◽  
pp. 1461-1474 ◽  
Author(s):  
Marcos Barrio Anta ◽  
Fernando Castedo Dorado ◽  
Ulises Diéguez-Aranda ◽  
Juan G Álvarez González ◽  
Bernard R Parresol ◽  
...  
Keyword(s):  
Basal Area ◽  
Maritime Pine ◽  
Model Parameters ◽  
Basal Area Growth ◽  
Starting Point ◽  
Area Growth ◽  
Growth System ◽  
Northwestern Spain ◽  
Algebraic Difference ◽  
Generalized Algebraic Difference Approach

A basal area growth system for single-species, even-aged maritime pine (Pinus pinaster Ait.) stands in Galicia (northwestern Spain) was developed from data of 212 plots measured between one and four times. Six dynamic equations were considered for analysis, and both numerical and graphical methods were used to compare alternative models. The double cross-validation approach was used to assess the predictive ability of the models. The data were best described by a dynamic equation derived from the Korf growth function using the generalized algebraic difference approach (GADA) by considering two parameters to be site specific. The equation was fitted in one stage using the base-age-invariant dummy variables method. In addition, the system incorporates a function for predicting initial stand basal area, in which the site-related variable was expressed as a power function of site index. This function can be used to establish the starting point for the projection equation when no inventory data are available. The two equations are compatible. The effect of thinning on basal area growth was examined; the results showed that there was no need to use a different equation to reliably predict postthinning basal area development. The nonlinear extra sum of squares method indicated differences in the model parameters for the two ecoregions (coastal and interior) defined for this species in the area of study.

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