Influence of Different Thinning Treatments on Stand Resistance to Snow and Wind in Loblolly Pine (Pinus taeda L.) Coastal Plantations of Northern Iran

Abstract

Loblolly pine (Pinus taeda L.) is one of the main exotic conifer species that has been widely planted for the past fifty years for timber production in the coastal areas of northern Iran. Heavy snowfall and strong winds can cause much damage to these forests over a short time span of only a few years. This study was conducted to estimate snow and wind damage and analyze the role of stand thinning in their resistance to snow and wind. Amount and type of snow and wind damage were examined through systematic (80 m × 80 m) sample plots (each plot area of 625 m2) in nine different stands (2–10 plots in each stand) in terms of age, structure, and silviculture history in three replications for each stand in April and May 2020. Results showed that the amount of snow and wind damage had a wide range from 1.3% to 30.7%. Snow damage was more than three times that of wind. Snow and wind damage in the young stands were significantly more serious (p < 0.01) than in the middle-aged and old stands, and damage was significantly higher (p < 0.01) in the unthinned stands than in the thinned ones. Slenderness coefficient (Height/Diameter ratio, HD ratio) of trees resulted to be a good indicator in young and middle-aged stands, while crown form indices (relative crown length and relative crown width) were acceptable indicators in old stands for risk of snow and wind damage. Our results showed that the normal thinning (15% of basal area) decreased snow and wind damage in all the stands, while the heavy thinning (35% of basal area) reduced the snow damage, but it increased the wind one. It is possible to recommend high intensity thinning in young stands, normal thinning in middle-aged stands, and light thinning (15% of basal area) in old ones.

Hubungan Karakteristik Biometrik Eucalytus pellita Terhadap Kerusakan Karena Angin

“…Penelitian Valinger & Fridman (1997) mendapatkan bahwa karakteristik pohon dapat digunakan sebagai ukuran kemungkinan kerusakan akibat salju dan angin. Picchio et al (2020) menemukan bahwa koefisien kelangsingan (rasio tinggi/diameter, rasio H/D) pohon menjadi indikator yang baik untuk tegakan muda, sedangkan indeks bentuk tajuk (panjang tajuk relatif dan lebar tajuk relatif) merupakan indikator pada tegakan tua terhadap risiko kerusakan karena salju dan angin.…”

Vegetation dynamics and soil properties following low-intensity wildfire in loblolly pine (Pinus taeda L.) planted forest in Northern Iran

“…It has rapid regeneration, substantial yields per hectare, and numerous marketable products (Fox et al 2007). In addition to the United States (Perdue et al 2017), Pinus taeda is widely cultivated in Brazil (Dobner, Campoe 2019), China (Jin et al 2019), Mozambique (Guedes et al 2018), Uruguay (Leites et al 2013), Argentina (Martiarena et al 2011), Iran (Picchio et al 2020) as an exotic (nonnative) fast-growing species. Therefore, as an exotic species planted in many countries, it is expected to be more impacted by natural disturbances.…”

Application of Innovative Silvicultural Treatments in Pine Forests

“…Thinning practices play a key role in increasing stands stability in the long term. The influence of thinning on snow and wind damages is investigated in the study of Picchio et al [3] developed in Pinus taeda L. plantations located in northern Iran. The research provides suggestions and best practices in choosing thinning strategies, recommending the precise planning of thinning operations finalized at reducing the risk of snow and wind in the different stages of the cultural cycle.…”