Management and restoration of Italian afforestations under global change

Abstract

As a consequence of past deforestation, degraded areas in Italy have been subjected to afforestation since the beginning of the XXI century. These afforestations have been done mainly with conifers (Pinus nigra, Pinus pinaster, Pinus halepensis, Pinus pinea), and with the aim to 1) protect the soil and to 2) prevent floods. Exotic forest tree species have been used for the afforestation of selected sites of the Apennine. In the case of Douglas fir, it is possible to state that after ninety years the results are very good in terms of both ecological adaptability and high growth-rate.Nowadays, the lack of silvicultural treatments, the ageing processes, insect and fungi outbreaks have led pine afforestations to a condition of an unsteady biological equilibrium in many sites. Moreover, this condition seems to be due to additional factors related to climate change such as wind storms and dryness. The restoration of these pine afforestations is therefore one of the main aims of the present Italian forest management policy which aims to increase their level of resilience. In particular, the priority of the researchers has been given to the most fragile stands where three possible objectives of restoration measures should be considered:To rehabilitate conifer stands by introducing native broadleaves when these stands are in a very degraded condition, and when the local wood energy chain needs to be started;To conserve the conifer stands in the cases where the cultural, aesthetic and recreational functions, are the prevailing obtainable ecosystem services;To foster the mixed stands, with the conifers of the old cycle and native broadleaves, which could increase resilience to the extreme events.In regards of Douglas-fir stands, new silvicultural models have been developed which aim to a) conserve these stands and to b) combine a higher growth rate with a much improved mechanical tree stability.

Strip Clear-Cutting Application and Logging Typologies for Renaturalization of Pine Afforestation—A Case Study

“…Among the possible renaturalization techniques [46], taking into account the stand age, the need to combine harvesting cost-effectiveness, that it was solid ground despite being on a high slope, and that the black pine forest was sheltered from northern winds, clear-cutting (dismantling cutting) on strips was chosen. This consisted of a series of strips 15 m wide and 100 m long, alternating with uncut strips (to eliminate 50% of the surface of the pine plantation).…”

“…Each SP consisted of a circular area 12 m in diameter. In each SP, three tests for every parameter were done, which measured: bulk density (BD), pH, organic matter content (OM), inorganic carbon content (IC), penetration resistance (PR), and shear resistance (or strength) (SR), and QBS-ar index as detailed in [43][44][45][46][47]. For the two blocks, two different control areas were selected at the edge of the blocks, which were at least 30 m from the edges.…”

Duglasul verde (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) în Ocolul silvic Călimănești: o utilizare de succes pe termen lung

“…In toate arboretele cercetate, duglasul verde a demonstrat creșteri în diametru și înălțime importante la toate vârstele, fiind, în cvasitotalitatea cazurilor, specia cu arborii cei mai groși și mai înalți comparativ cu speciile amestecate. Acest potențial de creștere a condus la volume ridicate, gen 600-700 m 3 •ha -1 la 45 de ani, similar cu arboretele de duglas verde de aceeași vârstă din Slovenia (Smolnikar et al 2021) sau Italia (La Marca et al 2016), dar mai mici decât cele atinse în Cehia la vârsta de 100 de ani (750 m 3 •ha -1 -Remeš și Zeidler 2014). Volumul pe picior maxim (peste 1.000 m 3 •ha -1 , la 115 ani) din u.a.…”

“…92G s-a atins și în Slovenia (1.154 m 3 •ha -1 -Čokl 1965) și Bulgaria (1.166 m 3 •ha -1 - Popov 2006Popov , 2009, însă în arborete mai tinere, de (60) 70-80 de ani. Creșterea medie în volum confirmă potențialul productiv ridicat al speciei, similar cu cea atinsă în arboretele de duglas verde din Slovenia (7.8-15.9 m 3 •an -1 •ha -1 -Čokl 1965), Croația (8.3-18.5 m 3 •an -1 •ha -1 -Klepac 1962), Franța (14.8 m 3 •an -1 •ha -1 - Kohnle et al 2019) sau Italia (15 m 3 •an -1 •ha -1 -La Marca et al 2016).…”