Effects of precommercial thinning on tree growth and lumber quality in a jack pine stand in New Brunswick, Canada

Abstract

A naturally regenerated jack pine (Pinus banksiana Lamb.) trial established in 1966 in New Brunswick was studied to determine how three precommercial thinning intensities (1.22 m × 1.22 m, 1.52 m × 1.52 m, and 2.13 m × 2.13 m) and a control (154 trees in total) affected tree growth and lumber quality. Mild (thinned to 1.22 m) and moderate (1.52 m) thinning had a modest impact on tree growth after 34 years (stand age 59). However, intensive thinning (2.13 m, or 2212 stems/ha) increased tree height by 13.1% compared with the control, whereas tree diameter and merchantable stem volume per tree increased by >20% and >75%, respectively. Yields of No. 2 and Better increased slightly with increasing thinning intensity, but lumber bending properties decreased with increasing thinning intensity. There was, respectively, >20% and >15% difference in lumber strength (modulus of rupture) and stiffness (modulus of elasticity) between the mild (1.22 m) and intensive (2.13 m) thinnings. Intensive precommercial thinning (2.13 m) is recommended for increased volume growth, but rotation age (>59 years) should not be reduced if lumber bending properties are of concern.

Application of Nondestructive Methods to Evaluate Mechanical Properties of 32-Year-Old Taiwan Incense Cedar (Calocedrus formosana) Wood

“…They presented a decreasing trend as follows: ¼ H > ½ H > ¾ H. This result is in agreement with a previous study (Zhang et al 2006) that illustrated lumber MOE decreased from the butt to top logs for their test stand densities. In addition, an increased proportion of juvenile wood at the top of the standing tree was considered a reason for MOE decreasing from butt to top logs.…”

Evaluating harvest costs and profit of commercial thinnings in softwood stands in west-central Maine: A case study

“…Precommercial thinning (PCT) is a common silvicultural treatment used in the early management of conifer forests across North America and Europe (Zhang et al 2006, Olson et al 2012, Bataineh et al 2013. The effects of PCT on tree growth have been investigated and documented for a wide range of forest types (Balmer et al 1978, Brissette et al 1999, Zhang et al 2006, Pitt and Lanteigne 2008, Olson et al 2012, Bataineh et al 2013, however, this treatment represents a significant financial investment by the landowner which must be carried many years before a commercial harvest.…”

Precommercial thinning of overtopping aspen to release coniferous regeneration in a boreal mixedwood stand

“…Monitoring aspen development in the two 3.0-m spacings with different levels of conifer retention (3.0A vs. 3.0S) would allow us to validate this assumption. Further, all treatments should ultimately be evaluated in terms of merchantable (DBH ≥9.1 cm) BA by species, and BA and volume per stem to assess sawlog potential with regard to branching (e.g., Weiskittel et al 2009), wood density and lumber strength (Zhang et al 2006).…”

“…Generally, both conifer and hardwood species benefit from increased resource availability with gains in diameter at breast height (DBH) that increase with spacing. For the two species groups however, high branch retention on the lower bole (Weiskittel et al 2009, Nicholson et al 2010, and low wood density and lumber strength (Zhang et al 2006) may result from wide spacing. Consequently, the trade-off between diameter gain and subsequent quality of the wood products is an important consideration when choosing an intensity of PCT (Nicholson et al 2010).…”

“…(Pitt and Lanteigne 2008), and to a lesser extent jack pine (Pinus banksiana Lamb.) (Zhang et al 2006). The effects observed on black spruce (Picea mariana (Mill.)…”