Culture and Density Effects on Tree Quality in Midrotation Non-Thinned Loblolly Pine Plantations

P Green,Michael Kane,Bronson Bullock

doi:10.3390/f9020082

Abstract

Six non-thinned loblolly pine (Pinus taeda L.) culture × density study sites in the Piedmont and Upper Coastal Plain of the Southeast U.S. were used to examine the effects of two cultural intensities and three planting densities on solid wood potential as well as the proportion and position of product-defining defects (forks, crooks, broken tops). A tree quality index (TQI) was used to grade stems for solid wood potential. The results show that an operational management regime exhibited a higher proportion of trees with solid wood product potential than did a very intensive management regime. Trees subject to operational management exhibited product-defining defects higher on the stem; however, the proportion of stems with defects was not significantly different from the intensive management. Planting densities of 741, 1482, and 2223 trees per hectare (TPH) exhibited a relatively narrow range of the proportion of trees with solid wood product potential that were not significantly different. Density did not have a significant effect on the heights of the product-defining defects. These results show that management intensity and less so planting density, affect the solid wood product potential indicators evaluated and should be considered when making management decisions.

Highlights

Pine (Pinus taeda L.) is the most commercially important and widely planted plantation species in the southern United States
Management intensity affected the distribution of tree quality index (TQI) scores
Intensive management reduced the proportion of stems that exhibited solid wood product potential (TQI 1) compared with the operational management regime (Figure 2)

Summary

Introduction

Pine (Pinus taeda L.) is the most commercially important and widely planted plantation species in the southern United States. While demands for forest products vary over time and by region, management for a diverse mix of products including solid wood products is a common objective for many pine plantations in the southeastern United States [1]. By age 16 in Virginia and North Carolina, loblolly pine grown at different densities showed significant differences in dominant height [2]. By age 8, no significant difference in dominant height was found for loblolly pine densities between 988 and 2470 trees per hectare (TPH) [6]. In a rotation length unthinned slash pine (Pinus elliottii Engelm.) study in South Africa, no significant differences in dominant height were found between the planting densities of 914 to 2964 trees per hectare [7]

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Discussion

Conclusion