Short-Term Recovery of Residual Tree Damage during Successive Thinning Operations

• Main Authors: Farzam Tavankar, Mehrdad Nikooy, Angela Lo Monaco, Francesco Latterini, Rachele Venanzi, Rodolfo Picchio
• Format: Article
• Language: English
• Published: MDPI AG 2020-07-01
• Series: Forests
• Subjects: loblolly pine; tree damage; bole wound; wound healing rate; diameter growth
• Online Access: https://www.mdpi.com/1999-4907/11/7/731

In this study, damage to residual trees during thinning performed by motor-manual felling and whole tree skidding was studied in a loblolly pine (<i>Pinus taeda</i> L.) plantation. Forest intervention was carried out in 2016 and tree wounds were studied and examined over a period of three years. The results indicated that 8% of the residual trees suffered damage, of which 52% was caused by felling operations and 48% by extraction operations. Among the damaged trees, 13% had damage to the root system, 53% to the bole, and 34% to the crown area. The average wound size at the time of occurrence was 71.3 cm². This was found to be reduced to 54.4 cm² after a three year period. Wound intensity decreased with higher wound height and increased size. Three years after wound occurrence, only 6.6% were closed, 90.6% were still open, and 2.8% were decayed. The diameter growth in damaged trees was 1.7% lower than in undamaged trees (<i>p</i> > 0.05). Damage to the root system of residual trees reduced diameter growth by 3% (<i>p</i> < 0.05). Intensive wounds (damaged wood) caused a reduction of 22.7% in diameter growth (<i>p</i> < 0.01). In addition, the diameter growth in trees with decayed wounds was 27.4% lower than unwounded trees (<i>p</i> < 0.01). Pre-harvest planning, directional tree felling, marking of the extraction path before logging operations, employment of skilled logging workers, and post-harvest assessment of damaged residual trees are essential implementations in timber plantations.