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A new type of density-management diagram for slash pine plantations

Informally Refereed

Abstract

Many Density-Management Diagrams (DMD) have been developed for conifer species throughout the world based on stand density index (SDI). The diagrams often plot the logarithm of average tree size (volume, weight, or quadratic mean diameter) over the logarithm of trees per unit area. A new type of DMD is presented for slash pine (Pinus elliottii var elliottii) plantations where SDI is plotted over age. This proposed DMD eliminates two existing problems with current DMDs: (1) the need to estimate age from other measures found on traditional DMDs, and (2) a second variable also directly dependent on either age or SDI can be placed on a third axis. Plotting SDI over age clearly shows when thinnings need to be conducted to obtain a certain tree size-density objective both in terms of stand density and age. Yet this proposed DMD does not violate the well-known principle that DMDs are independent of age. Understory models are usually developed using an overstory density measure that includes both trees per unit area and a diameter measure (i.e. basal area per unit area or SDI per unit area) making it difficult to include them on current DMDs. Plotting SDI over age allows understory vegetation development to be easily included on a DMD. This provides a natural resource manager the ability to see what impacts a particular tree sizedensity objective has on understory vegetation production over time. An understory vegetation model was developed to demonstrate the applicability of the proposed DMD.

Parent Publication

Citation

VanderSchaaf, Curtis L. 2006. A new type of density-management diagram for slash pine plantations. Gen. Tech. Rep. SRS-92. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. pp. 375-378
https://www.fs.usda.gov/research/treesearch/23421