Rapid Assessment of Relative Density in Mixed-Species Stands of the Northeastern United States

Ducey, Mark J.; Knapp, Rachel A.

doi:10.1155/2010/212068

Cited by 3 publications

(2 citation statements)

References 27 publications

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“…As well as, switching the rank between RDi, from one side, and both RDo and IVI from another side as the RDo and IVI are concerned with basal area. At the same time, the basal area depends on the size of the trees, and the species of these trees as explained by Ducey and Knapp, (2010). Also, the higher RDo of F. microcarpa and D. regia in the zoo garden may be due to the planting of these species to secure shade for visitors.…”

Section: Diversitymentioning

confidence: 98%

Evaluating the Biodiversity and Conservation Approach of Woody Taxa in Giza Zoo, Egypt

Khamis

Bahnasy

2023

Scient. J. of Flowers and Ornament. Plants

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This is the first study to measure the diversity of woody taxa in Giza Zoo garden considered an extraordinarily diverse hotspot with an unusually high number of woody taxa found nowhere else in Egypt especially, tropical species. This study was conducted in several stages, preparation, inventory, analysis, and evaluation. The study uses quantitative methods to evaluate the woody taxa diversity and the threatened species which are conserved in the garden across their main sections. Therefore, species richness, Shannon and Simpson's diversity indices were estimated. Also, the species importance value index, a measure of how dominant a species is in a given population, and conservation status were used to evaluate the conservation potential of the trees in the garden. The garden plays a vital role in conserving 145 individuals as threatened trees belonging to 18 species that are either endangered, near threatened or vulnerable according to the IUCN red list. The Weak conservation procedures in the zoo garden have led more individuals of species that are over-mature and over-aged to their demise therefore, it is feared that may be lost from the garden. So, it's imperative to immediately restore these lost species in the garden and place their diversity on a pathway to recovery. We warn to increase the area of impermeable pathways and more buildings that will increase the stresses upon the garden trees. Therefore, we suggest technical support for the botanic garden as the experts of the Timber Trees department will be essential for allowing this valuable garden to continue its work and expand its collections of critical but under-represented species. Also, the inventory of tree species entity and structure in this study will assist as a guide tool for the administration of the garden to reach the Egyptian sustainable development goals by 2030 and the global goals by 2050.

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Section: Diversitymentioning

confidence: 98%

Evaluating the Biodiversity and Conservation Approach of Woody Taxa in Giza Zoo, Egypt

Khamis

Bahnasy

2023

Scient. J. of Flowers and Ornament. Plants

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“…For stands with complementary growth characteristics, density measures such as stand density index (SDI) (Reineke 1933) and relative density index (RDI) (Curtis 1982) are widely used in forest research (Torres-Rojo, Martínez 2000;Ducey, Knapp 2010). The relative density index (RDI) is often used to determine the growth of trees (Ducey, Larson 2003).…”

mentioning

confidence: 99%

Birch (Betula papyrifera) × white spruce (Picea glauca) interactions in mixedwood stands: implications for management

Hawkins¹,

Dhar²

2013

J. For. Sci.

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Current British Columbia forest regulations drive the regeneration management towards pure conifer stands rather than remaining in a mixed-species condition. This approach may result in unnecessary vegetation control. The main objective of this investigation was to study the impact of variable paper birch densities on white spruce growth in 15-20 years old stands for management implications. Regression analysis was used to examine the effect of birch density and two competition indices to predict spruce growth. A mixed model ANOVA showed that spruce mean annual DBH and basal area increment differed significantly among sites and density. From the regression analysis it appears that birch density up to 4,000 stems·ha -1 had no significant influence on spruce growth which is much higher than the current BC reforestation guideline (1,000 stems·ha -1 broadleaves). Similarly, birch relative density index (RDI) had to exceed 3 to affect spruce DBH growth significantly on all sites except one. On most sites, spruce had a larger DBH than birch. Our results also suggest that rather than following the current broadcast approach to vegetation management, a targeted approach could enhance forest productivity and stand diversity.

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Silvicultural prescriptions for mixed-species forest stands. A European review and perspective

et al. 2021

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Compared with far-developed measures and methods for mono-specific forest stands, the silvicultural prescriptions for mixed-species stands are at their early beginning. However, they are essential for the well-conceived establishment, design, and control of mixed-species stands, currently promoted in many countries worldwide. Here, we review the state of the art and we further develop silvicultural prescriptions for mixed-species stands for steering of experiments, stand modeling, and silviculture. We review which aspects of tree species mixing are most relevant for management goal achievement. We found the maintenance of species diversity and structural heterogeneity for ecological purpose, stabilizing productivity, and social-economic performance as main objectives. We give an overview of quantitatively formulated silvicultural prescriptions for steering mixed-species stands for forest practice, long-term experiments, forest stand models. Compared with the sophisticated guidelines for mono-specific stands, prescriptions for mixed stand are often mainly qualitative and vague. Then, we introduce methodological approaches in development for steering mixture: measures for spatial and temporal separation, species-specific growing space requirements for crop trees, coefficients for equivalence and density modification, and basic relationships for steering tree number and area-based mixing proportions. Finally, we draw conclusions for further development of methodological approaches for silvicultural steering of experiments, implementation in stand simulators, and for silvicultural operations. We see the need for improving the quantitative spatially explicit rules based at tree or cohort level, for substantiating the knowledge on species-specific allometry, growing area, tree-to-tree distances, and position-dependent competition indices for steering tree removal. We discuss the prospects and limitations of establishing silvicultural prescriptions for mixed-species stands that inevitably will be more complicated than those for mono-specific stands, and we draw conclusions for next steps in science and practice.

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Rapid Assessment of Relative Density in Mixed-Species Stands of the Northeastern United States

Cited by 3 publications

References 27 publications

Evaluating the Biodiversity and Conservation Approach of Woody Taxa in Giza Zoo, Egypt

Evaluating the Biodiversity and Conservation Approach of Woody Taxa in Giza Zoo, Egypt

Birch (Betula papyrifera) × white spruce (Picea glauca) interactions in mixedwood stands: implications for management

Silvicultural prescriptions for mixed-species forest stands. A European review and perspective

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