Corsican Pine (Pinus laricio Poiret) Stand Management: Medium and Long Lasting Effects of Thinning on Biomass Growth

Abstract

With the aim of acquiring better comprehension of the ecological and productive aspects of the management of pine forests, we monitored logging damage and evaluated the effects of thinning on stand growth 20 years after the treatment in a Pinus laricio Poiret stand in central Italy. The objectives of the present study were to estimate the injury levels to the remaining trees after thinning; to assess logging damage in the long-term by monitoring residual trees at the end of thinning; to evaluate the effect of damage on the radial growth of trees; to assess the stand dynamics in relation to injury levels and the treatment applied in a twenty-year range; to understand a possible treatment return time; and to evaluate the existence of the "thinning shock". The results were that 20 years after treatment, the stand dynamics showed a complete recovery; logging damage did not affect the radial growth of P. laricio over time; a second treatment seem to be sustainable starting from the fifteenth year after the previous treatment; and the thinning shock can be clearly evaluated in the first six to seven years after the treatment.

How and How Much, Do Harvesting Activities Affect Forest Soil, Regeneration and Stands?

“…An interesting feature of this study was that, 10 years after harvesting/skidding, more damage was revealed (17%), which was explained by the fact that some trees may be hit but have no bark removal, and the consequences of this (dead cambium) may become visible after many years. Further studies, after 20 years, revealed nearly 18% of damage and that increase was explained by the mortality of some trees [11]. This study also confirmed that skidding caused more damage than felling, and the same was confirmed by Tavankar et al [88] (16.3% and 5.2% by skidding and felling, respectively).…”

“…One goal of forest managers in harvesting should be to minimise the impact of vehicles on the soil, the negative effects of which can be significant and long lasting, although often unrecognised or neglected [4]. The ongoing trend to constantly increase the size, power and load of machines makes it even more imperative to plan logging logistics in order to limit soil disturbance and stand damage [11]. In the available studies, suggestions to reduce soil damage due to forest operations can be grouped into the following: 2015 [42] Electrical conductivity-organic carbon-moisture-porosity-soil bulk density…”

“…Therefore, the setting of maximal limits, as in the case of stand damage, should further limit soil disturbance and injuries to natural regeneration. [89]: hardwood forest, thinning or selection cutting with chainsaw and skidder, published in [89], damage 3% ± 1.0%; Hw-Sh-HF [48]: hardwood forest, shelterwood cutting with harvester and forwarder, published in [48], damage 5% ± 1.1%; Hw-Sh-HF [87]: hardwood forest, shelterwood cutting by harvester and forwarder, published in [87], damage 8% ± 1.0%; Hw-Sc-CS [13]: hardwood forest, selection cutting with chainsaw and skidder, published in [13], damage 8% ± 1.4%; Hw-Sh-CS [48]: hardwood forest, shelterwood cutting with chainsaw and skidder, published in [48], damage 10%± 2.8%; Hw-Th-CS [11]: hardwood forest, thinning with chainsaw and skidder, published in [11], damage 14% ± 2.0%; Sw-Th-CS [73]: softwood forest (pine), thinning with chainsaw and skidder, published in [73], damage 16% ± 2.1%; Hw-Sc-CS [88]: hardwood forest, selection cutting with chainsaw and skidder, published in [88], damage 21% ± 1.0%; Sw-Sc-HF [76]: softwood forest, selection cutting with harvester and forwarder, published in [76], damage 21%± 2.6%; Hw-Sh-CS [91]: hardwood forest, shelterwood cutting with chainsaw and skidder, published in [91], damage 22% ± 2.0%; Hw-Sh-CS [87]: hardwood forest, shelterwood cutting with chainsaw and skidder, published in [87], damage 32% ± 4.9%; Sw-Th-CY [17]: softwood forest, thinning treatment by chainsaw and cable yarder, published in [18], damage 43%± 10.6%; Hw-Th-CS [90]: hardwood forest, thinning treatment by chainsaw and skidder, published in [90], damage 50%± 5.0%…”

“…Some studies reported that soil compaction due to the passing of machinery often leads to an inhibition of potential tree regeneration [8, 9•]. On the other hand, in other studies the improved recruitment of seedlings and saplings was observed in areas where soil had been scarified or modified by logging activities [10,11]. So, this particular aspect of forest operation sustainability is very difficult to analyse unequivocally in the short period of time after an operation.…”

“…The impact on the residual stand may decrease the quality of residual trees but also increase tree mortality due to insect and disease infestation [11] and fungal decay [12] as well as lead to stem deformity and significant losses in final crop volume and value [13]. Furthermore, excessive damage to residual trees during logging operations may change aesthetic value and directly influence other ecosystem services, including recreational ones.…”