Growth-Density Relationships in Loblolly Pine Plantations

Allen, Micky; Burkhart, Harold E.

doi:10.1093/forsci/fxy048

Cited by 15 publications

(15 citation statements)

References 23 publications

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“…Different models for the relation between forest density and production have been used. Based on previous work, Allen and Burkhart [53] defined three theoretical relationships between forest production and density, as "increasing," "optimal," and "constant." They pointed out that this relation is usually uncertain for very high densities.…”

Section: Relationship Between Forest Density and Productionmentioning

confidence: 99%

Patterns of Density and Production in the Community Forests of the Sierra Madre Occidental, Mexico

Padilla-Martínez

Corral-Rivas

Briseño-Reyes

et al. 2020

Forests

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The Mexican Sierra Madre Occidental (SMO) represents a region where hundreds of plant species reach the limits of their northern or southern range. The SMO also features a unique cultural diversity, and many communities living within the forest or in its close vicinity depend on the products and services that these forests provide. Our study was based on a large set of remeasured field plots placed in the forests of Durango which are part of the SMO. Using hierarchical clustering, three distinctly different forest types were identified based on structural differences and the relation between stem density and basal area. Maximum forest densities were estimated using a 0.975th quantile regression. Forest production (expressed as current periodic volume increment per unit of area and time) was estimated based on number of stems, forest density, mean height, and forest diversity. Forest density is the principal factors affecting periodic volume production. The discussion presented recommendations for the sustainable use of this unique natural resource. Maintaining minimum levels of residual density is key to ensuring the continued viability of the forests of the Mexican SMO. Future research is needed to identify optimum residual structures, productive residual densities, and desirable levels of biodiversity.

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Section: Relationship Between Forest Density and Productionmentioning

confidence: 99%

Patterns of Density and Production in the Community Forests of the Sierra Madre Occidental, Mexico

Padilla-Martínez

Corral-Rivas

Briseño-Reyes

et al. 2020

Forests

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“…Thinning and density control of forests has been used in many parts of the world to increase the flow of valuable forest products (e.g., Bergh et al 2005;Fox et al 2007;Gizachew and Brunner 2011;Allen and Burkhart 2018) but have not been widely applied on the public forests of Western Canada (Weetman 2002;Griess et al 2019). The reason for this stems not only from policy barriers (Pinno et al 2021), but also from managers' uncertainty in volume benefits of thinning, especially during this transitional era of taking stands from basic reforestation to more intensively managed systems (Bell et al 2006).…”

Section: Introductionmentioning

confidence: 99%

“…In addition to silvicultural treatments, site quality is known to have a significant impact on tree-and stand-level growth rates and the specific responses to thinning (e.g., Assmann 1970;Johnstone 1981;Pitt et al 2013;Allen and Burkhart 2018). However, for simplicity in most forest level management plans in Alberta, the average of a broad group of stand types (e.g., pure lodgepole pine) (Alberta Sustainable Resource Development 2006) is modelled forward.…”

Section: Introductionmentioning

confidence: 99%

Thinning to meet sawlog objectives at shorter rotation in lodgepole pine stands

2022

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We modelled how pre-commercial and commercial thinning affects development of merchantable timber, specifically large sawlogs (> 20 cm diameter), on various site qualities and at different harvest ages. Data from juvenile permanent sample plots from post-harvest regenerated lodgepole pine stands in Alberta were projected using the Mixedwood Growth Model (MGM 21). Pre-commercial thinning (PCT) and different levels of commercial thinning (CT) with PCT were assessed on stands of good, medium and fair site quality. Results show site quality alone had the greatest impact on merchantable yields with good sites producing ~1.5 times the yield of medium and ~4.3 times that of the fair sites. Moderate thinning on good sites produced a greater quantity of large sawlogs (> 20 cm diameter) and their associated volume over unthinned stands than that on medium or fair sites, though thinning positively influenced total yield on these sites as well. On good sites, at age 50, CT treatments produced about ~50 m3/ha more volume of large sawlogs (> 20 cm) than the control; such gain drops to 18 m3/ha on medium sites. In addition, mean annual increment culminated earlier on good sites, also enabling earlier harvest.

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“…In forest management, stand density is a term used to describe tree cover or stocking per unit area [3] and this term can be used to relate the tree shape, growth, and mortality. Lately, the stand growth volume has been related with the stand density for making informed management decisions [4], and the stand-density index (SDI) is an important predictor for estimating stand-level biomass [5]. The density level is an indicator of forest integrity, particularly because the stand density for a given tree size has a unique limit for a specific species or species group and is independent of other factors as age or site quality [6].…”

Section: Introductionmentioning

confidence: 99%

“…For mixed-species forests, site occupancy is normally defined for all combined species. The regulation of stand density via initial spacing and (or) thinning treatments are, among the controls of stand density, some of the oldest most commonly used methods for achieving forest management goals [4].…”

Section: Introductionmentioning

confidence: 99%

Can an Exponential Function Be Applied to the Asymptotic Density–Size Relationship? Two New Stand-Density Indices in Mixed-Species Forests

Quiñonez-Barraza

Ramírez-Maldonado

2018

Forests

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This study presents two stand-density indices (SDIs) based on exponential density decline as a function of quadratic mean diameter for all species combined in mixed-species forests with 22 species mix grouped in four species groups. The exponential-based density–diameter relationship, as well the density index corresponding to the slope or instantaneous mortality rate parameters, was compared with those based on power-law density–diameter relationship. A dataset of 202 fully stocked circular plots at maximum density was used for fitting the models, and a dataset of 122 circular plots was used for validation stand density index for all species combined of mixed-species stands. The dataset for validation was independent of dataset for model development. The first stand-density index showed a density management graphic (DMG) with a variable intercept and common instantaneous mortality rate, and the second index showed a DMG with common intercept and variable mortality rate. Additionally, the value of the initial density of the fitted line was more realistic than those generated by the potential model for all species combined. Moreover, the density management diagrams showed a curvilinear trend based on the maximum stand density index in graphical log–log scale. The DMGs could be interpreted as forest scenarios based on variable initial density and common management objectives or the same density and different management objectives for forest-rotation periods involving all species combined in mixed-species stands. The fitting of exponential and potential equations for species or species groups showed that the density–size relationships in mixed-species forests should be modeled for all species combined because the disaggregation of mixture species represented a weak tendency for each species or species group and the resultant fitted equations were unrealistic.

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Growth-Density Relationships in Loblolly Pine Plantations

Cited by 15 publications

References 23 publications

Patterns of Density and Production in the Community Forests of the Sierra Madre Occidental, Mexico

Patterns of Density and Production in the Community Forests of the Sierra Madre Occidental, Mexico

Thinning to meet sawlog objectives at shorter rotation in lodgepole pine stands

Can an Exponential Function Be Applied to the Asymptotic Density–Size Relationship? Two New Stand-Density Indices in Mixed-Species Forests

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